The Luminosity Function of OB Associations in the Galaxy

NASA Astrophysics Data System (ADS)

McKee, Christopher F.; Williams, Jonathan P.

1997-02-01

OB associations ionize the interstellar medium, producing both localized H II regions and diffuse ionized gas. The supernovae resulting from these associations pressurize and stir the interstellar medium. Using Smith, Biermann, & Mezger's compilation of radio H II regions in the Galaxy, and Kennicutt, Edgar, & Hodge's optical study of H II regions in nearby galaxies, we show that the luminosity distribution of giant OB associations in the Galaxy can be fit by a truncated power law of the form \\Nscra(>S)=\\Nscrau[(Su/S)-1], where S is the ionizing photon luminosity, \\Nscra(>S) is the number of associations with a luminosity of at least S, and Su is the upper limit to the distribution. The coefficient \\Nscrau is the number of the most luminous associations, with a luminosity between 0.5Su and Su. For the Galaxy, \\Nscrau=6.1 the fact that the number of the most luminous associations is significantly larger than unity indicates that there is a physical limit to the maximum size of H II regions in the Galaxy. To extend the luminosity distribution to small H II regions, we assume that the birthrate of associations, \\Nscr\\dota(>\\Nscr*), is also a truncated power law, \\Nscr\\dota(>\\Nscr*)~[(\\Nscr*u/\\Nscr*)-1], where \\Nscr* is the number of stars in the association. For large associations, the ionizing luminosity is proportional to the number of stars, S~\\Nscr* for smaller associations, we use both an analytic and a Monte Carlo approach to find the resulting luminosity distribution \\Nscra(>S). H II regions are generally centrally concentrated, with only the dense central regions being bright enough to appear in radio catalogs. Anantharamaiah postulated that radio H II regions have extended envelopes in order to account for diffuse radio recombination line emission in the Galaxy. Some of these envelopes are visible as the ionized ``worms'' discussed by Heiles and coworkers. We estimate that on the average the envelopes of radio H II regions absorb about twice

LUMINOSITY FUNCTIONS OF SPITZER-IDENTIFIED PROTOSTARS IN NINE NEARBY MOLECULAR CLOUDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kryukova, E.; Megeath, S. T.; Allen, T. S.

2012-08-15

We identify protostars in Spitzer surveys of nine star-forming (SF) molecular clouds within 1 kpc: Serpens, Perseus, Ophiuchus, Chamaeleon, Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over 700 protostar candidates. These clouds encompass a variety of SF environments, including both low-mass and high-mass SF regions, as well as dense clusters and regions of sparsely distributed star formation. Our diverse cloud sample allows us to compare protostar luminosity functions in these varied environments. We combine near- and mid-infrared photometry from the Two Micron All Sky Survey and Spitzer to create 1-24 {mu}m spectral energy distributions (SEDs). Usingmore » protostars from the c2d survey with well-determined bolometric luminosities, we derive a relationship between bolometric luminosity, mid-IR luminosity (integrated from 1-24 {mu}m), and SED slope. Estimations of the bolometric luminosities for protostar candidates are combined to create luminosity functions for each cloud. Contamination due to edge-on disks, reddened Class II sources, and galaxies is estimated and removed from the luminosity functions. We find that luminosity functions for high-mass SF clouds (Orion, Mon R2, and Cep OB3) peak near 1 L{sub Sun} and show a tail extending toward luminosities above 100 L{sub Sun }. The luminosity functions of the low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and Chamaeleon) do not exhibit a common peak, however the combined luminosity function of these regions peaks below 1 L{sub Sun }. Finally, we examine the luminosity functions as a function of the local surface density of young stellar objects. In the Orion molecular clouds, we find a significant difference between the luminosity functions of protostars in regions of high and low stellar density, the former of which is biased toward more luminous sources. This may be the result of primordial mass segregation, although this interpretation is not unique. We compare our

VY Canis Majoris: The Astrophysical Basis of Its Luminosity

NASA Astrophysics Data System (ADS)

Gehrz, Robert D.; Humphreys, R. M.; Jones, T. J.

2006-12-01

The luminosity of the famous red supergiant VY CMa ( L = 4 5 x 105 L ) is well-determined from its spectral energy distribution and distance, and places it near the empirical upper luminosity limit for cool hypergiants. In contrast, its surface temperature is fundamentally ill-defined. Implications for its location on the HR Diagram and its apparent size are discussed.

Luminosity function and cosmological evolution of X-ray selected quasars

NASA Technical Reports Server (NTRS)

Maccacaro, T.; Gioia, I. M.

1983-01-01

The preliminary analysis of a complete sample of 55 X-ray sources is presented as part of the Medium Sensitivity Survey of the Einstein Observatory. A pure luminosity evolutionary law is derived in order to determine the uniform distribution of the sources and the rates of evolution for Active Galactic Nuclei (AGNs) observed by X-ray and optical techniques are compared. A nonparametric representation of the luminosity function is fitted to the observational data. On the basis of the reduced data, it is determined that: (1) AGNs evolve cosmologically; (2) less evolution is required to explain the X-ray data than the optical data; (3) the high-luminosity portion of the X-ray luminosity can be described by a power-law with a slope of gamma = 3.6; and (4) the X-ray luminosity function flattens at low luminosities. Some of the implications of the results for conventional theoretical models of the evolution of quasars and Seyfert galaxies are discussed.

A cross-correlation-based estimate of the galaxy luminosity function

NASA Astrophysics Data System (ADS)

van Daalen, Marcel P.; White, Martin

2018-06-01

We extend existing methods for using cross-correlations to derive redshift distributions for photometric galaxies, without using photometric redshifts. The model presented in this paper simultaneously yields highly accurate and unbiased redshift distributions and, for the first time, redshift-dependent luminosity functions, using only clustering information and the apparent magnitudes of the galaxies as input. In contrast to many existing techniques for recovering unbiased redshift distributions, the output of our method is not degenerate with the galaxy bias b(z), which is achieved by modelling the shape of the luminosity bias. We successfully apply our method to a mock galaxy survey and discuss improvements to be made before applying our model to real data.

Observations of jets from low-luminosity stars - DG Tauri B

NASA Technical Reports Server (NTRS)

Jones, B. F.; Cohen, Martin

1986-01-01

Low spectral resolution studies of DG Tau B, the faint system of knots south of the T Tauri star DG Tau, are described. The observations show this object to be bipolar, with the blueshifted lobe having extraordinarily low excitation. Infrared observations of the exciting star show it to be of very low luminosity, with a bolometric luminosity of 0.88 solar luminosity. The visual extinction indicates a highly nonspherical distribution of circumstellar dust around the exciting star. In spite of this lack of embedding within an obvious dark cloud, the system is identified as a young one.

LUMINOSITY FUNCTIONS OF LMXBs IN CENTAURUS A: GLOBULAR CLUSTERS VERSUS THE FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voss, Rasmus; Gilfanov, Marat; Sivakoff, Gregory R.

2009-08-10

We study the X-ray luminosity function (XLF) of low-mass X-ray binaries (LMXB) in the nearby early-type galaxy Centaurus A, concentrating primarily on two aspects of binary populations: the XLF behavior at the low-luminosity limit and the comparison between globular cluster and field sources. The 800 ksec exposure of the deep Chandra VLP program allows us to reach a limiting luminosity of {approx}8 x 10{sup 35} erg s{sup -1}, about {approx}2-3 times deeper than previous investigations. We confirm the presence of the low-luminosity break of the overall LMXB XLF at log(L{sub X} ) {approx} 37.2-37.6, below which the luminosity distribution followsmore » a dN/d(ln L) {approx} const law. Separating globular cluster and field sources, we find a statistically significant difference between the two luminosity distributions with a relative underabundance of faint sources in the globular cluster population. This demonstrates that the samples are drawn from distinct parent populations and may disprove the hypothesis that the entire LMXB population in early-type galaxies is created dynamically in globular clusters. As a plausible explanation for this difference in the XLFs, we suggest an enhanced fraction of helium-accreting systems in globular clusters, which are created in collisions between red giants and neutron stars. Due to the four times higher ionization temperature of He, such systems are subject to accretion disk instabilities at {approx}20 times higher mass accretion rate and, therefore, are not observed as persistent sources at low luminosities.« less

Size–Luminosity Relations and UV Luminosity Functions at z = 6–9 Simultaneously Derived from the Complete Hubble Frontier Fields Data

NASA Astrophysics Data System (ADS)

Kawamata, Ryota; Ishigaki, Masafumi; Shimasaku, Kazuhiro; Oguri, Masamune; Ouchi, Masami; Tanigawa, Shingo

2018-03-01

We construct z ∼ 6–7, 8, and 9 faint Lyman break galaxy samples (334, 61, and 37 galaxies, respectively) with accurate size measurements with the software glafic from the complete Hubble Frontier Fields (HFF) cluster and parallel fields data. These are the largest samples hitherto and reach down to the faint ends of recently obtained deep luminosity functions. At faint magnitudes, however, these samples are highly incomplete for galaxies with large sizes, implying that derivation of the luminosity function sensitively depends on the intrinsic size–luminosity relation. We thus conduct simultaneous maximum-likelihood estimation of luminosity function and size–luminosity relation parameters from the observed distribution of galaxies on the size–luminosity plane with the help of a completeness map as a function of size and luminosity. At z ∼ 6–7, we find that the intrinsic size–luminosity relation expressed as r e ∝ L β has a notably steeper slope of β ={0.46}-0.09+0.08 than those at lower redshifts, which in turn implies that the luminosity function has a relatively shallow faint-end slope of α =-{1.86}-0.18+0.17. This steep β can be reproduced by a simple analytical model in which smaller galaxies have lower specific angular momenta. The β and α values for the z ∼ 8 and 9 samples are consistent with those for z ∼ 6–7 but with larger errors. For all three samples, there is a large, positive covariance between β and α, implying that the simultaneous determination of these two parameters is important. We also provide new strong lens mass models of Abell S1063 and Abell 370, as well as updated mass models of Abell 2744 and MACS J0416.1‑2403.

The Spectral Energy Distributions and Infrared Luminosities of z ≈ 2 Dust-obscured Galaxies from Herschel and Spitzer

NASA Astrophysics Data System (ADS)

Melbourne, J.; Soifer, B. T.; Desai, Vandana; Pope, Alexandra; Armus, Lee; Dey, Arjun; Bussmann, R. S.; Jannuzi, B. T.; Alberts, Stacey

2012-05-01

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z ≈ 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L IR > 1012 L ⊙). We present new far-infrared photometry, at 250, 350, and 500 μm (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 1011.6 L ⊙ 1013 L ⊙. The rest-frame near-IR (1-3 μm) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with "power-law" SEDs in the rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar "bump" in their rest-frame near-IR show observed-frame 250/24 μm flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 μm flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 μm flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within ~25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 μm luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 μm luminosity (the IR8 = L IR(8-1000 μm)/νL ν(8 μm) parameter of Elbaz et al.). Instead of lying on the z = 1-2 "infrared main sequence" of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up

Remarks on the maximum luminosity

NASA Astrophysics Data System (ADS)

Cardoso, Vitor; Ikeda, Taishi; Moore, Christopher J.; Yoo, Chul-Moon

2018-04-01

The quest for fundamental limitations on physical processes is old and venerable. Here, we investigate the maximum possible power, or luminosity, that any event can produce. We show, via full nonlinear simulations of Einstein's equations, that there exist initial conditions which give rise to arbitrarily large luminosities. However, the requirement that there is no past horizon in the spacetime seems to limit the luminosity to below the Planck value, LP=c5/G . Numerical relativity simulations of critical collapse yield the largest luminosities observed to date, ≈ 0.2 LP . We also present an analytic solution to the Einstein equations which seems to give an unboundedly large luminosity; this will guide future numerical efforts to investigate super-Planckian luminosities.

The luminosity function of quasars

NASA Technical Reports Server (NTRS)

Pei, Yichuan C.

1995-01-01

We propose a new evolutionary model for the optical luminosity function of quasars. Our analytical model is derived from fits to the empirical luminosity function estimated by Hartwick and Schade and Warren, Hewett, and Osmer on the basis of more than 1200 quasars over the range of redshifts 0 approximately less than z approximately less than 4.5. We find that the evolution of quasars over this entire redshift range can be well fitted by a Gaussian distribution, while the shape of the luminosity function can be well fitted by either a double power law or an exponential L(exp 1/4) law. The predicted number counts of quasars, as a function of either apparent magnitude or redshift, are fully consistent with the observed ones. Our model indicates that the evolution of quasars reaches its maximum at z approximately = 2.8 and declines at higher redshifts. An extrapolation of the evolution to z approximately greater than 4.5 implies that quasars may have started their cosmic fireworks at z(sub f) approximately = 5.2-5.5. Forthcoming surveys of quasars at these redshifts will be critical to constrain the epoch of quasar formation. All the results we derived are based on observed quasars and are therefore subject to the bias of obscuration by dust in damped Ly alpha systems. Future surveys of these absorption systems at z approximately greater than 3 will also be important if the formation epoch of quasars is to be known unambiguously.

Characterization of exoplanets from their formation. III. The statistics of planetary luminosities

NASA Astrophysics Data System (ADS)

Mordasini, C.; Marleau, G.-D.; Mollière, P.

2017-12-01

Context. This paper continues a series in which we predict the main observable characteristics of exoplanets based on their formation. In Paper I we described our global planet formation and evolution model that is based on the core accretion paradigm. In Paper II we studied the planetary mass-radius relationship with population syntheses. Aims: In this paper we present an extensive study of the statistics of planetary luminosities during both formation and evolution. Our results can be compared with individual directly imaged extrasolar (proto)planets and with statistical results from surveys. Methods: We calculated three populations of synthetic planets assuming different efficiencies of the accretional heating by gas and planetesimals during formation. We describe the temporal evolution of the planetary mass-luminosity relation. We investigate the relative importance of the shock and internal luminosity during formation, and predict a statistical version of the post-formation mass vs. entropy "tuning fork" diagram. Because the calculations now include deuterium burning we also update the planetary mass-radius relationship in time. Results: We find significant overlap between the high post-formation luminosities of planets forming with hot and cold gas accretion because of the core-mass effect. Variations in the individual formation histories of planets can still lead to a factor 5 to 20 spread in the post-formation luminosity at a given mass. However, if the gas accretional heating and planetesimal accretion rate during the runaway phase is unknown, the post-formation luminosity may exhibit a spread of as much as 2-3 orders of magnitude at a fixed mass. As a key result we predict a flat log-luminosity distribution for giant planets, and a steep increase towards lower luminosities due to the higher occurrence rate of low-mass (M ≲ 10-40 M⊕) planets. Future surveys may detect this upturn. Conclusions: Our results indicate that during formation an estimation of

X-ray emission from galaxies - The distribution of low-luminosity X-ray sources in the Galactic Centre region

NASA Astrophysics Data System (ADS)

Heard, Victoria; Warwick, Robert

2012-09-01

We report a study of the extended X-ray emission observed in the Galactic Centre (GC) region based on archival XMM-Newton data. The GC diffuse emission can be decomposed into three distinct components: the emission from low-luminosity point sources; the fluorescence of (and reflection from) dense molecular material; and soft (kT ~1 keV), diffuse thermal plasma emission most likely energised by supernova explosions. Here, we examine the emission due to unresolved point sources. We show that this source component accounts for the bulk of the 6.7-keV and 6.9-keV line emission. We fit the surface brightness distribution evident in these lines with an empirical 2-d model, which we then compare with a prediction derived from a 3-d mass model for the old stellar population in the GC region. We find that the X-ray surface brightness declines more rapidly with angular offset from Sgr A* than the mass-model prediction. One interpretation is that the X-ray luminosity per solar mass characterising the GC source population is increasing towards the GC. Alternatively, some refinement of the mass-distribution within the nuclear stellar disc may be required. The unresolved X-ray source population is most likely dominated by magnetic CVs. We use the X-ray observations to set constraints on the number density of such sources in the GC region. Our analysis does not support the premise that the GC is pervaded by very hot (~ 7.5 keV) thermal plasma, which is truly diffuse in nature.

THE SPECTRAL ENERGY DISTRIBUTIONS AND INFRARED LUMINOSITIES OF z Almost-Equal-To 2 DUST-OBSCURED GALAXIES FROM Herschel AND Spitzer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melbourne, J.; Soifer, B. T.; Desai, Vandana

Dust-obscured galaxies (DOGs) are a subset of high-redshift (z Almost-Equal-To 2) optically-faint ultra-luminous infrared galaxies (ULIRGs, e.g., L{sub IR} > 10{sup 12} L{sub Sun} ). We present new far-infrared photometry, at 250, 350, and 500 {mu}m (observed-frame), from the Herschel Space Telescope for a large sample of 113 DOGs with spectroscopically measured redshifts. Approximately 60% of the sample are detected in the far-IR. The Herschel photometry allows the first robust determinations of the total infrared luminosities of a large sample of DOGs, confirming their high IR luminosities, which range from 10{sup 11.6} L{sub Sun} 10{sup 13} L{sub Sun }. Themore » rest-frame near-IR (1-3 {mu}m) spectral energy distributions (SEDs) of the Herschel-detected DOGs are predictors of their SEDs at longer wavelengths. DOGs with 'power-law' SEDs in the rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to the QSO-like local ULIRG, Mrk 231. DOGs with a stellar 'bump' in their rest-frame near-IR show observed-frame 250/24 {mu}m flux density ratios similar to local star-bursting ULIRGs like NGC 6240. None show 250/24 {mu}m flux density ratios similar to extreme local ULIRG, Arp 220; though three show 350/24 {mu}m flux density ratios similar to Arp 220. For the Herschel-detected DOGs, accurate estimates (within {approx}25%) of total IR luminosity can be predicted from their rest-frame mid-IR data alone (e.g., from Spitzer observed-frame 24 {mu}m luminosities). Herschel-detected DOGs tend to have a high ratio of infrared luminosity to rest-frame 8 {mu}m luminosity (the IR8 = L{sub IR}(8-1000 {mu}m)/{nu}L{sub {nu}}(8 {mu}m) parameter of Elbaz et al.). Instead of lying on the z = 1-2 'infrared main sequence' of star-forming galaxies (like typical LIRGs and ULIRGs at those epochs) the DOGs, especially large fractions of the bump sources, tend to lie in the starburst sequence. While, Herschel-detected DOGs are similar to scaled up versions of local

The High Luminosity LHC Project

NASA Astrophysics Data System (ADS)

Rossi, Lucio

The High Luminosity LHC is one of the major scientific project of the next decade. It aims at increasing the luminosity reach of LHC by a factor five for peak luminosity and a factor ten in integrated luminosity. The project, now fully approved and funded, will be finished in ten years and will prolong the life of LHC until 2035-2040. It implies deep modifications of the LHC for about 1.2 km around the high luminosity insertions of ATLAS and CMS and relies on new cutting edge technologies. We are developing new advanced superconducting magnets capable of reaching 12 T field; superconducting RF crab cavities capable to rotate the beams with great accuracy; 100 kA and hundred meter long superconducting links for removing the power converter out of the tunnel; new collimator concepts, etc... Beside the important physics goals, the High Luminosity LHC project is an ideal test bed for new technologies for the next hadron collider for the post-LHC era.

Luminosity distance in ``Swiss cheese'' cosmology with randomized voids. II. Magnification probability distributions

NASA Astrophysics Data System (ADS)

Flanagan, Éanna É.; Kumar, Naresh; Wasserman, Ira; Vanderveld, R. Ali

2012-01-01

We study the fluctuations in luminosity distances due to gravitational lensing by large scale (≳35Mpc) structures, specifically voids and sheets. We use a simplified “Swiss cheese” model consisting of a ΛCDM Friedman-Robertson-Walker background in which a number of randomly distributed nonoverlapping spherical regions are replaced by mass-compensating comoving voids, each with a uniform density interior and a thin shell of matter on the surface. We compute the distribution of magnitude shifts using a variant of the method of Holz and Wald , which includes the effect of lensing shear. The standard deviation of this distribution is ˜0.027 magnitudes and the mean is ˜0.003 magnitudes for voids of radius 35 Mpc, sources at redshift zs=1.0, with the voids chosen so that 90% of the mass is on the shell today. The standard deviation varies from 0.005 to 0.06 magnitudes as we vary the void size, source redshift, and fraction of mass on the shells today. If the shell walls are given a finite thickness of ˜1Mpc, the standard deviation is reduced to ˜0.013 magnitudes. This standard deviation due to voids is a factor ˜3 smaller than that due to galaxy scale structures. We summarize our results in terms of a fitting formula that is accurate to ˜20%, and also build a simplified analytic model that reproduces our results to within ˜30%. Our model also allows us to explore the domain of validity of weak-lensing theory for voids. We find that for 35 Mpc voids, corrections to the dispersion due to lens-lens coupling are of order ˜4%, and corrections due to shear are ˜3%. Finally, we estimate the bias due to source-lens clustering in our model to be negligible.

The AGN Luminosity Fraction in Galaxy Mergers

NASA Astrophysics Data System (ADS)

Dietrich, Jeremy; Weiner, Aaron; Ashby, Matthew; Martinez-Galarza, Juan Rafael; Smith, Howard Alan

2017-01-01

Galaxy mergers are key events in galaxy evolution, generally triggering massive starbursts and AGNs. However, in these chaotic systems, it is not yet known what fraction each of these two mechanisms contributes to the total luminosity. Here we measure and model spectral energy distributions (SEDs) using the Code for Investigating Galaxy Emission (CIGALE) in up to 33 broad bands from the UV to the far-IR for 23 IR-luminous galaxies to estimate the fraction of the bolometric IR luminosity that can be attributed to the AGN. The galaxies are split nearly evenly into two subsamples: late-stage mergers, found in the IRAS Revised Bright Galaxy Sample or Faint Source Catalog, and early-stage mergers found in the Spitzer Interacting Galaxy Sample. We find that the AGN contribution to the total IR luminosity varies greatly from system to system, from 0% up to ~90%, but is substantially greater in the later-stage and brighter mergers. This is consistent with what is known about galaxy evolution and the triggering of AGNs.The SAO REU program is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851, and by the Smithsonian Institution.

THE SWIFT GRB HOST GALAXY LEGACY SURVEY. II. REST-FRAME NEAR-IR LUMINOSITY DISTRIBUTION AND EVIDENCE FOR A NEAR-SOLAR METALLICITY THRESHOLD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perley, D. A.; Tanvir, N. R.; Hjorth, J.

2016-01-20

We present rest-frame near-IR (NIR) luminosities and stellar masses for a large and uniformly selected population of gamma-ray burst (GRB) host galaxies using deep Spitzer Space Telescope imaging of 119 targets from the Swift GRB Host Galaxy Legacy Survey spanning 0.03 < z < 6.3, and we determine the effects of galaxy evolution and chemical enrichment on the mass distribution of the GRB host population across cosmic history. We find a rapid increase in the characteristic NIR host luminosity between z ∼ 0.5 and z ∼ 1.5, but little variation between z ∼ 1.5 and z ∼ 5. Dust-obscured GRBs dominate the massive host population but are only rarely seen associated withmore » low-mass hosts, indicating that massive star-forming galaxies are universally and (to some extent) homogeneously dusty at high redshift while low-mass star-forming galaxies retain little dust in their interstellar medium. Comparing our luminosity distributions with field surveys and measurements of the high-z mass–metallicity relation, our results have good consistency with a model in which the GRB rate per unit star formation is constant in galaxies with gas-phase metallicity below approximately the solar value but heavily suppressed in more metal-rich environments. This model also naturally explains the previously reported “excess” in the GRB rate beyond z ≳ 2; metals stifle GRB production in most galaxies at z < 1.5 but have only minor impact at higher redshifts. The metallicity threshold we infer is much higher than predicted by single-star models and favors a binary progenitor. Our observations also constrain the fraction of cosmic star formation in low-mass galaxies undetectable to Spitzer to be small at z < 4.« less

Radial distributions of surface mass density and mass-to-luminosity ratio in spiral galaxies

NASA Astrophysics Data System (ADS)

Sofue, Yoshiaki

2018-03-01

We present radial profiles of the surface mass density (SMD) in spiral galaxies directly calculated using rotation curves of two approximations of flat-disk (SMD-F) and spherical mass distribution (SMD-S). The SMDs are combined with surface brightness using photometric data to derive radial variations of the mass-to-luminosity ratio (ML). It is found that the ML generally has a central peak or a plateau, and decreases to a local minimum at R ˜ 0.1-0.2 h, where R is the radius and h is the scale radius of optical disk. The ML, then, increases rapidly until ˜0.5 h, and is followed by gradual rise till ˜2 h, remaining at around ˜2 [M_{⊙} L^{-1}_{⊙}] in the w1 band (infrared λ3.4 μm) and ˜ 10 [M_⊙ L_⊙ ^{-1}] in the r band (λ6200-7500 Å). Beyond this radius, the ML increases steeply with approaching the observed edges at R ˜ 5 h, attaining to as high values as ˜20 in w1 and ˜ 10^2 [M_⊙ L_⊙ ^{-1}] in the r band, which are indicative of dominant dark matter. The general properties of the ML distributions will be useful for constraining cosmological formation models of spiral galaxies.

Optimizing integrated luminosity of future hadron colliders

NASA Astrophysics Data System (ADS)

Benedikt, Michael; Schulte, Daniel; Zimmermann, Frank

2015-10-01

The integrated luminosity, a key figure of merit for any particle-physics collider, is closely linked to the peak luminosity and to the beam lifetime. The instantaneous peak luminosity of a collider is constrained by a number of boundary conditions, such as the available beam current, the maximum beam-beam tune shift with acceptable beam stability and reasonable luminosity lifetime (i.e., the empirical "beam-beam limit"), or the event pileup in the physics detectors. The beam lifetime at high-luminosity hadron colliders is largely determined by particle burn off in the collisions. In future highest-energy circular colliders synchrotron radiation provides a natural damping mechanism, which can be exploited for maximizing the integrated luminosity. In this article, we derive analytical expressions describing the optimized integrated luminosity, the corresponding optimum store length, and the time evolution of relevant beam parameters, without or with radiation damping, while respecting a fixed maximum value for the total beam-beam tune shift or for the event pileup in the detector. Our results are illustrated by examples for the proton-proton luminosity of the existing Large Hadron Collider (LHC) at its design parameters, of the High-Luminosity Large Hadron Collider (HL-LHC), and of the Future Circular Collider (FCC-hh).

THE LUMINOSITY FUNCTION OF FERMI-DETECTED FLAT-SPECTRUM RADIO QUASARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajello, M.; Shaw, M. S.; Romani, R. W.

2012-06-01

Fermi has provided the largest sample of {gamma}-ray-selected blazars to date. In this work we use a complete sample of flat spectrum radio quasars (FSRQs) detected during the first year of operation to determine the luminosity function (LF) and its evolution with cosmic time. The number density of FSRQs grows dramatically up to redshift {approx}0.5-2.0 and declines thereafter. The redshift of the peak in the density is luminosity dependent, with more luminous sources peaking at earlier times; thus the LF of {gamma}-ray FSRQs follows a luminosity-dependent density evolution similar to that of radio-quiet active galactic nuclei. Also, using data frommore » the Swift Burst Alert Telescope we derive the average spectral energy distribution (SED) of FSRQs in the 10 keV-300 GeV band and show that there is no correlation between the luminosity at the peak of the {gamma}-ray emission component and its peak frequency. Using this luminosity-independent SED with the derived LF allows us to predict that the contribution of FSRQs to the Fermi isotropic {gamma}-ray background is 9.3{sup +1.6}{sub -1.0}% ({+-}3% systematic uncertainty) in the 0.1-100 GeV band. Finally we determine the LF of unbeamed FSRQs, finding that FSRQs have an average Lorentz factor of {gamma} = 11.7{sup +3.3}{sub -2.2}, that most are seen within 5 Degree-Sign of the jet axis, and that they represent only {approx}0.1% of the parent population.« less

The origin of the infrared luminosity in Centaurus A

NASA Technical Reports Server (NTRS)

Joy, Marshall; Lester, Daniel F.; Harvey, Paul M.; Ellis, H. Benton

1988-01-01

The origin of the infrared luminosity in Centaurus A is studied using new tracking and data acquisition techniques which yield diffraction-limited profiles at both 50 and 100 microns. Ninety percent of the 100 micron flux is found to originate in a source which extends 5 kpc along the optical dust lane that bisects the galaxy; the remaining 10 percent comes from an unresolved source coincident with the active radio nucleus. The extended 100 micron emission profile is fully consistent with a uniform disk of thermally radiating particles; when combined with results of previous studies at shorter wavelengths, these measurements indicate that nearly all of the infrared luminosity is produced by thermally emitting grains which are heated by massive young stars distributed throughout the optically thick dust lane.

The 5-10 keV AGN luminosity function at 0.01 < z < 4.0

NASA Astrophysics Data System (ADS)

Fotopoulou, S.; Buchner, J.; Georgantopoulos, I.; Hasinger, G.; Salvato, M.; Georgakakis, A.; Cappelluti, N.; Ranalli, P.; Hsu, L. T.; Brusa, M.; Comastri, A.; Miyaji, T.; Nandra, K.; Aird, J.; Paltani, S.

2016-03-01

The active galactic nuclei (AGN) X-ray luminosity function traces actively accreting supermassive black holes and is essential for the study of the properties of the AGN population, black hole evolution, and galaxy-black hole coevolution. Up to now, the AGN luminosity function has been estimated several times in soft (0.5-2 keV) and hard X-rays (2-10 keV). AGN selection in these energy ranges often suffers from identification and redshift incompleteness and, at the same time, photoelectric absorption can obscure a significant amount of the X-ray radiation. We estimate the evolution of the luminosity function in the 5-10 keV band, where we effectively avoid the absorbed part of the spectrum, rendering absorption corrections unnecessary up to NH ~ 1023 cm-2. Our dataset is a compilation of six wide, and deep fields: MAXI, HBSS, XMM-COSMOS, Lockman Hole, XMM-CDFS, AEGIS-XD, Chandra-COSMOS, and Chandra-CDFS. This extensive sample of ~1110 AGN (0.01 < z < 4.0, 41 < log Lx < 46) is 98% redshift complete with 68% spectroscopic redshifts. For sources lacking a spectroscopic redshift estimation we use the probability distribution function of photometric redshift estimation specifically tuned for AGN, and a flat probability distribution function for sources with no redshift information. We use Bayesian analysis to select the best parametric model from simple pure luminosity and pure density evolution to more complicated luminosity and density evolution and luminosity-dependent density evolution (LDDE). We estimate the model parameters that describe best our dataset separately for each survey and for the combined sample. We show that, according to Bayesian model selection, the preferred model for our dataset is the LDDE. Our estimation of the AGN luminosity function does not require any assumption on the AGN absorption and is in good agreement with previous works in the 2-10 keV energy band based on X-ray hardness ratios to model the absorption in AGN up to redshift three

Is the Ratio of Observed X-ray Luminosity to Bolometric Luminosity in Early-type Stars Really a Constant?

NASA Technical Reports Server (NTRS)

Waldron, W. L.

1985-01-01

The observed X-ray emission from early-type stars can be explained by the recombination stellar wind model (or base coronal model). The model predicts that the true X-ray luminosity from the base coronal zone can be 10 to 1000 times greater than the observed X-ray luminosity. From the models, scaling laws were found for the true and observed X-ray luminosities. These scaling laws predict that the ratio of the observed X-ray luminosity to the bolometric luminosity is functionally dependent on several stellar parameters. When applied to several other O and B stars, it is found that the values of the predicted ratio agree very well with the observed values.

The luminosity function for different morphological types in the CfA Redshift Survey

NASA Technical Reports Server (NTRS)

Marzke, Ronald O.; Geller, Margaret J.; Huchra, John P.; Corwin, Harold G., Jr.

1994-01-01

We derive the luminosity function for different morphological types in the original CfA Redshift Survey (CfA1) and in the first two slices of the CfA Redshift Survey Extension (CfA2). CfA1 is a complete sample containing 2397 galaxies distributed over 2.7 steradians with m(sub z) less than or equal 14.5. The first two complete slices of CfA2 contain 1862 galaxies distributed over 0.42 steradians with m(sub z)=15.5. The shapes of the E-S0 and spiral luminosity functions (LF) are indistinguishable. We do not confirm the steeply decreasing faint end in the E-S0 luminosity function found by Loveday et al. for an independent sample in the southern hemisphere. We demonstrate that incomplete classification in deep redshift surveys can lead to underestimates of the faint end of the elliptical luminosity function and could be partially responsible for the difference between the CfA survey and other local field surveys. The faint end of the LF for the Magellanic spirals and irregulars is very steep. The Sm-Im luminosity function is well fit by a Schechter function with M*=-18.79, alpha=-1.87, and phi*=0.6x10(exp -3) for M(sub z) less than or equal to -13. These galaxies are largely responsible for the excess at the faint end of the general CfA luminosity function. The abundance of intrinsically faint, blue galaxies nearby affects the interpretation of deep number counts. The dwarf population increases the expected counts at B=25 in a no-evolution, q(sub 0)=0.05 model by a factor of two over standard no-evolution estimates. These dwarfs change the expected median redshift in deep redshift surveys by less than 10 percent . Thus the steep Sm-Im LF may contribute to the reconciliation of deep number counts with deep redshift surveys.

Consistency between the luminosity function of resolved millisecond pulsars and the galactic center excess

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ploeg, Harrison; Gordon, Chris; Crocker, Roland

Fermi Large Area Telescope data reveal an excess of GeV gamma rays from the direction of the Galactic Center and bulge. Several explanations have been proposed for this excess including an unresolved population of millisecond pulsars (MSPs) and self-annihilating dark matter. It has been claimed that a key discriminant for or against the MSP explanation can be extracted from the properties of the luminosity function describing this source population. Specifically, is the luminosity function of the putative MSPs in the Galactic Center consistent with that characterizing the resolved MSPs in the Galactic disk? To investigate this we have used amore » Bayesian Markov Chain Monte Carlo to evaluate the posterior distribution of the parameters of the MSP luminosity function describing both resolved MSPs and the Galactic Center excess. At variance with some other claims, our analysis reveals that, within current uncertainties, both data sets can be well fit with the same luminosity function.« less

Implications of Lag-Luminosity Relationship for Unified GRB Paradigms

NASA Technical Reports Server (NTRS)

Norris, J. P.; White, Nicholas E. (Technical Monitor)

2002-01-01

Spectral lags (tau(sub lag)) are deduced for 1437 long (T(sub 90) greater than 2 s) BATSE gamma-ray bursts (GRBs) with peak flux F(sub p) greater than 0.25 photons cm(sup -2)/s, near to the BATSE trigger threshold. The lags are modeled to approximate the observed distribution in the F(sub p)-T(sub lag) plane, realizing a noise-free representation. Assuming a two-branch lag-luminosity relationship, the lags are self-consistently corrected for cosmological effects to yield distributions in luminosity, distance, and redshift. The results have several consequences for GRB populations and for unified gamma-ray/afterglow scenarios which would account for afterglow break times and gamma-ray spectral evolution in terms of jet opening angle, viewing angle, or a profiled jet with variable Lorentz factor: A component of the burst sample is identified - those with few, wide pulses, lags of a few tenths to several seconds, and soft spectra - whose Log[N]-Log[F(sub p)] distribution approximates a -3/2 power-law, suggesting homogeneity and thus relatively nearby sources. The proportion of these long-lag bursts increases from negligible among bright BATSE bursts to approx. 50% at trigger threshold. Bursts with very long lags, approx. 1-2 less than tau(sub lag) (S) less than 10, show a tendency to concentrate near the Supergalactic Plane with a quadrupole moment of approx. -0.10 +/- 0.04. GRB 980425 (SN 1998bw) is a member of this subsample of approx. 90 bursts with estimated distances less than 100 Mpc. The frequency of the observed ultra-low luminosity bursts is approx. 1/4 that of SNe Ib/c within the same volume. If truly nearby, the core-collapse events associated with these GRBs might produce gravitational radiation detectable by LIGO-II. Such nearby bursts might also help explain flattening of the cosmic ray spectrum at ultra-high energies, as observed by AGASA.

The Luminosity Function of Fermi-detected Flat-Spectrum Radio Quasars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ajello, M.; Shaw, M.S.; Romani, R.W.

2012-04-16

Fermi has provided the largest sample of {gamma}-ray selected blazars to date. In this work we use a complete sample of FSRQs detected during the first year of operation to determine the luminosity function (LF) and its evolution with cosmic time. The number density of FSRQs grows dramatically up to redshift {approx}0.5-2.0 and declines thereafter. The redshift of the peak in the density is luminosity dependent, with more luminous sources peaking at earlier times; thus the LF of {gamma}-ray FSRQs follows a luminosity-dependent density evolution similarly to that of radio-quiet AGN. Also using data from the Swift Burst Alert Telescopemore » we derive the average spectral energy distribution of FSRQs in the 10 keV-100GeV band and show that there is no correlation of the peak {gamma}-ray luminosity with {gamma}-ray peak frequency. The coupling of the SED and LF allows us to predict that the contribution of FSRQs to the Fermi isotropic {gamma}-ray background is 9.3{sub -1.0}{sup +1.6}% ({+-}3% systematic uncertainty) in the 0.1-100GeV band. Finally we determine the LF of unbeamed FSRQs, finding that FSRQs have an average Lorentz factor of {gamma} = 11.7{sub -2.2}{sup +3.3}, that most are seen within 5{sup o} of the jet axis, and that they represent only {approx}0.1% of the parent population.« less

Gamma-ray luminosity and photon index evolution of FSRQ blazars and contribution to the gamma-ray background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singal, J.; Ko, A.; Petrosian, V., E-mail: jsingal@richmond.edu

We present the redshift evolutions and distributions of the gamma-ray luminosity and photon spectral index of flat spectrum radio quasar (FSRQ) type blazars, using non-parametric methods to obtain the evolutions and distributions directly from the data. The sample we use for analysis consists of almost all FSRQs observed with a greater than approximately 7σ detection threshold in the first-year catalog of the Fermi Gamma-ray Space Telescope's Large Area Telescope, with redshifts as determined from optical spectroscopy by Shaw et al. We find that FSQRs undergo rapid gamma-ray luminosity evolution, but negligible photon index evolution, with redshift. With these evolutions accountedmore » for we determine the density evolution and luminosity function of FSRQs and calculate their total contribution to the extragalactic gamma-ray background radiation, resolved and unresolved, which is found to be 16(+10/–4)%, in agreement with previous studies.« less

Luminosity of serendipitous x-ray QSOs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Margon, B.; Chanan, G.A.; Downes, R.A.

1982-02-01

We have identified the optical counterparts of 47 serendipitously discovered Einstein Observatory X-ray sources with previously unreported quasi-stellar objects. The mean ratio of X-ray to optical luminosity of this sample agrees reasonably well with that derived from X-ray observations of previously known QSOs. However, despite the fact that our limiting magnitude V = 18.5 should permit detection of typical QSOs (i.e., M/sub c/ = -26) to z = 0.9, the mean redshift of our sample is only z = 0.42 Thus the mean luminosity of these objects, M/sub c/ = -24, differs significantly from that of previous QSO surveys withmore » similar optical thresholds. The existence of large numbers of these lower luminosity QSOs which are difficult to discover by previous selection techniques, provides observational confirmation of the steep luminosity function inferred indirectly from optical counts. However, possible explanations for the lack of higher luminosity QSOs in our sample prove even more interesting. If one accepts the global value of the X-ray to optical luminosity ratio proposed by Zamorani et al, and Ku, Helfand, and Lucy, then reconciliation of this ratio with our observations severely constrains the QSO space density and luminosity functions. Alternatively, the ''typical'' QSO-a radio quiet, high redshift (z>1), optically luminous but not superluminous (M/sub c/> or =-27) object-may not be a strong X-ray source. This inference is not in conflict with existing results from Einstein X-ray surveys of preselected QSOs, which also fail to detect such objects. The contribution of QSOs to the diffuse X-ray background radiation is therefore highly uncertain, but may be quite small. Current X-ray data probably do not place significant constraints on the optical number counts of faint QSOs.« less

Spectral Energy Distribution Models for Low-Luminosity Active Galactic Nuclei in LINERs

NASA Technical Reports Server (NTRS)

Nemmen, Rodrigo S.; Storchi-Bergmann, Thaisa; Eracleous, Michael

2012-01-01

Low-luminosity active galactic nuclei (LLAGNs) represent the bulk of the AGN population in the present-day universe and they trace the low-level accreting supermassive black holes. In order to probe the accretion and jet physical properties in LLAGNs as a class, we model the broadband radio to X-rays spectral energy distributions (SEDs) of 21 LLAGNs in low-ionization nuclear emission-line regions (LINERs) with a coupled accretion-jet model. The accretion flow is modeled as an inner ADAF outside of which there is a truncated standard thin disk. We find that the radio emission is severely underpredicted by ADAF models and is explained by the relativistic jet. The origin of the X-ray radiation in most sources can be explained by three distinct scenarios: the X-rays can be dominated by emission from the ADAF, or the jet, or the X-rays can arise from a jet-ADAF combination in which both components contribute to the emission with similar importance. For 3 objects both the jet and ADAF fit equally well the X-ray spectrum and can be the dominant source of X-rays whereas for 11 LLAGNs a jet-dominated model accounts better than the ADAF-dominated model for the data. The individual and average SED models that we computed can be useful for different studies of the nuclear emission of LLAGNs. From the model fits, we estimate important parameters of the central engine powering LLAGNs in LINERs, such as the mass accretion rate and the mass-loss rate in the jet and the jet power - relevant for studies of the kinetic feedback from jets.

Evolution of the luminosity function of quasar accretion disks

NASA Technical Reports Server (NTRS)

Caditz, David M.; Petrosian, Vahe; Wandel, Amri

1991-01-01

Using an accretion-disk model, accretion disk luminosities are calculated for a grid of black hole masses and accretion rates. It is shown that, as the black-hole mass increases with time, the monochromatic luminosity at a given frequency first increases and then decreases rapidly as this frequency is crossed by the Wien cutoff. The upper limit on the monochromatic luminosity, which is characteristic for a given epoch, constrains the evolution of quasar luminosities and determines the evolultion of the quasar luminosity function.

A New Determination of the Luminosity Function of the Galactic Halo.

NASA Astrophysics Data System (ADS)

Dawson, Peter Charles

The luminosity function of the galactic halo is determined by subtracting from the observed numbers of proper motion stars in the LHS Catalogue the expected numbers of main-sequence, degenerate, and giant stars of the disk population. Selection effects are accounted for by Monte Carlo simulations based upon realistic colour-luminosity relations and kinematic models. The catalogue is shown to be highly complete, and a calibration of the magnitude estimates therein is presented. It is found that, locally, the ratio of disk to halo material is close to 950, and that the mass density in main sequence and subgiant halo stars with 3 < M(,v) < 14 is about 2 x 10('-5) M(,o) pc('-3). With due allowance for white dwarfs and binaries, and taking into account the possibility of a moderate rate of halo rotation, it is argued that the total density does not much exceed 5 x 10('-5) M(,o) pc('-3), in which case the total mass interior to the sun is of the order of 5 x 10('8) M(,o) for a density distribution which projects to a de Vaucouleurs r(' 1/4) law. It is demonstrated that if the Wielen luminosity function is a faithful representation of the stellar distribution in the solar neighbourhood, then the observed numbers of large proper motion stars are inconsistent with the presence of an intermediate popula- tion at the level, and with the kinematics advocated recently by Gilmore and Reid. The initial mass function (IMF) of the halo is considered, and weak evidence is presented that its slope is at least not shallower than that of the disk population IMF. A crude estimate of the halo's age, based on a comparison of the main sequence turnoff in the reduced proper motion diagram with theoretical models is obtained; a tentative lower limit is 15 Gyr with a best estimate of between 15 and 18 Gyr. Finally, the luminosity function obtained here is compared with those determined in other investigations.

Liners and Low Luminosity AGN in the ROSAT Database

NASA Technical Reports Server (NTRS)

Elvis, Martin; West, Donald K. (Technical Monitor)

2003-01-01

This program has led to a series of papers being written and published in the Astrophysical Journal. Together these papers try to explain major parts of the LINER and low luminosity AGN puzzle. One paper ('Accretion Disk Instabilities, Cold Dark Matter Models, and Their Role in Quasar Evolution', Hatziminaoglou E., Siemiginowska A., & Elvis M., 2001, ApJ, 547, 90) describes an analytical model for the evolution of the quasar luminosity function. By combining the Press-Schechter formalism for the masses of initial structures with the luminosity distribution for a population of single mass black holes given by an unstable accretion disk an almost complete end-to-end physics-based model of quasar evolution is produced. In this model black holes spend 75% of their time in a low accretion state (at L(Edd)). This low state population of black holes is likely to be observed as the LINER and low luminosity AGNs in the local universe. Another paper ('Broad Emission Line Regions in AGN: the Link with the Accretion Power', Nicastro F., 2000, ApJ Letters, 530, L65) gives a physical basis for why low state black holes appear as LINERS. By linking the Lightman-Eardley instability in an accretion disk to the ori.gin of a wind that contains the broad emission line cloud material this model explains the large widths seen in these lines as being the Keplerian velocity of the disk at the instability radius. For LINERS the key is that below an accretion rate of 10(exp -3)M(sub Edd)the Lightman-Eardley instability falls within the innermost stable orbit of the disk, and so leaves the entire disk stable. No wind occurs, and so no broad emission lines are seen. Most LINERS are likely to be black holes in this low state. Tests of this model are being considered.

Oxygen-rich Mira variables: Near-infrared luminosity calibrations. Populations and period-luminosity relations

NASA Technical Reports Server (NTRS)

Alvarez, R.; Mennessier, M.-O.; Barthes, D.; Luri, X.; Mattei, J. A.

1997-01-01

Hipparcos astrometric and kinematical data of oxygen-rich Mira variables are used to calibrate absolute near-infrared magnitudes and kinematic parameters. Three distinct classes of stars with different kinematics and scale heights were identified. The two most significant groups present characteristics close to those usually assigned to extended/thick disk-halo populations and old disk populations, respectively, and thus they may differ by their metallicity abundance. Two parallel period-luminosity relations are found, one for each population. The shift between these relations is interpreted as the consequence of the effects of metallicity abundance on the luminosity.

Simulations of fast crab cavity failures in the high luminosity Large Hadron Collider

NASA Astrophysics Data System (ADS)

Yee-Rendon, Bruce; Lopez-Fernandez, Ricardo; Barranco, Javier; Calaga, Rama; Marsili, Aurelien; Tomás, Rogelio; Zimmermann, Frank; Bouly, Frédéric

2014-05-01

Crab cavities (CCs) are a key ingredient of the high luminosity Large Hadron Collider (HL-LHC) project for increasing the luminosity of the LHC. At KEKB, CCs have exhibited abrupt changes of phase and voltage during a time period of the order of a few LHC turns and considering the significant stored energy in the HL-LHC beam, CC failures represent a serious threat in regard to LHC machine protection. In this paper, we discuss the effect of CC voltage or phase changes on a time interval similar to, or longer than, the one needed to dump the beam. The simulations assume a quasistationary-state distribution to assess the particles losses for the HL-LHC. These distributions produce beam losses below the safe operation threshold for Gaussian tails, while, for non-Gaussian tails are on the same order of the limit. Additionally, some mitigation strategies are studied for reducing the damage caused by the CC failures.

Solar gravitational energy and luminosity variations

NASA Astrophysics Data System (ADS)

Fazel, Z.; Rozelot, J. P.; Lefebvre, S.; Ajabshirizadeh, A.; Pireaux, S.

2008-02-01

Due to non-homogeneous mass distribution and non-uniform velocity rate inside the Sun, the solar outer shape is distorted in latitude. In this paper, we analyze the consequences of a temporal change in this figure on the luminosity. To do so, we use the Total Solar Irradiance (TSI) as an indicator of luminosity. Considering that most of the authors have explained the largest part of the TSI modulation with magnetic network (spots and faculae) but not the whole, we could set constraints on radius and effective temperature variations. Our best fit of modelled to observed irradiance gives d T = 1.2 K at d R = 10 mas. However computations show that the amplitude of solar irradiance modulation is very sensitive to photospheric temperature variations. In order to understand discrepancies between our best fit and recent observations of [Livingston, W.C., Gray, D., Wallace, L., White, O.R., 2005. In: Sankarasubramanian, K., Penn, M., Pevtsov, A. (Eds.), Large-scale Structures and their Role in Solar Activity, ASP Conference Series, vol. 346. Astronomical Society of the Pacific, p. 353], showing no effective surface temperature variation during the solar cycle, we investigated small effective temperature variation in irradiance modeling. We emphasized a phase-shift (correlated or anticorrelated radius and irradiance variations) in the (d R, d T)-parameter plane. We further obtained an upper limit on the amplitude of cyclic solar radius variations between 3.87 and 5.83 km, deduced from the gravitational energy variations. Our estimate is consistent with both observations of the helioseismic radius through the analysis of f-mode frequencies and observations of the basal photospheric temperature at Kitt Peak. Finally, we suggest a mechanism to explain weak changes in the solar shape due to variation of magnetic pressure which modifies the granules size. This mechanism is supported by an estimate of the asphericity-luminosity parameter, w = -7.61 × 10 -3, which implies an

The 2-10 keV unabsorbed luminosity function of AGN from the LSS, CDFS, and COSMOS surveys

NASA Astrophysics Data System (ADS)

Ranalli, P.; Koulouridis, E.; Georgantopoulos, I.; Fotopoulou, S.; Hsu, L.-T.; Salvato, M.; Comastri, A.; Pierre, M.; Cappelluti, N.; Carrera, F. J.; Chiappetti, L.; Clerc, N.; Gilli, R.; Iwasawa, K.; Pacaud, F.; Paltani, S.; Plionis, E.; Vignali, C.

2016-05-01

The XMM-Large scale structure (XMM-LSS), XMM-Cosmological evolution survey (XMM-COSMOS), and XMM-Chandra deep field south (XMM-CDFS) surveys are complementary in terms of sky coverage and depth. Together, they form a clean sample with the least possible variance in instrument effective areas and point spread function. Therefore this is one of the best samples available to determine the 2-10 keV luminosity function of active galactic nuclei (AGN) and their evolution. The samples and the relevant corrections for incompleteness are described. A total of 2887 AGN is used to build the LF in the luminosity interval 1042-1046 erg s-1 and in the redshift interval 0.001-4. A new method to correct for absorption by considering the probability distribution for the column density conditioned on the hardness ratio is presented. The binned luminosity function and its evolution is determined with a variant of the Page-Carrera method, which is improved to include corrections for absorption and to account for the full probability distribution of photometric redshifts. Parametric models, namely a double power law with luminosity and density evolution (LADE) or luminosity-dependent density evolution (LDDE), are explored using Bayesian inference. We introduce the Watanabe-Akaike information criterion (WAIC) to compare the models and estimate their predictive power. Our data are best described by the LADE model, as hinted by the WAIC indicator. We also explore the recently proposed 15-parameter extended LDDE model and find that this extension is not supported by our data. The strength of our method is that it provides unabsorbed, non-parametric estimates, credible intervals for luminosity function parameters, and a model choice based on predictive power for future data. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA member states and NASA.Tables with the samples of the posterior probability distributions

Luminosity variations of protostars at the Hayashi stage

NASA Astrophysics Data System (ADS)

Abdulmyanov, T. R.

2017-09-01

In the present paper, the luminosity variations of protostars at the Hayashi stage are considered. According to the density wave model, the luminosity of protostars will have significant variations throughout the Hayashi stage. The initial moments of the formation of protoplanetary rings of the Solar system and the luminosity of the protostar for these moments are obtained.

NLC Luminosity as a Function of Beam Parameters

NASA Astrophysics Data System (ADS)

Nosochkov, Y.

2002-06-01

Realistic calculation of NLC luminosity has been performed using particle tracking in DIMAD and beam-beam simulations in GUINEA-PIG code for various values of beam emittance, energy and beta functions at the Interaction Point (IP). Results of the simulations are compared with analytic luminosity calculations. The optimum range of IP beta functions for high luminosity was identified.

LOFAR/H-ATLAS: the low-frequency radio luminosity-star formation rate relation

NASA Astrophysics Data System (ADS)

Gürkan, G.; Hardcastle, M. J.; Smith, D. J. B.; Best, P. N.; Bourne, N.; Calistro-Rivera, G.; Heald, G.; Jarvis, M. J.; Prandoni, I.; Röttgering, H. J. A.; Sabater, J.; Shimwell, T.; Tasse, C.; Williams, W. L.

2018-04-01

Radio emission is a key indicator of star formation activity in galaxies, but the radio luminosity-star formation relation has to date been studied almost exclusively at frequencies of 1.4 GHz or above. At lower radio frequencies, the effects of thermal radio emission are greatly reduced, and so we would expect the radio emission observed to be completely dominated by synchrotron radiation from supernova-generated cosmic rays. As part of the LOFAR Surveys Key Science project, the Herschel-ATLAS NGP field has been surveyed with LOFAR at an effective frequency of 150 MHz. We select a sample from the MPA-JHU catalogue of Sloan Digital Sky Survey galaxies in this area: the combination of Herschel, optical and mid-infrared data enable us to derive star formation rates (SFRs) for our sources using spectral energy distribution fitting, allowing a detailed study of the low-frequency radio luminosity-star formation relation in the nearby Universe. For those objects selected as star-forming galaxies (SFGs) using optical emission line diagnostics, we find a tight relationship between the 150 MHz radio luminosity (L150) and SFR. Interestingly, we find that a single power-law relationship between L150 and SFR is not a good description of all SFGs: a broken power-law model provides a better fit. This may indicate an additional mechanism for the generation of radio-emitting cosmic rays. Also, at given SFR, the radio luminosity depends on the stellar mass of the galaxy. Objects that were not classified as SFGs have higher 150-MHz radio luminosity than would be expected given their SFR, implying an important role for low-level active galactic nucleus activity.

The Evolution of the Type Ia Supernova Luminosity Function

NASA Astrophysics Data System (ADS)

Shen, Ken J.; Toonen, Silvia; Graur, Or

2017-12-01

Type Ia supernovae (SNe Ia) exhibit a wide diversity of peak luminosities and light curve shapes: the faintest SNe Ia are 10 times less luminous and evolve more rapidly than the brightest SNe Ia. Their differing characteristics also extend to their stellar age distributions, with fainter SNe Ia preferentially occurring in old stellar populations and vice versa. In this Letter, we quantify this SN Ia luminosity–stellar age connection using data from the Lick Observatory Supernova Search (LOSS). Our binary population synthesis calculations agree qualitatively with the observed trend in the > 1 {Gyr} old populations probed by LOSS if the majority of SNe Ia arise from prompt detonations of sub-Chandrasekhar-mass white dwarfs (WDs) in double WD systems. Under appropriate assumptions, we show that double WD systems with less massive primaries, which yield fainter SNe Ia, interact and explode at older ages than those with more massive primaries. We find that prompt detonations in double WD systems are capable of reproducing the observed evolution of the SN Ia luminosity function, a constraint that any SN Ia progenitor scenario must confront.

Testing and Improving the Luminosity Relations for Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Collazzi, Andrew C.

2012-01-01

Gamma Ray Bursts (GRBs) have several luminosity relations where a measurable property of a burst light curve or spectrum is correlated with the burst luminosity. These luminosity relations are calibrated for the fraction of bursts with spectroscopic redshifts and hence the known luminosities. GRBs have thus become known as a type of "standard candle” where standard candle is meant in the usual sense that luminosities can be derived from measurable properties of the bursts. GRBs can therefore be used for the same cosmology applications as Type Ia supernovae, including the construction of the Hubble Diagram and measuring massive star formation rate. The greatest disadvantage of using GRBs as standard candles is that their accuracy is lower than desired. With the recent advent of GRBs as a new standard candle, every effort must be made to test and improve the distance measures. Here, methods are employed to do just that. First, generalized forms of two tests are performed on the luminosity relations. All the luminosity relations pass one of these tests, and all but two pass the other. Even with this failure, redundancies in using multiple luminosity relations allows all the luminosity relations to retain value. Next, the "Firmani relation” is shown to have poorer accuracy than first advertised. It is also shown to be derivable from two other luminosity relations. For these reasons, the Firmani relation is useless for cosmology. The Amati relation is then revisited and shown to be an artifact of a combination of selection effects. Therefore, the Amati relation is also not good for cosmology. Fourthly, the systematic errors involved in measuring a luminosity indicator (Epeak) are measured. The result is an irreducible systematic error of 28%. Finally, the work concludes with a discussion about the impact of the work and the future of GRB luminosity relations.

Powering the High-Luminosity Triplets

NASA Astrophysics Data System (ADS)

Ballarino, A.; Burnet, J. P.

The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

Correlation function of the luminosity distances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biern, Sang Gyu; Yoo, Jaiyul, E-mail: sgbiern@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch

We present the correlation function of the luminosity distances in a flat ΛCDM universe. Decomposing the luminosity distance fluctuation into the velocity, the gravitational potential, and the lensing contributions in linear perturbation theory, we study their individual contributions to the correlation function. The lensing contribution is important at large redshift ( z ∼> 0.5) but only for small angular separation (θ ∼< 3°), while the velocity contribution dominates over the other contributions at low redshift or at larger separation. However, the gravitational potential contribution is always subdominant at all scale, if the correct gauge-invariant expression is used. The correlation functionmore » of the luminosity distances depends significantly on the matter content, especially for the lensing contribution, thus providing a novel tool of estimating cosmological parameters.« less

Gamma-Ray Burst Host Galaxies Have "Normal" Luminosities.

PubMed

Schaefer

2000-04-10

The galactic environment of gamma-ray bursts can provide good evidence about the nature of the progenitor system, with two old arguments implying that the burst host galaxies are significantly subluminous. New data and new analysis have now reversed this picture: (1) Even though the first two known host galaxies are indeed greatly subluminous, the next eight hosts have absolute magnitudes typical for a population of field galaxies. A detailed analysis of the 16 known hosts (10 with redshifts) shows them to be consistent with a Schechter luminosity function with R*=-21.8+/-1.0, as expected for normal galaxies. (2) Bright bursts from the Interplanetary Network are typically 18 times brighter than the faint bursts with redshifts; however, the bright bursts do not have galaxies inside their error boxes to limits deeper than expected based on the luminosities for the two samples being identical. A new solution to this dilemma is that a broad burst luminosity function along with a burst number density varying as the star formation rate will require the average luminosity of the bright sample (>6x1058 photons s-1 or>1.7x1052 ergs s-1) to be much greater than the average luminosity of the faint sample ( approximately 1058 photons s-1 or approximately 3x1051 ergs s-1). This places the bright bursts at distances for which host galaxies with a normal luminosity will not violate the observed limits. In conclusion, all current evidence points to gamma-ray burst host galaxies being normal in luminosity.

The Luminosity Function of QSO Host Galaxies

NASA Technical Reports Server (NTRS)

Hamilton, Timothy S.; Casertano, Stefano; Turnshek, David A.; White, Nicholas E. (Technical Monitor)

2002-01-01

We present some results from our HST archival image study of 71 QSO host galaxies. The objects are selected to have z less than or equal to 0.46 and total absolute magnitude M(sub v) less than or equal to -23 in our adopted cosmology (H(sub 0) = 50 kilometers per second Mpc(sup-1), q(sub 0) = 0.5, lambda = 0)). The aim of this initial study is to investigate the composition of the sample with respect to host morphology and radio loudness, as well as derive the QSO host galaxy luminosity function. We have analyzed available WFPC2 images in R or I band (U in one case), using a uniform set of procedures. The host galaxies span a narrow range of luminosities and are exceptionally bright, much more so than normal galaxies, usually L greater than L*(sub v). The QSOs are almost equally divided among three subclasses: radio-loud QSOs with elliptical hosts, radio-quiet QSOs with elliptical hosts, and radio-quiet QSOs with spiral hosts. Radio-loud QSOs with spiral hosts are extremely rare. Using a weighting procedure, we derive the combined luminosity function of QSO host galaxies. We find that the luminosity function of QSO hosts differs in shape from that of normal galaxies but that they coincide at the highest luminosities. The ratio of the number of quasar hosts to the number of normal galaxies at a luminosity L*(sub v) is R = (Lv/11.48L*(sub v))(sup 2.46), where L*(sub v) corresponds to M*(sub v)= -22.35, and a QSO is defined to be an object with total nuclear plus host light M(sub v) less than or equal to -23. This ratio can be interpreted as the probability that a galaxy with luminosity L(sub V) will host a QSO at redshift z approximately equal to 0.26.

The X-Ray Luminosity-Mass Relation for Local Clusters of Galaxies

NASA Astrophysics Data System (ADS)

Stanek, R.; Evrard, A. E.; Böhringer, H.; Schuecker, P.; Nord, B.

2006-09-01

We investigate the relationship between soft X-ray luminosity and mass for low-redshift clusters of galaxies by comparing observed number counts and scaling laws to halo-based expectations of ΛCDM cosmologies. We model the conditional likelihood of halo luminosity as a lognormal distribution of fixed width, centered on a scaling relation, L~Mpρsc(z), and consider two values for s, appropriate for self-similar evolution or no evolution. Convolving with the halo mass function, we compute expected counts in redshift and flux that, after appropriate survey effects are included, we compare to REFLEX survey data. Counts alone provide only an upper limit on the scatter in mass at fixed luminosity, σlnM<0.4. We argue that the observed, intrinsic variance in the temperature-luminosity relation is directly indicative of mass-luminosity variance and derive σlnM=0.43+/-0.06 from HIFLUGCS data. When added to the likelihood analysis, we derive values p=1.59+/-0.05, lnL15,0=1.34+/-0.09, and σlnM=0.37+/-0.05 for self-similar redshift evolution in a concordance (Ωm=0.3, ΩΛ=0.7, σ8=0.9) universe. The present-epoch intercept is sensitive to power spectrum normalization, L15,0~σ-48, and the slope is weakly sensitive to the matter density, p~Ω1/2m. We find a substantially (factor 2) dimmer intercept and slightly steeper slope than the values published using hydrostatic mass estimates of the HIFLUGCS sample and show that a Malmquist bias of the X-ray flux-limited sample accounts for this effect. In light of new WMAP constraints, we discuss the interplay between parameters and sources of systematic error and offer a compromise model with Ωm=0.24, σ8=0.85, and somewhat lower scatter σlnM=0.25, in which hydrostatic mass estimates remain accurate to ~15%. We stress the need for independent calibration of the L-M relation via weak gravitational lensing.

Ultra-high-energy cosmic rays from low-luminosity active galactic nuclei

NASA Astrophysics Data System (ADS)

Duţan, Ioana; Caramete, Laurenţiu I.

2015-03-01

We investigate the production of ultra-high-energy cosmic ray (UHECR) in relativistic jets from low-luminosity active galactic nuclei (LLAGN). We start by proposing a model for the UHECR contribution from the black holes (BHs) in LLAGN, which present a jet power Pj ⩽1046 erg s-1. This is in contrast to the opinion that only high-luminosity AGN can accelerate particles to energies ⩾ 50 EeV. We rewrite the equations which describe the synchrotron self-absorbed emission of a non-thermal particle distribution to obtain the observed radio flux density from sources with a flat-spectrum core and its relationship to the jet power. We found that the UHECR flux is dependent on the observed radio flux density, the distance to the AGN, and the BH mass, where the particle acceleration regions can be sustained by the magnetic energy extraction from the BH at the center of the AGN. We use a complete sample of 29 radio sources with a total flux density at 5 GHz greater than 0.5 Jy to make predictions for the maximum particle energy, luminosity, and flux of the UHECRs from nearby AGN. These predictions are then used in a semi-analytical code developed in Mathematica (SAM code) as inputs for the Monte-Carlo simulations to obtain the distribution of the arrival direction at the Earth and the energy spectrum of the UHECRs, taking into account their deflection in the intergalactic magnetic fields. For comparison, we also use the CRPropa code with the same initial conditions as for the SAM code. Importantly, to calculate the energy spectrum we also include the weighting of the UHECR flux per each UHECR source. Next, we compare the energy spectrum of the UHECRs with that obtained by the Pierre Auger Observatory.

Constructing a bivariate distribution function with given marginals and correlation: application to the galaxy luminosity function

NASA Astrophysics Data System (ADS)

Takeuchi, Tsutomu T.

2010-08-01

We provide an analytic method to construct a bivariate distribution function (DF) with given marginal distributions and correlation coefficient. We introduce a convenient mathematical tool, called a copula, to connect two DFs with any prescribed dependence structure. If the correlation of two variables is weak (Pearson's correlation coefficient |ρ| < 1/3), the Farlie-Gumbel-Morgenstern (FGM) copula provides an intuitive and natural way to construct such a bivariate DF. When the linear correlation is stronger, the FGM copula cannot work anymore. In this case, we propose using a Gaussian copula, which connects two given marginals and is directly related to the linear correlation coefficient between two variables. Using the copulas, we construct the bivariate luminosity function (BLF) and discuss its statistical properties. We focus especially on the far-infrared-far-ulatraviolet (FUV-FIR) BLF, since these two wavelength regions are related to star-formation (SF) activity. Though both the FUV and FIR are related to SF activity, the univariate LFs have a very different functional form: the former is well described by the Schechter function whilst the latter has a much more extended power-law-like luminous end. We construct the FUV-FIR BLFs using the FGM and Gaussian copulas with different strengths of correlation, and examine their statistical properties. We then discuss some further possible applications of the BLF: the problem of a multiband flux-limited sample selection, the construction of the star-formation rate (SFR) function, and the construction of the stellar mass of galaxies (M*)-specific SFR (SFR/M*) relation. The copulas turn out to be a very useful tool to investigate all these issues, especially for including complicated selection effects.

A Solar-luminosity Model and Climate

NASA Technical Reports Server (NTRS)

Perry, Charles A.

1990-01-01

Although the mechanisms of climatic change are not completely understood, the potential causes include changes in the Sun's luminosity. Solar activity in the form of sunspots, flares, proton events, and radiation fluctuations has displayed periodic tendencies. Two types of proxy climatic data that can be related to periodic solar activity are varved geologic formations and freshwater diatom deposits. A model for solar luminosity was developed by using the geometric progression of harmonic cycles that is evident in solar and geophysical data. The model assumes that variation in global energy input is a result of many periods of individual solar-luminosity variations. The 0.1-percent variation of the solar constant measured during the last sunspot cycle provided the basis for determining the amplitude of each luminosity cycle. Model output is a summation of the amplitudes of each cycle of a geometric progression of harmonic sine waves that are referenced to the 11-year average solar cycle. When the last eight cycles in Emiliani's oxygen-18 variations from deep-sea cores were standardized to the average length of glaciations during the Pleistocene (88,000 years), correlation coefficients with the model output ranged from 0.48 to 0.76. In order to calibrate the model to real time, model output was graphically compared to indirect records of glacial advances and retreats during the last 24,000 years and with sea-level rises during the Holocene. Carbon-14 production during the last millenium and elevations of the Great Salt Lake for the last 140 years demonstrate significant correlations with modeled luminosity. Major solar flares during the last 90 years match well with the time-calibrated model.

Does the obscured AGN fraction really depend on luminosity?

NASA Astrophysics Data System (ADS)

Sazonov, S.; Churazov, E.; Krivonos, R.

2015-12-01

We use a sample of 151 local non-blazar active galactic nuclei (AGN) selected from the INTEGRAL all-sky hard X-ray survey to investigate if the observed declining trend of the fraction of obscured (i.e. showing X-ray absorption) AGN with increasing luminosity is mostly an intrinsic or selection effect. Using a torus-obscuration model, we demonstrate that in addition to negative bias, due to absorption in the torus, in finding obscured AGN in hard X-ray flux-limited surveys, there is also positive bias in finding unobscured AGN, due to Compton reflection in the torus. These biases can be even stronger taking into account plausible intrinsic collimation of hard X-ray emission along the axis of the obscuring torus. Given the AGN luminosity function, which steepens at high luminosities, these observational biases lead to a decreasing observed fraction of obscured AGN with increasing luminosity even if this fraction has no intrinsic luminosity dependence. We find that if the central hard X-ray source in AGN is isotropic, the intrinsic (i.e. corrected for biases) obscured AGN fraction still shows a declining trend with luminosity, although the intrinsic obscured fraction is significantly larger than the observed one: the actual fraction is larger than ˜85 per cent at L ≲ 1042.5 erg s-1 (17-60 keV), and decreases to ≲60 per cent at L ≳ 1044 erg s-1. In terms of the half-opening angle θ of an obscuring torus, this implies that θ ≲ 30° in lower luminosity AGN, and θ ≳ 45° in higher luminosity ones. If, however, the emission from the central supermassive black hole is collimated as dL/dΩ ∝ cos α, the intrinsic dependence of the obscured AGN fraction is consistent with a luminosity-independent torus half-opening angle θ ˜ 30°.

On two new X-ray sources in the SMC and the high luminosities of the Magellanic X-ray sources

NASA Technical Reports Server (NTRS)

Clark, G.; Doxsey, R.; Li, F.; Jernigan, J. G.; Van Paradijs, J.

1978-01-01

The discovery of two new X-ray sources, SMC X-2 and SMC X-3, in the Small Magellanic Cloud is reported. They have hard spectra, and their luminosities in the energy range 2-11 keV are 1.0 and 0.7 by 10 to the 38th power erg/sq cm per sec, respectively. It is shown that the luminosity distribution of the known Magellanic X-ray sources, which are now nine in number, is shifted toward higher luminosities with respect to that of similar sources in the Galaxy, and that the cause of the shift is probably an underabundance of heavy elements in the material accreted by the X-ray sources.

Unified treatment of the luminosity distance in cosmology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Jaiyul; Scaccabarozzi, Fulvio, E-mail: jyoo@physik.uzh.ch, E-mail: fulvio@physik.uzh.ch

Comparing the luminosity distance measurements to its theoretical predictions is one of the cornerstones in establishing the modern cosmology. However, as shown in Biern and Yoo, its theoretical predictions in literature are often plagued with infrared divergences and gauge-dependences. This trend calls into question the sanity of the methods used to derive the luminosity distance. Here we critically investigate four different methods—the geometric approach, the Sachs approach, the Jacobi mapping approach, and the geodesic light cone (GLC) approach to modeling the luminosity distance, and we present a unified treatment of such methods, facilitating the comparison among the methods and checkingmore » their sanity. All of these four methods, if exercised properly, can be used to reproduce the correct description of the luminosity distance.« less

Very low luminosity active galaxies and the X-ray background

NASA Technical Reports Server (NTRS)

Elvis, M.; Soltan, A.; Keel, W. C.

1984-01-01

The properties of very low luminosity active galactic nuclei are not well studied, and, in particular, their possible contribution to the diffuse X-ray background is not known. In the present investigation, an X-ray luminosity function for the range from 10 to the 39th to 10 to the 42.5th ergs/s is constructed. The obtained X-ray luminosity function is integrated to estimate the contribution of these very low luminosity active galaxies to the diffuse X-ray background. The construction of the X-ray luminosity function is based on data obtained by Keel (1983) and some simple assumptions about optical and X-ray properties.

Anisotropy of the galaxy cluster X-ray luminosity-temperature relation

NASA Astrophysics Data System (ADS)

Migkas, Konstantinos; Reiprich, Thomas H.

2018-03-01

We introduce a new test to study the cosmological principle with galaxy clusters. Galaxy clusters exhibit a tight correlation between the luminosity and temperature of the X-ray-emitting intracluster medium. While the luminosity measurement depends on cosmological parameters through the luminosity distance, the temperature determination is cosmology-independent. We exploit this property to test the isotropy of the luminosity distance over the full extragalactic sky, through the normalization a of the LX-T scaling relation and the cosmological parameters Ωm and H0. To this end, we use two almost independent galaxy cluster samples: the ASCA Cluster Catalog (ACC) and the XMM Cluster Survey (XCS-DR1). Interestingly enough, these two samples appear to have the same pattern for a with respect to the Galactic longitude. More specifically, we identify one sky region within l (-15°, 90°) (Group A) that shares very different best-fit values for the normalization of the LX-T relation for both ACC and XCS-DR1 samples. We use the Bootstrap and Jackknife methods to assess the statistical significance of these results. We find the deviation of Group A, compared to the rest of the sky in terms of a, to be 2.7σ for ACC and 3.1σ for XCS-DR1. This tension is not significantly relieved after excluding possible outliers and is not attributed to different redshift (z), temperature (T), or distributions of observable uncertainties. Moreover, a redshift conversion to the cosmic microwave background (CMB) frame does not have an important impact on our results. Using also the HIFLUGCS sample, we show that a possible excess of cool-core clusters in this region, is not able to explain the obtained deviations. Furthermore, we tested for a dependence of the results on supercluster environment, where the fraction of disturbed clusters might be enhanced, possibly affecting the LX-T relation. We indeed find a trend in the XCS-DR1 sample for supercluster members to be underluminous compared to

THE LOCAL [C ii] 158 μ m EMISSION LINE LUMINOSITY FUNCTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hemmati, Shoubaneh; Yan, Lin; Capak, Peter

We present, for the first time, the local [C ii] 158 μ m emission line luminosity function measured using a sample of more than 500 galaxies from the Revised Bright Galaxy Sample. [C ii] luminosities are measured from the Herschel PACS observations of the Luminous Infrared Galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey and estimated for the rest of the sample based on the far-infrared (far-IR) luminosity and color. The sample covers 91.3% of the sky and is complete at S{sub 60μm} > 5.24 Jy. We calculate the completeness as a function of [C ii] line luminosity and distance, basedmore » on the far-IR color and flux densities. The [C ii] luminosity function is constrained in the range ∼10{sup 7–9} L{sub ⊙} from both the 1/ V{sub max} and a maximum likelihood methods. The shape of our derived [C ii] emission line luminosity function agrees well with the IR luminosity function. For the CO(1-0) and [C ii] luminosity functions to agree, we propose a varying ratio of [C ii]/CO(1-0) as a function of CO luminosity, with larger ratios for fainter CO luminosities. Limited [C ii] high-redshift observations as well as estimates based on the IR and UV luminosity functions are suggestive of an evolution in the [C ii] luminosity function similar to the evolution trend of the cosmic star formation rate density. Deep surveys using the Atacama Large Millimeter Array with full capability will be able to confirm this prediction.« less

Luminosity Variations in Post-AGB Stars

NASA Astrophysics Data System (ADS)

Mesler, Robert; Henson, G.

2007-12-01

Although much is known about AGB stars and planetary nebulae, relatively little is known about the phase of a star's life in which it transitions between those two states. We have measured the variations in luminosity of a sample of known Post-AGB stars (as well as several candidates) relative to nearby, non-variable stars in order to compare them with theoretical models. The typical behavior of the observed variations is described and an attempt is made to discern whether any periodicity might be present. Luminosity variations were found to be on the order of a few hundredths to a few tenths of a magnitude for the stars that were surveyed, with occasional fluctuations of up to a magnitude. This agrees with current models of Post-AGB stars. Each star fell into one of three categories, which were termed groups 1, 2, and 3. Group 1 stars showed long term, non-periodic luminosity variations on the scale of weeks or longer and were most likely to display some sort of short term, coherent luminosity oscillation (each of which lasted for only a few cycles). Group 2 stars showed erratic, short-term magnitude variations occurring on scales of several days. Group 3 stars showed little or no variation in magnitude. Of the 27 Post-AGB stars that were sampled, five fell into group 1, fifteen fell into group 2, and seven fell into group 3. The luminosity variations tended to be color-independent, and occurred on timescales ranging nearly continuously from a few days to more than a year. No clear periodic behavior was found in any star in our sample. This project was funded by a partnership between the National Science Foundation (NSF AST-0552798), Research Experiences for Undergraduates (REU), and the Department of Defense (DoD) ASSURE (Awards to Stimulate and Support Undergraduate Research Experiences) programs.

The fraction of AGNs in major merger galaxies and its luminosity dependence

NASA Astrophysics Data System (ADS)

Weigel, Anna K.; Schawinski, Kevin; Treister, Ezequiel; Trakhtenbrot, Benny; Sanders, David B.

2018-05-01

We use a phenomenological model which connects the galaxy and active galactic nucleus (AGN) populations to investigate the process of AGNs triggering through major galaxy mergers at z ˜ 0. The model uses stellar mass functions as input and allows the prediction of AGN luminosity functions based on assumed Eddington ratio distribution functions (ERDFs). We show that the number of AGNs hosted by merger galaxies relative to the total number of AGNs increases as a function of AGN luminosity. This is due to more massive galaxies being more likely to undergo a merger and does not require the assumption that mergers lead to higher Eddington ratios than secular processes. Our qualitative analysis also shows that to match the observations, the probability of a merger galaxy hosting an AGN and accreting at a given Eddington value has to be increased by a factor ˜10 relative to the general AGN population. An additional significant increase of the fraction of high Eddington ratio AGNs among merger host galaxies leads to inconsistency with the observed X-ray luminosity function. Physically our results imply that, compared to the general galaxy population, the AGN fraction among merger galaxies is ˜10 times higher. On average, merger triggering does however not lead to significantly higher Eddington ratios.

Testing and Improving the Luminosity Relations for Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Collazzi, Andrew

2011-08-01

Gamma Ray Bursts (GRBs) have several luminosity relations where a measurable property of a burst light curve or spectrum is correlated with the burst luminosity. These luminosity relations are calibrated for the fraction of bursts with spectroscopic redshifts and hence the known luminosities. GRBs have thus become known as a type of 'standard candle'; where standard candle is meant in the usual sense that their luminosities can be derived from measurable properties of the bursts. GRBs can therefore be used for the same cosmology applications as Type Ia supernovae, including the construction of the Hubble Diagram and measuring massive star formation rate. The greatest disadvantage of using GRBs as standard candles is that their accuracy is lower than desired. With the recent advent of GRBs as a new standard candle, every effort must be made to test and improve the distance measures. Here, several methods are employed to do just that. First, generalized forms of two tests are performed on all of the luminosity relations. All the luminosity relations pass the second of these tests, and all but two pass the first. Even with this failure, the redundancy in using multiple luminosity relations allows all the luminosity relations to retain value. Next, the 'Firmani relation' is shown to have poorer accuracy than first advertised. In addition, it is shown to be exactly derivable from two other luminosity relations. For these reasons, the Firmani relation is useless for cosmology. The Amati relation is then revisited and shown to be an artifact of a combination of selection effects. Therefore, the Amati relation is also not good for cosmology. Fourthly, the systematic errors involved in measuring a popular luminosity indicator (Epeak ) are measured. The result is that an irreducible systematic error of 28% exists. After that, a preliminary investigation into the usefulness of breaking GRBs into individual pulses is conducted. The results of an 'ideal' set of data do not

Challenges in Finding AGNs in the Low Luminosity Regime

NASA Astrophysics Data System (ADS)

Satyapal, Shobita; Abel, Nick; Secrest, Nathan; Singh, Amrit; Ellison, Sara

2016-08-01

Low luminosity AGNs are an important component of the AGN population. They are often found in the lowest mass galaxies or galaxies that lack classical bulges, a demographic that places important constraints to models of supermassive black hole seed formation and merger-free models of AGN fueling. The detection of AGNs in this low luminosity regime is challenging both because star formation in the host galaxy can dominate the optical spectrum and gas and dust can obscure the central engine at both optical and X-ray wavelengths. Thus while mid-infrared color selection and X-ray observations at energies <10 keV are often powerful tools in uncovering optically unidentified AGNs at higher luminosities, this is not the case in the low luminosity regime. In this talk, I will review the effectiveness of uncovering AGNs in the low luminosity regime using multiwavength investigations, with a focus on infrared spectroscopic signatures.

Can Low-Luminosity Galaxies Reionize the Universe?

NASA Astrophysics Data System (ADS)

Ferguson, Harry

2017-08-01

The prevailing wisdom is that low-luminosity galaxies are responsible for cosmic reionization. If this is true, then low-luminosity galaxies at high redshift have to be different from most of the low-luminosity galaxies studied to date at low redshift, which absorb too much of their ionizing radiation. While it is possible that high-z dwarf galaxies have the same metallicity at fixed mass and star-formation rate as low-redshift galaxies, they are different in one key respect. At fixed dark-halo mass, they are probably much denser (having collapsed earlier). This could lead to higher star-formation surface densities more capable of creating cavities in the ISM. But the denser halos of surrounding gas could be harder to clear. There is a critical need for further observations to validate and test physical models for the trends of escaping ionizing continuum with redshift, luminosity, and surface density. JWST will not be able to measure ionizing radiation during the epoch of reionization because the IGM absorbs most of the photons. To prepare for JWST, we need to use the ultraviolet capabilities of HST to measure diverse samples of galaxies at z<3, where we can see the photons and quantify the trends with other galaxy properties. As a complement to other studies, we propose to constrain the Lyman-continuum emission from 8 relatively low-luminosity strongly-lensed galaxies at 1

The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys-Davidson limit revisited

NASA Astrophysics Data System (ADS)

Davies, Ben; Crowther, Paul A.; Beasor, Emma R.

2018-05-01

The empirical upper luminosity boundary Lmax of cool supergiants, often referred to as the Humphreys-Davidson limit, is thought to encode information on the general mass-loss behaviour of massive stars. Further, it delineates the boundary at which single stars will end their lives stripped of their hydrogen-rich envelope, which in turn is a key factor in the relative rates of Type-II to Type-Ibc supernovae from single star channels. In this paper we have revisited the issue of Lmax by studying the luminosity distributions of cool supergiants (SGs) in the Large and Small Magellanic Clouds (LMC/SMC). We assemble samples of cool SGs in each galaxy which are highly-complete above log L/L⊙=5.0, and determine their spectral energy distributions from the optical to the mid-infrared using modern multi-wavelength survey data. We show that in both cases Lmax appears to be lower than previously quoted, and is in the region of log L/L⊙=5.5. There is no evidence for Lmax being higher in the SMC than in the LMC, as would be expected if metallicity-dependent winds were the dominant factor in the stripping of stellar envelopes. We also show that Lmax aligns with the lowest luminosity of single nitrogen-rich Wolf-Rayet stars, indicating of a change in evolutionary sequence for stars above a critical mass. From population synthesis analysis we show that the Geneva evolutionary models greatly over-predict the numbers of cool SGs in the SMC. We also argue that the trend of earlier average spectral types of cool SGs in lower metallicity environments represents a genuine shift to hotter temperatures. Finally, we use our new bolometric luminosity measurements to provide updated bolometric corrections for cool supergiants.

Luminosity and cooling of highly magnetized white dwarfs: suppression of luminosity by strong magnetic fields

NASA Astrophysics Data System (ADS)

Bhattacharya, Mukul; Mukhopadhyay, Banibrata; Mukerjee, Subroto

2018-06-01

We investigate the luminosity and cooling of highly magnetized white dwarfs with electron-degenerate cores and non-degenerate surface layers where cooling occurs by diffusion of photons. We find the temperature and density profiles in the surface layers or envelope of white dwarfs by solving the magnetostatic equilibrium and photon diffusion equations in a Newtonian framework. We also obtain the properties of white dwarfs at the core-envelope interface, when the core is assumed to be practically isothermal. With the increase in magnetic field, the interface temperature increases whereas the interface radius decreases. For a given age of the white dwarf and for fixed interface radius or interface temperature, we find that the luminosity decreases significantly from about 10-6 to 10-9 L⊙ as the magnetic field strength increases from about 109 to 1012 G at the interface and hence the envelope. This is remarkable because it argues that magnetized white dwarfs are fainter and can be practically hidden in an observed Hertzsprung-Russell diagram. We also find the cooling rates corresponding to these luminosities. Interestingly, the decrease in temperature with time, for the fields under consideration, is not found to be appreciable.

Measuring the X-ray luminosities of SDSS DR7 clusters from ROSAT All Sky Survey

NASA Astrophysics Data System (ADS)

Wang, Lei; Yang, Xiaohu; Shen, Shiyin; Mo, H. J.; van den Bosch, Frank C.; Luo, Wentao; Wang, Yu; Lau, Erwin T.; Wang, Q. D.; Kang, Xi; Li, Ran

2014-03-01

We use ROSAT All Sky Survey broad-band X-ray images and the optical clusters identified from Sloan Digital Sky Survey Data Release 7 to estimate the X-ray luminosities around ˜65 000 candidate clusters with masses ≳ 1013 h- 1 M⊙ based on an optical to X-ray (OTX) code we develop. We obtain a catalogue with X-ray luminosity for each cluster. This catalogue contains 817 clusters (473 at redshift z ≤ 0.12) with signal-to-noise ratio >3 in X-ray detection. We find about 65 per cent of these X-ray clusters have their most massive member located near the X-ray flux peak; for the rest 35 per cent, the most massive galaxy is separated from the X-ray peak, with the separation following a distribution expected from a Navarro-Frenk-White profile. We investigate a number of correlations between the optical and X-ray properties of these X-ray clusters, and find that the cluster X-ray luminosity is correlated with the stellar mass (luminosity) of the clusters, as well as with the stellar mass (luminosity) of the central galaxy and the mass of the halo, but the scatter in these correlations is large. Comparing the properties of X-ray clusters of similar halo masses but having different X-ray luminosities, we find that massive haloes with masses ≳ 1014 h- 1 M⊙ contain a larger fraction of red satellite galaxies when they are brighter in X-ray. An opposite trend is found in central galaxies in relative low-mass haloes with masses ≲ 1014 h- 1 M⊙ where X-ray brighter clusters have smaller fraction of red central galaxies. Clusters with masses ≳ 1014 h- 1 M⊙ that are strong X-ray emitters contain many more low-mass satellite galaxies than weak X-ray emitters. These results are also confirmed by checking X-ray clusters of similar X-ray luminosities but having different characteristic stellar masses. A cluster catalogue containing the optical properties of member galaxies and the X-ray luminosity is available at http://gax.shao.ac.cn/data/Group.html.

Luminosity function and jet structure of Gamma-Ray Burst

NASA Astrophysics Data System (ADS)

Pescalli, A.; Ghirlanda, G.; Salafia, O. S.; Ghisellini, G.; Nappo, F.; Salvaterra, R.

2015-02-01

The structure of gamma-ray burst (GRB) jets impacts on their prompt and afterglow emission properties. The jet of GRBs could be uniform, with constant energy per unit solid angle within the jet aperture, or it could be structured, namely with energy and velocity that depend on the angular distance from the axis of the jet. We try to get some insight about the still unknown structure of GRBs by studying their luminosity function. We show that low (1046-48 erg s-1) and high (i.e. with L ≥ 1050 erg s-1) luminosity GRBs can be described by a unique luminosity function, which is also consistent with current lower limits in the intermediate luminosity range (1048-50 erg s-1). We derive analytical expressions for the luminosity function of GRBs in uniform and structured jet models and compare them with the data. Uniform jets can reproduce the entire luminosity function with reasonable values of the free parameters. A structured jet can also fit adequately the current data, provided that the energy within the jet is relatively strongly structured, i.e. E ∝ θ-k with k ≥ 4. The classical E ∝ θ-2 structured jet model is excluded by the current data.

The galaxy UV luminosity function at z ≃ 2-4; new results on faint-end slope and the evolution of luminosity density

NASA Astrophysics Data System (ADS)

Parsa, Shaghayegh; Dunlop, James S.; McLure, Ross J.; Mortlock, Alice

2016-03-01

We present a new, robust measurement of the evolving rest-frame ultraviolet (UV) galaxy luminosity function (LF) over the key redshift range from z ≃ 2 to z ≃ 4. Our results are based on the high dynamic range provided by combining the Hubble Ultra Deep Field (HUDF), CANDELS/GOODS-South, and UltraVISTA/COSMOS surveys. We utilize the unparalleled multifrequency photometry available in this survey `wedding cake' to compile complete galaxy samples at z ≃ 2, 3, 4 via photometric redshifts (calibrated against the latest spectroscopy) rather than colour-colour selection, and to determine accurate rest-frame UV absolute magnitudes (M1500) from spectral energy distribution (SED) fitting. Our new determinations of the UV LF extend from M1500 ≃ -22 (AB mag) down to M1500 = -14.5, -15.5 and -16 at z ≃ 2, 3 and 4, respectively (thus, reaching ≃ 3-4 mag fainter than previous blank-field studies at z ≃ 2,3). At z ≃ 2, 3, we find a much shallower faint-end slope (α = -1.32 ± 0.03) than reported in some previous studies (α ≃ -1.7), and demonstrate that this new measurement is robust. By z ≃ 4, the faint-end slope has steepened slightly, to α = -1.43 ± 0.04, and we show that these measurements are consistent with the overall evolutionary trend from z = 0 to 8. Finally, we find that while characteristic number density (φ*) drops from z ≃ 2 to z ≃ 4, characteristic luminosity (M*) brightens by ≃ 1 mag. This, combined with the new flatter faint-end slopes, has the consequence that UV luminosity density (and hence unobscured star formation density) peaks at z ≃ 2.5-3, when the Universe was ≃ 2.5 Gyr old.

Mass Accretion Rate of Very Low Luminosity Objects

NASA Astrophysics Data System (ADS)

Sung, Ren-Shiang; Lai, Shih-Ping; Hsieh, Tien-Hao

2013-08-01

We propose to measure the mass accretion rate of six Very Low Luminosity Objects (VeLLOs) using Near-infrared Integral Spectrometer (NIFS). The extremely low luminosity of VeLLOs, L_int ≤ 0.1 L_⊙, was previously thought not existing in the nature because the typical accretion rate gives much larger accretion luminosity even for the lowest mass star (``Luminosity Problem''). The commonly accepted solution is that the accretion rate is not constant but episodic. Thus, VeLLOs could be interpreted as protostars being in the quiescent phase of accretion activities. However, there is no observational data directly measuring the mass accretion rate of VeLLOs. The main goal of this proposal is to examine such theory and directly measure the mass accretion rate of VeLLOs for the first time. We propose to measure the blue continuum excess (veiling) of the stellar spectrum, which is the most reliable method for measuring the accretion rate. The measurements have to be made in infrared due to the very high extinction for highly embedded protostars. Our proposal provide a first opportunity to explain the long time ``Luminosity Problem'' through the observational aspects, and Gemini is the only instrument that can provide accurate and high sensitivity infrared spectroscopy measurements within reasonably short time scale.

Hard state neutron star and black hole X-ray binaries in the radio:X-ray luminosity plane

NASA Astrophysics Data System (ADS)

Gallo, Elena; Degenaar, Nathalie; van den Eijnden, Jakob

2018-07-01

Motivated by the large body of literature around the phenomenological properties of accreting black hole (BH) and neutron star (NS) X-ray binaries in the radio:X-ray luminosity plane, we carry out a comparative regression analysis on 36 BHs and 41 NSs in hard X-ray states, with data over 7 dex in X-ray luminosity for both. The BHs follow a radio to X-ray (logarithmic) luminosity relation with slope β = 0.59 ± 0.02, consistent with the NSs' slope (β =0.44^{+0.05}_{-0.04}) within 2.5σ. The best-fitting intercept for the BHs significantly exceeds that for the NSs, cementing BHs as more radio loud, by a factor ˜22. This discrepancy cannot be fully accounted for by the mass or bolometric correction gap, or by the NS boundary layer contribution to the X-rays, and is likely to reflect physical differences in the accretion flow efficiency, or the jet powering mechanism. Once importance sampling is implemented to account for the different luminosity distributions, the slopes of the non-pulsating and pulsating NS subsamples are formally inconsistent (>3σ), unless the transitional millisecond pulsars (whose incoherent radio emission mechanism is not firmly established) are excluded from the analysis. We confirm the lack of a robust partitioning of the BH data set into separate luminosity tracks.

Hard state neutron star and black hole X-ray binaries in the radio:X-ray luminosity plane

NASA Astrophysics Data System (ADS)

Gallo, Elena; Degenaar, Nathalie; van den Eijnden, Jakob

2018-05-01

Motivated by the large body of literature around the phenomenological properties of accreting black hole (BH) and neutron star (NS) X-ray binaries in the radio:X-ray luminosity plane, we carry out a comparative regression analysis on 36 BHs and 41 NSs in hard X-ray states, with data over 7 dex in X-ray luminosity for both. The BHs follow a radio to X-ray (logarithmic) luminosity relation with slope β = 0.59 ± 0.02, consistent with the NSs' slope (β =0.44^{+0.05}_{-0.04}) within 2.5σ. The best-fitting intercept for the BHs significantly exceeds that for the NSs, cementing BHs as more radio loud, by a factor ˜22. This discrepancy can not be fully accounted for by the mass or bolometric correction gap, nor by the NS boundary layer contribution to the X-rays, and is likely to reflect physical differences in the accretion flow efficiency, or the jet powering mechanism. Once importance sampling is implemented to account for the different luminosity distributions, the slopes of the non-pulsating and pulsating NS subsamples are formally inconsistent (>3σ), unless the transitional millisecond pulsars (whose incoherent radio emission mechanism is not firmly established) are excluded from the analysis. We confirm the lack of a robust partitioning of the BH data set into separate luminosity tracks.

A peculiar low-luminosity short gamma-ray burst from a double neutron star merger progenitor.

PubMed

Zhang, B-B; Zhang, B; Sun, H; Lei, W-H; Gao, H; Li, Y; Shao, L; Zhao, Y; Hu, Y-D; Lü, H-J; Wu, X-F; Fan, X-L; Wang, G; Castro-Tirado, A J; Zhang, S; Yu, B-Y; Cao, Y-Y; Liang, E-W

2018-01-31

Double neutron star (DNS) merger events are promising candidates of short gamma-ray burst (sGRB) progenitors as well as high-frequency gravitational wave (GW) emitters. On August 17, 2017, such a coinciding event was detected by both the LIGO-Virgo gravitational wave detector network as GW170817 and Gamma-Ray Monitor on board NASA's Fermi Space Telescope as GRB 170817A. Here, we show that the fluence and spectral peak energy of this sGRB fall into the lower portion of the distributions of known sGRBs. Its peak isotropic luminosity is abnormally low. The estimated event rate density above this luminosity is at least [Formula: see text] Gpc -3  yr -1 , which is close to but still below the DNS merger event rate density. This event likely originates from a structured jet viewed from a large viewing angle. There are similar faint soft GRBs in the Fermi archival data, a small fraction of which might belong to this new population of nearby, low-luminosity sGRBs.

The galaxy luminosity function around groups

NASA Astrophysics Data System (ADS)

González, R. E.; Padilla, N. D.; Galaz, G.; Infante, L.

2005-11-01

We present a study on the variations of the luminosity function of galaxies around clusters in a numerical simulation with semi-analytic galaxies, attempting to detect these variations in the 2dF Galaxy Redshift Survey. We subdivide the simulation box into equal-density regions around clusters, which we assume can be achieved by selecting objects at a given normalized distance (r/rrms, where rrms is an estimate of the halo radius) from the group centre. The semi-analytic model predicts important variations in the luminosity function out to r/rrms~= 5. In brief, variations in the mass function of haloes around clusters (large dark matter haloes with M > 1012h-1Msolar) lead to cluster central regions that present a high abundance of bright galaxies (high M* values) as well as low-luminosity galaxies (high α) at r/rrms~= 3 there is a lack of bright galaxies, which shows the depletion of galaxies in the regions surrounding clusters (minimum in M* and α), and a tendency to constant luminosity function parameters at larger cluster-centric distances. We take into account the observational biases present in the real data by reproducing the peculiar velocity effect on the redshifts of galaxies in the simulation box, and also by producing mock catalogues. We find that excluding from the analysis galaxies which in projection are close to the centres of the groups provides results that are qualitatively consistent with the full simulation box results. When we apply this method to mock catalogues of the 2dF Galaxy Redshift Survey (2dFGRS) and the 2PIGG catalogue of groups, we find that the variations in the luminosity function are almost completely erased by the Finger of God effect; only a lack of bright galaxies at r/rrms~= 3 can be marginally detected in the mock catalogues. The results from the real 2dFGRS data show a clearer detection of a dip in M* and α for r/rrms= 3, consistent with the semi-analytic predictions.

Correlation analysis of radio properties and accretion-disk luminosity for low luminosity AGNs

NASA Astrophysics Data System (ADS)

Su, Renzhi; Liu, Xiang; Zhang, Zhen

2017-01-01

The correlation between the jet power and accretion disk luminosity is investigated and analyzed with our model for 7 samples of low luminosity active galactic nuclei (LLAGNs). The main results are: (1) the power-law correlation index (P_{jet} ∝ L_{disk} ^{μ}) typically ranges μ=0.4-0.7 for the LLAGN samples, and there is a hint of steep index for the LLAGN sample which hosted by a high fraction of elliptical galaxies, and there are no significant correlation between the μ and the LLAGN types (Seyfert, LINER); (2) for μ≈1, as noted in Liu et al., the accretion disk dominates the jet power and the black hole (BH) spin is not important, for the LLAGN samples studied in this paper we find that the μ is significantly less than unity, implying that BH spin may play a significant role in the jet power of LLAGNs; (3) the BH spin-jet power is negatively correlated with the BH mass in our model, which means a high spin-jet efficiency in the `low' BH-mass LLAGNs; (4) an anti-correlation between radio loudness and disk luminosity is found, which is apparently due to the flatter power-law index in the jet-disk correlation of the LLAGNs, and the radio loudness can be higher in the LLAGNs than in luminous AGNs/quasars when the BH spin-jet power is comparable to or dominate over the accretion-jet power in the LLAGNs. The high radio-core dominance of the LLAGNs is also discussed.

Jet and disc luminosities in tidal disruption events

NASA Astrophysics Data System (ADS)

Piran, Tsvi; Sądowski, Aleksander; Tchekhovskoy, Alexander

2015-10-01

Tidal disruption events (TDEs) explore the whole range of accretion rates and configurations. A challenging question is what the corresponding light curves of these events are. We explore numerically the disc luminosity and the conditions within the inner region of the disc using a fully general relativistic slim disc model. Those conditions determine the magnitude of the magnetic field that engulfs the black hole and this, in turn, determines the Blandford-Znajek jet power. We estimate this power in two different ways and show that they are self-consistent. We find, as expected earlier from analytic arguments , that neither the disc luminosity nor the jet power follows the accretion rate throughout the disruption event. The disc luminosity varies only logarithmically with the accretion rate at super-Eddington luminosities. The jet power follows initially the accretion rate but remains constant after the transition from super- to sub-Eddington. At lower accretion rates at the end of the magnetically arrested disc (MAD) phase, the disc becomes thin and the jet may stop altogether. These new estimates of the jet power and disc luminosity that do not simply follow the mass fallback rate should be taken into account when searching for TDEs and analysing light curves of TDE candidates. Identification of some of the above-mentioned transitions may enable us to estimate better TDE parameters.

The luminosity function for the CfA redshift survey slices

NASA Technical Reports Server (NTRS)

De Lapparent, Valerie; Geller, Margaret J.; Huchra, John P.

1989-01-01

The luminosity function for two complete slices of the extension of the CfA redshift survey is calculated. The nonparametric technique of Lynden-Bell (1971) and Turner (1979) is used to determine the shape for the luminosity function of the 12 deg slice of the redshift survey. The amplitude of the luminosity function is determined, taking large-scale inhomogeneities into account. The effects of the Malmquist bias on a magnitude-limited redshift survey are examined, showing that the random errors in the magnitudes for the 12 deg slice affect both the determination of the luminosity function and the spatial density constrast of large scale structures.

Gravitational-Wave Luminosity of Binary Neutron Stars Mergers

NASA Astrophysics Data System (ADS)

Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim

2018-03-01

We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.

Gravitational-Wave Luminosity of Binary Neutron Stars Mergers.

PubMed

Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim

2018-03-16

We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.

Modeling the Redshift Evolution of the Normal Galaxy X-Ray Luminosity Function

NASA Technical Reports Server (NTRS)

Tremmel, M.; Fragos, T.; Lehmer, B. D.; Tzanavaris, P.; Belczynski, K.; Kalogera, V.; Basu-Zych, A. R.; Farr, W. M.; Hornschemeier, A.; Jenkins, L.;

Luminosity function of faint galaxies with ultraviolet continuum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stepanyan, D.A.

1985-05-01

The spatial density of faint galaxies with ultraviolet continuum in the Second Survey of the Byurakan Astrophysical Observatory is determined. The luminosity function of galaxies with ultraviolet continuum can be extended to objects fainter by 1-1.5 magnitudes. The spatial density of such galaxies in the interval of luminosities -16 /sup m/ .5 to -21 /sup m/ .5 is on the average 0.08 of the total density of field galaxies in the same interval of absolute magnitudes. The spatial density of low-luminosity galaxies with ultraviolet continuum is very high. In the interval from -12 /sup m/ .5 to -15 /sup m/more » .5 it is 0.23 Mpc/sup -3/.« less

Evolution of the X-ray luminosity in young HII galaxies

NASA Astrophysics Data System (ADS)

Rosa González, D.; Terlevich, E.; Jiménez Bailón, E.; Terlevich, R.; Ranalli, P.; Comastri, A.; Laird, E.; Nandra, K.

2009-10-01

In an effort to understand the correlation between X-ray emission and present star formation rate, we obtained XMM-Newton data to estimate the X-ray luminosities of a sample of actively star-forming HII galaxies. The obtained X-ray luminosities are compared to other well-known tracers of star formation activity such as the far-infrared and the ultraviolet luminosities. We also compare the obtained results with empirical laws from the literature and with recently published analysis applying synthesis models. We use the time delay between the formation of the stellar cluster and that of the first X-ray binaries, in order to put limits on the age of a given stellar burst. We conclude that the generation of soft X-rays, as well as the Hα or infrared luminosities is instantaneous. The relation between the observed radio and hard X-ray luminosities, on the other hand, points to the existence of a time delay between the formation of the stellar cluster and the explosion of the first massive stars and the consequent formation of supernova (SN) remnants and high-mass X-ray binaries, which originate the radio and hard X-ray fluxes, respectively. When comparing hard X-rays with a star formation indicator that traces the first million years of evolution (e.g. Hα luminosities), we found a deficit in the expected X-ray luminosity. This deficit is not found when the X-ray luminosities are compared with infrared luminosities, a star formation tracer that represents an average over the last 108yr. The results support the hypothesis that hard X-rays are originated in X-ray binaries which, as SN remnants, have a formation time delay of a few mega years after the star-forming burst. Partially based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. E-mail: danrosa@inaoep.mx ‡ Visiting Fellow, IoA, Cambridge, UK.

Populations of High-Luminosity Density-Bounded HII Regions in Spiral Galaxies? Evidence and Implications

NASA Technical Reports Server (NTRS)

Beckman, J. E.; Rozas, M.; Zurita, A.; Watson, R. A.; Knapen, J. H.

2000-01-01

ionize the diffuse medium, but to cause a typical spiral to emit significant ionizing flux into the intergalactic medium. The low scatter observed in Lstr, less than 0.1 mag rms in the still quite small sample measured to date, is an invitation to widen the data base, and to calibrate against primary standards, with the aim of obtaining a precise, approx. 10(exp 5) solar luminosity widely distributed standard candle.

Calibration of GRB Luminosity Relations with Cosmography

NASA Astrophysics Data System (ADS)

Gao, He; Liang, Nan; Zhu, Zong-Hong

For the use of gamma-ray bursts (GRBs) to probe cosmology in a cosmology-independent way, a new method has been proposed to obtain luminosity distances of GRBs by interpolating directly from the Hubble diagram of SNe Ia, and then calibrating GRB relations at high redshift. In this paper, following the basic assumption in the interpolation method that objects at the same redshift should have the same luminosity distance, we propose another approach to calibrate GRB luminosity relations with cosmographic fitting directly from SN Ia data. In cosmography, there is a well-known fitting formula which can reflect the Hubble relation between luminosity distance and redshift with cosmographic parameters which can be fitted from observation data. Using the Cosmographic fitting results from the Union set of SNe Ia, we calibrate five GRB relations using GRB sample at z ≤ 1.4 and deduce distance moduli of GRBs at 1.4 < z ≤ 6.6 by generalizing above calibrated relations at high redshift. Finally, we constrain the dark energy parameterization models of the Chevallier-Polarski-Linder (CPL) model, the Jassal-Bagla-Padmanabhan (JBP) model and the Alam model with GRB data at high redshift, as well as with the cosmic microwave background radiation (CMB) and the baryonic acoustic oscillation (BAO) observations, and we find the ΛCDM model is consistent with the current data in 1-σ confidence region.

Galaxy And Mass Assembly (GAMA): colour- and luminosity-dependent clustering from calibrated photometric redshifts

NASA Astrophysics Data System (ADS)

Christodoulou, L.; Eminian, C.; Loveday, J.; Norberg, P.; Baldry, I. K.; Hurley, P. D.; Driver, S. P.; Bamford, S. P.; Hopkins, A. M.; Liske, J.; Peacock, J. A.; Bland-Hawthorn, J.; Brough, S.; Cameron, E.; Conselice, C. J.; Croom, S. M.; Frenk, C. S.; Gunawardhana, M.; Jones, D. H.; Kelvin, L. S.; Kuijken, K.; Nichol, R. C.; Parkinson, H.; Pimbblet, K. A.; Popescu, C. C.; Prescott, M.; Robotham, A. S. G.; Sharp, R. G.; Sutherland, W. J.; Taylor, E. N.; Thomas, D.; Tuffs, R. J.; van Kampen, E.; Wijesinghe, D.

2012-09-01

We measure the two-point angular correlation function of a sample of 4289 223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey (SDSS) as a function of photometric redshift, absolute magnitude and colour down to Mr - 5 log h = -14 mag. Photometric redshifts are estimated from ugriz model magnitudes and two Petrosian radii using the artificial neural network package ANNz, taking advantage of the Galaxy And Mass Assembly (GAMA) spectroscopic sample as our training set. These photometric redshifts are then used to determine absolute magnitudes and colours. For all our samples, we estimate the underlying redshift and absolute magnitude distributions using Monte Carlo resampling. These redshift distributions are used in Limber's equation to obtain spatial correlation function parameters from power-law fits to the angular correlation function. We confirm an increase in clustering strength for sub-L* red galaxies compared with ˜L* red galaxies at small scales in all redshift bins, whereas for the blue population the correlation length is almost independent of luminosity for ˜L* galaxies and fainter. A linear relation between relative bias and log luminosity is found to hold down to luminosities L ˜ 0.03L*. We find that the redshift dependence of the bias of the L* population can be described by the passive evolution model of Tegmark & Peebles. A visual inspection of a random sample from our r < 19.4 sample of SDSS galaxies reveals that about 10 per cent are spurious, with a higher contamination rate towards very faint absolute magnitudes due to over-deblended nearby galaxies. We correct for this contamination in our clustering analysis.

Perceived area and the luminosity threshold.

PubMed

Bonato, F; Gilchrist, A L

1999-07-01

Observers made forced-choice opaque/luminous responses to targets of varying luminance and varying size presented (1) on the wall of a laboratory, (2) as a disk within an annulus, and (3) embedded within a Mondrian array presented within a vision tunnel. Lightness matches were also made for nearby opaque surfaces. The results show that the threshold luminance value at which a target begins to appear self-luminous increases with its size, defined as perceived size, not retinal size. More generally, the larger the target, the more an increase in its luminance induces grayness/blackness into the surround and the less it induces luminosity into the target, and vice versa. Corresponding to this luminosity/grayness tradeoff, there appears to be an invariant: Across a wide variety of conditions, a target begins to appear luminous when its luminance is about 1.7 times that of a surface that would appear white in the same illumination. These results show that the luminosity threshold behaves like a surface lightness value--the maximum lightness value, in fact--and is subject to the same laws of anchoring (such as the area rule proposed by Li & Gilchrist, 1999) as surface lightness.

X-ray and multiwavelength insights into the inner structure of high-luminosity disc-like emitters

NASA Astrophysics Data System (ADS)

Luo, B.; Brandt, W. N.; Eracleous, M.; Wu, Jian; Hall, P. B.; Rafiee, A.; Schneider, D. P.; Wu, Jianfeng

2013-02-01

We present X-ray and multiwavelength studies of a sample of eight high-luminosity active galactic nuclei (AGN) with disc-like Hβ emission-line profiles selected from the Sloan Digital Sky Survey Data Release 7. These sources have higher redshift (z ≈ 0.6) than the majority of the known disc-like emitters, and they occupy a largely unexplored space in the luminosity-redshift plane. Seven sources have typical AGN X-ray spectra with power-law photon indices of Γ ≈ 1.4-2.0; two of them show some X-ray absorption (column density NH ≈ 1021-1022 cm-2 for neutral gas). The other source, J0850+4451, has only three hard X-ray photons detected and is probably heavily obscured (NH ≳ 3 × 1023 cm-2). This object is also identified as a low-ionization broad absorption line (BAL) quasar based on Mg II λ2799 absorption; it is the first disc-like emitter reported that is also a BAL quasar. The infrared-to-ultraviolet (UV) spectral energy distributions (SEDs) of these eight sources are similar to the mean SEDs of typical quasars with a UV `bump', suggestive of standard accretion discs radiating with high efficiency, which differs from low-luminosity disc-like emitters. Studies of the X-ray-to-optical power-law slope parameters (αOX) indicate that there is no significant excess X-ray emission in these high-luminosity disc-like emitters. Energy budget analysis suggests that for disc-like emitters in general, the inner disc must illuminate and ionize the outer disc efficiently (≈15 per cent of the nuclear ionizing radiation is required on average) via direct illumination and/or scattering. Warped accretion discs are probably needed for direct illumination to work in high-luminosity objects, as their geometrically thin inner discs decrease the amount of direct illumination possible for a flat disc.

Gauge-invariance and infrared divergences in the luminosity distance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biern, Sang Gyu; Yoo, Jaiyul, E-mail: sgbiern@physik.uzh.ch, E-mail: jyoo@physik.uzh.ch

2017-04-01

Measurements of the luminosity distance have played a key role in discovering the late-time cosmic acceleration. However, when accounting for inhomogeneities in the Universe, its interpretation has been plagued with infrared divergences in its theoretical predictions, which are in some cases used to explain the cosmic acceleration without dark energy. The infrared divergences in most calculations are artificially removed by imposing an infrared cut-off scale. We show that a gauge-invariant calculation of the luminosity distance is devoid of such divergences and consistent with the equivalence principle, eliminating the need to impose a cut-off scale. We present proper numerical calculations ofmore » the luminosity distance using the gauge-invariant expression and demonstrate that the numerical results with an ad hoc cut-off scale in previous calculations have negligible systematic errors as long as the cut-off scale is larger than the horizon scale. We discuss the origin of infrared divergences and their cancellation in the luminosity distance.« less

Evolution of the Blue and Far-Infrared Galaxy Luminosity Functions

NASA Technical Reports Server (NTRS)

Lonsdale, Carol J.; Chokshi, Arati

1993-01-01

The space density of blue-selected galaxies at moderate redshifts is determined here directly by deriving the luminosity function. Evidence is found for density evolution for moderate luminosity galaxies at a rate of (1+z) exp delta, with a best fit of delta + 4 +/- 2, between the current epoch and Z greater than about 0.1. At M(b) less than -22 evidence is found for about 0.5-1.5 mag of luminosity evolution in addition to the density evolution, corresponding to an evolutionary rate of about (1+z) exp gamma, with gamma = 0.5-2.5, but a redshift of about 0.4. Assuming a steeper faint end slope of alpha = -1.3 similar to that observed in the Virgo cluster, could explain the data with a luminosity evolution rate of gamma = 1-2, without need for any density evolution. Acceptable fits are found by comparing composite density and luminosity evolution models to faint IRAS 60 micron source counts, implying that the blue and far-IR evolutionary rates may be similar.

The luminosity function of the CfA Redshift Survey

NASA Technical Reports Server (NTRS)

Marzke, R. O.; Huchra, J. P.; Geller, M. J.

1994-01-01

We use the CfA Reshift Survey of galaxies with m(sub z) less than or equal to 15.5 to calculate the galaxy luminosity function over the range -13 less than or equal to M(sub z) less than or equal to -22. The sample includes 9063 galaxies distributed over 2.1 sr. For galaxies with velocities cz greater or equal to 2500 km per sec, where the effects of peculiar velocities are small, the luminosity function is well represented by a Schechter function with parameters phi(sub star) = 0.04 +/- 0.01 per cu Mpc, M(sub star) = -18.8 +/- 0.3, and alpha = -1.0 +/- 0.2. When we include all galaxies with cz greater or equal to 500 km per sec, the number of galaxies in the range -16 less than or equal to M(sub z) less than or equal to -13 exceeds the extrapolation of the Schechter function by a factor of 3.1 +/- 0.5. This faint-end excess is not caused by the local peculiar velocity field but may be partially explained by small scale errors in the Zwicky magnitudes. Even with a scale error as large as 0.2 mag per mag, which is unlikely, the excess is still a factor of 1.8 +/- 0.3. If real, this excess affects the interpretation of deep counts of field galaxies.

A limit to the X-ray luminosity of nearby normal galaxies

NASA Technical Reports Server (NTRS)

Worrall, D. M.; Marshall, F. E.; Boldt, E. A.

1979-01-01

Emission is studied at luminosities lower than those for which individual discrete sources can be studied. It is shown that normal galaxies do not appear to provide the numerous low luminosity X-ray sources which could make up the 2-60 keV diffuse background. Indeed, upper limits suggest luminosities comparable with, or a little less than, that of the galaxy. This is consistent with the fact that the average optical luminosity of the sample galaxies within approximately 20 Mpc is slightly lower than that of the galaxy. An upper limit of approximately 1% of the diffuse background from such sources is derived.

Using luminosity data as a proxy for economic statistics

PubMed Central

Chen, Xi

2011-01-01

A pervasive issue in social and environmental research has been how to improve the quality of socioeconomic data in developing countries. Given the shortcomings of standard sources, the present study examines luminosity (measures of nighttime lights visible from space) as a proxy for standard measures of output (gross domestic product). We compare output and luminosity at the country level and at the 1° latitude × 1° longitude grid-cell level for the period 1992–2008. We find that luminosity has informational value for countries with low-quality statistical systems, particularly for those countries with no recent population or economic censuses. PMID:21576474

Keck Deep Fields. III. Luminosity-dependent Evolution of the Ultraviolet Luminosity and Star Formation Rate Densities at z~4, 3, and 2

NASA Astrophysics Data System (ADS)

Sawicki, Marcin; Thompson, David

2006-09-01

We use our very deep UnGRI catalog of z~4, 3, and 2 UV-selected star-forming galaxies to study the cosmological evolution of the rest-frame 1700 Å luminosity density. The ability to reliably constrain the contribution of faint galaxies is critical here, and our data do so by reaching deep into the galaxy population, to M*LBG+2 at z~4 and deeper still at lower redshifts (M*LBG=-21.0 and L*LBG is the corresponding luminosity). We find that the luminosity density at z>~2 is dominated by the hitherto poorly studied galaxies fainter than L*LBG, and, indeed, the bulk of the UV light at these epochs comes from galaxies in the rather narrow luminosity range L=(0.1-1)L*LBG. Overall, there is a gradual rise in total luminosity density starting at >~4 (we find twice as much UV light at z~3 as at z~4), followed by a shallow peak or plateau within z~3-1, finally followed by the well-known plunge to z~0. Within this total picture, luminosity density in sub-L*LBG galaxies at z>~2 evolves more rapidly than that in more luminous objects; this trend is reversed at lower redshifts, z<~1-a reversal that is reminiscent of galaxy downsizing. We find that within the context of commonly used models there seemingly are not enough faint or bright LBGs to maintain ionization of intergalactic gas even as recently as z~4, and the problem becomes worse at higher redshifts: apparently the universe must be easier to reionize than some recent studies have assumed. Nevertheless, sub-L*LBG galaxies do dominate the total UV luminosity density at z>~2, and this dominance highlights the need for follow-up studies that will teach us more about these very numerous but thus far largely unexplored systems. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA and was made possible by the generous financial support of the W. M. Keck Foundation.

Understanding The Time Evolution Of Luminosity And Associated Accretion Structures In X-Ray Pulsars

NASA Astrophysics Data System (ADS)

Laycock, Silas

We propose to analyze the large archive of RXTE, XMM-Newton and Chandra observations of X-ray Binary Pulsars in the Magellanic Clouds and Milky Way. There are some 2000 individual RXTE PCA pointings on the SMC spanning 15 years, and a smaller number on the LMC. Each PCA observation covers a large fraction of the whole SMC (or LMC) population, and we are able to deconvolve the sometimes simultaneous signals to create an unrivaled record of pulsar temporal behavior. More than 200 XMM- Newton and Chandra observations of the SMC/LMC and individual Galactic pulsars provide information at lower luminosity levels. Together, these datasets cover the entire range of variability timescales and accretion regimes in High Mass X-ray Binaries. We will produce a comprehensive library of energy- resolved pulse profiles covering the entire luminosity and spin-period parameter space, and make this available to the community. We will then model these pulse profiles using state of the art techniques to parameterize the morphology, and publish the resulting data-cube. This result will include for example the distribution of offsets between magnetic and spin axes. These products are needed for the next generation of advances in neutron star theory and modeling. The unique dataset will also enable us to determine the upper and lower limits of accretion powered luminosity in a large statistically complete sample of neutron stars, and hence make several direct tests of fundamental NS parameters and accretion physics. In addition the long-duration of the dataset and "whole-galaxy" nature of the SMC sample make possible a new statistical approach to uncover the duty-cycle distribution and hence population demographics of transient High Mass X-ray Binary (HMXB) populations.

Probing the accretion flow and emission-line regions of M81, the nearest broad-lined low-luminosity AGN

NASA Astrophysics Data System (ADS)

Barth, Aaron

2017-08-01

The nucleus of M81 is an object of singular importance as a template for low-luminosity accretion flows onto supermassive black holes. We propose to obtain a complete, small-aperture, high S/N STIS UV/optical spectrum of the M81 nucleus and multi-filter WFC3 imaging covering the UV through near-IR. Such data have never previously been obtained with HST; the only prior archival UV/optical spectra of M81 have low S/N, incomplete wavelength coverage, and are strongly contaminated by starlight. Combined with new Chandra X-ray data, our proposed observations will comprise the definitive reference dataset on the spectral energy distribution of this benchmark low-luminosity AGN. These data will provide unique new constraints on the possible contribution of a truncated thin accretion disk to the AGN emission spectrum, clarifying a fundamental property of low-luminosity accretion flows. The data will additionally provide new insights into broad-line region structure and black hole mass scaling relationships at the lowest AGN luminosities, and spatially resolved diagnostics of narrow-line region excitation conditions at unprecedented spatial resolution to assess the impact of the AGN on the ionization state of the gas in the host galaxy bulge.

Polycrystalline CdTe detectors: A luminosity monitor for the LHC

NASA Astrophysics Data System (ADS)

Gschwendtner, E.; Placidia, M.; Schmicklera, H.

2003-09-01

The luminosity at the four interaction points of the Large Hadron Collider must be continuously monitored in order to provide an adequate tool for the control and optimization of the collision parameters and the beam optics. At both sides of the interaction points absorbers are installed to protect the super-conducting accelerator elements from quenches caused by the deposited energy of collision products. The luminosity detectors will be installed in the copper core of these absorbers to measure the electromagnetic and hadronic showers caused by neutral particles that are produced at the proton-proton collision in the interaction points. The detectors have to withstand extreme radiation levels (108 Gy/yr at the design luminosity) and their long-term operation has to be assured without requiring human intervention. In addition the demand for bunch-by-bunch luminosity measurements, i.e. 40 MHz detection speed, puts severe constraints on the detectors. Polycrystalline CdTe detectors have a high potential to fulfill the requirements and are considered as LHC luminosity monitors. In this paper the interaction region is shown and the characteristics of the CdTe detectors are presented.

Luminosity-velocity diagrams for Virgo Cluster spirals. I - Inner rotation curves

NASA Technical Reports Server (NTRS)

Woods, David; Fahlman, Gregory G.; Madore, Barry F.

1990-01-01

Optical rotation curves are presented for the innermost portions of nine spiral galaxies in the Virgo Cluster. The emission-line (H-alpha and forbidden N II) velocity data are to be used in combination with new CCD photometry to construct luminosity-velocity diagrams, in a continuing investigation of an apparent initial linear branch and its potential as a distance indicator. Compared to recent H I data, the present optical rotation curves generally show systematically steeper inner gradients. This effect is ascribed to the poorer resolution of the H I data and/or to holes in the gas distribution.

Detector Developments for the High Luminosity LHC Era (1/4)

ScienceCinema

Straessner, Arno

2018-04-27

Calorimetry and Muon Spectrometers - Part I : In the first part of the lecture series, the motivation for a high luminosity upgrade of the LHC will be quickly reviewed together with the challenges for the LHC detectors. In particular, the plans and ongoing research for new calorimeter detectors will be explained. The main issues in the high-luminosity era are an improved radiation tolerance, natural ageing of detector components and challenging trigger and physics requirements. The new technological solutions for calorimetry at a high-luminosity LHC will be reviewed.

Luminosity and Stellar Mass Functions from the 6dF Galaxy Survey

NASA Astrophysics Data System (ADS)

Colless, M.; Jones, D. H.; Peterson, B. A.; Campbell, L.; Saunders, W.; Lah, P.

2007-12-01

The completed 6dF Galaxy Survey includes redshifts for over 124,000 galaxies. We present luminosity functions in optical and near-infrared passbands that span a range of 10^4 in luminosity. These luminosity functions show systematic deviations from the Schechter form. The corresponding luminosity densities in the optical and near-infrared are consistent with an old stellar population and a moderately declining star formation rate. Stellar mass functions, derived from the K band luminosities and simple stellar population models selected by b_J-r_F colour, lead to an estimate of the present-day stellar mass density of ρ_* = (5.00 ± 0.11) × 10^8 h M_⊙ Mpc^{-3}, corresponding to Ω_* h = (1.80 ± 0.04) × 10^{-3}.

The X-ray luminosity functions of Abell clusters from the Einstein Cluster Survey

NASA Technical Reports Server (NTRS)

Burg, R.; Giacconi, R.; Forman, W.; Jones, C.

1994-01-01

We have derived the present epoch X-ray luminosity function of northern Abell clusters using luminosities from the Einstein Cluster Survey. The sample is sufficiently large that we can determine the luminosity function for each richness class separately with sufficient precision to study and compare the different luminosity functions. We find that, within each richness class, the range of X-ray luminosity is quite large and spans nearly a factor of 25. Characterizing the luminosity function for each richness class with a Schechter function, we find that the characteristic X-ray luminosity, L(sub *), scales with richness class as (L(sub *) varies as N(sub*)(exp gamma), where N(sub *) is the corrected, mean number of galaxies in a richness class, and the best-fitting exponent is gamma = 1.3 +/- 0.4. Finally, our analysis suggests that there is a lower limit to the X-ray luminosity of clusters which is determined by the integrated emission of the cluster member galaxies, and this also scales with richness class. The present sample forms a baseline for testing cosmological evolution of Abell-like clusters when an appropriate high-redshift cluster sample becomes available.

Fossil group origins. III. The relation between optical and X-ray luminosities

NASA Astrophysics Data System (ADS)

Girardi, M.; Aguerri, J. A. L.; De Grandi, S.; D'Onghia, E.; Barrena, R.; Boschin, W.; Méndez-Abreu, J.; Sánchez-Janssen, R.; Zarattini, S.; Biviano, A.; Castro-Rodriguez, N.; Corsini, E. M.; del Burgo, C.; Iglesias-Páramo, J.; Vilchez, J. M.

2014-05-01

Aims: This study is part of the Fossil group origins (FOGO) project which aims to carry out a systematic and multiwavelength study of a large sample of fossil systems. Here we focus on the relation between the optical luminosity (Lopt) and X-ray luminosity (LX). Methods: Out of a total sample of 28 candidate fossil systems, we consider a sample of 12 systems whose fossil classification has been confirmed by a companion study. They are compared with the complementary sample of 16 systems whose fossil nature has not been confirmed and with a subsample of 102 galaxy systems from the RASS-SDSS galaxy cluster survey. Fossil and normal systems span the same redshift range 0 distribution. For each fossil system, the LX in the 0.1-2.4 keV band is computed using data from the ROSAT All Sky Survey to be comparable to the estimates of the comparison sample. For each fossil and normal system we homogeneously compute Lopt in the r-band within the characteristic cluster radius, using data from the Sloan Digital Sky Survey Data Release 7. Results: We sample the LX-Lopt relation over two orders of magnitude in LX. Our analysis shows that fossil systems are not statistically distinguishable from the normal systems through the 2D Kolmogorov-Smirnov test nor the fit of the LX-Lopt relation. Thus, the optical luminosity of the galaxy system does strongly correlate with the X-ray luminosity of the hot gas component, independently of whether the system is fossil or not. We discuss our results in comparison with previous literature. Conclusions: We conclude that our results are consistent with the classical merging scenario of the brightest galaxy formed via merger/cannibalism of other group galaxies with conservation of the optical light. We find no evidence for a peculiar state of the hot intracluster medium. Tables 1 and 2 are available in electronic form at http://www.aanda.org

Luminosity Classes of M-Stars in the SAO Catalogue

NASA Astrophysics Data System (ADS)

Robertson, T. H.

1986-08-01

A list of potential M dwarf stars was compiled from a magnetic-tape version of the Smithsonian Astrophysical Observatory star catalogue (SAO) (Smithsonian Astrophysical Observatory 1966) using an assumed thickness of 600 pc for the galactic plane as suggested by Nunez and Figueras (1983). Calculations of the number of M stars brighter than various limiting magnitudes based on known luminosity functions of dwarf and giant M stars show that the vast majority of sample stars are probably M giant stars rather than M dwarf stars having low transverse velocities. Analyses of the distribution in galactic longitude and latitude as well as the kinematic properties of this sample and of data from other published sources supporting this conclusion are also presented.

Measurement of the integrated Luminosities of cross-section scan data samples around the $${\\rm{\\psi }}$$(3770) mass region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ablikim, M.; Achasov, M. N.; Ahmed, S.

To investigate the nature of the (3770) resonance and to measure the cross section for e +e -→Dmore » $$\\bar{D}$$, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16±0.04±0.61 pb -1, where the first uncertainty is statistical and the second systematic.« less

Measurement of the integrated Luminosities of cross-section scan data samples around the $${\\rm{\\psi }}$$(3770) mass region

DOE PAGES

Ablikim, M.; Achasov, M. N.; Ahmed, S.; ...

2018-05-01

To investigate the nature of the (3770) resonance and to measure the cross section for e +e -→Dmore » $$\\bar{D}$$, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16±0.04±0.61 pb -1, where the first uncertainty is statistical and the second systematic.« less

Mass-Luminosity Relations for Rapid and Slow Rotators.

NASA Astrophysics Data System (ADS)

Malkov, O. Yu.

2006-08-01

Comparing the radii of eclipsing binaries components and single stars we have found a noticeable difference between observational parameters of B0V-G0V components of eclipsing binaries and those of single stars of the corresponding spectral type. This difference was confirmed by re-analysing the results of independent investigations published in the literature. Larger radii and higher temperatures of A-F eclipsing binaries can be explained by synchronization of such stars in close systems that prevents them to rotate rapidly. So, we have found that the mass-luminosity relation based on eclipsing binary data cannot be used to derive the initial mass function of single stars. While our current knowledge of the empirical mass-luminosity relation for intermediate-mass (1.5 to 10 m[*]) stars is based exclusively on data from eclipsing binaries, knowledge of the mass-luminosity relation should come from dynamical mass determinations of visual binaries, combined with spatially resolved precise photometry. Then the initial mass function should be revised for m>1.5m[*]. Data were collected on fundamental parameters of stars with masses m > 1.5.m [*]). They are components of binaries with P > 15^d and consequently are not synchronised with the orbital periods and presumably are rapid rotators. These stars are believed to evolve similarly with single stars, so these data allow us to construct mass-luminosity and other relations that can more confidently be used for statistical and astrophysical investigations of single stars than so called standard relations, based on data on detached main-sequence double-lined short-period eclipsing binaries. Mass-luminosity, mass-temperature and mass-radius relations of single stars are presented, as well as their HR diagram.

Regulation of the X-ray luminosity of clusters of galaxies by cooling and supernova feedback.

PubMed

Voit, G M; Bryan, G L

2001-11-22

Clusters of galaxies are thought to contain about ten times as much dark matter as baryonic matter. The dark component therefore dominates the gravitational potential of a cluster, and the baryons confined by this potential radiate X-rays with a luminosity that depends mainly on the gas density in the cluster's core. Predictions of the X-rays' properties based on models of cluster formation do not, however, agree with the observations. If the models ignore the condensation of cooling gas into stars and feedback from the associated supernovae, they overestimate the X-ray luminosity because the density of the core gas is too high. An early episode of uniformly distributed supernova feedback could rectify this by heating the uncondensed gas and therefore making it harder to compress into the core, but such a process seems to require an implausibly large number of supernovae. Here we show how radiative cooling of intergalactic gas and subsequent supernova heating conspire to eliminate highly compressible low-entropy gas from the intracluster medium. This brings the core entropy and X-ray luminosities of clusters into agreement with the observations, in a way that depends little on the efficiency of supernova heating in the early Universe.

A Multiwavelength Study of a Sample of 70 μm Selected Galaxies in the COSMOS Field. I. Spectral Energy Distributions and Luminosities

NASA Astrophysics Data System (ADS)

Kartaltepe, Jeyhan S.; Sanders, D. B.; Le Floc'h, E.; Frayer, D. T.; Aussel, H.; Arnouts, S.; Ilbert, O.; Salvato, M.; Scoville, N. Z.; Surace, J.; Yan, L.; Brusa, M.; Capak, P.; Caputi, K.; Carollo, C. M.; Civano, F.; Elvis, M.; Faure, C.; Hasinger, G.; Koekemoer, A. M.; Lee, N.; Lilly, S.; Liu, C. T.; McCracken, H. J.; Schinnerer, E.; Smolčić, V.; Taniguchi, Y.; Thompson, D. J.; Trump, J.

2010-02-01

We present a large robust sample of 1503 reliable and unconfused 70 μm selected sources from the multiwavelength data set of the Cosmic Evolution Survey. Using the Spitzer IRAC and MIPS photometry, we estimate the total infrared (IR) luminosity, L IR (8-1000 μm), by finding the best-fit template from several different template libraries. The long-wavelength 70 and 160 μm data allow us to obtain a reliable estimate of L IR, accurate to within 0.2 and 0.05 dex, respectively. The 70 μm data point enables a significant improvement over the luminosity estimates possible with only a 24 μm detection. The full sample spans a wide range in IR luminosity, L IR ≈ 108-1014 L sun, with a median luminosity of 1011.4 L sun. We identify a total of 687 luminous, 303 ultraluminous, and 31 hyperluminous infrared galaxies (LIRGs, ULIRGs, and HyLIRGs) over the redshift range 0.01 < z < 3.5 with a median redshift of 0.5. Presented here are the full spectral energy distributions (SEDs) for each of the sources compiled from the extensive multiwavelength data set from the ultraviolet (UV) to the far-infrared. A catalog of the general properties of the sample (including the photometry, redshifts, and L IR) is included with this paper. We find that the overall shape of the SED and trends with L IR (e.g., IR color temperatures and optical-IR ratios) are similar to what has been seen in studies of local objects; however, our large sample allows us to see the extreme spread in UV to near-infrared colors spanning nearly 3 orders of magnitude. In addition, using SED fits we find possible evidence for a subset of cooler ultraluminous objects than observed locally. However, until direct observations at longer wavelengths are obtained, the peak of emission and the dust temperature cannot be well constrained. We use these SEDs, along with the deep radio and X-ray coverage of the field, to identify a large sample of candidate active galactic nuclei (AGNs). We find that the fraction of AGNs

Type II supernovae in low luminosity host galaxies

NASA Astrophysics Data System (ADS)

Gutiérrez, C. P.; Anderson, J. P.; Sullivan, M.; Dessart, L.; González-Gaitan, S.; Galbany, L.; Dimitriadis, G.; Arcavi, I.; Bufano, F.; Chen, T.-W.; Dennefeld, M.; Gromadzki, M.; Haislip, J. B.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Kankare, E.; Leloudas, G.; Maguire, K.; McCully, C.; Morrell, N.; E, F. Olivares; Pignata, G.; Reichart, D. E.; Reynolds, T.; Smartt, S. J.; Sollerman, J.; Taddia, F.; Takáts, K.; Terreran, G.; Valenti, S.; Young, D. R.

2018-06-01

We present an analysis of a new sample of type II core-collapse supernovae (SNe II) occurring within low-luminosity galaxies, comparing these with a sample of events in brighter hosts. Our analysis is performed comparing SN II spectral and photometric parameters and estimating the influence of metallicity (inferred from host luminosity differences) on SN II transient properties. We measure the SN absolute magnitude at maximum, the light-curve plateau duration, the optically thick duration, and the plateau decline rate in the V -band, together with expansion velocities and pseudo-equivalent-widths (pEWs) of several absorption lines in the SN spectra. For the SN host galaxies, we estimate the absolute magnitude and the stellar mass, a proxy for the metallicity of the host galaxy. SNe II exploding in low luminosity galaxies display weaker pEWs of Fe II λ5018, confirming the theoretical prediction that metal lines in SN II spectra should correlate with metallicity. We also find that SNe II in low-luminosity hosts have generally slower declining light curves and display weaker absorption lines. We find no relationship between the plateau duration or the expansion velocities with SN environment, suggesting that the hydrogen envelope mass and the explosion energy are not correlated with the metallicity of the host galaxy. This result supports recent predictions that mass-loss for red supergiants is independent of metallicity.

Introductory Overview of Intermediate-luminosity X-ray Objects

NASA Astrophysics Data System (ADS)

Colbert, E. J. M.

2001-05-01

Intermediate-luminosity X-ray Objects (IXOs) are defined as compact objects having X-ray luminosities between those of X-ray binaries and low-luminosity AGNs (i.e., 1039.0 erg s-1 < ~ LX [IXOs] < ~ 1041.0 erg s-1). It is not currently known if these objects are intermediate-mass (M ~ 102-104 Msun) black holes accreting near the Eddington limit, near-solar-mass black holes in a super-Eddington state, or are, in some cases, just supermassive black holes accreting at very low rates. However, the first idea has been popularized by recent press coverage. IXOs are quite common (present in about half of spiral galaxies) and are typically found displaced from the optical nucleus, reducing the likelihood that they are low-luminosity AGN. Nearly all of our knowledge of these objects comes from X-ray observations, as observations of optical, NIR and radio counterparts are not widely known. In this session, we will address (1) the phenomenology of the objects, (2) possible geometry and accretion mechanisms for these objects (i.e., are they more similar to black hole X-ray binaries or AGNs), (3) the central black hole masses, and (4) the formation mechanism for these black holes, if they are of intermediate mass. In this talk, I will focus primarily on giving background information of these fascinating objects.

Galex Lyman-alpha Emitters: Physical Properties, Luminosity Bimodality, And Morphologies.

NASA Astrophysics Data System (ADS)

Mallery, Ryan P.

2010-01-01

The Galaxy Evolution Explorer spectroscopic survey has uncovered a large statistically significant sample of Lyman-alpha emitters at z sim0.3. ACS imaging of these sources in the COSMOS and AEGIS deep fields reveals that these Lyman-alpha emitters consist of two distinct galaxy morphologies, face on spiral galaxies and compact starburst/merging systems. The morphology bimodality also results in a bimodal distribution of optical luminosity. A comparison between the UV photometry and MIPS 24 micron detections of these sources indicates that they are bluer, and have less dust extinction than similar star forming galaxies that lack Lyman-alpha detection. Our findings show how the global gas and dust distribution of star forming galaxies inhibits Lyman-alpha emission in star forming galaxies. GALEX is a NASA Small Explorer, launched in April 2003. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the CNES of France and the Korean Ministry of Science and Technology.

The x-ray luminosity-redshift relationship of quasars

PubMed Central

Segal, I. E.; Segal, W.

1980-01-01

Chronometric cosmology provides an excellent fit for the phenomenological x-ray luminosity-redshift relationship for 49 quasars observed by the Einstein satellite. Analysis of the data on the basis of the Friedmann cosmology leads to a correlation of absolute x-ray luminosity with redshift of >0.8, which is increased to ∼1 in the bright envelope. Although the trend might be ascribed a priori to an observational magnitude bias, it persists after nonparametric, maximum-likelihood removal of this bias. PMID:16592826

OH megamasers in high-luminosity IRAS galaxies

NASA Technical Reports Server (NTRS)

Mirabel, I. F.; Sanders, D. B.

1987-01-01

OH megamaser emission and H I and CO profiles from the distant infrared galaxies IRAS 10173 + 0828, III Zw 035, and Zw 475.056 are reported. The OH isotropic luminosities at 1667 MHz are 463, 534, and 6.6 solar luminosities, respectively. Far-infrared pumping efficiencies of the OH greater than 1 percent are found in IRAS 10173 + 0828 and III Zw 035. These two galaxies show anomalously large 1667/1665 MHz emission line ratios. OH megamasers reside in the nuclei of superluminous far-infrared galaxies that have a high content of molecular gas, high efficiency of star formation, and in some instances, a striking deficiency of atomic hydrogen.

A Significantly off-center 56Ni Distribution for the Low-Luminosity Type Ia Supernova SN 2016brx from the 100IAS survey

NASA Astrophysics Data System (ADS)

Dong, Subo; Katz, Boaz; Kollmeier, Juna A.; Kushnir, Doron; Elias-Rosa, N.; Bose, Subhash; Morrell, Nidia; Prieto, J. L.; Chen, Ping; Kochanek, C. S.; Brandt, G. M.; Holoien, T. W.-S.; Gal-Yam, Avishay; Morales-Garoffolo, Antonia; Parker, Stuart; Phillips, M. M.; Piro, Anthony L.; Shappee, B. J.; Simon, Joshua D.; Stanek, K. Z.

2018-06-01

We present nebular-phase spectra of the Type Ia supernova (SN Ia) 2016brx, a member of the 1991bg-like subclass that lies at the faint end of the SN Ia luminosity function. Nebular spectra are available for only three other 1991bg-like SNe, and their Co line centers are all within ≲ 500 km/s of each other. In contrast, the nebular Co line center of SN 2016brx is blue-shifted by >1500 km/s compared to them and by ≈1200 km/s compared to the rest frame. This is a significant shift relative to the narrow nebular line velocity dispersion of ≲ 2000 km/s of these SNe. The large range of nebular line shifts implies that the 56Ni in the ejecta of SN 1991bg-like events is off-center by ˜1000 km/s rather than universally centrally confined as previously suggested. With the addition of SN 2016brx, the Co nebular line shapes of 1991bg-like objects appear to connect with the brighter SNe Ia that show double-peaked profiles, hinting at a continuous distribution of line profiles among SNe Ia. One class of models to produce both off-center and bi-modal 56Ni distributions is collisions of white dwarfs with unequal and equal masses.

LFsGRB: Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-04-01

LFsGRB models the luminosity function (LF) of short Gamma Ray Bursts (sGRBs) by using the available catalog data of all short GRBs (sGRBs) detected till 2017 October, estimating the luminosities via pseudo-redshifts obtained from the Yonetoku correlation, and then assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. The data are fit well both by exponential cutoff powerlaw and broken powerlaw models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of short GRBs is derived. Assuming a short GRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present and future configurations of the GW detector networks.

Bias Properties of Extragalactic Distance Indicators. VIII. H0 from Distance-limited Luminosity Class and Morphological Type-Specific Luminosity Functions for SB, SBC, and SC Galaxies Calibrated Using Cepheids

NASA Astrophysics Data System (ADS)

Sandage, Allan

1999-12-01

Relative, reduced to absolute, magnitude distributions are obtained for Sb, Sbc, and Sc galaxies in the flux-limited Revised Shapley-Ames Catalog (RSA2) for each van den Bergh luminosity class (L), within each Hubble type (T). The method to isolate bias-free subsets of the total sample is via Spaenhauer diagrams, as in previous papers of this series. The distance-limited type and class-specific luminosity functions are normalized to numbers of galaxies per unit volume (105 Mpc3), rather than being left as relative functions, as in Paper V. The functions are calculated using kinematic absolute magnitudes, based on an arbitrary trial value of H0=50. Gaussian fits to the individual normalized functions are listed for each T and L subclass. As in Paper V, the data can be freed from the T and L dependencies by applying a correction of 0.23T+0.5L to the individual absolute magnitudes. Here, T=3 for Sb, 4 for Sbc, and 5 for Sc galaxies, and the L values range from 1 to 6 as the luminosity class changes from I to III-IV. The total luminosity function, obtained by combining the volume-normalized Sb, Sbc, and Sc individual luminosity functions, each corrected for the T and L dependencies, has an rms dispersion of 0.67 mag, similar to much of the Tully-Fisher parameter space. Absolute calibration of the trial kinematic absolute magnitudes is made using 27 galaxies with known T and L that also have Cepheid distances. This permits the systematic correction to the H0=50 kinematic absolute magnitudes of 0.22+/-0.12 mag, givingH0=55+/-3(internal) km s-1 Mpc-1 . The Cepheid distances are based on the Madore/Freedman Cepheid period-luminosity (PL) zero point that requires (m-M)0=18.50 for the LMC. Using the modern LMC modulus of (m-M)0=18.58 requires a 4% decrease in H0, giving a final value of H0=53+/-7 (external) by this method. These values of H0, based here on the method of luminosity functions, are in good agreement with (1) H0=55+/-5 by Theureau and coworkers from their bias

X-ray constraints on the fraction of obscured active galactic nuclei at high accretion luminosities

NASA Astrophysics Data System (ADS)

Georgakakis, A.; Salvato, M.; Liu, Z.; Buchner, J.; Brandt, W. N.; Ananna, T. Tasnim; Schulze, A.; Shen, Yue; LaMassa, S.; Nandra, K.; Merloni, A.; McGreer, I. D.

2017-08-01

The wide-area XMM-XXL X-ray survey is used to explore the fraction of obscured active galactic nuclei (AGNs) at high accretion luminosities, LX(2-10 keV) ≳ 1044 erg s - 1, and out to redshift z ≈ 1.5. The sample covers an area of about 14 deg2 and provides constraints on the space density of powerful AGNs over a wide range of neutral hydrogen column densities extending beyond the Compton-thick limit, NH ≈ 1024 cm - 2. The fraction of obscured Compton-thin (NH = 1022-1024 cm - 2) AGNs is estimated to be ≈0.35 for luminosities LX(2-10 keV) > 1044 erg s - 1, independent of redshift. For less luminous sources, the fraction of obscured Compton-thin AGNs increases from 0.45 ± 0.10 at z = 0.25 to 0.75 ± 0.05 at z = 1.25. Studies that select AGNs in the infrared via template fits to the observed spectral energy distribution of extragalactic sources estimate space densities at high accretion luminosities consistent with the XMM-XXL constraints. There is no evidence for a large population of AGNs (e.g. heavily obscured) identified in the infrared and missed at X-ray wavelengths. We further explore the mid-infrared colours of XMM-XXL AGNs as a function of accretion luminosity, column density and redshift. The fraction of XMM-XXL sources that lie within the mid-infrared colour wedges defined in the literature to select AGNs is primarily a function of redshift. This fraction increases from about 20-30 per cent at z = 0.25 to about 50-70 per cent at z = 1.5.

The Next Generation Virgo Cluster Survey. VII. The Intrinsic Shapes of Low-luminosity Galaxies in the Core of the Virgo Cluster, and a Comparison with the Local Group

NASA Astrophysics Data System (ADS)

Sánchez-Janssen, Rubén; Ferrarese, Laura; MacArthur, Lauren A.; Côté, Patrick; Blakeslee, John P.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; McConnacchie, Alan W.; Boselli, Alessandro; Courteau, Stéphane; Emsellem, Eric; Mei, Simona; Peng, Eric; Puzia, Thomas H.; Roediger, Joel; Simard, Luc; Boyer, Fred; Santos, Matthew

2016-03-01

We investigate the intrinsic shapes of low-luminosity galaxies in the central 300 kpc of the Virgo Cluster using deep imaging obtained as part of the Next Generation Virgo Cluster Survey (NGVS). We build a sample of nearly 300 red-sequence cluster members in the yet-unexplored -14 < Mg < -8 mag range, and we measure their apparent axis ratios, q, through Sérsic fits to their two-dimensional light distribution, which is well described by a constant ellipticity parameter. The resulting distribution of apparent axis ratios is then fit by families of triaxial models with normally distributed intrinsic ellipticities, E = 1 - C/A, and triaxialities, T = (A2 - B2)/(A2 - C2). We develop a Bayesian framework to explore the posterior distribution of the model parameters, which allows us to work directly on discrete data, and to account for individual, surface-brightness-dependent axis ratio uncertainties. For this population we infer a mean intrinsic ellipticity \\bar{E} = {0.43}-0.02+0.02 and a mean triaxiality \\bar{T} = {0.16}-0.06+0.07. This implies that faint Virgo galaxies are best described as a family of thick, nearly oblate spheroids with mean intrinsic axis ratios 1:0.94:0.57. The core of Virgo lacks highly elongated low-luminosity galaxies, with 95% of the population having q > 0.45. We additionally attempt a study of the intrinsic shapes of Local Group (LG) satellites of similar luminosities. For the LG population we infer a slightly larger mean intrinsic ellipticity \\bar{E} = {0.51}-0.06+0.07, and the paucity of objects with round apparent shapes translates into more triaxial mean shapes, 1:0.76:0.49. Numerical studies that follow the tidal evolution of satellites within LG-sized halos are in good agreement with the inferred shape distributions, but the mismatch for faint galaxies in Virgo highlights the need for more adequate simulations of this population in the cluster environment. We finally compare the intrinsic shapes of NGVS low-mass galaxies with

Solar luminosity variations and the climate of Mars

NASA Technical Reports Server (NTRS)

Toon, O. B.; Gierasch, P. J.; Sagan, C.

1975-01-01

A simple climatological model of Mars indicates that its climate may be more sensitive to luminosity changes than earth's because of strong positive feedback mechanisms at work on Mars. Mariner 9 photographs of Mars show an abundance of large sinuous channels that point to an epoch of higher atmospheric pressures and abundant liquid water. Such an epoch could have been the result of large-scale solar luminosity variations. The climatological model suggests that other less controversial mechanisms, such as obliquity or polar albedo changes, also could have led to such an epoch.

Integral-moment analysis of the BATSE gamma-ray burst intensity distribution

NASA Technical Reports Server (NTRS)

Horack, John M.; Emslie, A. Gordon

1994-01-01

We have applied the technique of integral-moment analysis to the intensity distribution of the first 260 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. This technique provides direct measurement of properties such as the mean, variance, and skewness of the convolved luminosity-number density distribution, as well as associated uncertainties. Using this method, one obtains insight into the nature of the source distributions unavailable through computation of traditional single parameters such as V/V(sub max)). If the luminosity function of the gamma-ray bursts is strongly peaked, giving bursts only a narrow range of luminosities, these results are then direct probes of the radial distribution of sources, regardless of whether the bursts are a local phenomenon, are distributed in a galactic halo, or are at cosmological distances. Accordingly, an integral-moment analysis of the intensity distribution of the gamma-ray bursts provides for the most complete analytic description of the source distribution available from the data, and offers the most comprehensive test of the compatibility of a given hypothesized distribution with observation.

Galaxy and Mass Assembly (GAMA): ugriz galaxy luminosity functions

NASA Astrophysics Data System (ADS)

Loveday, J.; Norberg, P.; Baldry, I. K.; Driver, S. P.; Hopkins, A. M.; Peacock, J. A.; Bamford, S. P.; Liske, J.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cameron, E.; Conselice, C. J.; Croom, S. M.; Frenk, C. S.; Gunawardhana, M.; Hill, D. T.; Jones, D. H.; Kelvin, L. S.; Kuijken, K.; Nichol, R. C.; Parkinson, H. R.; Phillipps, S.; Pimbblet, K. A.; Popescu, C. C.; Prescott, M.; Robotham, A. S. G.; Sharp, R. G.; Sutherland, W. J.; Taylor, E. N.; Thomas, D.; Tuffs, R. J.; van Kampen, E.; Wijesinghe, D.

2012-02-01

Galaxy and Mass Assembly (GAMA) is a project to study galaxy formation and evolution, combining imaging data from ultraviolet to radio with spectroscopic data from the AAOmega spectrograph on the Anglo-Australian Telescope. Using data from Phase 1 of GAMA, taken over three observing seasons, and correcting for various minor sources of incompleteness, we calculate galaxy luminosity functions (LFs) and their evolution in the ugriz passbands. At low redshift, z < 0.1, we find that blue galaxies, defined according to a magnitude-dependent but non-evolving colour cut, are reasonably well fitted over a range of more than 10 magnitudes by simple Schechter functions in all bands. Red galaxies, and the combined blue plus red sample, require double power-law Schechter functions to fit a dip in their LF faintwards of the characteristic magnitude M* before a steepening faint end. This upturn is at least partly due to dust-reddened disc galaxies. We measure the evolution of the galaxy LF over the redshift range 0.002 < z < 0.5 both by using a parametric fit and by measuring binned LFs in redshift slices. The characteristic luminosity L* is found to increase with redshift in all bands, with red galaxies showing stronger luminosity evolution than blue galaxies. The comoving number density of blue galaxies increases with redshift, while that of red galaxies decreases, consistent with prevailing movement from blue cloud to red sequence. As well as being more numerous at higher redshift, blue galaxies also dominate the overall luminosity density beyond redshifts z≃ 0.2. At lower redshifts, the luminosity density is dominated by red galaxies in the riz bands, and by blue galaxies in u and g.

Galaxy luminosity function and Tully-Fisher relation: reconciled through rotation-curve studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cattaneo, Andrea; Salucci, Paolo; Papastergis, Emmanouil, E-mail: andrea.cattaneo@oamp.fr, E-mail: salucci@sissa.it, E-mail: papastergis@astro.cornell.edu

2014-03-10

The relation between galaxy luminosity L and halo virial velocity v {sub vir} required to fit the galaxy luminosity function differs from the observed Tully-Fisher relation between L and disk speed v {sub rot}. Because of this, the problem of reproducing the galaxy luminosity function and the Tully-Fisher relation simultaneously has plagued semianalytic models since their inception. Here we study the relation between v {sub rot} and v {sub vir} by fitting observational average rotation curves of disk galaxies binned in luminosity. We show that the v {sub rot}-v {sub vir} relation that we obtain in this way can fullymore » account for this seeming inconsistency. Therefore, the reconciliation of the luminosity function with the Tully-Fisher relation rests on the complex dependence of v {sub rot} on v {sub vir}, which arises because the ratio of stellar mass to dark matter mass is a strong function of halo mass.« less

On the Existence of Low-Luminosity Cataclysmic Variables Beyond the Orbital Period Minimum

NASA Technical Reports Server (NTRS)

Howell, Steve B.; Rappaport, Saul; Politano, Michael

1997-01-01

Models of the present-day intrinsic population of cataclysmic variables predict that 99 per cent of these systems should be of short orbital period. The Galaxy is old enough that approx. 70 per cent of these stars will have already reached their orbital period minimum (approx. 80 min), and should be evolving back toward longer periods. Mass-transfer rates in these highly evolved binaries are predicted to be less or equal to 10(exp -11), leading to M(sub V) of approx. 10 or fainter, and the secondaries would be degenerate, brown dwarf-like stars. Recent observations of a group of low-luminosity dwarf novae (TOADS) provide observational evidence for systems with very low intrinsic M,. and possibly low-mass secondaries. We carry out population synthesis and evolution calculations for a range of assumed ages of the Galaxy in order to study P(sub orb) and M distributions for comparison with the TOAD observations. We speculate that at least some of the TOADs are the predicted very low- luminosity, post-period-minimum cataclysmic variables containing degenerate (brown dwarf-like) secondaries having masses between 0.02 and 0.06 M, and radii near 0.1 R., We show that these low-luminosity systems are additionally interesting in that they can be used to set a lower limit on the age of the Galaxy. The TOAD with the longest orbital period currently known (123 min), corresponds to a Galaxy age of at least 8.6 x 10(exp 9) yr.

Modelling the luminosity function of long gamma-ray bursts using Swift and Fermi

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-01-01

I have used a sample of long gamma-ray bursts (GRBs) common to both Swift and Fermi to re-derive the parameters of the Yonetoku correlation. This allowed me to self-consistently estimate pseudo-redshifts of all the bursts with unknown redshifts. This is the first time such a large sample of GRBs from these two instruments is used, both individually and in conjunction, to model the long GRB luminosity function. The GRB formation rate is modelled as the product of the cosmic star formation rate and a GRB formation efficiency for a given stellar mass. An exponential cut-off power-law luminosity function fits the data reasonably well, with ν = 0.6 and Lb = 5.4 × 1052 ergs- 1, and does not require a cosmological evolution. In the case of a broken power law, it is required to incorporate a sharp evolution of the break given by Lb ∼ 0.3 × 1052(1 + z)2.90 erg s- 1, and the GRB formation efficiency (degenerate up to a beaming factor of GRBs) decreases with redshift as ∝ (1 + z)-0.80. However, it is not possible to distinguish between the two models. The derived models are then used as templates to predict the distribution of GRBs detectable by CZT Imager onboard AstroSat as a function of redshift and luminosity. This demonstrates that via a quick localization and redshift measurement of even a few CZT Imager GRBs, AstroSat will help in improving the statistics of GRBs both typical and peculiar.

Extragalactic High-energy Transients: Event Rate Densities and Luminosity Functions

NASA Astrophysics Data System (ADS)

Sun, Hui; Zhang, Bing; Li, Zhuo

2015-10-01

Several types of extragalactic high-energy transients have been discovered, which include high-luminosity and low-luminosity long-duration gamma-ray bursts (GRBs), short-duration GRBs, supernova shock breakouts (SBOs), and tidal disruption events (TDEs) without or with an associated relativistic jet. In this paper, we apply a unified method to systematically study the redshift-dependent event rate densities and the global luminosity functions (GLFs; ignoring redshift evolution) of these transients. We introduce some empirical formulae for the redshift-dependent event rate densities for different types of transients and derive the local specific event rate density, which also represents its GLF. Long GRBs (LGRBs) have a large enough sample to reveal features in the GLF, which is best charaterized as a triple power law (PL). All the other transients are consistent with having a single-power-law (SPL) LF. The total event rate density depends on the minimum luminosity, and we obtain the following values in units of Gpc-3 yr-1: {0.8}-0.1+0.1 for high-luminosity LGRBs above 1050 erg s-1 {164}-65+98 for low-luminosity LGRBs above 5 × 1046 erg s-1 {1.3}-0.3+0.4, {1.2}-0.3+0.4, and {3.3}-0.8+1.0 above 1050 erg s-1 for short GRBs with three different merger delay models (Gaussian, lognormal, and PL); {1.9}-1.2+2.4× {10}4 above 1044 erg s-1 for SBOs, {4.8}-2.1+3.2× {10}2 for normal TDEs above 1044 erg s-1 and {0.03}-0.02+0.04 above 1048 erg s-1 for TDE jets as discovered by Swift. Intriguingly, the GLFs of different kinds of transients, which cover over 12 orders of magnitude, are consistent with an SPL with an index of -1.6.

Accretion Disk and Dust Emission in Low-Luminosity AGN

NASA Astrophysics Data System (ADS)

Biddle, Lauren I.; Mason, Rachel; Alonso-Herrero, Almudena; Colina, Luis; Diaz, Ruben; Flohic, Helene; Gonzalez-Martin, Omaira; Ho, Luis C.; Lira, Paulina; Martins, Lucimara; McDermid, Richard; Perlman, Eric S.; Ramos Almeida, Christina; Riffel, Rogerio; Ardila, Alberto; Ruschel Dutra, Daniel; Schiavon, Ricardo; Thanjavur, Karun; Winge, Claudia

2015-01-01

Observations obtained in the near-infrared (near-IR; 0.8 - 2.5 μm) can assist our understanding of the physical and evolutionary processes of galaxies. Using a set of near-IR spectra of nearby galaxies obtained with the cross-dispersed mode of GNIRS on the Gemini North telescope, we investigate how the accretion disk and hot dust emission depend on the luminosity of the active nucleus. We recover faint AGN emission from the starlight-dominated nuclear regions of the galaxies, and measure properties such as the spectral shape and luminosity of the accretion disk and dust. The aim of this work is to establish whether the standard thin accretion disk may be truncated in low-accretion-rate AGN, as well as evaluate whether the torus of the AGN unified model still exists at low luminosities.

The luminosity of the double-mode Cepheid Y Carinae

NASA Technical Reports Server (NTRS)

Evans, Nancy R.

1992-01-01

IUE spectra of the double-mode Cepheid Y Carinae have been used to determine the spectral type of the binary companion. From the companion spectral type (B9.O V), the absolute magnitude of the Cepheid is found to be -2.94 mag, with an estimated uncertainty of +/-0.3. This luminosity is in good agreement with that from the period-luminosity-color relation of Feast and Walker for the fundamental mode. This agreement, together with the large magnitude difference between the B9.0 V star and the Cepheid, confirm that the Cepheid is a normal classical Cepheid with a mass much larger than that inferred from the ratio of the two periods (beat mass). The two double-mode Cepheids with independently determined luminosities (Y Car and V 367 Sct) both fall on the blue edge of the instability strip.

Obscured Black Hole Growth at High Redshift and High Luminosity

NASA Astrophysics Data System (ADS)

Urry, C. Megan

We propose to complete the census of cosmic black hole growth by measuring luminous and/or distant quasars using Spitzer, Herschel, Chandra and XMM-Newton imaging in Stripe 82 the deepest Sloan Digital Sky Survey field, and now the premier legacy field among 100 deg2 survey areas. These extensive ancillary data offer unsurpassed sensitivity to accreting supermassive black holes in luminous quasars out to z 6, including obscured objects missed by optical/UV surveys. We address six science goals centered on the growth of supermassive black holes: 1) We will constrain the mass accreted in luminous quasars by determining the evolving luminosity function of high-luminosity X-ray-selected AGN, including obscured quasars, especially at high redshift, where previous surveys have limited statistics. 2) We will build a comprehensive multi-wavelength population synthesis model that describes cosmic black hole accretion across most of the history of the Universe, constrained by the wealth of data now available. This will be the first population synthesis model that is constrained at high luminosity and high redshift (courtesy of Stripe 82X). 3) We will characterize the spectral energy distributions (SEDs) of luminous X-ray selected quasars, including obscured ones. We will assess the dust content in the host galaxies and diagnose the relative contributions of black hole fueling and star formation, using Herschel data to probe the cold molecular gas from which stars form and comparing X-rays from accretion onto the central black hole. We will also use high-quality optical imaging to disentangle nuclear from host galaxy emission in a representative sub-sample of quasars. 4) Using Spitzer, Herschel, Chandra, XMM-Newton, and optical data, we will identify candidates for the most heavily obscured black holes, which we will follow up with ground-based IR spectroscopy using Keck and Palomar (to which Yale has guaranteed access). In this way we will recover obscured AGN missed by

Parallax and Luminosity Measurements of an L SubDwarf

DTIC Science & Technology

2008-01-10

parallax and luminosity measurements for an L subdwarf, the sdL7 2MASS J05325346+ 8246465. Observations conducted over 3 years by the USNO infrared...comparable to mid-type L field dwarfs. Comparison of the luminosity of 2MASS J05325346+8246465 to theoretical evolutionary models indicates that its...The relatively bright J-bandmagnitude of 2MASS J05325346+8246465 implies significantly reduced opacity in the 1.2 m region, consistent with inhibited

Classical Cepheid luminosities from binary companions

NASA Technical Reports Server (NTRS)

Evans, Nancy Remage

1991-01-01

Luminosities for the classical Cepheids Eta Aql, W Sgr, and SU Cas are determined from IUE spectra of their binary companions. Spectral types of the companions are determined from the spectra by comparison with the spectra of standard stars. The absolute magnitude inferred from these spectral types is used to determine the absolute magnitude of the Cepheid, either directly or from the magnitude difference between the two stars. For the temperature range of the companions (A0 V), distinctions of a quarter of a spectral subclass can be made in the comparison between the companions and standard stars. The absolute magnitudes for Eta Aql and W Sgr agree well with the period-luminosity-color relation of Feast and Walker (1987). Random errors are estimated to be 0.3 mag. SU Cas, however, is overluminous for pulsation in the fundamental mode, implying that it is pulsating in an overtone.

RR Lyrae period luminosity relations with Spitzer

NASA Astrophysics Data System (ADS)

Neeley, Jillian R.; Marengo, Massimo; CRRP Team

2017-01-01

RR Lyrae variable stars have long been known to be valuable distance indicators, but only recently has a well defined period luminosity relationship been utilized at infrared wavelengths. In my thesis, I am combining Spitzer Space Telescope data of RR Lyrae stars obtained as part of the Carnegie RR Lyrae Program with ground based NIR data to characterize the period-luminosity-metallicity (PLZ) relation and provide an independent Population II calibration of the cosmic distance scale. I will discuss the ongoing efforts to calibrate this relation using objects such as M4 and NGC 6441 and how the first data release from the Gaia mission impacts our findings. I will also compare my preliminary empirical relations to theoretical PLZ relations derived from stellar pulsation models.

The most powerful astrophysical events: Gravitational-wave peak luminosity of binary black holes as predicted by numerical relativity

NASA Astrophysics Data System (ADS)

Keitel, David; Forteza, Xisco Jiménez; Husa, Sascha; London, Lionel; Bernuzzi, Sebastiano; Harms, Enno; Nagar, Alessandro; Hannam, Mark; Khan, Sebastian; Pürrer, Michael; Pratten, Geraint; Chaurasia, Vivek

2017-07-01

For a brief moment, a binary black hole (BBH) merger can be the most powerful astrophysical event in the visible Universe. Here we present a model fit for this gravitational-wave peak luminosity of nonprecessing quasicircular BBH systems as a function of the masses and spins of the component black holes, based on numerical relativity (NR) simulations and the hierarchical fitting approach introduced by X. Jiménez-Forteza et al. [Phys. Rev. D 95, 064024 (2017)., 10.1103/PhysRevD.95.064024]. This fit improves over previous results in accuracy and parameter-space coverage and can be used to infer posterior distributions for the peak luminosity of future astrophysical signals like GW150914 and GW151226. The model is calibrated to the ℓ≤6 modes of 378 nonprecessing NR simulations up to mass ratios of 18 and dimensionless spin magnitudes up to 0.995, and includes unequal-spin effects. We also constrain the fit to perturbative numerical results for large mass ratios. Studies of key contributions to the uncertainty in NR peak luminosities, such as (i) mode selection, (ii) finite resolution, (iii) finite extraction radius, and (iv) different methods for converting NR waveforms to luminosity, allow us to use NR simulations from four different codes as a homogeneous calibration set. This study of systematic fits to combined NR and large-mass-ratio data, including higher modes, also paves the way for improved inspiral-merger-ringdown waveform models.

The quasar luminosity function at redshift 4 with the Hyper Suprime-Cam Wide Survey

NASA Astrophysics Data System (ADS)

Akiyama, Masayuki; He, Wanqiu; Ikeda, Hiroyuki; Niida, Mana; Nagao, Tohru; Bosch, James; Coupon, Jean; Enoki, Motohiro; Imanishi, Masatoshi; Kashikawa, Nobunari; Kawaguchi, Toshihiro; Komiyama, Yutaka; Lee, Chien-Hsiu; Matsuoka, Yoshiki; Miyazaki, Satoshi; Nishizawa, Atsushi J.; Oguri, Masamune; Ono, Yoshiaki; Onoue, Masafusa; Ouchi, Masami; Schulze, Andreas; Silverman, John D.; Tanaka, Manobu M.; Tanaka, Masayuki; Terashima, Yuichi; Toba, Yoshiki; Ueda, Yoshihiro

2018-01-01

We present the luminosity function of z ˜ 4 quasars based on the Hyper Suprime-Cam Subaru Strategic Program Wide layer imaging data in the g, r, i, z, and y bands covering 339.8 deg2. From stellar objects, 1666 z ˜ 4 quasar candidates are selected via the g-dropout selection down to i = 24.0 mag. Their photometric redshifts cover the redshift range between 3.6 and 4.3, with an average of 3.9. In combination with the quasar sample from the Sloan Digital Sky Survey in the same redshift range, a quasar luminosity function covering the wide luminosity range of M1450 = -22 to -29 mag is constructed. The quasar luminosity function is well described by a double power-law model with a knee at M1450 = -25.36 ± 0.13 mag and a flat faint-end slope with a power-law index of -1.30 ± 0.05. The knee and faint-end slope show no clear evidence of redshift evolution from those seen at z ˜ 2. The flat slope implies that the UV luminosity density of the quasar population is dominated by the quasars around the knee, and does not support the steeper faint-end slope at higher redshifts reported at z > 5. If we convert the M1450 luminosity function to the hard X-ray 2-10 keV luminosity function using the relation between the UV and X-ray luminosity of quasars and its scatter, the number density of UV-selected quasars matches well with that of the X-ray-selected active galactic nuclei (AGNs) above the knee of the luminosity function. Below the knee, the UV-selected quasars show a deficiency compared to the hard X-ray luminosity function. The deficiency can be explained by the lack of obscured AGNs among the UV-selected quasars.

Exploring the Faint End of the Luminosity-Metallicity Relation with Hα Dots

NASA Astrophysics Data System (ADS)

Hirschauer, Alec S.; Salzer, John J.

2015-01-01

The well-known correlation between a galaxy's luminosity and its gas-phase oxygen abundance (the luminosity-metallicity (L-Z) relation) offers clues toward our understanding of chemical enrichment histories and evolution. Bright galaxies are comparatively better studied than faint ones, leaving a relative dearth of observational data points to constrain the L-Z relation in the low-luminosity regime. We present high S/N nebular spectroscopy of low-luminosity star-forming galaxies observed with the KPNO 4m using the new KOSMOS spectrograph to derive direct-method metallicities. Our targets are strong point-like emission-line sources discovered serendipitously in continuum-subtracted narrowband images from the ALFALFA Hα survey. Follow-up spectroscopy of these "Hα dots" shows that these objects represent some of the lowest luminosity star-forming systems in the local Universe. Our KOSMOS spectra cover the full optical region and include detection of [O III] λ4363 in roughly a dozen objects. This paper presents some of the first scientific results obtained using this new spectrograph, and demonstrates its capabilities and effectiveness in deriving direct-method metallicities of faint objects.

Mini Survey of SDSS [OIII] AGN with Swift: Testing the Hypothesis that L(sub [OIII]) Traces AGN Luminosity

NASA Technical Reports Server (NTRS)

2007-01-01

The number of AGN and their luminosity distribution are crucial parameters for our understanding of the AGN phenomenon. Recent work strongly suggests every massive galaxy has a central black hole. However most of these objects either are not radiating or have been very difficult to detect We are now in the era of large surveys, and the luminosity function (LF] of AGN has been estimated in various ways. In the X-ray band. Chandra and XMM surveys have revealed that the LF of hard X-ray selected AGN shows a strong luminosity-dependent evolution with a dramatic break towards low L(sub x) (at all z). This is seen for all types of AGN, but is stronger for the broad-line objects. In sharp contrast, the local LF of optically-selected samples shows no such break and no differences between narrow and broad-line objects. If as been suggested, hard X ray and optical emission line can both can be fair indicators of AGN activity, it is important to first understand how reliable these characteristics are if we hope to understand the apparent discrepancy in the LFs.

Luminosity Function of Faint Globular Clusters in M87

NASA Astrophysics Data System (ADS)

Waters, Christopher Z.; Zepf, Stephen E.; Lauer, Tod R.; Baltz, Edward A.; Silk, Joseph

2006-10-01

We present the luminosity function to very faint magnitudes for the globular clusters in M87, based on a 30 orbit Hubble Space Telescope (HST) WFPC2 imaging program. The very deep images and corresponding improved false source rejection allow us to probe the mass function further beyond the turnover than has been done before. We compare our luminosity function to those that have been observed in the past, and confirm the similarity of the turnover luminosity between M87 and the Milky Way. We also find with high statistical significance that the M87 luminosity function is broader than that of the Milky Way. We discuss how determining the mass function of the cluster system to low masses can constrain theoretical models of the dynamical evolution of globular cluster systems. Our mass function is consistent with the dependence of mass loss on the initial cluster mass given by classical evaporation, and somewhat inconsistent with newer proposals that have a shallower mass dependence. In addition, the rate of mass loss is consistent with standard evaporation models, and not with the much higher rates proposed by some recent studies of very young cluster systems. We also find that the mass-size relation has very little slope, indicating that there is almost no increase in the size of a cluster with increasing mass.

The line continuum luminosity ratio in AGN: Or on the Baldwin Effect

NASA Technical Reports Server (NTRS)

Mushotzky, R.; Ferland, F. J.

1983-01-01

The luminosity dependence of the equivalent width of CIV in active galaxies, the "Baldwin" effect, is shown to be a consequence of a luminosity dependent ionization parameter. This law also agrees with the lack of a "Baldwin" effect in Ly alpha or other hydrogen lines. A fit to the available data gives a weak indication that the mean covering factor decreases with increasing luminosity, consistent with the inference from X-ray observations. The effects of continuum shape and density on various line ratios of interest are discussed.

Is drag luminosity effective in recurrent novae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kato, Mariko; Hachisu, Izumi

1991-06-01

A study has been made of the efficiency of frictional processes in common envelope phase at outbursts of three recurrent novae T Pyx, U Sco, and RS Oph, by using steady-state wind models. The drag luminosity is found to depend strongly on the envelope mass. It may play an important role for a relatively massive envelope of about 0.0001 solar mass or more. For recurrent novae, however, acceleration due to the drag force is not important to eject the envelope mass because of its small envelope mass. Since the drag luminosity can be neglected at the extended phase of novamore » outburst, the light curves of these recurrent novae are determined only by the wind-driven mass loss as shown by Kato (1990). 23 refs.« less

Examining an AGN Luminosity – SFR relation

NASA Astrophysics Data System (ADS)

Stemo, Aaron; Comerford, Julia M.; Barrows, Robert Scott

2018-06-01

The relation between the star formation rate (SFR) of a galaxy and the accretion rate of its supermassive black hole is not well understood. Some observations show that active galactic nuclei (AGN) activity and SFR are correlated while other observations show no relation between the two. In this work we present a large, uniformly-selected catalog of HST galaxies that host AGN. Using available multiwavelength photometric data, we are able to determine AGN bolometric luminosity, host galaxy SFR, host galaxy stellar mass, and redshift for our sample. Using this catalog, we are able to compare AGN bolometric luminosity and SFR, while controlling for redshift and stellar mass. These comparisons will be used to make a statistically significant statement on the correlation between AGN activity and a host galaxy’s SFR.

SLHC, the High-Luminosity Upgrade (public event)

ScienceCinema

None

2017-12-09

In the morning of June 23rd a public event is organised in CERN's Council Chamber with the aim of providing the particle physics community with up-to-date information about the strategy for the LHC luminosity upgrade and to describe the current status of preparation work. The presentations will provide an overview of the various accelerator sub-projects, the LHC physics prospects and the upgrade plans of ATLAS and CMS. This event is organised in the framework of the SLHC-PP project, which receives funding from the European Commission for the preparatory phase of the LHC High Luminosity Upgrade project. Informing the public is among the objectives of this EU-funded project. A simultaneous transmission of this meeting will be broadcast, available at the following address: http://webcast.cern.ch/

The quasar luminosity function from a variability-selected sample

NASA Astrophysics Data System (ADS)

Hawkins, M. R. S.; Veron, P.

1993-01-01

A sample of quasars is selected from a 10-yr sequence of 30 UK Schmidt plates. Luminosity functions are derived in several redshift intervals, which in each case show a featureless power-law rise towards low luminosities. There is no sign of the 'break' found in the recent UVX sample of Boyle et al. It is suggested that reasons for the disagreement are connected with biases in the selection of the UVX sample. The question of the nature of quasar evolution appears to be still unresolved.

Gamma-Ray Burst Intensity Distributions

NASA Technical Reports Server (NTRS)

Band, David L.; Norris, Jay P.; Bonnell, Jerry T.

2004-01-01

We use the lag-luminosity relation to calculate self-consistently the redshifts, apparent peak bolometric luminosities L(sub B1), and isotropic energies E(sub iso) for a large sample of BATSE bursts. We consider two different forms of the lag-luminosity relation; for both forms the median redshift, for our burst database is 1.6. We model the resulting sample of burst energies with power law and Gaussian dis- tributions, both of which are reasonable models. The power law model has an index of a = 1.76 plus or minus 0.05 (95% confidence) as opposed to the index of a = 2 predicted by the simple universal jet profile model; however, reasonable refinements to this model permit much greater flexibility in reconciling predicted and observed energy distributions.

Potential for luminosity improvement for low-energy RHIC operation with long bunches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedotov, A.; Blaskiewicz, M.

Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beams at low energies. Luminosity decreases as the square of bunch intensity due to the beam loss from the RF bucket as a result of the longitudinal intra beam scattering (IBS), as well as due to the transverse emittance growth because of the transverse IBS. Both transverse and longitudinal IBS can be counteracted with electron cooling. This would allow one to keep the initial peak luminosity close to constant throughout the store essentially without the beam loss. In addition, the phase-space density of the hadron beamsmore » can be further increased by providing stronger electron cooling. Unfortunately, the defining limitation for low energies in RHIC is expected to be the space charge. Here we explore an idea of additional improvement in luminosity, on top of the one coming from just IBS compensation and longer stores, which may be expected if one can operate with longer bunches at the space-charge limit in a collider. This approach together with electron cooling may result in about 10-fold improvement in total luminosity for low-energy RHIC program.« less

An extended galactic population of low-luminosity x-ray sources (CVs?) and the diffuse x-ray background

NASA Technical Reports Server (NTRS)

Maoz, Eyal; Grindlay, Jonathan E.

1995-01-01

The incompatibility of the properties of the X-ray background (XRB) with active galactic nuclei (AGNs) contributing approximately greater than 60% at energies of a few keV has often been interpreted as being due to a substantial contribution of a new population of yet unrecognized X-ray sources. The existence of such population has been recently suggested also by an analysis of very deep ROSAT observations which revealed a considerable excess of faint X-ray sources over that expected from QSO evolution models, and that the average spectrum of the resolved sources becomes harder with decreasing flux limit. These sources could be extragalactic in origin, but if they make a substantial contribution to the XRB then they must exhibit much weaker clustering than galaxies or QSOs in order to be consistent with the stringent constraints on source clustering imposed by autocorrelation analyses of the unresolved XRB. We investigate the possibility that the indicated new population of X-ray sources is Galactic in origin. Examining spherical halo and thick disk distributions, we derive the allowed properties of such populations which would resolve the discrepancy found in the number counts of faint sources and be consistent with observational constraints on the total background intensity, the XRB anisotropy, the number of unidentified bright sources, the Galaxy's total X-ray luminosity, and with the results of fluctuation analyses of the unresolved XRB. We find that a flattened Galactic halo (or a thick disk) distribution with a scale height of a few kpc is consistent with all the above requirements. The typical X-ray luminosity of the sources is approximately equal to 10(exp 30-31)ergs/s in the 0.5-2 keV band, the number density of sources in the solar vicinity is approximately 10(exp -4.5)pc(exp -3), their total number in the Galaxy is approximately 10(exp 8.5), and their total contribution to the Galaxy's X-ray luminosity is approximately 10(exp 39) ergs/s. We discuss the

Accelerator Science: Luminosity vs. Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

In the world of high energy physics there are several parameters that are important when one constructs a particle accelerator. Two crucial ones are the energy of the beam and the luminosity, which is another word for the number of particles in the beam. In this video, Fermilab’s Dr. Don Lincoln explains the differences and the pros and cons. He even works in an unexpected sporting event.

Accelerator Science: Luminosity vs. Energy

ScienceCinema

Lincoln, Don

2018-06-12

In the world of high energy physics there are several parameters that are important when one constructs a particle accelerator. Two crucial ones are the energy of the beam and the luminosity, which is another word for the number of particles in the beam. In this video, Fermilab’s Dr. Don Lincoln explains the differences and the pros and cons. He even works in an unexpected sporting event.

Progenitors of low-luminosity Type II-Plateau supernovae

NASA Astrophysics Data System (ADS)

Lisakov, Sergey M.; Dessart, Luc; Hillier, D. John; Waldman, Roni; Livne, Eli

2018-01-01

The progenitors of low-luminosity Type II-Plateau supernovae (SNe II-P) are believed to be red supergiant (RSG) stars, but there is much disparity in the literature concerning their mass at core collapse and therefore on the main sequence. Here, we model the SN radiation arising from the low-energy explosion of RSG stars of 12, 25 and 27 M⊙ on the main sequence and formed through single star evolution. Despite the narrow range in ejecta kinetic energy (2.5-4.2 × 1050 erg) in our model set, the SN observables from our three models are significantly distinct, reflecting the differences in progenitor structure (e.g. surface radius, H-rich envelope mass and He-core mass). Our higher mass RSG stars give rise to Type II SNe that tend to have bluer colours at early times, a shorter photospheric phase, and a faster declining V-band light curve (LC) more typical of Type II-linear SNe, in conflict with the LC plateau observed for low-luminosity SNe II. The complete fallback of the CO core in the low-energy explosions of our high-mass RSG stars prevents the ejection of any 56Ni (nor any core O or Si), in contrast to low-luminosity SNe II-P, which eject at least 0.001 M⊙ of 56Ni. In contrast to observations, Type II SN models from higher mass RSGs tend to show an H α absorption that remains broad at late times (due to a larger velocity at the base of the H-rich envelope). In agreement with the analyses of pre-explosion photometry, we conclude that low-luminosity SNe II-P likely arise from low-mass rather than high-mass RSG stars.

High-luminosity primary vertex selection in top-quark studies using the Collider Detector at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buzatu, Adrian; /McGill U.

2006-08-01

Improving our ability to identify the top quark pair (t{bar t}) primary vertex (PV) on an event-by-event basis is essential for many analyses in the lepton-plus-jets channel performed by the Collider Detector at Fermilab (CDF) Collaboration. We compare the algorithm currently used by CDF (A1) with another algorithm (A2) using Monte Carlo simulation at high instantaneous luminosities. We confirm that A1 is more efficient than A2 at selecting the t{bar t} PV at all PV multiplicities, both with efficiencies larger than 99%. Event selection rejects events with a distance larger than 5 cm along the proton beam between the t{barmore » t} PV and the charged lepton. We find flat distributions for the signal over background significance of this cut for all cut values larger than 1 cm, for all PV multiplicities and for both algorithms. We conclude that any cut value larger than 1 cm is acceptable for both algorithms under the Tevatron's expected instantaneous luminosity improvements.« less

On the Scatter in the Radius-Luminosity Relationship for Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Kilerci Eser, E.; Vestergaard, M.; Peterson, B. M.; Denney, K. D.; Bentz, M. C.

2015-03-01

We investigate and quantify the observed scatter in the empirical relationship between the broad line region size R and the luminosity of the active galactic nucleus, in order to better understand its origin. This study is motivated by the indispensable role of this relationship in the mass estimation of cosmologically distant black holes, but may also be relevant to the recently proposed application of this relationship for measuring cosmic distances. We study six nearby reverberation-mapped active galactic nuclei (AGNs) for which simultaneous UV and optical monitoring data exist. We also examine the long-term optical luminosity variations of the Seyfert 1 galaxy NGC 5548 and employ Monte Carlo simulations to study the effects of the intrinsic variability of individual objects on the scatter in the global relationship for a sample of ~40 AGNs. We find the scatter in this relationship has a correctable dependence on color. For individual AGNs, the size of the Hβ emitting region has a steeper dependence on the nuclear optical luminosity than on the UV luminosity, which can introduce a scatter of ~0.08 dex into the global relationship, due the nonlinear relationship between the variations in the ionizing continuum and those in the optical continuum. Also, our analysis highlights the importance of understanding and minimizing the scatter in the relationship traced by the intrinsic variability of individual AGNs since it propagates directly into the global relationship. We find that using the UV luminosity as a substitute for the ionizing luminosity can reduce a sizable fraction of the current observed scatter of ~0.13 dex.

High Luminosity LHC: challenges and plans

NASA Astrophysics Data System (ADS)

Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.; Brüning, O.; Buffat, X.; Cai, Y.; Carver, L. R.; Fartoukh, S.; Giovannozzi, M.; Iadarola, G.; Li, K.; Lechner, A.; Medina Medrano, L.; Métral, E.; Nosochkov, Y.; Papaphilippou, Y.; Pellegrini, D.; Pieloni, T.; Qiang, J.; Redaelli, S.; Romano, A.; Rossi, L.; Rumolo, G.; Salvant, B.; Schenk, M.; Tambasco, C.; Tomás, R.; Valishev, S.; Van der Veken, F. F.

2016-12-01

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 T superconducting magnets, including Nb3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. The dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

Optical and X-ray luminosities of expanding nebulae around ultraluminous X-ray sources

NASA Astrophysics Data System (ADS)

Siwek, Magdalena; Sądowski, Aleksander; Narayan, Ramesh; Roberts, Timothy P.; Soria, Roberto

2017-09-01

We have performed a set of simulations of expanding, spherically symmetric nebulae inflated by winds from accreting black holes in ultraluminous X-ray sources (ULXs). We implemented a realistic cooling function to account for free-free and bound-free cooling. For all model parameters we considered, the forward shock in the interstellar medium becomes radiative at a radius ˜100 pc. The emission is primarily in optical and UV, and the radiative luminosity is about 50 per cent of the total kinetic luminosity of the wind. In contrast, the reverse shock in the wind is adiabatic so long as the terminal outflow velocity of the wind vw ≳ 0.003c. The shocked wind in these models radiates in X-rays, but with a luminosity of only ˜1035 erg s-1. For wind velocities vw ≲ 0.001c, the shocked wind becomes radiative, but it is no longer hot enough to produce X-rays. Instead it emits in optical and UV, and the radiative luminosity is comparable to 100 per cent of the wind kinetic luminosity. We suggest that measuring the optical luminosities and putting limits on the X-ray and radio emission from shock-ionized ULX bubbles may help in estimating the mass outflow rate of the central accretion disc and the velocity of the outflow.

Evolution of the dusty infrared luminosity function from z = 0 to z = 2.3 using observations from Spitzer

NASA Astrophysics Data System (ADS)

Magnelli, B.; Elbaz, D.; Chary, R. R.; Dickinson, M.; Le Borgne, D.; Frayer, D. T.; Willmer, C. N. A.

2011-04-01

Aims: We derive the evolution of the infrared luminosity function (LF) over the last 4/5ths of cosmic time using deep 24 and 70 μm imaging of the GOODS North and South fields. Methods: We use an extraction technique based on prior source positions at shorter wavelengths to build the 24 and 70 μm source catalogs. The majority (93%) of the sources have a spectroscopic (39%) or a photometric redshift (54%) and, in our redshift range of interest (i.e., 1.3 < z < 2.3) s20% of the sources have a spectroscopic redshift. To extend our study to lower 70 μm luminosities we perform a stacking analysis and we characterize the observed L24/(1 + z) vs. L70/(1 + z) correlation. Using spectral energy distribution (SED) templates which best fit this correlation, we derive the infrared luminosity of individual sources from their 24 and 70 μm luminosities. We then compute the infrared LF at zs1.55 ± 0.25 and zs2.05 ± 0.25. Results: We observe the break in the infrared LF up to zs2.3. The redshift evolution of the infrared LF from z = 1.3 to z = 2.3 is consistent with a luminosity evolution proportional to (1 + z)1.0 ± 0.9 combined with a density evolution proportional to (1 + z)-1.1 ± 1.5. At zs2, luminous infrared galaxies (LIRGs: 1011L⊙ < LIR < 1012 L⊙) are still the main contributors to the total comoving infrared luminosity density of the Universe. At zs2, LIRGs and ultra-luminous infrared galaxies (ULIRGs: 1012L⊙ < LIR) account for s49% and s17% respectively of the total comoving infrared luminosity density of the Universe. Combined with previous results using the same strategy for galaxies at z < 1.3 and assuming a constant conversion between the infrared luminosity and star-formation rate (SFR) of a galaxy, we study the evolution of the SFR density of the Universe from z = 0 to z = 2.3. We find that the SFR density of the Universe strongly increased with redshift from z = 0 to z = 1.3, but is nearly constant at higher redshift out to z = 2.3. As part of the

ON THE SCATTER IN THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilerci Eser, E.; Vestergaard, M.; Peterson, B. M.

2015-03-01

We investigate and quantify the observed scatter in the empirical relationship between the broad line region size R and the luminosity of the active galactic nucleus, in order to better understand its origin. This study is motivated by the indispensable role of this relationship in the mass estimation of cosmologically distant black holes, but may also be relevant to the recently proposed application of this relationship for measuring cosmic distances. We study six nearby reverberation-mapped active galactic nuclei (AGNs) for which simultaneous UV and optical monitoring data exist. We also examine the long-term optical luminosity variations of the Seyfert 1more » galaxy NGC 5548 and employ Monte Carlo simulations to study the effects of the intrinsic variability of individual objects on the scatter in the global relationship for a sample of ∼40 AGNs. We find the scatter in this relationship has a correctable dependence on color. For individual AGNs, the size of the Hβ emitting region has a steeper dependence on the nuclear optical luminosity than on the UV luminosity, which can introduce a scatter of ∼0.08 dex into the global relationship, due the nonlinear relationship between the variations in the ionizing continuum and those in the optical continuum. Also, our analysis highlights the importance of understanding and minimizing the scatter in the relationship traced by the intrinsic variability of individual AGNs since it propagates directly into the global relationship. We find that using the UV luminosity as a substitute for the ionizing luminosity can reduce a sizable fraction of the current observed scatter of ∼0.13 dex.« less

Intermediate-Band Photometric Luminosity Descrimination for M Stars

NASA Astrophysics Data System (ADS)

Robertson, T. H.; Furiak, N. M.

1995-12-01

Synthetic photometry has been used to design an intermediate-band filter to be used with CCD cameras to facilitate the luminosity classification of M stars. Spectrophotometric data published by Gunn & Stryker (1983) were used to test various bandwidths and centers. Based on these calculations an intermediate-band filter has been purchased. This filter is being used in conjunction with standard BVRI filters to test its effectiveness in luminosity classification of M stars having a wide range of temperatures and different chemical compositions. The results of the theoretical calculations, filter design specifications and preliminary results of the testing program are presented. This research is supported in part by funds provided by Ball State University, The Fund for Astrophysical Research and the Indiana Academy of Science.

Discovery of a low-luminosity spiral DRAGN

NASA Astrophysics Data System (ADS)

Mulcahy, D. D.; Mao, M. Y.; Mitsuishi, I.; Scaife, A. M. M.; Clarke, A. O.; Babazaki, Y.; Kobayashi, H.; Suganuma, R.; Matsumoto, H.; Tawara, Y.

2016-11-01

Standard galaxy formation models predict that large-scale double-lobed radio sources, known as DRAGNs, will always be hosted by elliptical galaxies. In spite of this, in recent years a small number of spiral galaxies have also been found to host such sources. These so-called spiral DRAGNs are still extremely rare, with only 5 cases being widely accepted. Here we report on the serendipitous discovery of a new spiral DRAGN in data from the Giant Metrewave Radio Telescope (GMRT) at 322 MHz. The host galaxy, MCG+07-47-10, is a face-on late-type Sbc galaxy with distinctive spiral arms and prominent bulge suggesting a high black hole mass. Using WISE infra-red and GALEX UV data we show that this galaxy has a star formation rate of 0.16-0.75 M⊙ yr-1, and that the radio luminosity is dominated by star-formation. We demonstrate that this spiral DRAGN has similar environmental properties to others of this class, but has a comparatively low radio luminosity of L1.4 GHz = 1.12 × 1022 W Hz-1, two orders of magnitude smaller than other known spiral DRAGNs. We suggest that this may indicate the existence of a previously unknown low-luminosity population of spiral DRAGNS. FITS cutout image of the observed spiral DRAGN MCG+07-47- 10 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/L8

Solar Luminosity on the Main Sequence, Standard Model and Variations

NASA Astrophysics Data System (ADS)

Ayukov, S. V.; Baturin, V. A.; Gorshkov, A. B.; Oreshina, A. V.

2017-05-01

Our Sun became Main Sequence star 4.6 Gyr ago according Standard Solar Model. At that time solar luminosity was 30% lower than current value. This conclusion is based on assumption that Sun is fueled by thermonuclear reactions. If Earth's albedo and emissivity in infrared are unchanged during Earth history, 2.3 Gyr ago oceans had to be frozen. This contradicts to geological data: there was liquid water 3.6-3.8 Gyr ago on Earth. This problem is known as Faint Young Sun Paradox. We analyze luminosity change in standard solar evolution theory. Increase of mean molecular weight in the central part of the Sun due to conversion of hydrogen to helium leads to gradual increase of luminosity with time on the Main Sequence. We also consider several exotic models: fully mixed Sun; drastic change of pp reaction rate; Sun consisting of hydrogen and helium only. Solar neutrino observations however exclude most non-standard solar models.

Luminosity Dependence and Search Doppler

NASA Technical Reports Server (NTRS)

VanParadijs, Johannes A.

1998-01-01

The research supported by this grant covered two projects: (1) a study of the luminosity dependence of the properties of atoll sources; and (2) a search for Doppler shifts in the pulse arrival times of the anomalous pulsar 4U 0142+61. Following the discovery of kilohertz quasi-periodic oscillations (QPOS) in Sco X-1 studies of the X-ray properties of atoll sources have been dominated by searches for these QPOS, and the study of their dependence on other source properties, such as X-ray luminosity and spectral state. In the project supported by grant NAG5-3269 we have detected kHz QPOs for several atoll sources. The physical interpretation of these QPO is as yet unclear, but simple models (such as the Keplerian beat frequency model) can probably be excluded. The results of this research have been reported. We have studied the X-ray pulsations of the anomalous X-ray pulsar 4U 0142+61 using the Rossi XTE. A detailed search for Doppler shifts did not lead to a positive detection. The upper limits exclude almost all types of possible companion stars, except white dwarfs. However, the latter can be excluded since anomalous X-ray pulsars are very young objects. We therefore conclude that anomalous X-ray pulsars are single neutron stars.

The size-luminosity relationship of quasar narrow-line regions

NASA Astrophysics Data System (ADS)

Dempsey, Ross; Zakamska, Nadia L.

2018-07-01

The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105-107 M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g. star formation). We find that the observed saturation of sizes at ˜10 kpc which is observed at high AGN luminosities (Lion ≃ 1046 erg s-1) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size-IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.

The Size-Luminosity Relationship of Quasar Narrow-Line Regions

NASA Astrophysics Data System (ADS)

Dempsey, Ross; Zakamska, Nadia L.

2018-04-01

The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105M⊙ to 107M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g., star formation). We find that the observed saturation of sizes at ˜10kpc which is observed at high AGN luminosities (Lion ≃ 1046erg/s) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size - IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.

The RMS survey: galactic distribution of massive star formation

NASA Astrophysics Data System (ADS)

Urquhart, J. S.; Figura, C. C.; Moore, T. J. T.; Hoare, M. G.; Lumsden, S. L.; Mottram, J. C.; Thompson, M. A.; Oudmaijer, R. D.

2014-01-01

We have used the well-selected sample of ˜1750 embedded, young, massive stars identified by the Red MSX Source (RMS) survey to investigate the Galactic distribution of recent massive star formation. We present molecular line observations for ˜800 sources without existing radial velocities. We describe the various methods used to assign distances extracted from the literature and solve the distance ambiguities towards approximately 200 sources located within the solar circle using archival H I data. These distances are used to calculate bolometric luminosities and estimate the survey completeness (˜2 × 104 L⊙). In total, we calculate the distance and luminosity of ˜1650 sources, one third of which are above the survey's completeness threshold. Examination of the sample's longitude, latitude, radial velocities and mid-infrared images has identified ˜120 small groups of sources, many of which are associated with well-known star formation complexes, such as G305, G333, W31, W43, W49 and W51. We compare the positional distribution of the sample with the expected locations of the spiral arms, assuming a model of the Galaxy consisting of four gaseous arms. The distribution of young massive stars in the Milky Way is spatially correlated with the spiral arms, with strong peaks in the source position and luminosity distributions at the arms' Galactocentric radii. The overall source and luminosity surface densities are both well correlated with the surface density of the molecular gas, which suggests that the massive star formation rate per unit molecular mass is approximately constant across the Galaxy. A comparison of the distribution of molecular gas and the young massive stars to that in other nearby spiral galaxies shows similar radial dependences. We estimate the total luminosity of the embedded massive star population to be ˜0.76 × 108 L⊙, 30 per cent of which is associated with the 10 most active star-forming complexes. We measure the scaleheight as a

Solar luminosity variations in solar cycle 21

NASA Technical Reports Server (NTRS)

Willson, Richard C.; Hudson, H. S.

1988-01-01

Long-term variations in the solar total irradiance found in the ACRIM I experiment on the SMM satellite have revealed a downward trend during the declining phase of solar cycle 21 of the sunspot cycle, a flat period between mid-1095 and mid-1987, and an upturn in late 1987 which suggests a direct correlation of luminosity and solar active region population. If the upturn continues into the activity maximum of solar cycle 22, a relation between solar activity and luminosity of possible climatological significance could be ascertained. The best-fit relationship for the variation of total irradiance S with sunspot number Rz and 10-cm flux F(10) are S = 1366.82 + 7.71 x 10 to the -3rd Rz and S = 1366.27 + 8.98 x 10 to the -3rd F(10)(W/sq m). These findings could be used to approximate total irradiance variations over the periods for which these indices have been compiled.

Bolometric Luminosities of Peculiar Type II-P Supernovae: Observational and Theoretical Approaches

NASA Astrophysics Data System (ADS)

Lusk, Jeremy Alexander

2018-01-01

In the three decades since the explosion of SN 1987A, only a handful of other supernovae have been detected which are also thought to originate from blue supergiant progenitors. In this study, we use the five best observed of these supernovae (SNe 1998A, 2000cb, 2006V, 2006au, and 2009E) to examine the bolometric properties of the class through observations and theoretical models. Several techniques for taking photometric observations and inferring bolometric luminosities have been used in the literature. Our newly-improved python package SuperBoL implements many of these techniques. The challenge remains that the true bolometric luminosity of the supernova cannot be directly observed. We must turn to theoretical models in order to examine the validity of the different observationally-based techniques. In this work, we make use of the NLTE generalized atmosphere code PHOENIX to produce synthetic spectra of known luminosity which match the observed supernova spectra. Synthetic photometry of these models is then used as input to SuperBoL to test the different observationally-based bolometric luminosity techniques.

High Luminosity LHC: Challenges and plans

DOE PAGES

Arduini, G.; Barranco, J.; Bertarelli, A.; ...

2016-12-28

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), willmore » rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 T superconducting magnets, including Nb 3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. As a result, the dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.« less

VizieR Online Data Catalog: Quasar luminosity function (Hawkins+, 1993)

NASA Astrophysics Data System (ADS)

Hawkins, M. R. S.; Veron, P.

1994-11-01

A sample of quasars is selected from a 10-yr sequence of 30 UK Schmidt plates. Luminosity functions are derived in several redshift intervals, which in each case show a featureless power-law rise towards low luminosities. There is no sigh of the 'break' found in the recent UVX sample of Boyle, Shanks & Peterson. It is suggested that reasons for the disagreement are connected with biases in the selection of the UVX sample. The question of the nature of quasar evolution appears to be still unresolved. (1 data file).

Galaxy luminosity profiles of SARS clusters

NASA Astrophysics Data System (ADS)

Coenda, V.; Donzelli, C.; Muriel, H.; Quintana, H.; Infante, L.

We have analyzed CCD images in the R filter of 14 Abell clusters of the SARS survey, with cz<40000 km/s. We have obtained the luminosity profiles of 507 galaxies and we have studied several relations between the photometric and structural parameters. In the present contributed paper we analyze the following relations: the Kormendy relation and the correlations among the Sérsic parameters.

On the existence of a luminosity threshold of GRB jets in massive stars

NASA Astrophysics Data System (ADS)

Aloy, M. A.; Cuesta-Martínez, C.; Obergaulinger, M.

2018-05-01

Motivated by the many associations of γ-ray bursts (GRBs) with energetic supernova (SN) explosions, we study the propagation of relativistic jets within the progenitor star in which a SN shock wave may be launched briefly before the jets start to propagate. Based on analytic considerations and verified with an extensive set of 2D axisymmetric relativistic hydrodynamic simulations, we have estimated a threshold intrinsic jet luminosity, L_j^thr, for successfully launching a jet. This threshold depends on the structure of the progenitor and, thus, it is sensitive to its mass and to its metallicity. For a prototype host of cosmological long GRBs, a low-metallicity star of 35 M⊙, it is L_j^thr˜eq 1.35× 10^{49} erg s-1. The observed equivalent isotropic γ-ray luminosity, L_{γ ,iso,BO} ˜eq 4 ɛ _γ L_j θ _BO^{-2}, crucially depends on the jet opening angle after breakout, θBO, and on the efficiency for converting the intrinsic jet luminosity into γ-radiation, ɛγ. Highly energetic jets can produce low-luminosity events if either their opening angle after the breakout is large, which is found in our models, or if the conversion efficiency of kinetic and internal energy into radiation is low enough. Beyond this theoretical analysis, we show how the presence of a SN shock wave may reduce this luminosity threshold by means of numerical simulations. We foresee that the high-energy transients released by jets produced near the luminosity threshold will be more similar to llGRBs or XRFs than to GRBs.

Investigation of Spectral Lag and Epeak as Joint Luminosity Indicators in GRBs

NASA Technical Reports Server (NTRS)

White, Nicholas E. (Technical Monitor); Norris, Jay P.

2003-01-01

Models for gamma-ray bursts which invoke jetted, colliding shells would appear to have at least two determinants for luminosity, e.g., observer viewing angle and Lorentz factor, or possibly shell mass. The latter two internal physical parameters may vary from pulse to pulse within a burst, and such variation might be reflected in evolution of observables such as spectral lag and peak in the spectral energy distribution. We analyze bright BATSE bursts using the 16-channel medium energy resolution (MER) data, with time resolutions of 16 and 64 ms, measuring spectral lags and peak energies for significant pulse structures within a burst, identified using a Bayesian block algorithm. We then explore correlations between the measured parameters and total flux for the individual pulse structures.

IBS FOR ION DISTRIBUTION UNDER ELECTRON COOLING.

DOE Office of Scientific and Technical Information (OSTI.GOV)

FEDOTOV,A.V.; BEN-ZVI,I.; EIDELMAN, YU.

Standard models of the intra-beam scattering (IBS) are based on the growth of the rms beam parameters for a Gaussian distribution. As a result of electron cooling, the core of beam distribution is cooled much faster than the tails, producing a denser core. In this paper, we compare various approaches to IBS treatment for such distribution. Its impact on the luminosity is also discussed.

The Herschel ATLAS: Evolution of the 250 Micrometer Luminosity Function Out to z = 0.5

NASA Technical Reports Server (NTRS)

Dye, S.; Dunne, L.; Eales, S.; Smith, D. J. B.; Amblard, A.; Auld, R.; Baes, M.; Baldry, I. K.; Bamford, S.; Blain, A. W.;

A Search for Low-Luminosity BL Lacertae Objects

NASA Astrophysics Data System (ADS)

Rector, Travis A.; Stocke, John T.; Perlman, Eric S.

1999-05-01

Many properties of BL Lacs have become explicable in terms of the ``relativistic beaming'' hypothesis, whereby BL Lacs are FR 1 radio galaxies viewed nearly along the jet axis. However, a possible problem with this model is that a transition population between beamed BL Lacs and unbeamed FR 1 galaxies has not been detected. A transition population of ``low-luminosity BL Lacs'' was predicted to exist in abundance in X-ray-selected samples such as the Einstein Extended Medium Sensitivity Survey (EMSS) by Browne & Marcha. However, these BL Lacs may have been misidentified as clusters of galaxies. We have conducted a search for such objects in the EMSS with the ROSAT High-Resolution Imager (HRI) here we present ROSAT HRI images, optical spectra, and VLA radio maps for a small number of BL Lacs that were previously misidentified in the EMSS catalog as clusters of galaxies. While these objects are slightly lower in luminosity than other EMSS BL Lacs, their properties are too similar to the other BL Lacs in the EMSS sample to ``bridge the gap'' between BL Lacs and FR 1 radio galaxies. Also, the number of new BL Lacs found is too low to alter significantly the X-ray luminosity function or value for the X-ray-selected EMSS BL Lac sample. Thus, these observations do not explain fully the discrepancy between the X-ray- and radio-selected BL Lac samples.

A Correlation Between Changes in Solar Luminosity and Differential Radius Measurements

NASA Technical Reports Server (NTRS)

Kroll, R. J.; Hill, H. A.; Beardsley, B. J.

1990-01-01

Solar luminosity variations occurring during solar cycle 21 can be attributed in large part to the presence of sunspots and faculae. Nevertheless, there remains a residual portion of the luminosity variation distinctly unaccounted for by these phenomena of solar activity. At the Santa Catalina Laboratory for Experimental Relativity by Astrometry (SCLERA), observations of the solar limb are capable of detecting changes in the solar limb darkening function by monitoring a quantity known as the differential radius. These observations are utilized in such a way that the effects of solar activity are minimized in order to reveal the more fundamental structure of the photosphere. The results of observations made during solar cycle 21 at various solar latitudes indicate that a measurable change did occur in the global photospheric limb darkening function. It is proposed that the residual luminosity change is associated in part with this change in limb darkening.

Spectral-luminosity evolution of active galactic nuclei (AGN)

NASA Technical Reports Server (NTRS)

Leiter, Darryl; Boldt, Elihu

1992-01-01

The origin of the cosmic X-ray and gamma-ray backgrounds is explained via the mechanism of AGN spectral-luminosity evolution. The spectral evolution of precursor active galaxies into AGN, and Newton-Raphson input and output parameters are discussed.

The white dwarf luminosity function - A possible probe of the galactic halo

NASA Technical Reports Server (NTRS)

Tamanaha, Christopher M.; Silk, Joseph; Wood, M. A.; Winget, D. E.

1990-01-01

The dynamically inferred dark halo mass density, amounting to above 0.01 solar masses/cu pc at the sun's Galactocentric radius, can be composed of faint white dwarfs provided that the halo formed in a sufficiently early burst of star formation. The model is constrained by the observed disk white dwarf luminosity function which falls off below log (L/solar L) = -4.4, due to the onset of star formation in the disk. By using a narrow range for the initial mass function and an exponentially decaying halo star formation rate with an e-folding time equal to the free-fall time, all the halo dark matter is allowed to be in cool white dwarfs which lie beyond the falloff in the disk luminosity function. Although it is unlikely that all the dark matter is in these dim white dwarfs, a definite signature in the low-luminosity end of the white dwarf luminosity function is predicted even if they comprise only 1 percent of the dark matter. Current CCD surveys should answer the question of the existence of this population within the next few years.

A Search for Water Maser Emission from Brown Dwarfs and Low-luminosity Young Stellar Objects

NASA Astrophysics Data System (ADS)

Gómez, José F.; Palau, Aina; Uscanga, Lucero; Manjarrez, Guillermo; Barrado, David

2017-05-01

We present a survey for water maser emission toward a sample of 44 low-luminosity young objects, comprising (proto-)brown dwarfs, first hydrostatic cores (FHCs), and other young stellar objects (YSOs) with bolometric luminosities lower than 0.4 L ⊙. Water maser emission is a good tracer of energetic processes, such as mass-loss and/or accretion, and is a useful tool to study these processes with very high angular resolution. This type of emission has been confirmed in objects with L bol ≳ 1 L ⊙. Objects with lower luminosities also undergo mass-loss and accretion, and thus, are prospective sites of maser emission. Our sensitive single-dish observations provided a single detection when pointing toward the FHC L1448 IRS 2E. However, follow-up interferometric observations showed water maser emission associated with the nearby YSO L1448 IRS 2 (a Class 0 protostar of L bol ≃ 3.6-5.3 L ⊙) and did not find any emission toward L1448 IRS 2E. The upper limits for water maser emission determined by our observations are one order of magnitude lower than expected from the correlation between water maser luminosities and bolometric luminosities found for YSOs. This suggests that this correlation does not hold at the lower end of the (sub)stellar mass spectrum. Possible reasons are that the slope of this correlation is steeper at L bol ≤ 1 L ⊙ or that there is an absolute luminosity threshold below which water maser emission cannot be produced. Alternatively, if the correlation still stands at low luminosity, the detection rates of masers would be significantly lower than the values obtained in higher-luminosity Class 0 protostars.

A Search for Water Maser Emission from Brown Dwarfs and Low-luminosity Young Stellar Objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez, José F.; Manjarrez, Guillermo; Palau, Aina

We present a survey for water maser emission toward a sample of 44 low-luminosity young objects, comprising (proto-)brown dwarfs, first hydrostatic cores (FHCs), and other young stellar objects (YSOs) with bolometric luminosities lower than 0.4 L {sub ⊙}. Water maser emission is a good tracer of energetic processes, such as mass-loss and/or accretion, and is a useful tool to study these processes with very high angular resolution. This type of emission has been confirmed in objects with L {sub bol} ≳ 1 L {sub ⊙}. Objects with lower luminosities also undergo mass-loss and accretion, and thus, are prospective sites of maser emission.more » Our sensitive single-dish observations provided a single detection when pointing toward the FHC L1448 IRS 2E. However, follow-up interferometric observations showed water maser emission associated with the nearby YSO L1448 IRS 2 (a Class 0 protostar of L {sub bol} ≃ 3.6–5.3 L {sub ⊙}) and did not find any emission toward L1448 IRS 2E. The upper limits for water maser emission determined by our observations are one order of magnitude lower than expected from the correlation between water maser luminosities and bolometric luminosities found for YSOs. This suggests that this correlation does not hold at the lower end of the (sub)stellar mass spectrum. Possible reasons are that the slope of this correlation is steeper at L {sub bol} ≤ 1 L {sub ⊙} or that there is an absolute luminosity threshold below which water maser emission cannot be produced. Alternatively, if the correlation still stands at low luminosity, the detection rates of masers would be significantly lower than the values obtained in higher-luminosity Class 0 protostars.« less

Black holes, disks, and jets following binary mergers and stellar collapse: The narrow range of electromagnetic luminosities and accretion rates.

PubMed

Shapiro, Stuart L

2017-05-15

We have performed magnetohydrodynamic simulations in general relativity of binary neutron star and binary black hole-neutron star mergers, as well as the magnetorotational collapse of supermassive stars. In many cases the outcome is a spinnng black hole (BH) immersed in a magnetized disk, with a jet emanating from the poles of the BH. While their formation scenarios differ and their BH masses, as well as their disk masses, densities, and magnetic field strengths, vary by orders of magnitude, these features conspire to generate jet Poynting luminosities that all lie in the same, narrow range of ~10 52±1 erg s -1 . A similar result applies to their BH accretion rates upon jet launch, which is ~0.1-10 M ⊙ s -1 . We provide a simple model that explains these unanticipated findings. Interestingly, these luminosities reside in the same narrow range characterizing the observed luminosity distributions of over 400 short and long GRBs with distances inferred from spectroscopic redshifts or host galaxies. This result, together with the GRB lifetimes predicted by the model, supports the belief that a compact binary merger is the progenitor of an SGRB, while a massive, stellar magnetorotational collapse is the progenitor of an LGRB.

Black holes, disks, and jets following binary mergers and stellar collapse: The narrow range of electromagnetic luminosities and accretion rates

PubMed Central

Shapiro, Stuart L.

2018-01-01

We have performed magnetohydrodynamic simulations in general relativity of binary neutron star and binary black hole-neutron star mergers, as well as the magnetorotational collapse of supermassive stars. In many cases the outcome is a spinnng black hole (BH) immersed in a magnetized disk, with a jet emanating from the poles of the BH. While their formation scenarios differ and their BH masses, as well as their disk masses, densities, and magnetic field strengths, vary by orders of magnitude, these features conspire to generate jet Poynting luminosities that all lie in the same, narrow range of ~1052±1 erg s−1. A similar result applies to their BH accretion rates upon jet launch, which is ~0.1–10 M⊙ s−1. We provide a simple model that explains these unanticipated findings. Interestingly, these luminosities reside in the same narrow range characterizing the observed luminosity distributions of over 400 short and long GRBs with distances inferred from spectroscopic redshifts or host galaxies. This result, together with the GRB lifetimes predicted by the model, supports the belief that a compact binary merger is the progenitor of an SGRB, while a massive, stellar magnetorotational collapse is the progenitor of an LGRB. PMID:29881790

The power of relativistic jets is larger than the luminosity of their accretion disks.

PubMed

Ghisellini, G; Tavecchio, F; Maraschi, L; Celotti, A; Sbarrato, T

2014-11-20

Theoretical models for the production of relativistic jets from active galactic nuclei predict that jet power arises from the spin and mass of the central supermassive black hole, as well as from the magnetic field near the event horizon. The physical mechanism underlying the contribution from the magnetic field is the torque exerted on the rotating black hole by the field amplified by the accreting material. If the squared magnetic field is proportional to the accretion rate, then there will be a correlation between jet power and accretion luminosity. There is evidence for such a correlation, but inadequate knowledge of the accretion luminosity of the limited and inhomogeneous samples used prevented a firm conclusion. Here we report an analysis of archival observations of a sample of blazars (quasars whose jets point towards Earth) that overcomes previous limitations. We find a clear correlation between jet power, as measured through the γ-ray luminosity, and accretion luminosity, as measured by the broad emission lines, with the jet power dominating the disk luminosity, in agreement with numerical simulations. This implies that the magnetic field threading the black hole horizon reaches the maximum value sustainable by the accreting matter.

The Discovery of Low-Luminosity BL Lacs

NASA Astrophysics Data System (ADS)

Rector, Travis A.; Stocke, John T.

1995-12-01

Many of the properties of BL Lacs have become explicable in terms of the ``relativistic beaming'' hypothesis whereby BL Lacs are ``highly beamed'' FR-I radio galaxies (i.e. our line of sight to these objects is nearly along the jet axis). Further, radio-selected BL Lacs (RBLs) are believed to be seen nearly ``on-axis'' (the line-of-sight angle theta ~ 8deg ) while X-ray selected BL Lacs (XBLs) are seen at larger angles (theta ~ 30deg ; the X-ray emitting jet is believed to be less collimated). However, a major problem with this model was that a transition population between beamed BL Lacs and unbeamed FR-Is had not been detected. Low-luminosity BL Lacs may be such a transition population, and were predicted to exist by Browne and Marcha (1993). We present ROSAT HRI images, VLA radio maps and optical spectra which confirm the existence of low-luminosity BL Lacs, objects which were previously mis-identified in the EMSS catalog as clusters of galaxies. Thus our results strengthen the relativistic beaming hypothesis.

The XXL Survey. II. The bright cluster sample: catalogue and luminosity function

NASA Astrophysics Data System (ADS)

Pacaud, F.; Clerc, N.; Giles, P. A.; Adami, C.; Sadibekova, T.; Pierre, M.; Maughan, B. J.; Lieu, M.; Le Fèvre, J. P.; Alis, S.; Altieri, B.; Ardila, F.; Baldry, I.; Benoist, C.; Birkinshaw, M.; Chiappetti, L.; Démoclès, J.; Eckert, D.; Evrard, A. E.; Faccioli, L.; Gastaldello, F.; Guennou, L.; Horellou, C.; Iovino, A.; Koulouridis, E.; Le Brun, V.; Lidman, C.; Liske, J.; Maurogordato, S.; Menanteau, F.; Owers, M.; Poggianti, B.; Pomarède, D.; Pompei, E.; Ponman, T. J.; Rapetti, D.; Reiprich, T. H.; Smith, G. P.; Tuffs, R.; Valageas, P.; Valtchanov, I.; Willis, J. P.; Ziparo, F.

2016-06-01

Context. The XXL Survey is the largest survey carried out by the XMM-Newton satellite and covers a total area of 50 square degrees distributed over two fields. It primarily aims at investigating the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. The survey will ultimately uncover several hundreds of galaxy clusters out to a redshift of ~2 at a sensitivity of ~10-14 erg s-1 cm-2 in the [0.5-2] keV band. Aims: This article presents the XXL bright cluster sample, a subsample of 100 galaxy clusters selected from the full XXL catalogue by setting a lower limit of 3 × 10-14 erg s-1 cm-2 on the source flux within a 1' aperture. Methods: The selection function was estimated using a mixture of Monte Carlo simulations and analytical recipes that closely reproduce the source selection process. An extensive spectroscopic follow-up provided redshifts for 97 of the 100 clusters. We derived accurate X-ray parameters for all the sources. Scaling relations were self-consistently derived from the same sample in other publications of the series. On this basis, we study the number density, luminosity function, and spatial distribution of the sample. Results: The bright cluster sample consists of systems with masses between M500 = 7 × 1013 and 3 × 1014 M⊙, mostly located between z = 0.1 and 0.5. The observed sky density of clusters is slightly below the predictions from the WMAP9 model, and significantly below the prediction from the Planck 2015 cosmology. In general, within the current uncertainties of the cluster mass calibration, models with higher values of σ8 and/or ΩM appear more difficult to accommodate. We provide tight constraints on the cluster differential luminosity function and find no hint of evolution out to z ~ 1. We also find strong evidence for the presence of large-scale structures in the XXL bright cluster sample and identify five new superclusters. Based on

The Velocity Distribution of Isolated Radio Pulsars

NASA Technical Reports Server (NTRS)

Arzoumanian, Z.; Chernoff, D. F.; Cordes, J. M.; White, Nicholas E. (Technical Monitor)

2002-01-01

We infer the velocity distribution of radio pulsars based on large-scale 0.4 GHz pulsar surveys. We do so by modelling evolution of the locations, velocities, spins, and radio luminosities of pulsars; calculating pulsed flux according to a beaming model and random orientation angles of spin and beam; applying selection effects of pulsar surveys; and comparing model distributions of measurable pulsar properties with survey data using a likelihood function. The surveys analyzed have well-defined characteristics and cover approx. 95% of the sky. We maximize the likelihood in a 6-dimensional space of observables P, dot-P, DM, absolute value of b, mu, F (period, period derivative, dispersion measure, Galactic latitude, proper motion, and flux density). The models we test are described by 12 parameters that characterize a population's birth rate, luminosity, shutoff of radio emission, birth locations, and birth velocities. We infer that the radio beam luminosity (i) is comparable to the energy flux of relativistic particles in models for spin-driven magnetospheres, signifying that radio emission losses reach nearly 100% for the oldest pulsars; and (ii) scales approximately as E(exp 1/2) which, in magnetosphere models, is proportional to the voltage drop available for acceleration of particles. We find that a two-component velocity distribution with characteristic velocities of 90 km/ s and 500 km/ s is greatly preferred to any one-component distribution; this preference is largely immune to variations in other population parameters, such as the luminosity or distance scale, or the assumed spin-down law. We explore some consequences of the preferred birth velocity distribution: (1) roughly 50% of pulsars in the solar neighborhood will escape the Galaxy, while approx. 15% have velocities greater than 1000 km/ s (2) observational bias against high velocity pulsars is relatively unimportant for surveys that reach high Galactic absolute value of z distances, but is severe for

Optical Variability of Two High-Luminosity Radio-Quiet Quasars, PDS 456 and PHL 1811

NASA Astrophysics Data System (ADS)

Gaskell, C. M.; Benker, A. J.; Campbell, J. S.; Crowley, K. A.; George, T. A.; Hedrick, C. H.; Hiller, M. E.; Klimek, E. S.; Leonard, J. P.; Peterson, B. W.; Sanders, K. M.

2003-12-01

PDS 456 and PHL 1811 are two of the highest luminosity low-redshift quasars. Both have optical luminosities comparable to 3C 273, but they have low radio luminosities. PDS 456 is a broad line object but PHL 1811 could be classified as a high-luminosity Narrow-Line Seyfert 1 (NLS1) object. We present the results of optical (V-band) continuum monitoring of PDS 456 and PHL 1811. We compare the variability properties of these two very different AGNs compared with the radio-loud AGN 3C 273, and we discuss the implications for the origin of the optical continuum variability in AGNs. This research has been supported in part by the Howard Hughes Foundation, Nebraska EPSCoR, the University of Nebraska Layman Fund, the University of Nebraska Undergraduate Creative Activities and Research Experiences, Pepsi-Cola, and the National Science Foundation through grant AST 03-07912.

A luminous hot accretion flow in the low-luminosity active galactic nucleus NGC 7213

NASA Astrophysics Data System (ADS)

Xie, Fu-Guo; Zdziarski, Andrzej A.; Ma, Renyi; Yang, Qi-Xiang

2016-12-01

The active galactic nucleus (AGN) NGC 7213 shows a complex correlation between the monochromatic radio luminosity LR and the 2-10 keV X-ray luminosity LX, I.e. the correlation is unusually weak with p ˜ 0 (in the form L_R∝ L_X^p) when LX is below a critical luminosity, and steep with p > 1 when LX is above that luminosity. Such a hybrid correlation in individual AGNs is unexpected as it deviates from the Fundamental Plane of AGN activity. Interestingly, a similar correlation pattern is observed in the black hole X-ray binary H1743-322, where it has been modelled by switching between different modes of accretion. We propose that the flat LR-LX correlation of NGC 7213 is due to the presence of a luminous hot accretion flow, an accretion model whose radiative efficiency is sensitive to the accretion rate. Given the low luminosity of the source, LX ˜ 10-4 of the Eddington luminosity, the viscosity parameter is determined to be small, α ≈ 0.01. We also modelled the broad-band spectrum from radio to γ-rays, the time lag between the radio and X-ray light curves, and the implied size and the Lorentz factor of the radio jet. We predict that NGC 7213 will enter into a two-phase accretion regime when LX ≳ 1.5 × 1042 erg s- 1. When this happens, we predict a softening of the X-ray spectrum with the increasing flux and a steep radio/X-ray correlation.

Do You See What I See? Exploring the Consequences of Luminosity Limits in Black Hole-Galaxy Evolution Studies

NASA Astrophysics Data System (ADS)

Jones, Mackenzie L.; Hickox, Ryan C.; Mutch, Simon J.; Croton, Darren J.; Ptak, Andrew F.; DiPompeo, Michael A.

2017-07-01

In studies of the connection between active galactic nuclei (AGNs) and their host galaxies, there is widespread disagreement on some key aspects of the connection. These disagreements largely stem from a lack of understanding of the nature of the full underlying AGN population. Recent attempts to probe this connection utilize both observations and simulations to correct for a missed population, but presently are limited by intrinsic biases and complicated models. We take a simple simulation for galaxy evolution and add a new prescription for AGN activity to connect galaxy growth to dark matter halo properties and AGN activity to star formation. We explicitly model selection effects to produce an “observed” AGN population for comparison with observations and empirically motivated models of the local universe. This allows us to bypass the difficulties inherent in models that attempt to infer the AGN population by inverting selection effects. We investigate the impact of selecting AGNs based on thresholds in luminosity or Eddington ratio on the “observed” AGN population. By limiting our model AGN sample in luminosity, we are able to recreate the observed local AGN luminosity function and specific star formation-stellar mass distribution, and show that using an Eddington ratio threshold introduces less bias into the sample by selecting the full range of growing black holes, despite the challenge of selecting low-mass black holes. We find that selecting AGNs using these various thresholds yield samples with different AGN host galaxy properties.

Do You See What I See? Exploring the Consequences of Luminosity Limits in Black Hole–Galaxy Evolution Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, Mackenzie L.; Hickox, Ryan C.; DiPompeo, Michael A.

In studies of the connection between active galactic nuclei (AGNs) and their host galaxies, there is widespread disagreement on some key aspects of the connection. These disagreements largely stem from a lack of understanding of the nature of the full underlying AGN population. Recent attempts to probe this connection utilize both observations and simulations to correct for a missed population, but presently are limited by intrinsic biases and complicated models. We take a simple simulation for galaxy evolution and add a new prescription for AGN activity to connect galaxy growth to dark matter halo properties and AGN activity to starmore » formation. We explicitly model selection effects to produce an “observed” AGN population for comparison with observations and empirically motivated models of the local universe. This allows us to bypass the difficulties inherent in models that attempt to infer the AGN population by inverting selection effects. We investigate the impact of selecting AGNs based on thresholds in luminosity or Eddington ratio on the “observed” AGN population. By limiting our model AGN sample in luminosity, we are able to recreate the observed local AGN luminosity function and specific star formation-stellar mass distribution, and show that using an Eddington ratio threshold introduces less bias into the sample by selecting the full range of growing black holes, despite the challenge of selecting low-mass black holes. We find that selecting AGNs using these various thresholds yield samples with different AGN host galaxy properties.« less

Cosmic reionization on computers: The faint end of the galaxy luminosity function

DOE PAGES

Gnedin, Nickolay Y.

2016-07-01

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

Cosmic reionization on computers: The faint end of the galaxy luminosity function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gnedin, Nickolay Y.

Using numerical cosmological simulations completed under the “Cosmic Reionization On Computers” project, I explore theoretical predictions for the faint end of the galaxy UV luminosity functions atmore » $$z\\gtrsim 6$$. A commonly used Schechter function approximation with the magnitude cut at $${M}_{{\\rm{cut}}}\\sim -13$$ provides a reasonable fit to the actual luminosity function of simulated galaxies. When the Schechter functional form is forced on the luminosity functions from the simulations, the magnitude cut $${M}_{{\\rm{cut}}}$$ is found to vary between -12 and -14 with a mild redshift dependence. Here, an analytical model of reionization from Madau et al., as used by Robertson et al., provides a good description of the simulated results, which can be improved even further by adding two physically motivated modifications to the original Madau et al. equation.« less

A Study of Low-mass X-Ray Binaries in the Low-luminosity Regime

NASA Astrophysics Data System (ADS)

Sonbas, E.; Dhuga, K. S.; Göğüş, E.

2018-02-01

A recent study of a small sample of X-ray binaries (XRBs) suggests a significant softening of spectra of neutron star (NS) binaries as compared to black hole (BH) binaries in the luminosity range 1034–1037 erg s‑1. This softening is quantified as an anticorrelation between the spectral index and the 0.5–10 keV X-ray luminosity. We extend the study to significantly lower luminosities (i.e., ∼a few × 1030 erg s‑1) for a larger sample of XRBs. We find evidence for a significant anticorrelation between the spectral index and the luminosity for a group of NS binaries in the luminosity range 1032–1033 erg s‑1. Our analysis suggests a steep slope for the correlation i.e., ‑2.12 ± 0.63. In contrast, BH binaries do not exhibit the same behavior. We examine the possible dichotomy between NS and BH binaries in terms of a Comptonization model that assumes a feedback mechanism between an optically thin hot corona and an optically thick cool source of soft photons. We gauge the NS–BH dichotomy by comparing the extracted corona temperatures, Compton-y parameters, and the Comptonization amplification factors: the mean temperature of the NS group is found to be significantly lower than the equivalent temperature for the BH group. The extracted Compton-y parameters and the amplification factors follow the theoretically predicted relation with the spectral index.

On the luminosity function, lifetimes, and origin of blue stragglers in globular clusters

NASA Technical Reports Server (NTRS)

Bailyn, Charles D.; Pinsonneault, Marc H.

1995-01-01

We compute theoretical evolutionary tracks of blue stragglers created by mergers. Two formation scenarios are considered: mergers of primordial binaries, and stellar collisions. These two scenarios predict strikingly different luminosity functions, which are potentially distinguishable observationally. Tabulated theoretical luminosity functions and lifetimes are presented for blue stragglers formed under a variety of input conditions. We compare our results with observations of the blue straggler sequences in 47 Tucanae and M3. In the case of 47 Tuc, the luminosity function and the formation rate are compatible with the hypothesis that the blue stragglers formed through the collision of single stars. Mergers of primordial binaries are only marginally cosistent with the data, and a significant enhancement of the collision cross section by binary-single-star encounters appears to be ruled out. In the case of M3, we find that the innermost blue stragglers have a luminosity function significantly different from that of the outer stragglers, thus confirming earlier suggestions that there are two distinct populations of blue stragglers in this cluster. The inner stragglers are preferentially brighter and bluer, as would be expected if they were made by collisions, but there are so many of them that the collision rate would need to be enhanced by interactions involving wide binaries. The luminosity function of the outer stragglers is almost identical to the predictions of mergers from primordial binaries and is inconsistent with the collision hypothesis.

The structure of galaxies : the division of stellar mass by morphological type and structural component

NASA Astrophysics Data System (ADS)

Kelvin, Lee Steven

This thesis explores the relation between galaxy structure, morphology and stellar mass. In the first part I present single-Sersic two-dimensional model fits to 167,600 galaxies modelled independently in the ugrizYJHK bandpasses using reprocessed Sloan Digital Sky Survey Data Release Seven (SDSS DR7) and UKIRT Infrared Deep Sky Survey Large Area Survey (UKIDSS LAS) imaging data available via the Galaxy and Mass Assembly (GAMA) data base. In order to facilitate this study, we developed Structural Investigation of Galaxies via Model Analysis (SIGMA): an automated wrapper around several contemporary astronomy software packages. We confirm that variations in global structural measurements with wavelength arise due to the effects of dust attenuation and stellar population/metallicity gradients within galaxies. In the second part of this thesis we establish a volume-limited sample of 3,845 galaxies in the local Universe and visually classify these galaxies according to their morphological Hubble type. We find that single-Sersic photometry accurately reproduces the morphology luminosity functions predicted in the literature. We employ multi-component Sersic profiling to provide bulge-disk decompositions for this sample, allowing for the luminosity and stellar mass to be divided between the key structural components: spheroids and disks. Grouping the stellar mass in these structures by the evolutionary mechanisms that formed them, we find that hot-mode collapse, merger or otherwise turbulent mechanisms account for ~46% of the total stellar mass budget, cold-mode gas accretion and splashback mechanisms account for ~48% of the total stellar mass budget and secular evolutionary processes for ~6.5% of the total stellar mass budget in the local (z<0.06) Universe.

The nature of very low luminosity objects (VeLLOs)

NASA Astrophysics Data System (ADS)

Vorobyov, Eduard I.; Elbakyan, Vardan; Dunham, Michael M.; Guedel, Manuel

2017-04-01

Aims: The nature of very low luminosity objects (VeLLOs) with the internal luminosity Lobj ≤ 0.1 L⊙ is investigated by means of numerical modeling coupling the core collapse simulations with the stellar evolution calculations. Methods: The gravitational collapse of a large sample of model cores in the mass range 0.1-2.0 M⊙ is investigated. Numerical simulations were started at the pre-stellar phase and terminated at the end of the embedded phase when 90% of the initial core mass had been accreted onto the forming protostar plus disk system. The disk formation and evolution was studied using numerical hydrodynamics simulations, while the formation and evolution of the central star was calculated using a stellar evolution code. Three scenarios for mass accretion from the disk onto the star were considered: hybrid accretion in which a fraction of accreted energy absorbed by the protostar depends on the accretion rate, hot accretion wherein a fraction of accreted energy is constant, and cold accretion wherein all accretion energy is radiated away. Results: Our conclusions on the nature of VeLLOs depend crucially on the character of protostellar accretion. In the hybrid accretion scenario, most VeLLOs (90.6%) are expected to be the first hydrostatic cores (FHSCs) and only a small fraction (9.4%) are true protostars. In the hot accretion scenario, all VeLLOs are FHSCs due to overly high photospheric luminosity of protostars. In the cold accretion scenario, on the contrary, the majority of VeLLOs belong to the Class I phase of stellar evolution. The reason is that the stellar photospheric luminosity, which sets the floor for the total internal luminosity of a young star, is lower in cold accretion, thus enabling more VeLLOs in the protostellar stage. VeLLOs are relatively rare objects occupying 7%-11% of the total duration of the embedded phase and their masses do not exceed 0.3 M⊙. When compared with published observations inferring a fraction of VeLLOs in the

The Radio Luminosity Function and Galaxy Evolution in the Coma Cluster

NASA Technical Reports Server (NTRS)

Miller, Neal A.; Hornschemeier, Ann E.; Mabasher, Bahram; Brudgesm Terrry J.; Hudson, Michael J.; Marzke, Ronald O.; Smith, Russell J.

2008-01-01

We investigate the radio luminosity function and radio source population for two fields within the Coma cluster of galaxies, with the fields centered on the cluster core and southwest infall region and each covering about half a square degree. Using VLA data with a typical rms sensitivity of 28 (mu)Jy per 4.4" beam, we identify 249 radio sources with optical counterparts brighter than r = 22 (equivalent to M(sub r) = -13 for cluster member galaxies). Comprehensive optical spectroscopy identifies 38 of these as members of the Coma cluster, evenly split between sources powered by an active nucleus and sources powered by active star formation. The radio-detected star-forming galaxies are restricted to radio luminosities between about 10(exp 21) and 10(exp 22) W/Hz, an interesting result given that star formation dominates field radio luminosity functions below about 10(exp 23) W/Hz. The majority of the radio-detected star-forming galaxies have characteristics of starbursts, including high specific star formation rates and optical spectra with strong emission lines. In conjunction with prior studies on post-starburst galaxies within the Coma cluster, this is consistent with a picture in which late-type galaxies entering Coma undergo a starburst prior to a rapid cessation of star formation. Optically bright elliptical galaxies (Mr less than or equals -20.5) make the largest contribution to the radio luminosity function at both the high (> approx. 3x10(exp 22) W/Hz) and low (< approx. 10(exp 21) W/Hz) ends. Through a stacking analysis of these optically-bright ellipticals we find that they continue to harbor radio sources down to luminosities as faint as 3x10(exp 19) W/Hz. However, contrary to published results for the Virgo cluster we find no evidence for the existence of a population of optically faint (M(sub r) approx. equals -14) dwarf ellipticals hosting strong radio AGN.

Critical radiation fluxes and luminosities of black holes and relativistic stars

NASA Technical Reports Server (NTRS)

Lamb, Frederick K.; Miller, M. Coleman

1995-01-01

The critial luminosity at which the outward force of radiation balances the inward force of gravity plays an important role in many astrophysical systems. We present expressions for the radiation force on particles with arbitrary cross sections and analyze the radiation field produced by radiating matter, such as a disk, ring, boundary layer, or stellar surface, that rotates slowly around a slowly rotating gravitating mass. We then use these results to investigate the critical radiation flux and, where possible, the critical luminosity of such a system in genral relativity. We demonstrate that if the radiation source is axisymmetric and emission is back-front symmetric with repect to the local direction of motion of the radiating matter, as seen in the comoving frame, then the radial component of the radiation flux and the diagonal components of the radiation stress-energy tensor outside the source are the same, to first order in the rotation rates, as they would be if the radiation source and gravitating mass were not rotating. We argue that the critical radiation flux for matter at rest in the locally nonrotating frame is often satisfactory as an astrophysical benchmark flux and show that if this benchmark is adopted, many of the complications potentially introduced by rotation of the radiation source and the gravitating mass are avoided. We show that if the radiation field in the absence of rotation would be spherically symmetric and the opacity is independent of frequency and direction, one can define a critical luminosity for the system that is independent of frequency and direction, one can define a critical luminosity for the system that is independent of the spectrum and angular size of the radiation source and is unaffected by rotation of the source and mass and orbital motion of the matter, to first order. Finally, we analyze the conditions under which the maximum possible luminosity of a star or black hole powered by steady spherically symmetric radial

Cosmic evolution of AGN with moderate-to-high radiative luminosity in the COSMOS field

NASA Astrophysics Data System (ADS)

Ceraj, L.; Smolčić, V.; Delvecchio, I.; Delhaize, J.; Novak, M.

2018-05-01

We study the moderate-to-high radiative luminosity active galactic nuclei (HLAGN) within the VLA-COSMOS 3 GHz Large Project. The survey covers 2.6 square degrees centered on the COSMOS field with a 1σ sensitivity of 2.3 μJy/beam across the field. This provides the simultaneously largest and deepest radio continuum survey available to date with exquisite multi-wavelength coverage. The survey yields 10,830 radio sources with signal-to-noise ratios >=5. A subsample of 1,604 HLAGN is analyzed here. These were selected via a combination of X-ray luminosity and mid-infrared colors. We derive luminosity functions for these AGN and constrain their cosmic evolution out to a redshift of z ~ 6, for the first time decomposing the star formation and AGN contributions to the radio continuum emission in the AGN. We study the evolution of number density and luminosity density finding a peak at z ~ 1.5 followed by a decrease out to a redshift z ~ 6.

Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-04-01

The luminosity function of short Gamma Ray Bursts (GRBs) is modelled by using the available catalogue data of all short GRBs (sGRBs) detected till October, 2017. The luminosities are estimated via the `pseudo-redshifts' obtained from the `Yonetoku correlation', assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. While the simple powerlaw is ruled out to high confidence, the data is fit well both by exponential cutoff powerlaw and broken powerlaw models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of short GRBs are derived. Assuming a short GRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present and future configurations of the GW detector networks. Stringent lower limits of 1.87yr-1 for the aLIGO-VIRGO, and 3.11yr-1 for the upcoming aLIGO-VIRGO-KAGRA-LIGO/India configurations are thus derived for the BNSM rate at 68% confidence. The BNSM rates calculated from this work and that independently inferred from the observation of the only confirmed BNSM observed till date, are shown to have a mild tension; however the scenario that all BNSMs produce sGRBs cannot be ruled out.

Clustering, Cosmology and a New Era of Black Hole Demographics: The Conditional Luminosity Function of AGNs

NASA Astrophysics Data System (ADS)

Ballantyne, David R.

2016-04-01

Deep X-ray surveys have provided a comprehensive and largely unbiased view of AGN evolution stretching back to z˜5. However, it has been challenging to use the survey results to connect this evolution to the cosmological environment that AGNs inhabit. Exploring this connection will be crucial to understanding the triggering mechanisms of AGNs and how these processes manifest in observations at all wavelengths. In anticipation of upcoming wide-field X-ray surveys that will allow quantitative analysis of AGN environments, we present a method to observationally constrain the Conditional Luminosity Function (CLF) of AGNs at a specific z. Once measured, the CLF allows the calculation of the AGN bias, mean dark matter halo mass, AGN lifetime, halo occupation number, and AGN correlation function - all as a function of luminosity. The CLF can be constrained using a measurement of the X-ray luminosity function and the correlation length at different luminosities. The method is demonstrated at z ≈0 and 0.9, and clear luminosity dependence in the AGN bias and mean halo mass is predicted at both z. The results support the idea that there are at least two different modes of AGN triggering: one, at high luminosity, that only occurs in high mass, highly biased haloes, and one that can occur over a wide range of halo masses and leads to luminosities that are correlated with halo mass. This latter mode dominates at z<0.9. The CLFs for Type 2 and Type 1 AGNs are also constrained at z ≈0, and we find evidence that unobscured quasars are more likely to be found in higher mass halos than obscured quasars. Thus, the AGN unification model seems to fail at quasar luminosities.

Correlations of the IR Luminosity and Eddington Ratio with a Hard X-ray Selected Sample of AGN

NASA Technical Reports Server (NTRS)

Mushotzy, Richard F.; Winter, Lisa M.; McIntosh, Daniel H.; Tueller, Jack

2008-01-01

We use the SWIFT Burst Alert Telescope (BAT) sample of hard x-ray selected active galactic nuclei (AGN) with a median redshift of 0.03 and the 2MASS J and K band photometry to examine the correlation of hard x-ray emission to Eddington ratio as well as the relationship of the J and K band nuclear luminosity to the hard x-ray luminosity. The BAT sample is almost unbiased by the effects of obscuration and thus offers the first large unbiased sample for the examination of correlations between different wavelength bands. We find that the near-IR nuclear J and K band luminosity is related to the BAT (14 - 195 keV) luminosity over a factor of 10(exp 3) in luminosity (L(sub IR) approx.equals L(sub BAT)(sup 1.25) and thus is unlikely to be due to dust. We also find that the Eddington ratio is proportional to the x-ray luminosity. This new result should be a strong constraint on models of the formation of the broad band continuum.

The X-Ray and Mid-infrared Luminosities in Luminous Type 1 Quasars

NASA Astrophysics Data System (ADS)

Chen, Chien-Ting J.; Hickox, Ryan C.; Goulding, Andrew D.; Stern, Daniel; Assef, Roberto; Kochanek, Christopher S.; Brown, Michael J. I.; Harrison, Chris M.; Hainline, Kevin N.; Alberts, Stacey; Alexander, David M.; Brodwin, Mark; Del Moro, Agnese; Forman, William R.; Gorjian, Varoujan; Jones, Christine; Murray, Stephen S.; Pope, Alexandra; Rovilos, Emmanouel

2017-03-01

Several recent studies have reported different intrinsic correlations between the active galactic nucleus (AGN) mid-IR luminosity ({L}MIR}) and the rest-frame 2–10 keV luminosity (L X) for luminous quasars. To understand the origin of the difference in the observed {L}{{X}}{--}{L}MIR} relations, we study a sample of 3247 spectroscopically confirmed type 1 AGNs collected from Boötes, XMM-COSMOS, XMM-XXL-North, and the Sloan Digital Sky Survey quasars in the Swift/XRT footprint spanning over four orders of magnitude in luminosity. We carefully examine how different observational constraints impact the observed {L}{{X}}{--}{L}MIR} relations, including the inclusion of X-ray-nondetected objects, possible X-ray absorption in type 1 AGNs, X-ray flux limits, and star formation contamination. We find that the primary factor driving the different {L}{{X}}{--}{L}MIR} relations reported in the literature is the X-ray flux limits for different studies. When taking these effects into account, we find that the X-ray luminosity and mid-IR luminosity (measured at rest-frame 6 μ {{m}}, or {L}6μ {{m}}) of our sample of type 1 AGNs follow a bilinear relation in the log–log plane: {log}{L}{{X}}=(0.84+/- 0.03)× {log}{L}6μ {{m}}/{10}45 erg s‑1 + (44.60 ± 0.01) for {L}6μ {{m}}< {10}44.79 erg s‑1, and {log}{L}{{X}}=(0.40+/- 0.03)× {log}{L}6μ {{m}}/{10}45 erg s‑1 + (44.51 ± 0.01) for {L}6μ {{m}} ≥slant {10}44.79 erg s‑1. This suggests that the luminous type 1 quasars have a shallower {L}{{X}}{--}{L}6μ {{m}} correlation than the approximately linear relations found in local Seyfert galaxies. This result is consistent with previous studies reporting a luminosity-dependent {L}{{X}}{--}{L}MIR} relation and implies that assuming a linear {L}{{X}}{--}{L}6μ {{m}} relation to infer the neutral gas column density for X-ray absorption might overestimate the column densities in luminous quasars.

Effects of variability of X-ray binaries on the X-ray luminosity functions of Milky Way

NASA Astrophysics Data System (ADS)

Islam, Nazma; Paul, Biswajit

2016-08-01

The X-ray luminosity functions of galaxies have become a useful tool for population studies of X-ray binaries in them. The availability of long term light-curves of X-ray binaries with the All Sky X-ray Monitors opens up the possibility of constructing X-ray luminosity functions, by also including the intensity variation effects of the galactic X-ray binaries. We have constructed multiple realizations of the X-ray luminosity functions (XLFs) of Milky Way, using the long term light-curves of sources obtained in the 2-10 keV energy band with the RXTE-ASM. The observed spread seen in the value of slope of both HMXB and LMXB XLFs are due to inclusion of variable luminosities of X-ray binaries in construction of these XLFs as well as finite sample effects. XLFs constructed for galactic HMXBs in the luminosity range 1036-1039 erg/sec is described by a power-law model with a mean power-law index of -0.48 and a spread due to variability of HMXBs as 0.19. XLFs constructed for galactic LMXBs in the luminosity range 1036-1039 erg/sec has a shape of cut-off power-law with mean power-law index of -0.31 and a spread due to variability of LMXBs as 0.07.

The VIMOS Ultra Deep Survey. Luminosity and stellar mass dependence of galaxy clustering at z 3

NASA Astrophysics Data System (ADS)

Durkalec, A.; Le Fèvre, O.; Pollo, A.; Zamorani, G.; Lemaux, B. C.; Garilli, B.; Bardelli, S.; Hathi, N.; Koekemoer, A.; Pforr, J.; Zucca, E.

2018-04-01

We present a study of the dependence of galaxy clustering on luminosity and stellar mass in the redshift range 2 < z < 3.5 using 3236 galaxies with robust spectroscopic redshifts from the VIMOS Ultra Deep Survey (VUDS), covering a total area of 0.92 deg2. We measured the two-point real-space correlation function wp(rp) for four volume-limited subsamples selected by stellar mass and four volume-limited subsamples selected by MUV absolute magnitude. We find that the scale-dependent clustering amplitude r0 significantly increases with increasing luminosity and stellar mass. For the least luminous galaxies (MUV < -19.0), we measured a correlation length r0 = 2.87 ± 0.22 h-1 Mpc and slope γ = 1.59 ± 0.07, while for the most luminous (MUV < -20.2) r0 = 5.35 ± 0.50 h-1 Mpc and γ = 1.92 ± 0.25. These measurements correspond to a strong relative bias between these two subsamples of Δb/b* = 0.43. Fitting a five-parameter halo occupation distribution (HOD) model, we find that the most luminous (MUV < -20.2) and massive (M⋆ > 1010 h-1 M⊙) galaxies occupy the most massive dark matter haloes with ⟨Mh⟩ = 1012.30 h-1 M⊙. Similar to the trends observed at lower redshift, the minimum halo mass Mmin depends on the luminosity and stellar mass of galaxies and grows from Mmin = 109.73 h-1 M⊙ to Mmin = 1011.58 h-1 M⊙ from the faintest to the brightest among our galaxy sample, respectively. We find the difference between these halo masses to be much more pronounced than is observed for local galaxies of similar properties. Moreover, at z 3, we observe that the masses at which a halo hosts, on average, one satellite and one central galaxy is M1 ≈ 4Mmin over all luminosity ranges, which is significantly lower than observed at z 0; this indicates that the halo satellite occupation increases with redshift. The luminosity and stellar mass dependence is also reflected in the measurements of the large-scale galaxy bias, which we model as bg,HOD (>L) = 1.92 + 25.36(L/L*)7

A multiparametric analysis of the Einstein sample of early-type galaxies. 1: Luminosity and ISM parameters

NASA Technical Reports Server (NTRS)

Eskridge, Paul B.; Fabbiano, Giuseppina; Kim, Dong-Woo

1995-01-01

We have conducted bivariate and multivariate statistical analysis of data measuring the luminosity and interstellar medium of the Einstein sample of early-type galaxies (presented by Fabbiano, Kim, & Trinchieri 1992). We find a strong nonlinear correlation between L(sub B) and L(sub X), with a power-law slope of 1.8 +/- 0.1, steepening to 2.0 +/- if we do not consider the Local Group dwarf galaxies M32 and NGC 205. Considering only galaxies with log L(sub X) less than or equal to 40.5, we instead find a slope of 1.0 +/- 0.2 (with or without the Local Group dwarfs). Although E and S0 galaxies have consistent slopes for their L(sub B)-L(sub X) relationships, the mean values of the distribution functions of both L(sub X) and L(sub X)/L(sub B) for the S0 galaxies are lower than those for the E galaxies at the 2.8 sigma and 3.5 sigma levels, respectively. We find clear evidence for a correlation between L(sub X) and the X-ray color C(sub 21), defined by Kim, Fabbiano, & Trinchieri (1992b), which indicates that X-ray luminosity is correlated with the spectral shape below 1 keV in the sense that low-L(sub X) systems have relatively large contributions from a soft component compared with high-L(sub X) systems. We find evidence from our analysis of the 12 micron IRAS data for our sample that our S0 sample has excess 12 micron emission compared with the E sample, scaled by their optical luminosities. This may be due to emission from dust heated in star-forming regions in S0 disks. This interpretation is reinforced by the existence of a strong L(sub 12)-L(sub 100) correlation for our S0 sample that is not found for the E galaxies, and by an analysis of optical-IR colors. We find steep slopes for power-law relationships between radio luminosity and optical, X-ray, and far-IR (FIR) properties. This last point argues that the presence of an FIR-emitting interstellar medium (ISM) in early-type galaxies is coupled to their ability to generate nonthermal radio continuum, as

Formation and Recondensation of Complex Organic Molecules During Protostellar Luminosity Outbursts

NASA Technical Reports Server (NTRS)

Taquet, Vianney; Wirstrom, Eva S.; Charnley, Steven B.

2016-01-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion-molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

Formation and Recondensation of Complex Organic Molecules during Protostellar Luminosity Outbursts

NASA Astrophysics Data System (ADS)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-04-01

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The model calculations presented here demonstrate that ion-molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.

FORMATION AND RECONDENSATION OF COMPLEX ORGANIC MOLECULES DURING PROTOSTELLAR LUMINOSITY OUTBURSTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taquet, Vianney; Wirström, Eva S.; Charnley, Steven B.

2016-04-10

During the formation of stars, the accretion of surrounding material toward the central object is thought to undergo strong luminosity outbursts followed by long periods of relative quiescence, even at the early stages of star formation when the protostar is still embedded in a large envelope. We investigated the gas-phase formation and recondensation of the complex organic molecules (COMs) di-methyl ether and methyl formate, induced by sudden ice evaporation processes occurring during luminosity outbursts of different amplitudes in protostellar envelopes. For this purpose, we updated a gas-phase chemical network forming COMs in which ammonia plays a key role. The modelmore » calculations presented here demonstrate that ion–molecule reactions alone could account for the observed presence of di-methyl ether and methyl formate in a large fraction of protostellar cores without recourse to grain-surface chemistry, although they depend on uncertain ice abundances and gas-phase reaction branching ratios. In spite of the short outburst timescales of about 100 years, abundance ratios of the considered species higher than 10% with respect to methanol are predicted during outbursts due to their low binding energies relative to water and methanol which delay their recondensation during cooling. Although the current luminosity of most embedded protostars would be too low to produce complex organics in the hot-core regions that are observable with current sub-millimetric interferometers, previous luminosity outburst events would induce the formation of COMs in extended regions of protostellar envelopes with sizes increasing by up to one order of magnitude.« less

The Abundance of Low-Luminosity Lyα Emitters at High Redshift

NASA Astrophysics Data System (ADS)

Santos, Michael R.; Ellis, Richard S.; Kneib, Jean-Paul; Richard, Johan; Kuijken, Konrad

2004-05-01

We derive the luminosity function of high-redshift Lyα-emitting sources from a deep, blind, spectroscopic survey that utilized strong-lensing magnification by intermediate-redshift clusters of galaxies. We observed carefully selected regions near nine clusters, consistent with magnification factors generally greater than 10 for the redshift range 4.5luminosity function to unprecedented limits of 1040 ergs s -1, corresponding to a star formation rate of 0.01 Msolar yr-1. Our cumulative z~=5 Lyα luminosity function is consistent with a power-law form n(>L)~L-1 over 1041-1042.5 ergs s-1. When combined with the results of other surveys, limited at higher luminosities, our results suggest evidence for the suppression of star formation in low-mass halos, as predicted in popular models of galaxy formation. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Quantitative evidence of an intrinsic luminosity spread in the Orion nebula cluster

NASA Astrophysics Data System (ADS)

Reggiani, M.; Robberto, M.; Da Rio, N.; Meyer, M. R.; Soderblom, D. R.; Ricci, L.

2011-10-01

Aims: We study the distribution of stellar ages in the Orion nebula cluster (ONC) using accurate HST photometry taken from HST Treasury Program observations of the ONC utilizing the cluster distance estimated by Menten and collaborators. We investigate whether there is an intrinsic age spread in the region and whether the age depends on the spatial distribution. Methods: We estimate the extinction and accretion luminosity towards each source by performing synthetic photometry on an empirical calibration of atmospheric models using the package Chorizos of Maiz-Apellaniz. The position of the sources in the HR-diagram is compared with different theoretical isochrones to estimate the mean cluster age and age dispersion. On the basis of Monte Carlo simulations, we quantify the amount of intrinsic age spread in the region, taking into account uncertainties in the distance, spectral type, extinction, unresolved binaries, accretion, and photometric variability. Results: According to the evolutionary models of Siess and collaborators, the mean age of the Cluster is 2.2 Myr with a scatter of few Myr. With Monte Carlo simulations, we find that the observed age spread is inconsistent with that of a coeval stellar population, but in agreement with a star formation activity between 1.5 and 3.5 Myr. We also observe some evidence that ages depends on the spatial distribution.

A high-redshift IRAS galaxy with huge luminosity - Hidden quasar or protogalaxy?

NASA Technical Reports Server (NTRS)

Rowan-Robinson, M.; Broadhurst, T.; Oliver, S. J.; Taylor, A. N.; Lawrence, A.; Mcmahon, R. G.; Lonsdale, C. J.; Hacking, P. B.; Conrow, T.

1991-01-01

An emission line galaxy with the enormous far-IR luminosity of 3 x 10 to the 14th solar has been found at z = 2.286. The spectrum is very unusual, showing lines of high excitation but with very weak Lyman-alpha emission. A self-absorbed synchrotron model for the IR energy distribution cannot be ruled out, but a thermal origin seems more plausible. A radio-quiet quasar embedded in a very dusty galaxy could account for the IR emission, as might a starburst embedded in 1-10 billion solar masses of dust. The latter case demands so much dust that the object would probably be a massive galaxy in the process of formation. The presence of a large amount of dust in an object of such high redshift implies the generation of heavy elements at an early cosmological epoch.

Morphology and luminosity segregation of galaxies in nearby loose groups

NASA Astrophysics Data System (ADS)

Girardi, M.; Rigoni, E.; Mardirossian, F.; Mezzetti, M.

2003-08-01

We study morphology and luminosity segregation of galaxies in loose groups. We analyze the two catalogs of groups identified in the Nearby Optical Galaxy (NOG) sample, by means of hierarchical and percolation ``friends-of-friends'' methods (HG and PG catalogs, respectively). In the first part of our analysis we consider 387 and 436 groups of HG and PG and compare morphology- (luminosity-) weighted to unweighted group properties: velocity dispersion, mean pairwise distance, and mean groupcentric distance of member galaxies. The second part of our analysis is based on two ensemble systems, one for each catalog, built by suitably combining together galaxies of all groups (1584 and 1882 galaxies for HG and PG groups). We find that earlier-type (brighter) galaxies are more clustered and lie closer to the group centers, both in position and in velocity, than later-type (fainter) galaxies. Spatial segregations are stronger than kinematical segregations. These effects are generally detected at the >˜ 3-sigma level. Luminosity segregation is shown to be independent of morphology segregation. Our main conclusions are strengthened by the detection of segregation in both hierarchical and percolation catalogs. Our results agree with a continuum of segregation properties of galaxies in systems, from low-mass groups to massive clusters.

The graviton luminosity of the sun and other stars

NASA Technical Reports Server (NTRS)

Gould, R. J.

1985-01-01

Graviton production in electron-electron (e-e) and electron-ion (e-z) scattering is evaluated in the Born approximation. The calculation is compared with that for photon production, that is, Coulomb quadrupole bremsstrahlung, and a number of results are taken over from that problem. Application is made to the sun, and it is found that for the solar plasma the main contribution to the graviton luminosity comes from the central core at r/R approximately 0.1. The total luminosity (Lg) in gravitons is about 7.9 x 10 to the 14th ergs/s, close to an earlier estimate by Weinberg (1965, 1972); about 33 percent of the total results from e-e collisions with the rest from e-z collisions (mainly e-p and e-alpha). Approximate corrections to Born formulas are evaluated, and this Lg includes the associated (approximately + or - 10 percent, respectively) modification. The quantum-mechanical aspects of the solar Lg problem are discussed, and it is shown why a previous classical calculation overestimated Lg by about an order of magnitude. Production of gravitons in binary collisions in other types of stars is discussed briefly. It is found that Lg varies very little along the main sequence. White dwarfs have a typical graviton luminosity LWD approximately 10 to the 19th ergs/s, while neutron stars have LNS approximately 10 to the 25th ergs/s; these estimates are very rough.

THE DISTRIBUTION OF FAINT SATELLITES AROUND CENTRAL GALAXIES IN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, C. Y.; Jing, Y. P.; Li, Cheng

2012-11-20

We investigate the radial number density profile and the abundance distribution of faint satellites around central galaxies in the low-redshift universe using the Canada-France-Hawaii Telescope (CFHT) Legacy Survey. We consider three samples of central galaxies with magnitudes of M {sub r} = -21, -22, and -23 selected from the Sloan Digital Sky Survey group catalog of Yang et al. The satellite distribution around these central galaxies is obtained by cross-correlating these galaxies with the photometric catalog of the CFHT Legacy Survey. The projected radial number density of the satellites obeys a power-law form with the best-fit logarithmic slope of -1.05,more » independent of both the central galaxy luminosity and the satellite luminosity. The projected cross-correlation function between central and satellite galaxies exhibits a non-monotonic trend with satellite luminosity. It is most pronounced for central galaxies with M {sub r} = -21, where the decreasing trend of clustering amplitude with satellite luminosity is reversed when satellites are fainter than central galaxies by more than 2 mag. A comparison with the satellite luminosity functions in the Milky Way (MW) and M31 shows that the MW/M31 system has about twice as many satellites as around a typical central galaxy of similar luminosity. The implications for theoretical models are briefly discussed.« less

Luminosity segregation in galaxy clusters as an indication of dynamical evolution

NASA Technical Reports Server (NTRS)

Baier, F. W.; Schmidt, K.-H.

1993-01-01

Theoretical models describing the dynamical evolution of self-gravitating systems predict a spatial mass segregation for more evolved systems, with the more massive objects concentrated toward the center of the configuration. From the observational point of view, however, the existence of mass segregation in galaxy clusters seems to be a matter of controversy. A special problem in this connection is the formation of cD galaxies in the centers of galaxy clusters. The most promising scenarios of their formation are galaxy cannibalism (merger scenario) and growing by cooling flows. It seems to be plausible to consider the swallowing of smaller systems by a dominant galaxy as an important process in the evolution of a cD galaxy. The stage of the evolution of the dominant galaxy should be reflected by the surrounding galaxy population, especially by possible mass segregation effects. Assuming that mass segregation is tantamount to luminosity segregation we analyzed luminosity segregation in roughly 40 cD galaxy clusters. Obviously there are three different groups of clusters: (1) clusters with luminosity segregation, (2) clusters without luminosity segregation, and (3) such objects exhibiting a phenomenon which we call antisegregation in luminosity, i.e. a deficiency of bright galaxies in the central regions of clusters. This result is interpreted in the sense of different degrees of mass segregation and as an indication for different evolution stages of these clusters. The clusters are arranged in the three segregation classes 2, 1, and 0 (S2 = strong mass segregation, S1 = moderate mass segregation, S0 = weak or absent mass segregation). We assume that a galaxy cluster starts its dynamical evolution after virialization without any radial mass segregation. Energy exchange during encounters of cluster members as well as merger processes between cluster galaxies lead to an increasing radial mass segregation in the cluster (S1). If a certain degree of segregation (S2) has

Luminosity determination in pp collisions at √{s} = 8 TeV using the ATLAS detector at the LHC

NASA Astrophysics Data System (ADS)

Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Verzini, M. J. Alconada; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alstaty, M.; Gonzalez, B. Alvarez; Piqueras, D. Álvarez; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Coutinho, Y. Amaral; Amelung, C.; Amidei, D.; Santos, S. P. Amor Dos; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Anulli, F.; Aoki, M.; Bella, L. Aperio; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Navarro, L. Barranco; Barreiro, F.; da Costa, J. Barreiro Guimarães; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Noccioli, E. Benhar; Benitez, J.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Kuutmann, E. Bergeaas; Berger, N.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bylund, O. Bessidskaia; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; De Mendizabal, J. Bilbao; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bokan, P.; Bold, T.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Sola, J. D. Bossio; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Madden, W. D. Breaden; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; de Renstrom, P. A. Bruckman; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Bruni, L. S.; Brunt, BH; Bruschi, M.; Bruscino, N.; Bryant, P.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. A.; Buehrer, F.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burka, K.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Urbán, S. Cabrera; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Calvet, T. P.; Toro, R. Camacho; Camarda, S.; Camarri, P.; Cameron, D.; Armadans, R. Caminal; Camincher, C.; Campana, S.; Campanelli, M.; Camplani, A.; Campoverde, A.; Canale, V.; Canepa, A.; Bret, M. Cano; Cantero, J.; Cantrill, R.; Cao, T.; Garrido, M. D. M. Capeans; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, I.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. W.; Castaneda-Miranda, E.; Castelijn, R.; Castelli, A.; Gimenez, V. Castillo; Castro, N. F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavallaro, E.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Alberich, L. Cerda; Cerio, B. C.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chan, S. K.; Chan, Y. L.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chatterjee, A.; Chau, C. C.; Barajas, C. A. Chavez; Che, S.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, H. J.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Moursli, R. Cherkaoui El; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chomont, A. R.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Citterio, M.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, M. R.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Colasurdo, L.; Cole, B.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Muiño, P. Conde; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cormier, K. J. R.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Crawley, S. J.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Ortuzar, M. Crispin; Cristinziani, M.; Croft, V.; Crosetti, G.; Donszelmann, T. Cuhadar; Cummings, J.; Curatolo, M.; Cúth, J.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'amen, G.; D'Auria, S.; D'Onofrio, M.; De Sousa, M. J. Da Cunha Sargedas; Via, C. Da; Dabrowski, W.; Dado, T.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Hoffmann, M. Dano; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Maria, A.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Regie, J. B. De Vivie; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Dehghanian, N.; Deigaard, I.; Del Gaudio, M.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Clemente, W. K.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Du, Y.; Duarte-Campderros, J.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duffield, E. M.; Duflot, L.; Duguid, L.; Dührssen, M.; Dumancic, M.; Dunford, M.; Yildiz, H. Duran; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edwards, N. C.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; Kacimi, M. El; Ellajosyula, V.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Ennis, J. S.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, F.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farina, C.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Giannelli, M. Faucci; Favareto, A.; Fawcett, W. J.; Fayard, L.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Martinez, P. Fernandez; Perez, S. Fernandez; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; de Lima, D. E. Ferreira; Ferrer, A.; Ferrere, D.; Ferretti, C.; Parodi, A. Ferretto; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fletcher, G. T.; Fletcher, R. R. M.; Flick, T.; Floderus, A.; Castillo, L. R. Flores; Flowerdew, M. J.; Forcolin, G. T.; Formica, A.; Forti, A.; Foster, A. G.; Fournier, D.; Fox, H.; Fracchia, S.; Francavilla, P.; Franchini, M.; Francis, D.; Franconi, L.; Franklin, M.; Frate, M.; Fraternali, M.; Freeborn, D.; Fressard-Batraneanu, S. M.; Friedrich, F.; Froidevaux, D.; Frost, J. A.; Fukunaga, C.; Torregrosa, E. Fullana; Fusayasu, T.; Fuster, J.; Gabaldon, C.; Gabizon, O.; Gabrielli, A.; Gabrielli, A.; Gach, G. P.; Gadatsch, S.; Gadomski, S.; Gagliardi, G.; Gagnon, L. G.; Gagnon, P.; Galea, C.; Galhardo, B.; Gallas, E. J.; Gallop, B. J.; Gallus, P.; Galster, G.; Gan, K. K.; Gao, J.; Gao, Y.; Gao, Y. S.; Walls, F. M. Garay; García, C.; Navarro, J. E. García; Garcia-Sciveres, M.; Gardner, R. W.; Garelli, N.; Garonne, V.; Bravo, A. Gascon; Gatti, C.; Gaudiello, A.; Gaudio, G.; Gaur, B.; Gauthier, L.; Gavrilenko, I. L.; Gay, C.; Gaycken, G.; Gazis, E. N.; Gecse, Z.; Gee, C. N. P.; Geich-Gimbel, Ch.; Geisen, M.; Geisler, M. P.; Gemme, C.; Genest, M. H.; Geng, C.; Gentile, S.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghazlane, H.; Ghneimat, M.; Giacobbe, B.; Giagu, S.; Giannetti, P.; Gibbard, B.; Gibson, S. M.; Gignac, M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuli, F.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Costa, J. Goncalves Pinto Firmino Da; Gonella, G.; Gonella, L.; Gongadze, A.; de la Hoz, S. González; Parra, G. Gonzalez; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goudet, C. R.; Goujdami, D.; Goussiou, A. G.; Govender, N.; Gozani, E.; Graber, L.; Grabowska-Bold, I.; Gradin, P. O. J.; Grafström, P.; Gramling, J.; Gramstad, E.; Grancagnolo, S.; Gratchev, V.; Gravila, P. M.; Gray, H. M.; Graziani, E.; Greenwood, Z. D.; Grefe, C.; Gregersen, K.; Gregor, I. M.; Grenier, P.; Grevtsov, K.; Griffiths, J.; Grillo, A. A.; Grimm, K.; Grinstein, S.; Gris, Ph.; Grivaz, J.-F.; Groh, S.; Grohs, J. P.; Gross, E.; Grosse-Knetter, J.; Grossi, G. C.; Grout, Z. J.; Guan, L.; Guan, W.; Guenther, J.; Guescini, F.; Guest, D.; Gueta, O.; Guido, E.; Guillemin, T.; Guindon, S.; Gul, U.; Gumpert, C.; Guo, J.; Guo, Y.; Gupta, S.; Gustavino, G.; Gutierrez, P.; Ortiz, N. G. Gutierrez; Gutschow, C.; Guyot, C.; Gwenlan, C.; Gwilliam, C. B.; Haas, A.; Haber, C.; Hadavand, H. K.; Haddad, N.; Hadef, A.; Haefner, P.; Hageböck, S.; Hajduk, Z.; Hakobyan, H.; Haleem, M.; Haley, J.; Halladjian, G.; Hallewell, G. D.; Hamacher, K.; Hamal, P.; Hamano, K.; Hamilton, A.; Hamity, G. N.; Hamnett, P. G.; Han, L.; Hanagaki, K.; Hanawa, K.; Hance, M.; Haney, B.; Hanke, P.; Hanna, R.; Hansen, J. B.; Hansen, J. D.; Hansen, M. C.; Hansen, P. H.; Hara, K.; Hard, A. S.; Harenberg, T.; Hariri, F.; Harkusha, S.; Harrington, R. D.; Harrison, P. F.; Hartjes, F.; Hartmann, N. M.; Hasegawa, M.; Hasegawa, Y.; Hasib, A.; Hassani, S.; Haug, S.; Hauser, R.; Hauswald, L.; Havranek, M.; Hawkes, C. M.; Hawkings, R. J.; Hayden, D.; Hays, C. P.; Hays, J. M.; Hayward, H. S.; Haywood, S. J.; Head, S. J.; Heck, T.; Hedberg, V.; Heelan, L.; Heim, S.; Heim, T.; Heinemann, B.; Heinrich, J. J.; Heinrich, L.; Heinz, C.; Hejbal, J.; Helary, L.; Hellman, S.; Helsens, C.; Henderson, J.; Henderson, R. C. W.; Heng, Y.; Henkelmann, S.; Correia, A. M. Henriques; Henrot-Versille, S.; Herbert, G. H.; Jiménez, Y. Hernández; Herten, G.; Hertenberger, R.; Hervas, L.; Hesketh, G. G.; Hessey, N. P.; Hetherly, J. W.; Hickling, R.; Higón-Rodriguez, E.; Hill, E.; Hill, J. C.; Hiller, K. H.; Hillier, S. J.; Hinchliffe, I.; Hines, E.; Hinman, R. R.; Hirose, M.; Hirschbuehl, D.; Hobbs, J.; Hod, N.; Hodgkinson, M. C.; Hodgson, P.; Hoecker, A.; Hoeferkamp, M. R.; Hoenig, F.; Hohn, D.; Holmes, T. R.; Homann, M.; Hong, T. M.; Hooberman, B. H.; Hopkins, W. H.; Horii, Y.; Horton, A. J.; Hostachy, J.-Y.; Hou, S.; Hoummada, A.; Howarth, J.; Hrabovsky, M.; Hristova, I.; Hrivnac, J.; Hryn'ova, T.; Hrynevich, A.; Hsu, C.; Hsu, P. J.; Hsu, S.-C.; Hu, D.; Hu, Q.; Huang, Y.; Hubacek, Z.; Hubaut, F.; Huegging, F.; Huffman, T. B.; Hughes, E. W.; Hughes, G.; Huhtinen, M.; Hülsing, T. A.; Huo, P.; Huseynov, N.; Huston, J.; Huth, J.; Iacobucci, G.; Iakovidis, G.; Ibragimov, I.; Iconomidou-Fayard, L.; Ideal, E.; Idrissi, Z.; Iengo, P.; Igonkina, O.; Iizawa, T.; Ikegami, Y.; Ikeno, M.; Ilchenko, Y.; Iliadis, D.; Ilic, N.; Ince, T.; Introzzi, G.; Ioannou, P.; Iodice, M.; Iordanidou, K.; Ippolito, V.; Ishino, M.; Ishitsuka, M.; Ishmukhametov, R.; Issever, C.; Istin, S.; Ito, F.; Ponce, J. M. Iturbe; Iuppa, R.; Iwanski, W.; Iwasaki, H.; Izen, J. M.; Izzo, V.; Jabbar, S.; Jackson, B.; Jackson, M.; Jackson, P.; Jain, V.; Jakobi, K. B.; Jakobs, K.; Jakobsen, S.; Jakoubek, T.; Jamin, D. O.; Jana, D. K.; Jansen, E.; Jansky, R.; Janssen, J.; Janus, M.; Jarlskog, G.; Javadov, N.; Javůrek, T.; Jeanneau, F.; Jeanty, L.; Jejelava, J.; Jeng, G.-Y.; Jennens, D.; Jenni, P.; Jentzsch, J.; Jeske, C.; Jézéquel, S.; Ji, H.; Jia, J.; Jiang, H.; Jiang, Y.; Jiggins, S.; Pena, J. Jimenez; Jin, S.; Jinaru, A.; Jinnouchi, O.; Johansson, P.; Johns, K. A.; Johnson, W. J.; Jon-And, K.; Jones, G.; Jones, R. W. L.; Jones, S.; Jones, T. J.; Jongmanns, J.; Jorge, P. M.; Jovicevic, J.; Ju, X.; Rozas, A. Juste; Köhler, M. K.; Kaczmarska, A.; Kado, M.; Kagan, H.; Kagan, M.; Kahn, S. J.; Kajomovitz, E.; Kalderon, C. W.; Kaluza, A.; Kama, S.; Kamenshchikov, A.; Kanaya, N.; Kaneti, S.; Kanjir, L.; Kantserov, V. A.; Kanzaki, J.; Kaplan, B.; Kaplan, L. S.; Kapliy, A.; Kar, D.; Karakostas, K.; Karamaoun, A.; Karastathis, N.; Kareem, M. J.; Karentzos, E.; Karnevskiy, M.; Karpov, S. N.; Karpova, Z. M.; Karthik, K.; Kartvelishvili, V.; Karyukhin, A. N.; Kasahara, K.; Kashif, L.; Kass, R. D.; Kastanas, A.; Kataoka, Y.; Kato, C.; Katre, A.; Katzy, J.; Kawagoe, K.; Kawamoto, T.; Kawamura, G.; Kazama, S.; Kazanin, V. F.; Keeler, R.; Kehoe, R.; Keller, J. S.; Kempster, J. J.; Kawade, K.; Keoshkerian, H.; Kepka, O.; Kerševan, B. P.; Kersten, S.; Keyes, R. A.; Khalil-zada, F.; Khanov, A.; Kharlamov, A. G.; Khoo, T. J.; Khovanskiy, V.; Khramov, E.; Khubua, J.; Kido, S.; Kim, H. Y.; Kim, S. H.; Kim, Y. K.; Kimura, N.; Kind, O. M.; King, B. T.; King, M.; King, S. B.; Kirk, J.; Kiryunin, A. E.; Kishimoto, T.; Kisielewska, D.; Kiss, F.; Kiuchi, K.; Kivernyk, O.; Kladiva, E.; Klein, M. H.; Klein, M.; Klein, U.; Kleinknecht, K.; Klimek, P.; Klimentov, A.; Klingenberg, R.; Klinger, J. A.; Klioutchnikova, T.; Kluge, E.-E.; Kluit, P.; Kluth, S.; Knapik, J.; Kneringer, E.; Knoops, E. B. F. G.; Knue, A.; Kobayashi, A.; Kobayashi, D.; Kobayashi, T.; Kobel, M.; Kocian, M.; Kodys, P.; Koffas, T.; Koffeman, E.; Koi, T.; Kolanoski, H.; Kolb, M.; Koletsou, I.; Komar, A. A.; Komori, Y.; Kondo, T.; Kondrashova, N.; Köneke, K.; König, A. C.; Kono, T.; Konoplich, R.; Konstantinidis, N.; Kopeliansky, R.; Koperny, S.; Köpke, L.; Kopp, A. K.; Korcyl, K.; Kordas, K.; Korn, A.; Korol, A. A.; Korolkov, I.; Korolkova, E. V.; Kortner, O.; Kortner, S.; Kosek, T.; Kostyukhin, V. V.; Kotwal, A.; Kourkoumeli-Charalampidi, A.; Kourkoumelis, C.; Kouskoura, V.; Kowalewska, A. B.; Kowalewski, R.; Kowalski, T. Z.; Kozakai, C.; Kozanecki, W.; Kozhin, A. S.; Kramarenko, V. A.; Kramberger, G.; Krasnopevtsev, D.; Krasny, M. W.; Krasznahorkay, A.; Kraus, J. K.; Kravchenko, A.; Kretz, M.; Kretzschmar, J.; Kreutzfeldt, K.; Krieger, P.; Krizka, K.; Kroeninger, K.; Kroha, H.; Kroll, J.; Kroseberg, J.; Krstic, J.; Kruchonak, U.; Krüger, H.; Krumnack, N.; Kruse, A.; Kruse, M. C.; Kruskal, M.; Kubota, T.; Kucuk, H.; Kuday, S.; Kuechler, J. T.; Kuehn, S.; Kugel, A.; Kuger, F.; Kuhl, A.; Kuhl, T.; Kukhtin, V.; Kukla, R.; Kulchitsky, Y.; Kuleshov, S.; Kuna, M.; Kunigo, T.; Kupco, A.; Kurashige, H.; Kurochkin, Y. A.; Kus, V.; Kuwertz, E. S.; Kuze, M.; Kvita, J.; Kwan, T.; Kyriazopoulos, D.; Rosa, A. La; Navarro, J. L. La Rosa; Rotonda, L. La; Lacasta, C.; Lacava, F.; Lacey, J.; Lacker, H.; Lacour, D.; Lacuesta, V. R.; Ladygin, E.; Lafaye, R.; Laforge, B.; Lagouri, T.; Lai, S.; Lammers, S.; Lampl, W.; Lançon, E.; Landgraf, U.; Landon, M. P. J.; Lang, V. S.; Lange, J. C.; Lankford, A. J.; Lanni, F.; Lantzsch, K.; Lanza, A.; Laplace, S.; Lapoire, C.; Laporte, J. F.; Lari, T.; Manghi, F. Lasagni; Lassnig, M.; Laurelli, P.; Lavrijsen, W.; Law, A. T.; Laycock, P.; Lazovich, T.; Lazzaroni, M.; Le, B.; Dortz, O. Le; Guirriec, E. Le; Quilleuc, E. P. Le; LeBlanc, M.; LeCompte, T.; Ledroit-Guillon, F.; Lee, C. A.; Lee, S. C.; Lee, L.; Lefebvre, G.; Lefebvre, M.; Legger, F.; Leggett, C.; Lehan, A.; Miotto, G. Lehmann; Lei, X.; Leight, W. A.; Leisos, A.; Leister, A. G.; Leite, M. A. L.; Leitner, R.; Lellouch, D.; Lemmer, B.; Leney, K. J. C.; Lenz, T.; Lenzi, B.; Leone, R.; Leone, S.; Leonidopoulos, C.; Leontsinis, S.; Lerner, G.; Leroy, C.; Lesage, A. A. J.; Lester, C. G.; Levchenko, M.; Levêque, J.; Levin, D.; Levinson, L. J.; Levy, M.; Lewis, D.; Leyko, A. M.; Leyton, M.; Li, B.; Li, H.; Li, H. L.; Li, L.; Li, L.; Li, Q.; Li, S.; Li, X.; Li, Y.; Liang, Z.; Liberti, B.; Liblong, A.; Lichard, P.; Lie, K.; Liebal, J.; Liebig, W.; Limosani, A.; Lin, S. C.; Lin, T. H.; Lindquist, B. E.; Lionti, A. E.; Lipeles, E.; Lipniacka, A.; Lisovyi, M.; Liss, T. M.; Lister, A.; Litke, A. M.; Liu, B.; Liu, D.; Liu, H.; Liu, H.; Liu, J.; Liu, J. B.; Liu, K.; Liu, L.; Liu, M.; Liu, M.; Liu, Y. L.; Liu, Y.; Livan, M.; Lleres, A.; Merino, J. Llorente; Lloyd, S. L.; Sterzo, F. Lo; Lobodzinska, E.; Loch, P.; Lockman, W. S.; Loebinger, F. K.; Loevschall-Jensen, A. E.; Loew, K. M.; Loginov, A.; Lohse, T.; Lohwasser, K.; Lokajicek, M.; Long, B. A.; Long, J. D.; Long, R. E.; Longo, L.; Looper, K. A.; Lopes, L.; Mateos, D. Lopez; Paredes, B. Lopez; Paz, I. Lopez; Solis, A. Lopez; Lorenz, J.; Martinez, N. Lorenzo; Losada, M.; Lösel, P. J.; Lou, X.; Lounis, A.; Love, J.; Love, P. A.; Lu, H.; Lu, N.; Lubatti, H. J.; Luci, C.; Lucotte, A.; Luedtke, C.; Luehring, F.; Lukas, W.; Luminari, L.; Lundberg, O.; Lund-Jensen, B.; Luzi, P. M.; Lynn, D.; Lysak, R.; Lytken, E.; Lyubushkin, V.; Ma, H.; Ma, L. L.; Ma, Y.; Maccarrone, G.; Macchiolo, A.; Macdonald, C. M.; Maček, B.; Miguens, J. Machado; Madaffari, D.; Madar, R.; Maddocks, H. J.; Mader, W. F.; Madsen, A.; Maeda, J.; Maeland, S.; Maeno, T.; Maevskiy, A.; Magradze, E.; Mahlstedt, J.; Maiani, C.; Maidantchik, C.; Maier, A. A.; Maier, T.; Maio, A.; Majewski, S.; Makida, Y.; Makovec, N.; Malaescu, B.; Malecki, Pa.; Maleev, V. P.; Malek, F.; Mallik, U.; Malon, D.; Malone, C.; Maltezos, S.; Malyukov, S.; Mamuzic, J.; Mancini, G.; Mandelli, B.; Mandelli, L.; Mandić, I.; Maneira, J.; Filho, L. Manhaes de Andrade; Ramos, J. Manjarres; Mann, A.; Manousos, A.; Mansoulie, B.; Mansour, J. D.; Mantifel, R.; Mantoani, M.; Manzoni, S.; Mapelli, L.; Marceca, G.; March, L.; Marchiori, G.; Marcisovsky, M.; Marjanovic, M.; Marley, D. E.; Marroquim, F.; Marsden, S. P.; Marshall, Z.; Marti-Garcia, S.; Martin, B.; Martin, T. A.; Martin, V. J.; Latour, B. Martin dit; Martinez, M.; Martin-Haugh, S.; Martoiu, V. S.; Martyniuk, A. C.; Marx, M.; Marzin, A.; Masetti, L.; Mashimo, T.; Mashinistov, R.; Masik, J.; Maslennikov, A. L.; Massa, I.; Massa, L.; Mastrandrea, P.; Mastroberardino, A.; Masubuchi, T.; Mättig, P.; Mattmann, J.; Maurer, J.; Maxfield, S. J.; Maximov, D. A.; Mazini, R.; Mazza, S. M.; Fadden, N. C. Mc; Goldrick, G. Mc; Kee, S. P. Mc; McCarn, A.; McCarthy, R. L.; McCarthy, T. G.; McClymont, L. I.; McDonald, E. F.; McFarlane, K. W.; Mcfayden, J. A.; Mchedlidze, G.; McMahon, S. J.; McPherson, R. A.; Medinnis, M.; Meehan, S.; Mehlhase, S.; Mehta, A.; Meier, K.; Meineck, C.; Meirose, B.; Melini, D.; Garcia, B. R. Mellado; Melo, M.; Meloni, F.; Menary, S. B.; Mengarelli, A.; Menke, S.; Meoni, E.; Mergelmeyer, S.; Mermod, P.; Merola, L.; Meroni, C.; Merritt, F. S.; Messina, A.; Metcalfe, J.; Mete, A. S.; Meyer, C.; Meyer, C.; Meyer, J.-P.; Meyer, J.; Theenhausen, H. Meyer Zu; Miano, F.; Middleton, R. P.; Miglioranzi, S.; Mijović, L.; Mikenberg, G.; Mikestikova, M.; Mikuž, M.; Milesi, M.; Milic, A.; Miller, D. W.; Mills, C.; Milov, A.; Milstead, D. A.; Minaenko, A. A.; Minami, Y.; Minashvili, I. A.; Mincer, A. I.; Mindur, B.; Mineev, M.; Ming, Y.; Mir, L. M.; Mistry, K. P.; Mitani, T.; Mitrevski, J.; Mitsou, V. A.; Miucci, A.; Miyagawa, P. S.; Mjörnmark, J. U.; Moa, T.; Mochizuki, K.; Mohapatra, S.; Molander, S.; Moles-Valls, R.; Monden, R.; Mondragon, M. C.; Mönig, K.; Monk, J.; Monnier, E.; Montalbano, A.; Berlingen, J. Montejo; Monticelli, F.; Monzani, S.; Moore, R. W.; Morange, N.; Moreno, D.; Llácer, M. Moreno; Morettini, P.; Mori, D.; Mori, T.; Morii, M.; Morinaga, M.; Morisbak, V.; Moritz, S.; Morley, A. K.; Mornacchi, G.; Morris, J. D.; Mortensen, S. S.; Morvaj, L.; Mosidze, M.; Moss, J.; Motohashi, K.; Mount, R.; Mountricha, E.; Mouraviev, S. V.; Moyse, E. J. W.; Muanza, S.; Mudd, R. D.; Mueller, F.; Mueller, J.; Mueller, R. S. P.; Mueller, T.; Muenstermann, D.; Mullen, P.; Mullier, G. A.; Sanchez, F. J. Munoz; Quijada, J. A. Murillo; Murray, W. J.; Musheghyan, H.; Muškinja, M.; Myagkov, A. G.; Myska, M.; Nachman, B. P.; Nackenhorst, O.; Nagai, K.; Nagai, R.; Nagano, K.; Nagasaka, Y.; Nagata, K.; Nagel, M.; Nagy, E.; Nairz, A. M.; Nakahama, Y.; Nakamura, K.; Nakamura, T.; Nakano, I.; Namasivayam, H.; Garcia, R. F. Naranjo; Narayan, R.; Villar, D. I. Narrias; Naryshkin, I.; Naumann, T.; Navarro, G.; Nayyar, R.; Neal, H. A.; Nechaeva, P. Yu.; Neep, T. J.; Nef, P. D.; Negri, A.; Negrini, M.; Nektarijevic, S.; Nellist, C.; Nelson, A.; Nemecek, S.; Nemethy, P.; Nepomuceno, A. A.; Nessi, M.; Neubauer, M. S.; Neumann, M.; Neves, R. M.; Nevski, P.; Newman, P. R.; Nguyen, D. H.; Manh, T. Nguyen; Nickerson, R. B.; Nicolaidou, R.; Nielsen, J.; Nikiforov, A.; Nikolaenko, V.; Nikolic-Audit, I.; Nikolopoulos, K.; Nilsen, J. K.; Nilsson, P.; Ninomiya, Y.; Nisati, A.; Nisius, R.; Nobe, T.; Nodulman, L.; Nomachi, M.; Nomidis, I.; Nooney, T.; Norberg, S.; Nordberg, M.; Norjoharuddeen, N.; Novgorodova, O.; Nowak, S.; Nozaki, M.; Nozka, L.; Ntekas, K.; Nurse, E.; Nuti, F.; O'grady, F.; O'Neil, D. C.; O'Rourke, A. A.; O'Shea, V.; Oakham, F. G.; Oberlack, H.; Obermann, T.; Ocariz, J.; Ochi, A.; Ochoa, I.; Ochoa-Ricoux, J. P.; Oda, S.; Odaka, S.; Ogren, H.; Oh, A.; Oh, S. H.; Ohm, C. C.; Ohman, H.; Oide, H.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olariu, A.; Seabra, L. F. Oleiro; Pino, S. A. Olivares; Damazio, D. Oliveira; Olszewski, A.; Olszowska, J.; Onofre, A.; Onogi, K.; Onyisi, P. U. E.; Oreglia, M. J.; Oren, Y.; Orestano, D.; Orlando, N.; Orr, R. S.; Osculati, B.; Ospanov, R.; Garzon, G. Otero y.; Otono, H.; Ouchrif, M.; Ould-Saada, F.; Ouraou, A.; Oussoren, K. P.; Ouyang, Q.; Owen, M.; Owen, R. E.; Ozcan, V. E.; Ozturk, N.; Pachal, K.; Pages, A. Pacheco; Aranda, C. Padilla; Pagáčová, M.; Griso, S. Pagan; Paige, F.; Pais, P.; Pajchel, K.; Palacino, G.; Palestini, S.; Palka, M.; Pallin, D.; Palma, A.; Panagiotopoulou, E. St.; Pandini, C. E.; Vazquez, J. G. Panduro; Pani, P.; Panitkin, S.; Pantea, D.; Paolozzi, L.; Papadopoulou, Th. D.; Papageorgiou, K.; Paramonov, A.; Hernandez, D. Paredes; Parker, A. J.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pascuzzi, V. R.; Pasqualucci, E.; Passaggio, S.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Lopez, S. Pedraza; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penwell, J.; Peralva, B. S.; Perego, M. M.; Perepelitsa, D. V.; Codina, E. Perez; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrov, M.; Petrucci, F.; Pettersson, N. E.; Peyaud, A.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pin, A. W. J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Astigarraga, M. E. Pozo; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Ratti, M. G.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Ravinovich, I.; Raymond, M.; Read, A. L.; Readioff, N. P.; Reale, M.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reisin, H.; Rembser, C.; Ren, H.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rimoldi, M.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Rizzi, C.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Rodina, Y.; Perez, A. Rodriguez; Rodriguez, D. Rodriguez; Roe, S.; Rogan, C. S.; Røhne, O.; Romaniouk, A.; Romano, M.; Saez, S. M. Romano; Adam, E. Romero; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosenthal, O.; Rosien, N.-A.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryu, S.; Ryzhov, A.; Rzehorz, G. F.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Sadrozinski, H. F.-W.; Sadykov, R.; Tehrani, F. Safai; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Loyola, J. E. Salazar; Salek, D.; De Bruin, P. H. Sales; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Martinez, V. Sanchez; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Castillo, I. Santoyo; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schachtner, B. M.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schier, S.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmidt-Sommerfeld, K. R.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, S.; Schneider, B.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schott, M.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shaikh, N. W.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Saadi, D. Shoaleh; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Sicho, P.; Sickles, A. M.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simon, M.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Slovak, R.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smiesko, J.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Sanchez, C. A. Solans; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sood, A.; Sopczak, A.; Sopko, V.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; Denis, R. D. St.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Araya, S. Tapia; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Delgado, A. Tavares; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teischinger, F. A.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Kate, H. Ten; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Tibbetts, M. J.; Torres, R. E. Ticse; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Torrence, E.; Torres, H.; Pastor, E. Torró; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turgeman, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tyndel, M.; Ucchielli, G.; Ueda, I.; Ueno, R.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Santurio, E. Valdes; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallecorsa, S.; Ferrer, J. A. Valls; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vazeille, F.; Schroeder, T. Vazquez; Veatch, J.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Vigne, R.; Villa, M.; Perez, M. Villaplana; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Milosavljevic, M. Vranjes; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, W.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, M. D.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Wong, K. H. Yau; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Nedden, M. zur; Zurzolo, G.; Zwalinski, L.

2016-12-01

The luminosity determination for the ATLAS detector at the LHC during pp collisions at √{s} = 8 TeV in 2012 is presented. The evaluation of the luminosity scale is performed using several luminometers, and comparisons between these luminosity detectors are made to assess the accuracy, consistency and long-term stability of the results. A luminosity uncertainty of δ L/L = ± 1.9% is obtained for the 22.7 fb^{-1} of pp collision data delivered to ATLAS at √{s} = 8 TeV in 2012.

Keck Deep Fields. II. The Ultraviolet Galaxy Luminosity Function at z ~ 4, 3, and 2

NASA Astrophysics Data System (ADS)

Sawicki, Marcin; Thompson, David

2006-05-01

We use very deep UnGRI multifield imaging obtained at the Keck telescope to study the evolution of the rest-frame 1700 Å galaxy luminosity function as the universe doubles its age from z~4 to ~2. We use exactly the same filters and color-color selection as those used by the Steidel team but probe significantly fainter limits, well below L*. The depth of our imaging allows us to constrain the faint end of the luminosity function, reaching M1700~-18.5 at z~3 (equivalent to ~1 Msolar yr-1), accounting for both N1/2 uncertainty in the number of galaxies and cosmic variance. We carefully examine many potential sources of systematic bias in our LF measurements before drawing the following conclusions. We find that the luminosity function of Lyman break galaxies evolves with time and that this evolution is differential with luminosity. The result is best constrained between the epochs at z~4 and ~3, where we find that the number density of sub-L* galaxies increases with time by at least a factor of 2.3 (11 σ statistical confidence); while the faint end of the LF evolves, the bright end appears to remain virtually unchanged, indicating that there may be differential, luminosity-dependent evolution (98.5% statistical probability). Potential systematic biases restrict our ability to draw strong conclusions about continued evolution of the luminosity function to lower redshifts, z~2.2 and ~1.7, but, nevertheless, it appears certain that the number density of z~2.2 galaxies at all luminosities we studied, -22>M1700>-18, is at least as high as that of their counterparts at z~3. While it is not yet clear what mechanism underlies the observed evolution, the fact that this evolution is differential with luminosity opens up new avenues of improving our understanding of how galaxies form and evolve at high redshift. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of

Dust Grains and the Luminosity of Circumnuclear Water Masers in Active Galaxies

NASA Technical Reports Server (NTRS)

Collison, Alan J.; Watson, William D.

1995-01-01

In previous calculations for the luminosities of 22 GHz water masers, the pumping is reduced and ultimately quenched with increasing depth into the gas because of trapping of the infrared (approximately equals 30-150 micrometers), spectral line radiation of the water molecule. When the absorption (and reemission) of infrared radiation by dust grains is included, we demonstrate that the pumping is no longer quenched but remains constant with increasing optical depth. A temperature difference between the grains and the gas is required. Such conditions are expected to occur, for example, in the circumnuclear masing environments created by X-rays in active galaxies. Here, the calculated 22 GHz maser luminosities are increased by more than an order of magnitude. Application to the well-studied, circumnuclear masing disk in the galaxy NGC 4258 yields a maser luminosity near that inferred from observations if the observed X-ray flux is assumed to be incident onto only the inner surface of the disk.

The Halo Occupation Distribution of Active Galactic Nuclei

NASA Astrophysics Data System (ADS)

Chatterjee, Suchetana; Nagai, D.; Richardson, J.; Zheng, Z.; Degraf, C.; DiMatteo, T.

2011-05-01

We investigate the halo occupation distribution of active galactic nuclei (AGN) using a state-of-the-art cosmological hydrodynamic simulation that self-consistently incorporates the growth and feedback of supermassive black holes and the physics of galaxy formation (DiMatteo et al. 2008). We show that the mean occupation function can be modeled as a softened step function for central AGN and a power law for the satellite population. The satellite occupation is consistent with weak redshift evolution and a power law index of unity. The number of satellite black holes at a given halo mass follows a Poisson distribution. We show that at low redshifts (z=1.0) feedback from AGN is responsible for higher suppression of black hole growth in higher mass halos. This effect introduces a bias in the correlation between instantaneous AGN luminosity and the host halo mass, making AGN clustering depend weakly on luminosity at low redshifts. We show that the radial distribution of AGN follows a power law which is fundamentally different from those of galaxies and dark matter. The best-fit power law index is -2.26 ± 0.23. The power law exponent do not show any evolution with redshift, host halo mass and AGN luminosity within statistical limits. Incorporating the environmental dependence of supermassive black hole accretion and feedback, our formalism provides the most complete theoretical tool for interpreting current and future measurements of AGN clustering.

Luminosity determination in pp collisions at $$\\sqrt{s} = 8$$ TeV using the ATLAS detector at the LHC

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2016-11-28

The luminosity determination for the ATLAS detector at the LHC during pp collisions atmore » $$\\sqrt{s} = 8$$ TeV in 2012 is presented. The evaluation of the luminosity scale is performed using several luminometers, and comparisons between these luminosity detectors are made to assess the accuracy, consistency and long-term stability of the results. A luminosity uncertainty of $δL/L$= ± 1.9% is obtained for the 22.7fb –1 of pp collision data delivered to ATLAS at $$\\sqrt{s} = 8$$ TeV in 2012.« less

Testing Ultracool Models with Precise Luminosities and Masses

NASA Astrophysics Data System (ADS)

Dupuy, Trent; Cushing, Michael; Liu, Michael; Burningham, Ben; Leggett, Sandy; Albert, Loic; Delorme, Philippe

2011-05-01

After years of patient orbital monitoring, there is a growing sample of brown dwarfs with well-determined dynamical masses, representing the gold standard for testing substellar models. A key element of our model tests to date has been the use of integrated-light photometry to provide accurate total luminosity measurements for these binaries. However, some of the ultracool binaries with the most promising orbit motion for yielding dynamical in the masses lack the mid-infrared photometry needed to constrain their SEDs. This is especially crucial for the latest type binaries (spectral types >T5) that will probe the coldest temperature regimes previously untested with dynamical masses. We propose to use IRAC to obtain the needed mid-infrared photometry for a sample of binaries that are part of our ongoing orbital monitoring program with Keck laser guide star adaptive optics. The observational effort needed to characterize these binaries' luminosities using Spitzer is much less daunting in than the years of orbital monitoring needed to measure precise dynamical masses, but it is equally vital for robust tests of theory.

New calibrators for the Cepheid period-luminosity relation

NASA Technical Reports Server (NTRS)

Evans, Nancy R.

1992-01-01

IUE spectra of six Cepheids have been used to determine their absolute magnitudes from the spectral types of their binary companions. The stars observed are U Aql, V659 Cen, Y Lac, S Nor, V350 Sgr, and V636 Sco. The absolute magnitude for V659 Cen is more uncertain than for the others because its reddening is poorly determined and the spectral type is hotter than those of the others. In addition, a reddening law with extra absorption in the 2200 A region is necessary, although this has a negligible effect on the absolute magnitude. For the other Cepheids, and also Eta Aql and W Sgr, the standard deviation from the Feast and Walker period-luminosity-color (PLC) relation is 0.37 mag, confirming the previously estimated internal uncertainty. The absolute magnitudes for S Nor from the binary companion and from cluster membership are very similar. The preliminary PLC zero point is less than 2 sigma (+0.21 mag) different from that of Feast and Walker. The same narrowing of the instability strip at low luminosities found by Fernie is seen.

Low-luminosity stellar mass functions in globular clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richer, H.B.; Fahlman, G.G.; Buonanno, R.

New data are presented on cluster luminosity functions and mass functions for selected fields in the globular clusters M13 and M71, extending down the main sequence to at least 0.2 solar mass. In this experiment, CCD photometry data were obtained at the prime focus of the CFHT on the cluster fields that were far from the cluster center. Luminosity functions were constructed, using the ADDSTAR routine to correct for the background, and mass functions were derived using the available models. The mass functions obtained for M13 and M71 were compared to existing data for NGC 6397. Results show that (1)more » all three globular clusters display a marked change in slope at about 0.4 solar mass, with the slopes becoming considerably steeper toward lower masses; (2) there is no correlation between the slope of the mass function and metallicity; and (3) the low-mass slope of the mass function for M13 is much steeper than for NGC 6397 and M71. 22 refs.« less

Observations of low-luminosity X-ray sources in Vela-Puppis

NASA Technical Reports Server (NTRS)

Pravdo, S. H.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Swank, J. H.

1978-01-01

Results are presented for a study of the X-ray emission from a small portion of the galactic plane near galactic longitude 260 deg. This region contains at least six low-luminosity X-ray sources within about 10 deg of PSR 0833-45, which is near the center of the Gum nebula. The X-ray source 4U 0833-45, associated with the Vela pulsar, is observed at twice its 4U catalog intensity. The lack of X-ray pulsations at the pulsar period (greater than 99% nonpulsed), the nonthermal power-law spectrum, and models of the X-ray source distribution in this region suggest that a large fraction of the X-rays come from an extended source about 1 deg of arc in radius. The observation of a high-temperature (effective temperature at least 100 million K) spectrum in a field of view containing only Puppis A among known sources has led to the discovery of new OSO 8 source, OS 0752-39. Other spectra from this region are discussed.

Induced activation studies for the LHC upgrade to High Luminosity LHC

NASA Astrophysics Data System (ADS)

Adorisio, C.; Roesler, S.

2018-06-01

The Large Hadron Collider (LHC) will be upgraded in 2019/2020 to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor ten, in order to maintain scientific progress and exploit its full capacity. The novel machine configuration, called High Luminosity LHC (HL-LHC), will increase consequently the level of activation of its components. The evaluation of the radiological impact of the HL-LHC operation in the Long Straight Sections of the Insertion Region 1 (ATLAS) and Insertion Region 5 (CMS) is presented. Using the Monte Carlo code FLUKA, ambient dose equivalent rate estimations have been performed on the basis of two announced operating scenarios and using the latest available machine layout. The HL-LHC project requires new technical infrastructure with caverns and 300 m long tunnels along the Insertion Regions 1 and 5. The new underground service galleries will be accessible during the operation of the accelerator machine. The radiological risk assessment for the Civil Engineering work foreseen to start excavating the new galleries in the next LHC Long Shutdown and the radiological impact of the machine operation will be discussed.

Thermodynamics and luminosities of rainbow black holes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Benrong; Wang, Peng; Yang, Haitang, E-mail: mubenrong@uestc.edu.cn, E-mail: pengw@scu.edu.cn, E-mail: hyanga@scu.edu.cn

2015-11-01

Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is ''Gravity's rainbow'', where the spacetime background felt by a test particle would depend on its energy. Focusing on the ''Amelino-Camelia dispersion relation'' which is E{sup 2} = m{sup 2}+p{sup 2}[1−η(E/m{sub p}){sup n}] with n > 0, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of η and n in the framework ofmore » rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with η < 0 and n ≥ 2. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of η and n.« less

High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary Design Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apollinari, G.; Béjar Alonso, I.; Brüning, O.

2015-12-17

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 7,000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total collisions created) by a factor ten. The LHCmore » is already a highly complex and exquisitely optimised machine so this upgrade must be carefully conceived and will require about ten years to implement. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 tesla superconducting magnets, compact superconducting cavities for beam rotation with ultra-precise phase control, new technology and physical processes for beam collimation and 300 metre-long high-power superconducting links with negligible energy dissipation. The present document describes the technologies and components that will be used to realise the project and is intended to serve as the basis for the detailed engineering design of HL-LHC.« less

Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-07-01

The luminosity function of short gamma ray bursts (GRBs) is modelled by using the available catalogue data of all short GRBs (sGRBs) detected till 2017 October. The luminosities are estimated via the `pseudo-redshifts' obtained from the `Yonetoku correlation', assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. While the simple power law is ruled out to high confidence, the data is fit well both by exponential cutoff power law and broken power law models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of sGRBs is derived. Assuming a sGRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present, and future configurations of the GW detector networks. Stringent lower limits of 1.87 { yr^{-1}} for the aLIGO-VIRGO, and 3.11 { yr^{-1}} for the upcoming aLIGO-VIRGO-KAGRA-LIGO/India configurations are thus derived for the BNSM rate at 68 per cent confidence. The BNSM rates calculated from this work and that independently inferred from the observation of the only confirmed BNSM observed till date are shown to have a mild tension; however, the scenario that all BNSMs produce sGRBs cannot be ruled out.

Evolution of the Quasar Luminosity Function: Implications for EoR-21cm

NASA Astrophysics Data System (ADS)

Kulkarni, Girish; Choudhury, Tirthankar Roy; Puchwein, Ewald; Haehnelt, Martin G.

2018-05-01

We present predictions for the spatial distribution of 21 cm brightness temperature fluctuations from high-dynamic-range simulations for AGN-dominated reionization histories that have been tested against available Lyα and CMB data. We model AGN by extrapolating the observed Mbh-σ relation to high redshifts and assign them ionizing emissivities consistent with recent UV luminosity function measurements. AGN-dominated reionization histories increase the variance of the 21 cm emission by a factor of up to ten compared to similar reionization histories dominated by faint galaxies, to values close to 100 mK2 at scales accessible to experiments (k <~ 1 cMpc-1h). This is lower than the sensitivity reached by ongoing experiments by only a factor of about two or less. AGN dominated reionization should be easily detectable by LOFAR (and later HERA and SKA1) at their design sensitivity.

Axions and the luminosity function of white dwarfs. The thin and thick disks, and the halo

NASA Astrophysics Data System (ADS)

Isern, J.; García-Berro, E.; Torres, S.; Cojocaru, R.; Catalán, S.

2018-05-01

The evolution of white dwarfs is a simple gravothermal process of cooling. Since the shape of their luminosity function is sensitive to the characteristic cooling time, it is possible to use its slope to test the existence of additional sources or sinks of energy, such as those predicted by alternative physical theories. The aim of this paper is to study if the changes in the slope of the white dwarf luminosity function around bolometric magnitudes ranging from 8 to 10 and previously attributed to axion emission are, effectively, a consequence of the existence of axions and not an artifact introduced by the star formation rate. We compute theoretical luminosity functions of the thin and thick disk, and of the stellar halo including axion emission and we compare them with the existing observed luminosity functions. Since these stellar populations have different star formation histories, the slope change should be present in all of them at the same place if it is due to axions or any other intrinsic cooling mechanism. The signature of an unexpected cooling seems to be present in the luminosity functions of the thin and thick disks, as well as in the halo luminosity function. This additional cooling is compatible with axion emission, thus supporting to the idea that DFSZ axions, with a mass in the range of 4 to 10 meV, could exist. If this were the case, these axions could be detected by the future solar axioscope IAXO.

Ultra-faint ultraviolet galaxies at z ∼ 2 behind the lensing cluster A1689: The luminosity function, dust extinction, and star formation rate density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alavi, Anahita; Siana, Brian; Freeman, William R.

We have obtained deep ultraviolet imaging of the lensing cluster A1689 with the WFC3/UVIS camera onboard the Hubble Space Telescope in the F275W (30 orbits) and F336W (4 orbits) filters. These images are used to identify z ∼ 2 star-forming galaxies via their Lyman break, in the same manner that galaxies are typically selected at z ≥ 3. Because of the unprecedented depth of the images and the large magnification provided by the lensing cluster, we detect galaxies 100× fainter than previous surveys at this redshift. After removing all multiple images, we have 58 galaxies in our sample in themore » range –19.5 < M {sub 1500} < –13 AB mag. Because the mass distribution of A1689 is well constrained, we are able to calculate the intrinsic sensitivity of the observations as a function of source plane position, allowing for accurate determinations of effective volume as a function of luminosity. We fit the faint-end slope of the luminosity function to be α = –1.74 ± 0.08, which is consistent with the values obtained for 2.5 < z < 6. Notably, there is no turnover in the luminosity function down to M {sub 1500} = –13 AB mag. We fit the UV spectral slopes with photometry from existing Hubble optical imaging. The observed trend of increasingly redder slopes with luminosity at higher redshifts is observed in our sample, but with redder slopes at all luminosities and average reddening of (E(B – V)) = 0.15 mag. We assume the stars in these galaxies are metal poor (0.2 Z {sub ☉}) compared to their brighter counterparts (Z {sub ☉}), resulting in bluer assumed intrinsic UV slopes and larger derived values for dust extinction. The total UV luminosity density at z ∼ 2 is 4.31{sub −0.60}{sup +0.68}×10{sup 26} erg s{sup –1} Hz{sup –1} Mpc{sup –3}, more than 70% of which is emitted by galaxies in the luminosity range of our sample. Finally, we determine the global star formation rate density from UV-selected galaxies at z ∼ 2 (assuming a constant dust

Luminosity variations in several parallel auroral arcs before auroral breakup

NASA Astrophysics Data System (ADS)

Safargaleev, V.; Lyatsky, W.; Tagirov, V.

1997-08-01

Variation of the luminosity in two parallel auroral arcs before auroral breakup has been studied by using digitised TV-data with high temporal and spatial resolution. The intervals when a new arc appears near already existing one were chosen for analysis. It is shown, for all cases, that the appearance of a new arc is accompanied by fading or disappearance of another arc. We have named these events out-of-phase events, OP. Another type of luminosity variation is characterised by almost simultaneous enhancement of intensity in the both arcs (in-phase event, IP). The characteristic time of IP events is 10-20 s, whereas OP events last about one minute. Sometimes out-of-phase events begin as IP events. The possible mechanisms for OP and IP events are discussed.

Chandra Survey of Nearby Galaxies: Testing the Accretion Model for Low-luminosity AGNs

NASA Astrophysics Data System (ADS)

She, Rui; Ho, Luis C.; Feng, Hua; Cui, Can

2018-06-01

From a Chandra sample of active galactic nuclei (AGNs) in nearby galaxies, we find that for low-luminosity AGNs, either the intrinsic absorption column density, or the fraction of absorbed AGNs, positively scales with the Eddington ratio for L bol/L Edd ≲ 10‑2. Such a behavior, along with the softness of the X-ray spectrum at low luminosities, is in good agreement with the picture that they are powered by hot accretion flows surrounding supermassive black holes. Numerical simulations find that outflows are inevitable with hot accretion flows, and the outflow rate is correlated with the innermost accretion rate in the low-luminosity regime. This agrees well with our results, suggesting that the X-ray absorption originates from, or is associated with, the outflow material. Gas and dust on larger scales may also produce the observed correlation. Future correlation analyses may help differentiate the two scenarios.

Predicting the Redshift 2 H-Alpha Luminosity Function Using [OIII] Emission Line Galaxies

NASA Technical Reports Server (NTRS)

Mehta, Vihang; Scarlata, Claudia; Colbert, James W.; Dai, Y. S.; Dressler, Alan; Henry, Alaina; Malkan, Matt; Rafelski, Marc; Siana, Brian; Teplitz, Harry I.;

A Size-Luminosity Relationship for Protoplanetary Disks in Lupus

NASA Astrophysics Data System (ADS)

Terrell, Marie; Andrews, Sean

2018-01-01

The sizes of the 340 GHz continuum emission from 56 protoplanetary disks in the Lupus star-forming region were measured by modeling their ALMA visibility profiles. We describe the mechanism for these measurements and some preliminary results regarding the correlation between the continuum luminosities and sizes.

The clustering amplitude of X-ray-selected AGN at z ˜ 0.8: evidence for a negative dependence on accretion luminosity

NASA Astrophysics Data System (ADS)

Mountrichas, G.; Georgakakis, A.; Menzel, M.-L.; Fanidakis, N.; Merloni, A.; Liu, Z.; Salvato, M.; Nandra, K.

2016-04-01

The northern tile of the wide-area and shallow XMM-XXL X-ray survey field is used to estimate the average dark matter halo mass of relatively luminous X-ray-selected active galactic nucleus (AGN) [log {L}_X (2-10 keV)= 43.6^{+0.4}_{-0.4} erg s^{-1}] in the redshift interval z = 0.5-1.2. Spectroscopic follow-up observations of X-ray sources in the XMM-XXL field by the Sloan telescope are combined with the VIMOS Public Extragalactic Redshift Survey spectroscopic galaxy survey to determine the cross-correlation signal between X-ray-selected AGN (total of 318) and galaxies (about 20 000). We model the large scales (2-25 Mpc) of the correlation function to infer a mean dark matter halo mass of log M / (M_{{⊙}} h^{-1}) = 12.50 ^{+0.22} _{-0.30} for the X-ray-selected AGN sample. This measurement is about 0.5 dex lower compared to estimates in the literature of the mean dark matter halo masses of moderate-luminosity X-ray AGN [LX(2-10 keV) ≈ 1042-1043 erg s- 1] at similar redshifts. Our analysis also links the mean clustering properties of moderate-luminosity AGN with those of powerful ultraviolet/optically selected QSOs, which are typically found in haloes with masses few times 1012 M⊙. There is therefore evidence for a negative luminosity dependence of the AGN clustering. This is consistent with suggestions that AGN have a broad dark matter halo mass distribution with a high mass tail that becomes subdominant at high accretion luminosities. We further show that our results are in qualitative agreement with semi-analytic models of galaxy and AGN evolution, which attribute the wide range of dark matter halo masses among the AGN population to different triggering mechanisms and/or black hole fuelling modes.

The Luminosity Measurement for the DZERO Experiment at Fermilab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snow, Gregory R.

Primary project objective: The addition of University of Nebraska-Lincoln (UNL) human resources supported by this grant helped ensure that Fermilab’s DZERO experiment had a reliable luminosity measurement through the end of Run II data taking and an easily-accessible repository of luminosity information for all collaborators performing physics analyses through the publication of its final physics results. Secondary project objective: The collaboration between the UNL Instrument Shop and Fermilab’s Scintillation Detector Development Center enhanced the University of Nebraska’s future role as a particle detector R&D and production facility for future high energy physics experiments. Overall project objective: This targeted project enhancedmore » the University of Nebraska’s presence in both frontier high energy physics research in DZERO and particle detector development, and it thereby served the goals of the DOE Office of Science and the Experimental Program to Stimulate Competitive Research (EPSCoR) for the state of Nebraska.« less

IBS and Potential Luminosity Improvement for RHIC Operation Below Transition Energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fedotov,A.

There is a strong interest in low-energy RHIC operations in the single-beam total energy range of 2.5-25 GeV/nucleon [1-3]. Collisions in this energy range, much of which is below nominal RHIC injection energy, will help to answer one of the key questions in the field of QeD about the existence and location of a critical point on the QCD phase diagram [4]. There have been several short test runs during 2006-2008 RHIC operations to evaluate RHIC operational challenges at these low energies [5]. Beam lifetimes observed during the test runs were limited by machine nonlinearities. This performance limit can bemore » improved with sufficient machine tuning. The next luminosity limitation comes from transverse and longitudinal Intra-beam Scattering (IBS), and ultimately from the space-charge limit. Detailed discussion of limiting beam dynamics effects and possible luminosity improvement with electron cooling can be found in Refs. [6-8]. For low-energy RHIC operation, particle losses from the RF bucket are of particular concern since the longitudinal beam size is comparable to the existing RF bucket at low energies. However, operation below transition energy allows us to exploit an Intra-beam Scattering (IBS) feature that drives the transverse and longitudinal beam temperatures towards equilibrium by minimizing the longitudinal diffusion rate using a high RF voltage. Simulation studies were performed with the goal to understand whether one can use this feature of IBS to improve luminosity of RHIC collider at low-energies. This Note presents results of simulations which show that additional luminosity improvement for low-energy RHIC project may be possible with high RF voltage from a 56 MHz superconducting RF cavity that is presently under development for RHIC.« less

Long term dynamics of the high luminosity Large Hadron Collider with crab cavities

NASA Astrophysics Data System (ADS)

Barranco García, J.; De Maria, R.; Grudiev, A.; Tomás García, R.; Appleby, R. B.; Brett, D. R.

2016-10-01

The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) aims to achieve an integrated luminosity of 200 - 300 fb-1 per year, including the contribution from the upgrade of the injector chain. For the HL-LHC the larger crossing angle together with a smaller beta function at the collision point would result in more than 70% luminosity loss due to the incomplete geometric overlap of colliding bunches. To recover head-on collisions at the high-luminosity particle-physics detectors ATLAS and CMS and benefit from the very low β* provided by the Achromatic Telescopic Squeezing (ATS) optics, a local crab cavity scheme provides transverse kicks to the proton bunches. The tight space constraints at the location of these cavities leads to designs which are axially non-symmetric, giving rise to high order multipoles components of the main deflecting mode and, since these kicks are harmonic in time, we expand them in a series of multipoles in a similar fashion as is done for static field magnets. In this work we calculate, for the first time, the higher order multipoles and their impact on beam dynamics for three different crab cavity prototypes. Different approaches to calculate the multipoles are presented. Furthermore, we perform the first calculation of their impact on the long term stability of the machine using the concept of dynamic aperture.

The NGC 7742 star cluster luminosity function: a population analysis revisited

NASA Astrophysics Data System (ADS)

de Grijs, Richard; Ma, Chao

2018-02-01

We re-examine the properties of the star cluster population in the circumnuclear starburst ring in the face-on spiral galaxy NGC 7742, whose young cluster mass function has been reported to exhibit significant deviations from the canonical power law. We base our reassessment on the clusters’ luminosities (an observational quantity) rather than their masses (a derived quantity), and confirm conclusively that the galaxy’s starburst-ring clusters—and particularly the youngest subsample, {log}(t {{{yr}}}-1)≤ 7.2—show evidence of a turnover in the cluster luminosity function well above the 90% completeness limit adopted to ensure the reliability of our results. This confirmation emphasizes the unique conundrum posed by this unusual cluster population.

Dark-ages reionization and galaxy formation simulation - IV. UV luminosity functions of high-redshift galaxies

NASA Astrophysics Data System (ADS)

Liu, Chuanwu; Mutch, Simon J.; Angel, P. W.; Duffy, Alan R.; Geil, Paul M.; Poole, Gregory B.; Mesinger, Andrei; Wyithe, J. Stuart B.

2016-10-01

In this paper, we present calculations of the UV luminosity function (LF) from the Dark-ages Reionization And Galaxy-formation Observables from Numerical Simulations project, which combines N-body, semi-analytic and seminumerical modelling designed to study galaxy formation during the Epoch of Reionization. Using galaxy formation physics including supernova feedback, the model naturally reproduces the UV LFs for high-redshift star-forming galaxies from z ˜ 5 through to z ˜ 10. We investigate the luminosity-star formation rate (SFR) relation, finding that variable SFR histories of galaxies result in a scatter around the median relation of 0.1-0.3 dex depending on UV luminosity. We find close agreement between the model and observationally derived SFR functions. We use our calculated luminosities to investigate the LF below current detection limits, and the ionizing photon budget for reionization. We predict that the slope of the UV LF remains steep below current detection limits and becomes flat at MUV ≳ -14. We find that 48 (17) per cent of the total UV flux at z ˜ 6 (10) has been detected above an observational limit of MUV ˜ -17, and that galaxies fainter than MUV ˜ -17 are the main source of ionizing photons for reionization. We investigate the luminosity-stellar mass relation, and find a correlation for galaxies with MUV < -14 that has the form M_{ast } ∝ 10^{-0.47M_UV}, in good agreement with observations, but which flattens for fainter galaxies. We determine the luminosity-halo mass relation to be M_vir ∝ 10^{-0.35M_UV}, finding that galaxies with MUV = -20 reside in host dark matter haloes of 1011.0±0.1 M⊙ at z ˜ 6, and that this mass decreases towards high redshift.

Studying the accretion geometry of EXO 2030+375 at luminosities close to the propeller regime

NASA Astrophysics Data System (ADS)

Fürst, F.; Kretschmar, P.; Kajava, J. J. E.; Alfonso-Garzón, J.; Kühnel, M.; Sanchez-Fernandez, C.; Blay, P.; Wilson-Hodge, C. A.; Jenke, P.; Kreykenbohm, I.; Pottschmidt, K.; Wilms, J.; Rothschild, R. E.

2017-10-01

The Be X-ray binary EXO 2030+375was in an extended low-luminosity state during most of 2016. We observed this state with NuSTARand Swift, supported by INTEGRALobservations and optical spectroscopy with the Nordic Optical Telescope (NOT). We present a comprehensive spectral and timing analysis of these data here to study the accretion geometry and investigate a possible onset of the propeller effect. The Hα data show that the circumstellar disk of the Be-star is still present. We measure equivalent widths similar to values found during more active phases in the past, indicating that the low-luminosity state is not simply triggered by a smaller Be disk. The NuSTARdata, taken at a 3-78 keV luminosity of 6.8 × 1035 erg s-1 (for a distance of 7.1 kpc), are nicely described by standard accreting pulsar models such as an absorbed power law with a high-energy cutoff. We find that pulsations are still clearly visible at these luminosities, indicating that accretion is continuing despite the very low mass transfer rate. In phase-resolved spectroscopy we find a peculiar variation of the photon index from 1.5 to 2.5 over only about 3% of the rotational period. This variation is similar to that observed with XMM-Newtonat much higher luminosities. It may be connected to the accretion column passing through our line of sight. With Swift/XRT we observe luminosities as low as 1034 erg s-1 where the data quality did not allow us to search for pulsations, but the spectrum is much softer and well described by either a blackbody or soft power-law continuum. This softer spectrum might be due to the accretion being stopped by the propeller effect and we only observe the neutron star surface cooling.

Calibrating Star Formation in WISE Using Total Infrared Luminosity

NASA Astrophysics Data System (ADS)

Cluver, M. E.; Jarrett, T. H.; Dale, D. A.; Smith, J.-D. T.; August, Tamlyn; Brown, M. J. I.

2017-11-01

We present accurate resolved WISE photometry of galaxies in the combined SINGS and KINGFISH sample. The luminosities in the W3 12 μm and W4 23 μm bands are calibrated to star formation rates (SFRs) derived using the total infrared luminosity, avoiding UV/optical uncertainties due to dust extinction corrections. The W3 relation has a 1σ scatter of 0.15 dex that is over nearly 5 orders of magnitude in SFR and 12 μm luminosity, and a range in host stellar mass from dwarfs (107 {M}⊙ ) to ˜ 3× {M}{\\star } (1011.5 {M}⊙ ) galaxies. In the absence of deep silicate absorption features and powerful active galactic nuclei, we expect this to be a reliable SFR indicator chiefly due to the broad nature of the W3 band. By contrast, the W4 SFR relation shows more scatter (1σ =0.18 dex). Both relations show reasonable agreement with radio-continuum-derived SFRs and excellent accordance with so-called “hybrid” Hα + 24 μm and FUV+24 μm indicators. Moreover, the WISE SFR relations appear to be insensitive to the metallicity range in the sample. We also compare our results with IRAS-selected luminous infrared galaxies, showing that the WISE relations maintain concordance, but systematically deviate for the most extreme galaxies. Given the all-sky coverage of WISE and the performance of the W3 band as an SFR indicator, the {L}12μ {{m}} SFR relation could be of great use to studies of nearby galaxies and forthcoming large-area surveys at optical and radio wavelengths.

Clustering, Cosmology and a New Era of Black Hole Demographics: The Conditional Luminosity Function of AGNs

NASA Astrophysics Data System (ADS)

Ballantyne, David R.

2017-01-01

Deep X-ray surveys have provided a comprehensive and largely unbiased view of active galactic nuclei (AGN) evolution stretching back to z~5. However, it has been challenging to use the survey results to connect this evolution to the cosmological environment that AGNs inhabit. Exploring this connection will be crucial to understanding the triggering mechanisms of AGNs and how these processes manifest in observations at all wavelengths. In anticipation of upcoming wide-field X-ray surveys that will allow quantitative analysis of AGN environments, we present a method to observationally constrain the Conditional Luminosity Function (CLF) of AGNs at a specific z. Once measured, the CLF allows the calculation of the AGN bias, mean dark matter halo mass, AGN lifetime, halo occupation number, and AGN correlation function -- all as a function of luminosity. The CLF can be constrained using a measurement of the X-ray luminosity function and the correlation length at different luminosities. The method is illustrated at z≈0 and 0.9 using the limited data that is currently available, and a clear luminosity dependence in the AGN bias and mean halo mass is predicted at both, supporting the idea that there are at least two different modes of AGN triggering. In addition, the CLF predicts that z≈0.9 quasars may be commonly hosted by haloes with Mh ~ 1014 M⊙. These `young cluster' environments may provide the necessary interactions between gas-rich galaxies to fuel luminous accretion. The results derived from this method will be useful to populate AGNs of different luminosities in cosmological simulations.

AKARI IRC 2.5-5 μm spectroscopy of infrared galaxies over a wide luminosity range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ichikawa, Kohei; Ueda, Yoshihiro; Imanishi, Masatoshi

2014-10-20

We present the result of a systematic infrared 2.5-5 μm spectroscopic study of 22 nearby infrared galaxies over a wide infrared luminosity range (10{sup 10} L {sub ☉} < L {sub IR} < 10{sup 13} L {sub ☉}) obtained from the AKARI Infrared Camera (IRC). The unique band of the AKARI IRC spectroscopy enables us to access both the 3.3 μm polycyclic aromatic hydrocarbon (PAH) emission feature from star-forming activity and the continuum of torus-dust emission heated by an active galactic nucleus (AGN). Applying our AGN diagnostics to the AKARI spectra, we discover 14 buried AGNs. The large fraction ofmore » buried AGNs suggests that AGN activity behind the dust is almost ubiquitous in ultra-/luminous infrared galaxies (U/LIRGs). We also find that both the fraction and energy contribution of buried AGNs increase with infrared luminosity from 10{sup 10} L {sub ☉} to 10{sup 13} L {sub ☉}, including normal infrared galaxies with L {sub IR} < 10{sup 11} L {sub ☉}. The energy contribution from AGNs in the total infrared luminosity is only ∼7% in LIRGs and ∼20% in ULIRGs, suggesting that the majority of the infrared luminosity originates from starburst activity. Using the PAH emission, we investigate the luminosity relation between star formation and AGNs. We find that these infrared galaxies exhibit higher star formation rates than optically selected Seyfert galaxies with the same AGN luminosities, implying that infrared galaxies could be an early evolutionary phase of AGN.« less

Do Radio Jets Contribute to Driving Ionized Gas Outflows in Moderate Luminosity Type 2 AGN?

NASA Astrophysics Data System (ADS)

Fowler, Julia; Sajina, Anna; Lacy, Mark

2016-01-01

This poster examines the role of AGN-driven feedback in low to intermediate power radio galaxies. We begin with [OIII] measurements of ionized gas outflows in 29 moderate AGN-luminosity z~0.3-0.7 dust-obscured Type 2 AGN. We aim to examine the relative role of the AGN itself, of star-formation and of nascent radio jets in driving these outflows. The strength of the AGN and star formation are based on the [OIII] luminosities, and the far-IR luminosities respectively. For the radio jets, we present multi-frequency radio (X, S, and L-bands) JVLA imaging of our sample, which allows us both to constrain the overall radio power, but also look for signatures of young radio sources, including Giga-hertz Peaked Spectrum (GPS) sources, as well as small-scale jets. While radio jet-driven outflows are well known for powerful radio-loud galaxies, this study allows us to constrain the degree to which this mechanism is significant at more modest radio luminosities of L5GHz~10^22-25 W/Hz.

Detection prospects for high energy neutrino sources from the anisotropic matter distribution in the local Universe

NASA Astrophysics Data System (ADS)

Mertsch, Philipp; Rameez, Mohamed; Tamborra, Irene

2017-03-01

Constraints on the number and luminosity of the sources of the cosmic neutrinos detected by IceCube have been set by targeted searches for point sources. We set complementary constraints by using the 2MASS Redshift Survey (2MRS) catalogue, which maps the matter distribution of the local Universe. Assuming that the distribution of the neutrino sources follows that of matter, we look for correlations between ``warm'' spots on the IceCube skymap and the 2MRS matter distribution. Through Monte Carlo simulations of the expected number of neutrino multiplets and careful modelling of the detector performance (including that of IceCube-Gen2), we demonstrate that sources with local density exceeding 10-6 Mpc-3 and neutrino luminosity Lν lesssim 1042 erg s-1 (1041 erg s-1) will be efficiently revealed by our method using IceCube (IceCube-Gen2). At low luminosities such as will be probed by IceCube-Gen2, the sensitivity of this analysis is superior to requiring statistically significant direct observation of a point source.

Luminosity determination in pp collisions at $$\\sqrt{s} = 7$$ TeV using the ATLAS detector at the LHC

DOE PAGES

Aad, G.; Abbott, B.; Abdallah, J.; ...

2011-04-27

Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at √s = 7 TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of μ, the average number of inelastic interactions per bunch crossing. Residual time- and μ-dependence between the methods is less than 2% for 0 < μ < 2.5. Absolute luminosity calibrations, performed using beam separation scans, have amore » common systematic uncertainty of ±11%, dominated by the measurement of the LHC beam currents. After calibration, the luminosities obtained from the different methods differ by at most ±2%. The visible cross sections measured using the beam scans are compared to predictions obtained with the PYTHIA and PHOJET event generators and the ATLAS detector simulation.« less

Precision Luminosity of LHC Proton-Proton Collisions at 13 TeV Using Hit Counting With TPX Pixel Devices

NASA Astrophysics Data System (ADS)

Sopczak, André; Ali, Babar; Asawatavonvanich, Thanawat; Begera, Jakub; Bergmann, Benedikt; Billoud, Thomas; Burian, Petr; Caicedo, Ivan; Caforio, Davide; Heijne, Erik; Janeček, Josef; Leroy, Claude; Mánek, Petr; Mochizuki, Kazuya; Mora, Yesid; Pacík, Josef; Papadatos, Costa; Platkevič, Michal; Polanský, Štěpán; Pospíšil, Stanislav; Suk, Michal; Svoboda, Zdeněk

2017-03-01

A network of Timepix (TPX) devices installed in the ATLAS cavern measures the LHC luminosity as a function of time as a stand-alone system. The data were recorded from 13-TeV proton-proton collisions in 2015. Using two TPX devices, the number of hits created by particles passing the pixel matrices was counted. A van der Meer scan of the LHC beams was analyzed using bunch-integrated luminosity averages over the different bunch profiles for an approximate absolute luminosity normalization. It is demonstrated that the TPX network has the capability to measure the reduction of LHC luminosity with precision. Comparative studies were performed among four sensors (two sensors in each TPX device) and the relative short-term precision of the luminosity measurement was determined to be 0.1% for 10-s time intervals. The internal long-term time stability of the measurements was below 0.5% for the data-taking period.

Recalculating the quasar luminosity function of the extended Baryon Oscillation Spectroscopic Survey

NASA Astrophysics Data System (ADS)

Caditz, David M.

2017-12-01

Aims: The extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey provides a uniform sample of over 13 000 variability selected quasi-stellar objects (QSOs) in the redshift range 0.68 luminosity function (QLF), parametric model fits, and projected number counts based on this survey may be in error because the k-correction has apparently been misapplied, which results in underestimating the intrinsic brightness of roughly half of the eBOSS sources. This work provides new estimates of the QLF based on a corrected eBOSS dataset. Methods: Intrinsic luminosities were recalculated using the appropriate g-band k-correction function. The QLF was determined for the corrected dataset using a model-weighted estimator, and parametric models were refit to the corrected luminosity function. Projected number counts based on the corrected models are also provided. Results: At redshifts higher than the "pivot" redshift, zp = 2.2, the original and recalculated results differ significantly; in particular, the new results show stronger high-redshift evolution in the best-fit models than the original eBOSS analysis. A new seven-parameter QLF model is provided that fits the corrected eBOSS dataset.

How Accurate Are Infrared Luminosities from Monochromatic Photometric Extrapolation?

NASA Astrophysics Data System (ADS)

Lin, Zesen; Fang, Guanwen; Kong, Xu

2016-12-01

Template-based extrapolations from only one photometric band can be a cost-effective method to estimate the total infrared (IR) luminosities ({L}{IR}) of galaxies. By utilizing multi-wavelength data that covers across 0.35-500 μm in GOODS-North and GOODS-South fields, we investigate the accuracy of this monochromatic extrapolated {L}{IR} based on three IR spectral energy distribution (SED) templates out to z˜ 3.5. We find that the Chary & Elbaz template provides the best estimate of {L}{IR} in Herschel/Photodetector Array Camera and Spectrometer (PACS) bands, while the Dale & Helou template performs best in Herschel/Spectral and Photometric Imaging Receiver (SPIRE) bands. To estimate {L}{IR}, we suggest that extrapolations from the available longest wavelength PACS band based on the Chary & Elbaz template can be a good estimator. Moreover, if the PACS measurement is unavailable, extrapolations from SPIRE observations but based on the Dale & Helou template can also provide a statistically unbiased estimate for galaxies at z≲ 2. The emission with a rest-frame 10-100 μm range of IR SED can be well described by all three templates, but only the Dale & Helou template shows a nearly unbiased estimate of the emission of the rest-frame submillimeter part.

Low-luminosity Blazars in Wise: A Mid-infrared View of Unification

NASA Astrophysics Data System (ADS)

Plotkin, Richard M.; Anderson, S. F.; Brandt, W. N.; Markoff, S.; Shemmer, O.; Wu, J.

2012-01-01

We use the preliminary data release from the Wide-Field Infrared Survey Explorer (WISE) to perform the first statistical study on the mid-infrared (IR) properties of a large number ( 102) of BL Lac objects -- low-luminosity Active Galactic Nuclei (AGN) with a jet beamed toward the Earth. As expected, many BL Lac objects are so highly beamed that their jet synchrotron emission dominates their IR spectral energy distributions (SEDs), and the shape of their SEDs in the IR correlates well with SED peak frequency. In other BL Lac objects, the jet is not strong enough to completely dilute the rest of the AGN, and we do not see observational signatures of the dusty torus from these weakly beamed BL Lac objects. While at odds with simple unification, the missing torus is consistent with recent suggestions that BL Lac objects are fed by radiatively inefficient accretion flows. We discuss implications on the ``nature vs. nurture" debate for FR I and FR II galaxies, and also on the standard orientation-based AGN unification model.

The effects of pure density evolution on the brightness distribution of cosmological gamma-ray bursts

NASA Technical Reports Server (NTRS)

Horack, J. M.; Emslie, A. G.; Hartmann, D. H.

1995-01-01

In this work, we explore the effects of burst rate density evolution on the observed brightness distribution of cosmological gamma-ray bursts. Although the brightness distribution of gamma-ray bursts observed by the BATSE experiment has been shown to be consistent with a nonevolving source population observed to redshifts of order unity, evolution of some form is likely to be present in the gamma-ray bursts. Additionally, nonevolving models place significant constraints on the range of observed burst luminosities, which are relaxed if evolution of the burst population is present. In this paper, three analytic forms of density evolution are examined. In general, forms of evolution with densities that increase monotonically with redshift require that the BATSE data correspond to bursts at larger redshifts, or to incorporate a wider range of burst luminosities, or both. Independent estimates of the maximum observed redshift in the BATSE data and/or the range of luminosity from which a large fraction of the observed bursts are drawn therefore allow for constraints to be placed on the amount of evolution that may be present in the burst population. Specifically, if recent measurements obtained from analysis of the BATSE duration distribution of the actual limiting redshift in the BATSE data at z(sub lim) = 2 are correct, the BATSE N(P) distribution in a Lambda = 0 universe is inconsistent at a level of approximately 3 alpha with nonevolving gamma-ray bursts and some form of evolution in the population is required. The sense of this required source evolution is to provide a higher density, larger luminosities, or both with increasing redshift.

QSO Narrow [OIII] Line Width and Host Galaxy Luminosity

NASA Astrophysics Data System (ADS)

Bonning, E. W.; Shields, G. A.; Salviander, S.

2004-05-01

Established correlations between galaxy bulge luminosity L, black hole mass MBH, and stellar velocity dispersion sigma in galaxies suggest a close relationship between the growth of supermassive black holes and their host galaxies. Measurements of the MBH - sigma relationship as a function of cosmic time may shed light on the origin of this relationship. One approach is to derive MBH and sigma from the widths of QSO broad and narrow lines, respectively (Shields et al. 2003, ApJ, 583, 124; Nelson 2000, ApJ, 544, L91). We investigate the utility of using the velocity of the narrow line emitting gas as a surrogate for stellar velocity dispersion in QSOs by examining host magnitudes and [OIII] line widths for low redshift QSOs. For our limited range of L, the increase in sigma with L predicted by the Faber-Jackson relation is substantially obscured by scatter. However, sigma([O III]) is consistent in the mean with host galaxy luminosity. EWB is a NASA GSRP fellow. GAS and SS are supported under Texas Advanced Research Program grant 003658-0177-2001 and NSF grant AST-0098594.

Supernova neutrinos and antineutrinos: ternary luminosity diagram and spectral split patterns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fogli, Gianluigi; Marrone, Antonio; Tamborra, Irene

2009-10-01

In core-collapse supernovae, the ν{sub e} and ν-bar {sub e} species may experience collective flavor swaps to non-electron species ν{sub x}, within energy intervals limited by relatively sharp boundaries (''splits''). These phenomena appear to depend sensitively upon the initial energy spectra and luminosities. We investigate the effect of generic variations of the fractional luminosities (l{sub e}, l{sub ē}, l{sub x}) with respect to the usual ''energy equipartition'' case (1/6, 1/6, 1/6), within an early-time supernova scenario with fixed thermal spectra and total luminosity. We represent the constraint l{sub e}+l{sub ē}+4l{sub x} = 1 in a ternary diagram, which is exploredmore » via numerical experiments (in single-angle approximation) over an evenly-spaced grid of points. In inverted hierarchy, single splits arise in most cases, but an abrupt transition to double splits is observed for a few points surrounding the equipartition one. In normal hierarchy, collective effects turn out to be unobservable at all grid points but one, where single splits occur. Admissible deviations from equipartition may thus induce dramatic changes in the shape of supernova (anti)neutrino spectra. The observed patterns are interpreted in terms of initial flavor polarization vectors (defining boundaries for the single/double split transitions), lepton number conservation, and minimization of potential energy.« less

The evolution of temperature and bolometric luminosity in Type II supernovae

NASA Astrophysics Data System (ADS)

Faran, T.; Nakar, E.; Poznanski, D.

2018-01-01

In this work, we present a uniform analysis of the temperature evolution and bolometric luminosity of a sample of 29 Type II supernovae (SNe), by fitting a blackbody model to their multiband photometry. Our sample includes only SNe with high quality multiband data and relatively well-sampled time coverage. Most of the SNe in our sample were detected less than a week after explosion so their light curves cover the evolution both before and after recombination starts playing a role. We use this sample to study the signature of hydrogen recombination, which is expected to appear once the observed temperature drops to ≈7000 K. Theory predicts that before recombination starts affecting the light curve, both the luminosity and the temperature should drop relatively fast, following a power law in time. Once the recombination front reaches inner parts of the outflow, it sets the observed temperature to be nearly constant, and slows the decline of the luminosity (or even leads to a re-brightening). We compare our data to analytic studies and find strong evidence for the signature of recombination. We also find that the onset of the optical plateau in a given filter, is effectively the time at which the blackbody peak reaches the central wavelength of the filter, as it cools, and it does not correspond to the time at which recombination starts affecting the emission.

The V-band Empirical Mass-luminosity Relation for Main Sequence Stars

NASA Astrophysics Data System (ADS)

Xia, Fang; Fu, Yan-Ning

2010-07-01

Stellar mass is an indispensable parameter in the studies of stellar physics and stellar dynamics. On the one hand, the most reliable way to determine the stellar dynamical mass is via orbital determinations of binaries. On the other hand, however, most stellar masses have to be estimated by using the mass luminosity relation (MLR). Therefore, it is important to obtain the empirical MLR through fitting the data of stellar dynamical mass and luminosity. The effect of metallicity can make this relation disperse in the V-band, but studies show that this is mainly limited to the case when the stellar mass is less than 0.6M⊙ Recently, many relevant data have been accumulated for main sequence stars with larger masses, which make it possible to significantly improve the corresponding MLR. Using a fitting method which can reasonably assign weights to the observational data including two quantities with different dimensions, we obtain a V-band MLR based on the dynamical masses and luminosities of 203 main sequence stars. In comparison with the previous work, the improved MLR is statistically significant, and the relative error of mass estimation reaches about 5%. Therefore, our MLR is useful not only in the studies of statistical nature, but also in the studies of concrete stellar systems, such as the long-term dynamical study and the short-term positioning study of a specific multiple star system.

The V Band Empirical Mass-Luminosity Relation for Main Sequence Stars

NASA Astrophysics Data System (ADS)

Xia, F.; Fu, Y. N.

2010-01-01

Stellar mass is an indispensable parameter in the studies of stellar physics and stellar dynamics. On the one hand, the most reliable way to determine the stellar dynamical mass is via orbital determination of binaries. On the other hand, however, most stellar masses have to be estimated by using the mass-luminosity relation (MLR). Therefore, it is important to obtain the empirical MLR through fitting the data of stellar dynamical mass and luminosity. The effect of metallicity can make this relation disperse in the V-band, but studies show that this is mainly limited to the case when the stellar mass is less than 0.6M⊙. Recently, many relevant data have been accumulated for main sequence stars with larger mass, which make it possible to significantly improve the corresponding MLR. Using a fitting method which can reasonably assign weight to the observational data including two quantities with different dimensions, we obtain a V-band MLR based on the dynamical masses and luminosities of 203 main sequence stars. Compared with the previous work, the improved MLR is statistically significant, and the relative error of mass estimation reaches about 5%. Therefore, our MLR is useful not only in studies of statistical nature, but also in studies of concrete stellar systems, such as the long-term dynamical study and the short-term positioning study of a specific multiple star system.

Luminosities and mass-loss rates of Local Group AGB stars and red supergiants

NASA Astrophysics Data System (ADS)

Groenewegen, M. A. T.; Sloan, G. C.

2018-01-01

Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking. Aims: We aim to investigate mass loss and luminosity in a large sample of evolved stars in several Local Group galaxies with a variety of metalliticies and star-formation histories: the Small and Large Magellanic Cloud, and the Fornax, Carina, and Sculptor dwarf spheroidal galaxies (dSphs). Methods: Dust radiative transfer models are presented for 225 carbon stars and 171 oxygen-rich evolved stars in several Local Group galaxies for which spectra from the Infrared Spectrograph on Spitzer are available. The spectra are complemented with available optical and infrared photometry to construct spectral energy distributions. A minimization procedure was used to determine luminosity and mass-loss rate (MLR). Pulsation periods were derived for a large fraction of the sample based on a re-analysis of existing data. Results: New deep K-band photometry from the VMC survey and multi-epoch data from IRAC (at 4.5 μm) and AllWISE and NEOWISE have allowed us to derive pulsation periods longer than 1000 days for some of the most heavily obscured and reddened objects. We derive (dust) MLRs and luminosities for the entire sample. The estimated MLRs can differ significantly from estimates for the same objects in the literature due to differences in adopted optical constants (up to factors of several) and details in the radiative transfer modelling. Updated parameters for the super-AGB candidate MSX SMC 055 (IRAS 00483-7347) are presented. Its current mass is estimated to be 8.5 ± 1.6 M⊙, suggesting an initial mass well above 8 M⊙ in agreement with estimates based on its large Rubidium abundance. Using synthetic photometry, we present and discuss colour-colour and

Explaining the luminosity spread in young clusters: proto and pre-main sequence stellar evolution in a molecular cloud environment

NASA Astrophysics Data System (ADS)

Jensen, Sigurd S.; Haugbølle, Troels

2018-02-01

Hertzsprung-Russell diagrams of star-forming regions show a large luminosity spread. This is incompatible with well-defined isochrones based on classic non-accreting protostellar evolution models. Protostars do not evolve in isolation of their environment, but grow through accretion of gas. In addition, while an age can be defined for a star-forming region, the ages of individual stars in the region will vary. We show how the combined effect of a protostellar age spread, a consequence of sustained star formation in the molecular cloud, and time-varying protostellar accretion for individual protostars can explain the observed luminosity spread. We use a global magnetohydrodynamic simulation including a sub-scale sink particle model of a star-forming region to follow the accretion process of each star. The accretion profiles are used to compute stellar evolution models for each star, incorporating a model of how the accretion energy is distributed to the disc, radiated away at the accretion shock, or incorporated into the outer layers of the protostar. Using a modelled cluster age of 5 Myr, we naturally reproduce the luminosity spread and find good agreement with observations of the Collinder 69 cluster, and the Orion Nebular Cluster. It is shown how stars in binary and multiple systems can be externally forced creating recurrent episodic accretion events. We find that in a realistic global molecular cloud model massive stars build up mass over relatively long time-scales. This leads to an important conceptual change compared to the classic picture of non-accreting stellar evolution segmented into low-mass Hayashi tracks and high-mass Henyey tracks.

MEASURING THE LUMINOSITY AND VIRIAL BLACK HOLE MASS DEPENDENCE OF QUASAR–GALAXY CLUSTERING AT z ∼ 0.8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krolewski, Alex G.; Eisenstein, Daniel J., E-mail: akrolewski@college.harvard.edu

2015-04-10

We study the dependence of quasar clustering on quasar luminosity and black hole mass by measuring the angular overdensity of photometrically selected galaxies imaged by the Wide-field Infrared Survey Explorer (WISE) about z ∼ 0.8 quasars from SDSS. By measuring the quasar–galaxy cross-correlation function and using photometrically selected galaxies, we achieve a higher density of tracer objects and a more sensitive detection of clustering than measurements of the quasar autocorrelation function. We test models of quasar formation and evolution by measuring the luminosity dependence of clustering amplitude. We find a significant overdensity of WISE galaxies about z ∼ 0.8 quasarsmore » at 0.2–6.4 h{sup −1} Mpc in projected comoving separation. We find no appreciable increase in clustering amplitude with quasar luminosity across a decade in luminosity, and a power-law fit between luminosity and clustering amplitude gives an exponent of −0.01 ± 0.06 (1 σ error). We also fail to find a significant relationship between clustering amplitude and black hole mass, although our dynamic range in true mass is suppressed due to the large uncertainties in virial black hole mass estimates. Our results indicate that a small range in host dark matter halo mass maps to a large range in quasar luminosity.« less

Energy deposition studies for the high-luminosity Large Hadron Collider inner triplet magnets

NASA Astrophysics Data System (ADS)

Mokhov, N. V.; Rakhno, I. L.; Tropin, I. S.; Cerutti, F.; Esposito, L. S.; Lechner, A.

2015-05-01

A detailed model of the high-luminosity LHC inner triplet region with new large-aperture Nb3Sn magnets, field maps, corrector packages, and segmented tungsten inner absorbers was built and implemented into the fluka and mars15 codes. Detailed simulations have been performed coherently with the codes on the impact of particle debris from the 14-TeV center-of-mass pp-collisions on the short- and long-term stability of the inner triplet magnets. After optimizing the absorber configuration, the peak power density averaged over the magnet inner cable width is found to be safely below the quench limit at the luminosity of 5 ×1034 cm-2 s-1 . For the anticipated lifetime integrated luminosity of 3000 fb-1 , the peak dose calculated for the innermost magnet insulator ranges from 20 to 35 MGy, a figure close to the commonly accepted limit. Dynamic heat loads to the triplet magnet cold mass are calculated to evaluate the cryogenic capability. fluka and mars results on energy deposition are in very good agreement.

Spectral Properties, Generation Order Parameters, and Luminosities for Spin-powered X-Ray Pulsars

NASA Astrophysics Data System (ADS)

Wang, Wei; Zhao, Yongheng

2004-02-01

We show the spectral properties of 15 spin-powered X-ray pulsars, and the correlation between the average power-law photon index and spin-down rate. Generation order parameters (GOPs) based on polar cap models are introduced to characterize the X-ray pulsars. We calculate three definitions of generation order parameters arising from the different effects of magnetic and electric fields on photon absorption during cascade processes, and study the relations between the GOPs and spectral properties of X-ray pulsars. There exists a possible correlation between the photon index and GOP in our pulsar sample. Furthermore, we present a method stemming from the concept of GOPs to estimate the nonthermal X-ray luminosity for spin-powered pulsars. Then X-ray luminosity is calculated in the context of our polar cap accelerator model, which is consistent with most observed X-ray pulsar data. The ratio between the X-ray luminosity estimated by our method and the pulsar's spin-down power is consistent with the LX~10-3Lsd feature.

Energy deposition studies for the high-luminosity Large Hadron Collider inner triplet magnets

DOE PAGES

Mokhov, N. V.; Rakhno, I. L.; Tropin, I. S.; ...

2015-05-06

A detailed model of the high-luminosity LHC inner triplet region with new large-aperture Nb 3Sn magnets, field maps, corrector packages, and segmented tungsten inner absorbers was built and implemented into the fluka and mars15 codes. Detailed simulations have been performed coherently with the codes on the impact of particle debris from the 14-TeV center-of-mass pp-collisions on the short- and long-term stability of the inner triplet magnets. After optimizing the absorber configuration, the peak power density averaged over the magnet inner cable width is found to be safely below the quench limit at the luminosity of 5×10 34 cm -2s -1.more » For the anticipated lifetime integrated luminosity of 3000 fb -1, the peak dose calculated for the innermost magnet insulator ranges from 20 to 35 MGy, a figure close to the commonly accepted limit. Dynamic heat loads to the triplet magnet cold mass are calculated to evaluate the cryogenic capability. fluka and mars results on energy deposition are in very good agreement.« less

Galaxy clustering dependence on the [O II] emission line luminosity in the local Universe

NASA Astrophysics Data System (ADS)

Favole, Ginevra; Rodríguez-Torres, Sergio A.; Comparat, Johan; Prada, Francisco; Guo, Hong; Klypin, Anatoly; Montero-Dorta, Antonio D.

2017-11-01

We study the galaxy clustering dependence on the [O II] emission line luminosity in the SDSS DR7 Main galaxy sample at mean redshift z ∼ 0.1. We select volume-limited samples of galaxies with different [O II] luminosity thresholds and measure their projected, monopole and quadrupole two-point correlation functions. We model these observations using the 1 h-1 Gpc MultiDark-Planck cosmological simulation and generate light cones with the SUrvey GenerAtoR algorithm. To interpret our results, we adopt a modified (Sub)Halo Abundance Matching scheme, accounting for the stellar mass incompleteness of the emission line galaxies. The satellite fraction constitutes an extra parameter in this model and allows to optimize the clustering fit on both small and intermediate scales (i.e. rp ≲ 30 h-1 Mpc), with no need of any velocity bias correction. We find that, in the local Universe, the [O II] luminosity correlates with all the clustering statistics explored and with the galaxy bias. This latter quantity correlates more strongly with the SDSS r-band magnitude than [O II] luminosity. In conclusion, we propose a straightforward method to produce reliable clustering models, entirely built on the simulation products, which provides robust predictions of the typical ELG host halo masses and satellite fraction values. The SDSS galaxy data, MultiDark mock catalogues and clustering results are made publicly available.

GRB 120422A: a Low-Luminosity Gamma-Ray Burst Driven by a Central Engine

NASA Technical Reports Server (NTRS)

Zhang, Bin-Bin; Fan, Yi-Zhong; Shen, Rong-Feng; Xu, Dong; Zhang, Fu-Wen; Wei, Da-Ming; Burrows, David N.; Zhang, Bing; Gehrels, Neil

2012-01-01

GRB 120422A is a low-luminosity gamma-ray burst (GRB) associated with a bright supernova, which distinguishesitself by its relatively short T(sub 90) (approximately 5 s) and an energetic and steep-decaying X-ray tail. We analyze the Swift BurstAlert Telescope and X-ray Telescope data and discuss the physical implications. We show that the steep declineearly in the X-ray light curve can be interpreted as the curvature tail of a late emission episode around 58-86 s,with a curved instantaneous spectrum at the end of the emission episode. Together with the main activity in thefirst 20 s and the weak emission from 40 s to 60 s, the prompt emission is variable, which points to a centralengine origin in contrast to a shock-breakout origin, which is used to interpret some other nearby low-luminosity supernova GRBs. Both the curvature effect model and interpreting the early shallow decay as the coasting externalforward shock emission in a wind medium provide a constraint on the bulk Lorentz factor to be around several.Comparing the properties ofGRB 120422A and other supernova GRBs,we find that themain criterion to distinguish engine-driven GRBs from shock-breakout GRBs is the time-averaged -ray luminosity. Engine-driven GRBs likelyhave a luminosity above approximately 10(sup 48) erg s(sup -1).

VLA observations of unidentified Leiden-Berkeley Deep-Survey sources - Luminosity and redshift dependence of spectral properties

NASA Technical Reports Server (NTRS)

Kapahi, Vijay K.; Kulkarni, Vasant K.

1990-01-01

VLA observations of a complete subset of the Leiden-Berkeley Deep Survey sources that have S(1.4 GHz) greater than 10 mJy and are not optically identified down to F=22 mag are reported. By comparing the spectral and structural properties of the sources with samples from the literature, an attempt was made to disentangle the luminosity and redshift dependence of the spectral indices of extended emission in radio galaxies and of the incidence of compact steep-spectrum sources. It is found that the fraction of compact sources among those with a steep spectrum is related primarily to redshift, being much larger at high redshifts for sources of similar radio luminosity. Only a weak and marginally significant dependence of spectral indices of the extended sources on luminosity and redshift is found in samples selected at 1.4 and 2.7 GHz. It is pointed out that the much stronger correlation of spectral indices with luminosity may be arising partly from spectral curvature, and partly due to the preferential inclusion of very steep-spectrum sources from high redshift in low-frequency surveys.

Upgrade of Tile Calorimeter of the ATLAS Detector for the High Luminosity LHC.

NASA Astrophysics Data System (ADS)

Valdes Santurio, Eduardo; Tile Calorimeter System, ATLAS

2017-11-01

The Tile Calorimeter (TileCal) is the hadronic calorimeter of ATLAS covering the central region of the ATLAS experiment. TileCal is a sampling calorimeter with steel as absorber and scintillators as active medium. The scintillators are read out by wavelength shifting fibers coupled to photomultiplier tubes (PMT). The analogue signals from the PMTs are amplified, shaped and digitized by sampling the signal every 25 ns. The High Luminosity Large Hadron Collider (HL-LHC) will have a peak luminosity of 5 × 1034 cm -2 s -1, five times higher than the design luminosity of the LHC. TileCal will undergo a major replacement of its on- and off-detector electronics for the high luminosity programme of the LHC in 2026. The calorimeter signals will be digitized and sent directly to the off-detector electronics, where the signals are reconstructed and shipped to the first level of trigger at a rate of 40 MHz. This will provide a better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Three different options are presently being investigated for the front-end electronic upgrade. Extensive test beam studies will determine which option will be selected. Field Programmable Gate Arrays (FPGAs) are extensively used for the logic functions of the off- and on-detector electronics. One hybrid demonstrator prototype module with the new calorimeter module electronics, but still compatible with the present system, may be inserted in ATLAS at the end of 2016.

Truncation of the Inner Accretion Disk Around a Black Hole at Low Luminosity

NASA Technical Reports Server (NTRS)

Tomsick, John A.; Yamoka, Kazutaka; Corbel, Stephane; Kaaret, Philip; Kalemci, Emrah; Migliari, Simone

2011-01-01

Most black hole binaries show large changes in X-ray luminosity caused primarily by variations in mass accretion rate. An important question for understanding black hole accretion and jet production is whether the inner edge of the accretion disk recedes at low accretion rate. Measurements of the location of the inner edge (R(sub in)) can be made using iron emission lines that arise due to fluorescence of iron in the disk, and these indicate that R(sub in) is very close to the black hole at high and moderate luminosities (greater than or equal to 1% of the Eddington luminosity, L(sub Edd). Here, we report on X-ray observations of the black hole GX 339-4 in the hard state by Suzaku and the Rossi X-ray Timing Explorer that extend iron line studies to 0.14% L(sub Edd) and show that R(sub in) increases by a factor of greater than 27 over the value found when GX 339-4 was bright. The exact value of R(sub in) depends on the inclination of the inner disk (i), and we derive 90% confidence limits of R(sub in) greater than 35 R(sub g) at i = 0 degrees and R(sub in) greater than 175 R(sub g) at i = 30 degrees. This provides direct evidence that the inner portion of the disk is not present at low luminosity, allowing for the possibility that the inner disk is replaced by advection- or magnetically dominated accretion flows.

Truncation of the Inner Accretion Disk Around a Black Hole at Low Luminosity

NASA Technical Reports Server (NTRS)

Tomsick, John A.; Yamaoka, Kazutaka; Corbel, Stephane; Kaaret, Philip; Kalemci, Emrah; Migliari, Simone

2009-01-01

Most black hole binaries show large changes in X-ray luminosity caused primarily by variations in mass accretion rate. An important question for understanding black hole accretion and jet production is whether the inner edge of the accretion disk recedes at low accretion rate. Measurements of the location of the inner edge (R(sub in)) can be made using iron emission lines that arise due to fluorescence of iron in the disk, and these indicate that R(sub in) is very close to the black hole at high and moderate luminosities (greater than approximately equal to 1% of the Eddington luminosity, L(sub Edd). Here, we report on X-ray observation of the black hole GX 339-4 in the hard state by Suzaku and the Rossi X-ray Timing Explorer (RXTE) that extend iron line studies to 0.14% L(sub Edd) and show that R(sub in) increases by a factor of greater than 27 over the value found when GX 339-4 was bright. The exact value of R(sub in) depends on the inclination of the inner disk (i), and we derive 90% confidence limits of R(sub in) greater than 35R(sub g) at i = 0 degrees and R(sub in) greater than 175R(sub g) at i = 30 degrees. This provides direct evidence that the inner portion of the disk is not present at low luminosity, allowing for the possibility that the inner disk is replaced by advection- or magnetically-dominated accretion flows.

Correction of beam-beam effects in luminosity measurement in the forward region at CLIC

NASA Astrophysics Data System (ADS)

Lukić, S.; Božović-Jelisavčić, I.; Pandurović, M.; Smiljanić, I.

2013-05-01

Procedures for correcting the beam-beam effects in luminosity measurements at CLIC at 3 TeV center-of-mass energy are described and tested using Monte Carlo simulations. The angular counting loss due to the combined Beamstrahlung and initial-state radiation effects is corrected based on the reconstructed velocity of the collision frame of the Bhabha scattering. The distortion of the luminosity spectrum due to the initial-state radiation is corrected by deconvolution. At the end, the counting bias due to the finite calorimeter energy resolution is numerically corrected. To test the procedures, BHLUMI Bhabha event generator, and Guinea-Pig beam-beam simulation were used to generate the outgoing momenta of Bhabha particles in the bunch collisions at CLIC. The systematic effects of the beam-beam interaction on the luminosity measurement are corrected with precision of 1.4 permille in the upper 5% of the energy, and 2.7 permille in the range between 80 and 90% of the nominal center-of-mass energy.

EDDINGTON RATIO DISTRIBUTION OF X-RAY-SELECTED BROAD-LINE AGNs AT 1.0 < z < 2.2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suh, Hyewon; Hasinger, Günther; Steinhardt, Charles

2015-12-20

We investigate the Eddington ratio distribution of X-ray-selected broad-line active galactic nuclei (AGNs) in the redshift range 1.0 < z < 2.2, where the number density of AGNs peaks. Combining the optical and Subaru/Fiber Multi Object Spectrograph near-infrared spectroscopy, we estimate black hole masses for broad-line AGNs in the Chandra Deep Field South (CDF-S), Extended Chandra Deep Field South (E-CDF-S), and the XMM-Newton Lockman Hole (XMM-LH) surveys. AGNs with similar black hole masses show a broad range of AGN bolometric luminosities, which are calculated from X-ray luminosities, indicating that the accretion rate of black holes is widely distributed. We find a substantial fraction ofmore » massive black holes accreting significantly below the Eddington limit at z ≲ 2, in contrast to what is generally found for luminous AGNs at high redshift. Our analysis of observational selection biases indicates that the “AGN cosmic downsizing” phenomenon can be simply explained by the strong evolution of the comoving number density at the bright end of the AGN luminosity function, together with the corresponding selection effects. However, one might need to consider a correlation between the AGN luminosity and the accretion rate of black holes, in which luminous AGNs have higher Eddington ratios than low-luminosity AGNs, in order to understand the relatively small fraction of low-luminosity AGNs with high accretion rates in this epoch. Therefore, the observed downsizing trend could be interpreted as massive black holes with low accretion rates, which are relatively fainter than less-massive black holes with efficient accretion.« less

Hubble Space Telescope Hx Imaging of Star-forming Galaxies at z approximately equal to 1-1.5: Evolution in the Size and Luminosity of Giant H II Regions

NASA Technical Reports Server (NTRS)

Livermore, R. C.; Jones, T.; Richard, J.; Bower, R. G.; Ellis, R. S.; Swinbank, A. M.; Rigby, J. R.; Smail, Ian; Arribas, S.; Rodriguez-Zaurin, J.;

Detection prospects for high energy neutrino sources from the anisotropic matter distribution in the local Universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mertsch, Philipp; Rameez, Mohamed; Tamborra, Irene, E-mail: mertsch@nbi.ku.dk, E-mail: mohamed.rameez@nbi.ku.dk, E-mail: tamborra@nbi.ku.dk

Constraints on the number and luminosity of the sources of the cosmic neutrinos detected by IceCube have been set by targeted searches for point sources. We set complementary constraints by using the 2MASS Redshift Survey (2MRS) catalogue, which maps the matter distribution of the local Universe. Assuming that the distribution of the neutrino sources follows that of matter, we look for correlations between ''warm'' spots on the IceCube skymap and the 2MRS matter distribution. Through Monte Carlo simulations of the expected number of neutrino multiplets and careful modelling of the detector performance (including that of IceCube-Gen2), we demonstrate that sourcesmore » with local density exceeding 10{sup −6} Mpc{sup −3} and neutrino luminosity L {sub ν} ∼< 10{sup 42} erg s{sup −1} (10{sup 41} erg s{sup −1}) will be efficiently revealed by our method using IceCube (IceCube-Gen2). At low luminosities such as will be probed by IceCube-Gen2, the sensitivity of this analysis is superior to requiring statistically significant direct observation of a point source.« less

CONSTRAINTS ON THE FAINT END OF THE QUASAR LUMINOSITY FUNCTION AT z {approx} 5 IN THE COSMOS FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ikeda, H.; Matsuoka, K.; Kajisawa, M.

2012-09-10

We present the result of our low-luminosity quasar survey in the redshift range of 4.5 {approx}< z {approx}< 5.5 in the COSMOS field. Using the COSMOS photometric catalog, we selected 15 quasar candidates with 22 < i' < 24 at z {approx} 5 that are {approx}3 mag fainter than the Sloan Digital Sky Survey quasars in the same redshift range. We obtained optical spectra for 14 of the 15 candidates using FOCAS on the Subaru Telescope and did not identify any low-luminosity type-1 quasars at z {approx} 5, while a low-luminosity type-2 quasar at z {approx} 5.07 was discovered. Inmore » order to constrain the faint end of the quasar luminosity function at z {approx} 5, we calculated the 1{sigma} confidence upper limits of the space density of type-1 quasars. As a result, the 1{sigma} confidence upper limits on the quasar space density are {Phi} < 1.33 Multiplication-Sign 10{sup -7} Mpc{sup -3} mag{sup -1} for -24.52 < M{sub 1450} < -23.52 and {Phi} < 2.88 Multiplication-Sign 10{sup -7} Mpc{sup -3} mag{sup -1} for -23.52 < M{sub 1450} < -22.52. The inferred 1{sigma} confidence upper limits of the space density are then used to provide constraints on the faint-end slope and the break absolute magnitude of the quasar luminosity function at z {approx} 5. We find that the quasar space density decreases gradually as a function of redshift at low luminosity (M{sub 1450} {approx} -23), being similar to the trend found for quasars with high luminosity (M{sub 1450} < -26). This result is consistent with the so-called downsizing evolution of quasars seen at lower redshifts.« less

A magnetically driven origin for the low luminosity GRB 170817A associated with GW170817

NASA Astrophysics Data System (ADS)

Tong, Hao; Yu, Cong; Huang, Lei

2018-06-01

The gamma-ray burst GR170817A associated with GW170817 is subluminous and subenergetic compared with other typical short gamma-ray bursts. It may be due to a relativistic jet viewed off-axis, or a structured jet or cocoon emission. Giant flares from magnetars may possibly be ruled out. However, the luminosity and energetics of GRB 170817A are coincident with those of magnetar giant flares. After the coalescence of a binary neutron star, a hypermassive neutron star may be formed. The hypermassive neutron star may have a magnetar-strength magnetic field. During the collapse of this hypermassive neutron star, magnetic field energy will also be released. This giant-flare-like event may explain the luminosity and energetics of GRB 170817A. Bursts with similar luminosity and energetics are expected in future neutron star-neutron star or neutron star-black hole mergers.

Luminosity function of [OII] emission-line galaxies in the MassiveBlack-II simulation

DOE PAGES

Park, KwangHo; Khandai, Nishikanta; Matteo, Tiziana Di; ...

2015-09-18

We examine the luminosity function (LF) of [OII] emission-line galaxies in the high-resolution cosmological simulation MassiveBlack-II (MBII). From the spectral energy distribution of each galaxy, we select a sub-sample of star-forming galaxies at 0.06 ≤ z ≤ 3.0 using the [OII] emission line luminosity L([OII]). We confirm that the specific star formation rate matches that in the Galaxy And Mass Assembly survey. We show that the [OII] LF at z = 1.0 from the MBII shows good agreement with the LFs from several surveys below L([OII]) = 10 43.0 erg s –1 while the low redshifts (z ≤ 0.3) showmore » an excess in the prediction of bright [OII] galaxies, but still displaying a good match with observations below L([OII]) = 10 41.6 erg s –1. Based on the validity in reproducing the properties of [OII] galaxies at low redshift (z ≤ 1), we forecast the evolution of the [OII] LF at high redshift (z ≤ 3), which can be tested by upcoming surveys such as the Hobby-Eberly Telescope Dark Energy Experiment and Dark Energy Spectroscopic Instrument. The slopes of the LFs at bright and faint ends range from –3 to –2 showing minima at z = 2. The slope of the bright end evolves approximately as (z + 1) –1 at z ≤ 2 while the faint end evolves as ~3(z + 1) –1 at 0.6 ≤ z ≤ 2. In addition, a similar analysis is applied for the evolution of [OIII] LFs, which is to be explored in the forthcoming survey Wide-Field InfraRed Survey Telescope-Astrophysics Focused Telescope Assets. As a result, we show that the auto-correlation function of [OII] and [OIII] emitting galaxies shows a rapid evolution from z = 2 to 1.« less

V and K-band Mass-Luminosity Relations for M Dwarf Stars

NASA Astrophysics Data System (ADS)

Benedict, George Frederick; Henry, Todd J.; McArthur, Barbara E.; Franz, Otto; Wasserman, Larry H.; Dieterich, Sergio

2015-08-01

Applying Hubble Space Telescope Fine Guidance Sensor astrometric techniques developed to establish relative orbits for binary stars (Franz et al. 1998, AJ, 116, 1432), determine masses of binary components (Benedict et al. 2001, AJ, 121, 1607), and measure companion masses of exoplanet host stars (McArthur et al. 2010, ApJ, 715, 1203), we derive masses with an average 2% error for 28 components of 14 M dwarf binary star systems. With these and other published masses we update the lower Main Sequence V-band Mass-Luminosity Relation first shown in Henry et al. 1999, ApJ, 512, 864. We demonstrate that a Mass-Luminosity Relation in the K-band has far less scatter. These relations can be used to estimate the masses of the ubiquitous red dwarfs (75% of all stars) to an accuracy of better than 5%.

LHC Abort Gap Cleaning Studies During Luminosity Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gianfelice-Wendt, E.; /Fermilab; Bartmann, W.

2012-05-11

The presence of significant intensities of un-bunched beam is a potentially serious issue in the LHC. Procedures using damper kickers for cleaning both the Abort Gap (AG) and the buckets targeted for injection, are currently in operation at flat bottom. Recent observations of relatively high population of the AG during physics runs brought up the need for AG cleaning during luminosity operation. In this paper the results of experimental studies performed in October 2011 are presented.

Improved luminosity determination in pp collisions at $$\\sqrt {s} = 7\\ \\mathrm{TeV}$$ using the ATLAS detector at the LHC

DOE PAGES

Aad, G.; Abajyan, T.; Abbott, B.; ...

2013-08-14

The luminosity calibration for the ATLAS detector at the LHC during pp collisions at √s = 7 TeV in 2010 and 2011 is presented. Evaluation of the luminosity scale is performed using several luminosity-sensitive detectors, and comparisons are made of the long-term stability and accuracy of this calibration applied to the pp collisions at √s = 7 TeV. A luminosity uncertainty of δL/L= ± 3.5 % is obtained for the 47 pb -1 of data delivered to ATLAS in 2010, and an uncertainty of δL/L= ± 1.8 % is obtained for the 5.5 fb -1 delivered in 2011.

Local Luminosity Function at 15 micro m and Galaxy Evolution Seen by ISOCAM 15 micro m Surveys

NASA Technical Reports Server (NTRS)

Xu, C.

2000-01-01

A local luminosity function at 15 micro m is derived using the bivariate (15 micro m vs. 60 micro m luminosities) method, based on the newly published ISOCAM LW3-band (15 micro m) survey of the very deep IRAS 60 micro m sample in the north ecliptic pole region (NEPR).

The X-Ray Background and the AGN Luminosity Function

NASA Astrophysics Data System (ADS)

Hasinger, G.

The deepest X-ray surveys performed with ROSAT were able to resolve as much as 70-80% of the 1-2 keV X-ray background into resolved sources. Optical follow-up observations were able to identify the majority of faint X-ray sources as active galactic nuclei (AGN) out to redshifts of 4.5 as well as a sizeable fraction as groups of galaxies out to redshifts of 0.7. A new population of X-ray luminous, optically innocent narrow emission line galaxies (NELGs) at the faintest X-ray fluxes is still a matter of debate, most likely many of them are also connected to AGN. First deep surveys with the Japanese ASCA satellite give us a glimpse of the harder X-ray background where the bulk of the energy density resides. Future X-ray observatories (XMM and AXAF) will be able to resolve the harder X-ray background. For the first time we are now in a position to study the cosmological evolution of the X-ray luminosity function of AGN, groups of galaxies and galaxies and simultaneously constrain their total luminosity output over cosmic time.

Variations of the core luminosity and solar neutrino fluxes

NASA Astrophysics Data System (ADS)

Grandpierre, Attila

The aim of the present work is to analyze the geological and astrophysical data as well as presenting theoretical considerations indicating the presence of dynamic processes present in the solar core. The dynamic solar model (DSM) is suggested to take into account the presence of cyclic variations in the temperature of the solar core. Comparing the results of calculations of the CO2 content, albedo and solar evolutionary luminosity changes with the empirically determined global earthly temperatures, and taking into account climatic models, I determined the relation between the earthly temperature and solar luminosity. These results indicate to the observed maximum of 10o change on the global terrestrial surface temperature a related solar luminosity change around 4-5 % on a ten million years timescale, which is the timescale of heat diffusion from the solar core to the surface. The related solar core temperature changes are around 1 % only. At the same time, the cyclic luminosity changes of the solar core are shielded effectively by the outer zones since the radiation diffusion takes more than 105 years to reach the solar surface. The measurements of the solar neutrino fluxes with Kamiokande 1987-1995 showed variations higher than 40 % around the average, at the Super-Kamiokande the size of the apparent scatter decreased to 13 %. This latter scatter, if would be related completely to stochastic variations of the central temperature, would indicate a smaller than 1 % change. Fourier and wavelet analysis of the solar neutrino fluxes indicate only a marginally significant period around 200 days (Haubold, 1998). Helioseismic measurements are known to be very constraining. Actually, Castellani et al. (1999) remarked that the different solar models lead to slightly different sound speeds, and the different methods of regularization yield slightly different sound speeds, too. Therefore, they doubled the found parameter variations, and were really conservative assuming

Detector Developments for the High Luminosity LHC Era (4/4)

ScienceCinema

Bortoletto, Daniela

2018-02-09

Tracking Detectors - Part II. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

Detector Developments for the High Luminosity LHC Era (3/4)

ScienceCinema

Bortoletto, Daniela

2018-01-23

Tracking Detectors - Part I. Calorimetry, muon detection, vertexing, and tracking will play a central role in determining the physics reach for the High Luminosity LHC Era. In these lectures we will cover the requirements, options, and the R&D; efforts necessary to upgrade the current LHC detectors and enabling discoveries.

The Rest-Frame Optical Luminosity Functions of Galaxies at 2<=z<=3.5

NASA Astrophysics Data System (ADS)

Marchesini, D.; van Dokkum, P.; Quadri, R.; Rudnick, G.; Franx, M.; Lira, P.; Wuyts, S.; Gawiser, E.; Christlein, D.; Toft, S.

2007-02-01

We present the rest-frame optical (B, V, and R band) luminosity functions (LFs) of galaxies at 2<=z<=3.5, measured from a K-selected sample constructed from the deep NIR MUSYC, the ultradeep FIRES, and the GOODS-CDFS. This sample is unique for its combination of area and range of luminosities. The faint-end slopes of the LFs at z>2 are consistent with those at z~0. The characteristic magnitudes are significantly brighter than the local values (e.g., ~1.2 mag in the R band), while the measured values for Φ* are typically ~5 times smaller. The B-band luminosity density at z~2.3 is similar to the local value, and in the R band it is ~2 times smaller than the local value. We present the LF of distant red galaxies (DRGs), which we compare to that of non-DRGs. While DRGs and non-DRGs are characterized by similar LFs at the bright end, the faint-end slope of the non-DRG LF is much steeper than that of DRGs. The contribution of DRGs to the global densities down to the faintest probed luminosities is 14%-25% in number and 22%-33% in luminosity. From the derived rest-frame U-V colors and stellar population synthesis models, we estimate the mass-to-light ratios (M/L) of the different subsamples. The M/L ratios of DRGs are ~5 times higher (in the R and V bands) than those of non-DRGs. The global stellar mass density at 2<=z<=3.5 appears to be dominated by DRGs, whose contribution is of order ~60%-80% of the global value. Qualitatively similar results are obtained when the population is split by rest-frame U-V color instead of observed J-K color. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS5-26555. Also based on observations collected at the European Southern Observatories on Paranal, Chile as part of the ESO program 164.O-0612.

VLA observations of unidentified Leiden-Berkeley Deep-Survey sources - Luminosity and redshift dependence of spectral properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kapahi, V.K.; Kulkarni, V.K.

1990-05-01

VLA observations of a complete subset of the Leiden-Berkeley Deep Survey sources that have S(1.4 GHz) greater than 10 mJy and are not optically identified down to F=22 mag are reported. By comparing the spectral and structural properties of the sources with samples from the literature, an attempt was made to disentangle the luminosity and redshift dependence of the spectral indices of extended emission in radio galaxies and of the incidence of compact steep-spectrum sources. It is found that the fraction of compact sources among those with a steep spectrum is related primarily to redshift, being much larger at highmore » redshifts for sources of similar radio luminosity. Only a weak and marginally significant dependence of spectral indices of the extended sources on luminosity and redshift is found in samples selected at 1.4 and 2.7 GHz. It is pointed out that the much stronger correlation of spectral indices with luminosity may be arising partly from spectral curvature, and partly due to the preferential inclusion of very steep-spectrum sources from high redshift in low-frequency surveys. 54 refs.« less

The mysterious age invariance of the planetary nebula luminosity function bright cut-off

NASA Astrophysics Data System (ADS)

Gesicki, K.; Zijlstra, A. A.; Miller Bertolami, M. M.

2018-05-01

Planetary nebulae mark the end of the active life of 90% of all stars. They trace the transition from a red giant to a degenerate white dwarf. Stellar models1,2 predicted that only stars above approximately twice the solar mass could form a bright nebula. But the ubiquitous presence of bright planetary nebulae in old stellar populations, such as elliptical galaxies, contradicts this: such high-mass stars are not present in old systems. The planetary nebula luminosity function, and especially its bright cut-off, is almost invariant between young spiral galaxies, with high-mass stars, and old elliptical galaxies, with only low-mass stars. Here, we show that new evolutionary tracks of low-mass stars are capable of explaining in a simple manner this decades-old mystery. The agreement between the observed luminosity function and computed stellar evolution validates the latest theoretical modelling. With these models, the planetary nebula luminosity function provides a powerful diagnostic to derive star formation histories of intermediate-age stars. The new models predict that the Sun at the end of its life will also form a planetary nebula, but it will be faint.

Wavelength Dependent Luminosity Functions for Super Star Clusters

NASA Astrophysics Data System (ADS)

Garmany, Catharine

1997-07-01

Starburst galaxies, considered to exhibit enhanced star formation on a galaxy-wide scale, have now been found with HST to contain very intense knots of star formation, referred to as ``super star clusters'', or SSCs. A steepening of the luminosity function with increasing wavelength for young burst populations, such as SSCs, has recently been predicted by Hogg & Phinney {1997}. This prediction, not previously addressed in the literature, is straightforward to test with multi- wavelength photometry. Using the colors of the SSCs in a galaxy in combination with the difference in slopes of the luminosity functions derived from different wavelength bands and applying population synthesis models, we can also constrain the high mass stellar initial mass function {IMF}. Recent work has suggested that the slope of the IMF is roughly constant in a variety of local environments, from galactic OB associations to the closest analog of a super star cluster, R136 in the LMC. This investigation will allow us to compare the IMFs in the extreme environments of SSCs in starburst galaxies to IMFs found locally in the Galaxy, LMC, and SMC. Archival imaging data in both the UV and optical bands is available for about 10 young starburst systems. These data will allow us to test the predictions of Hogg & Phinney, as well as constrain the IMF for environments not found in the nearby universe.

Mass-loss rates and luminosities of evolved stars in the Magellanic Clouds .

NASA Astrophysics Data System (ADS)

Groenewegen, M. A. T.; Sloan, G. C.

Stars on the asymptotic giant branch (AGB) stars play an important role in the chemical evolution of their host galaxies and the life cycle of dust in the interstellar medium. A detailed and quantitative understanding of they lose mass and eject their envelopes remains elusive, particularly how that process depends on metallicity. Groenewegen & Sloan (2017, hereafter GS17) recently presented dust radiative transfer models for 225 carbon stars and 171 oxygen-rich evolved stars in the Magellanic Clouds and four nearby dSphs which were observed with the Infrared spectrograph on the Spitzer Space Telescope. They applied a minimisation procedure to fit models to spectral energy distributions constructed from the infrared spectra and the available optical and infrared photometry for each star to determine its luminosity and dust mass-loss rate (MLR). In this contribution two items from that paper are highlighted: an update on MSX SMC 055, which Groenewegen et al. (2009) suggested could be a super-AGB star, and a discussion of synthetic colour-colour and colour-magnitude diagrams expected from the James Webb Space Telescope.

The Hard X-ray 20-40 keV AGN Luminosity Function

NASA Technical Reports Server (NTRS)

Beckmann, V.; Soldi, S.; Shrader, C. R.; Gehrels, N.; Produit, N.

2006-01-01

We have compiled a complete, significance limited extragalactic sample based on approximately 25,000 deg(sup 2) to a limiting flux of 3 x 10(exp -11) ergs per square centimeter per second. (approximately 7,000 deg(sup 2)) to a flux limit of 10(exp -11) ergs per square centimeter per second)) in the 20 - 40 keV band with INTEGRAL. We have constructed a detailed exposure map to compensate for effects of non-uniform exposure. The flux-number relation is best described by a power-law with a slope of alpha = 1.66 plus or minus 0.11. The integration of the cumulative flux per unit area leads to f(sub 20-40 keV) = 2.6 x 10(exp -10) ergs per square centimeter per second per sr(sup -1) which is about 1% of the known 20-40 keV X-ray background. We present the first luminosity function of AGN in the 20-40 keV energy range, based on 68 extragalactic objects detected by the imager IBIS/ISGRI on-board INTEGRAL. The luminosity function shows a smoothly connected two power-law form, with an index of gamma (sub 1) = 0.9 below, and gamma (sub 2) = 2.2 above the turn-over luminosity of L(sub *), = 4.6 x 10(sup 43) ergs per second. The emissivity of all INTEGRAL AGNs per unit volume is W(sub 20-40keV)(greater than 10(sup 41) ergs per second) = 2.8 x 10(sup 38) ergs per second h(sup 3)(sub 70) Mpc(sup -3). These results are consistent with those derived in the 2-20keV energy band and do not show a significant contribution by Compton-thick objects. Because the sample used in this study is truly local (z(raised bar) = 0.022)), only limited conclusions can be drawn for the evolution of AGNs in this energy band. But the objects explaining the peak in the cosmic X-ray background are likely to be either low luminosity AGN (L(sub x) less than 10(sup 41) ergs per second) or of other type, such as intermediate mass black holes, clusters, and star forming regions.

Comparison of star formation rates from Hα and infrared luminosity as seen by Herschel

NASA Astrophysics Data System (ADS)

Domínguez Sánchez, H.; Mignoli, M.; Pozzi, F.; Calura, F.; Cimatti, A.; Gruppioni, C.; Cepa, J.; Sánchez Portal, M.; Zamorani, G.; Berta, S.; Elbaz, D.; Le Floc'h, E.; Granato, G. L.; Lutz, D.; Maiolino, R.; Matteucci, F.; Nair, P.; Nordon, R.; Pozzetti, L.; Silva, L.; Silverman, J.; Wuyts, S.; Carollo, C. M.; Contini, T.; Kneib, J.-P.; Le Fèvre, O.; Lilly, S. J.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Coppa, G.; Cucciati, O.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Kampczyk, P.; Knobel, C.; Kovač, K.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Magnelli, B.; Pelló, R.; Peng, Y.; Perez-Montero, E.; Ricciardelli, E.; Riguccini, L.; Tanaka, M.; Tasca, L. A. M.; Tresse, L.; Vergani, D.; Zucca, E.

2012-10-01

We empirically MD test the relation between the SFR(LIR) derived from the infrared luminosity, LIR, and the SFR(Hα) derived from the Hα emission line luminosity using simple conversion relations. We use a sample of 474 galaxies at z = 0.06-0.46 with both Hα detection [from 20k redshift Cosmological Evolution (zCOSMOS) survey] and new far-IR Herschel data (100 and 160 μm). We derive SFR(Hα) from the Hα extinction corrected emission line luminosity. We find a very clear trend between E(B - V) and LIR that allows us to estimate extinction values for each galaxy even if the Hβ emission line measurement is not reliable. We calculate the LIR by integrating from 8 up to 1000 μm the spectral energy distribution (SED) that is best fitting our data. We compare the SFR(Hα) with the SFR(LIR). We find a very good agreement between the two star formation rate (SFR) estimates, with a slope of m = 1.01 ± 0.03 in the log SFR(LIR) versus log SFR(Hα) diagram, a normalization constant of a = -0.08 ± 0.03 and a dispersion of σ = 0.28 dex. We study the effect of some intrinsic properties of the galaxies in the SFR(LIR)-SFR(Hα) relation, such as the redshift, the mass, the specific star formation rate (SSFR) or the metallicity. The metallicity is the parameter that affects most the SFR comparison. The mean ratio of the two SFR estimators log[SFR(LIR)/SFR(Hα)] varies by ˜0.6 dex from metal-poor to metal-rich galaxies [8.1 < log (O/H) + 12 < 9.2]. This effect is consistent with the prediction of a theoretical model for the dust evolution in spiral galaxies. Considering different morphological types, we find a very good agreement between the two SFR indicators for the Sa, Sb and Sc morphologically classified galaxies, both in slope and in normalization. For the Sd, irregular sample (Sd/Irr), the formal best-fitting slope becomes much steeper (m = 1.62 ± 0.43), but it is still consistent with 1 at the 1.5σ level, because of the reduced statistics of this sub

Luminosity distance in Swiss-cheese cosmology with randomized voids and galaxy halos

NASA Astrophysics Data System (ADS)

Flanagan, Éanna É.; Kumar, Naresh; Wasserman, Ira

2013-08-01

We study the fluctuations in luminosity distance due to gravitational lensing produced both by galaxy halos and large-scale voids. Voids are represented via a “Swiss-cheese” model consisting of a ΛCDM Friedmann-Robertson-Walker background from which a number of randomly distributed, spherical regions of comoving radius 35 Mpc are removed. A fraction of the removed mass is then placed on the shells of the spheres, in the form of randomly located halos. The halos are assumed to be nonevolving and are modeled with Navarro-Frenk-White profiles of a fixed mass. The remaining mass is placed in the interior of the spheres, either smoothly distributed or as randomly located halos. We compute the distribution of magnitude shifts using a variant of the method of Holz and Wald [Phys. Rev. D 58, 063501 (1998)], which includes the effect of lensing shear. In the two models we consider, the standard deviation of this distribution is 0.065 and 0.072 magnitudes and the mean is -0.0010 and -0.0013 magnitudes, for voids of radius 35 Mpc and the sources at redshift 1.5, with the voids chosen so that 90% of the mass is on the shell today. The standard deviation due to voids and halos is a factor ˜3 larger than that due to 35 Mpc voids alone with a 1 Mpc shell thickness, which we studied in our previous work. We also study the effect of the existence of evacuated voids, by comparing to a model where all the halos are randomly distributed in the interior of the sphere with none on its surface. This does not significantly change the variance but does significantly change the demagnification tail. To a good approximation, the variance of the distribution depends only on the mean column density of halos (halo mass divided by its projected area), the concentration parameter of the halos, and the fraction of the mass density that is in the form of halos (as opposed to smoothly distributed); it is independent of how the halos are distributed in space. We derive an approximate analytic

The Evolution of the Galaxy Rest-Frame Ultraviolet Luminosity Function Over the First Two Billion Years

NASA Technical Reports Server (NTRS)

Finkelstein, Steven L.; Ryan, Russell E., Jr.; Papovich, Casey; Dickinson, Mark; Song, Mimi; Somerville, Rachel; Ferguson, Henry C.; Salmon, Brett; Giavalisco, Mauro; Koekomoer, Anton M.;

Revisiting the "Fundamental Plane" of Black Hole Activity at Extremely Low Luminosities

NASA Astrophysics Data System (ADS)

Yuan, F.; Yu, Z.; Ho, L. C.

2010-10-01

We investigate the origin of the X-ray emission in low-luminosity AGNs (LLAGNs). Yuan & Cui (2005) predicted that the X-ray emission should originate from jets rather than from an advection-dominated accretion flow (ADAF) when the X-ray luminosity LX of the source is below a critical value of LX,crit ≍ 10-6 LEdd. This prediction implies that the X-ray spectrum in such sources should be fitted by jets rather than ADAFs. Furthermore, below LX,crit the correlation between radio (LR) and X-ray (LX) luminosities and the black hole mass (M)—the so-called fundamental plane of black hole activity—should deviate from the general correlation obtained by Merloni, Heinz & Di Matteo (2003) and become steeper. The Merloni et al. correlation is described by logLR = 0.6logLX + 0.78logM + 7.33, while the predicted correlation is logL_R = 1.23logLX + 0.25logM - 13.45. We collect data from the literature to check the validity of these two expectations. We find that among the 16 LLAGNs with good X-ray and radio spectra, 13 are consistent with the Yuan & Cui prediction. For the 22 LLAGNs with LX < LX,crit, the fundamental plane correlation is described by logLR = 1.22logLX + 0.23logM - 12.46, also in excellent agreement with the prediction.

Upper limits on the mass and luminosity of Population III-dominated galaxies

NASA Astrophysics Data System (ADS)

Yajima, Hidenobu; Khochfar, Sadegh

2017-05-01

We here derive upper limits on the mass and luminosity of Population III (POPIII) dominated proto-galaxies based on the collapse of primordial gas under the effect of angular momentum loss via Lyα radiation drag and the gas accretion on to a galactic centre. Our model predicts that POPIII-dominated galaxies at z ˜ 7 are hosted by haloes with Mh ˜ 1.5 × 108-1.1 × 109 M⊙, that they have Lyα luminosities of LLyα ˜ 3.0 × 1042-2.1 × 1043 erg s- 1, stellar mass of Mstar ˜ 0.8 × 105-2.5 × 106 M⊙ and outflowing gas with velocities Vout ˜ 40 km s- 1 due to Lyα radiation pressure. We show that the POPIII galaxy candidate CR7 violates the derived limits on stellar mass and Lyα luminosity and thus is unlikely to be a POPIII galaxy. POPIII-dominated galaxies at z ˜ 7 have He II line emission that is ˜1-3 orders of magnitude lower than that of Lyα, they have high Lyα equivalent width of ≳ 300 Å and should be found close to bright star-forming galaxies. The He II 1640 Å line is in comfortable reach of next generation telescopes, like the James Webb Space Telescope (JWST) or Thirty Meter Telescope (TMT).

libprofit: Image creation from luminosity profiles

NASA Astrophysics Data System (ADS)

Robotham, A. S. G.; Taranu, D.; Tobar, R.

2016-12-01

libprofit is a C++ library for image creation based on different luminosity profiles. It offers fast and accurate two-dimensional integration for a useful number of profiles, including Sersic, Core-Sersic, broken-exponential, Ferrer, Moffat, empirical King, point-source and sky, with a simple mechanism for adding new profiles. libprofit provides a utility to read the model and profile parameters from the command-line and generate the corresponding image. It can output the resulting image as text values, a binary stream, or as a simple FITS file. It also provides a shared library exposing an API that can be used by any third-party application. R and Python interfaces are available: ProFit (ascl:1612.004) and PyProfit (ascl:1612.005).

The CMS High Granularity Calorimeter for the High Luminosity LHC

NASA Astrophysics Data System (ADS)

Sauvan, J.-B.

2018-02-01

The High Luminosity LHC (HL-LHC) will integrate 10 times more luminosity than the LHC, posing significant challenges for radiation tolerance and event pileup on detectors, especially for forward calorimetry, and hallmarks the issue for future colliders. As part of its HL-LHC upgrade program, the CMS collaboration is designing a High Granularity Calorimeter to replace the existing endcap calorimeters. It features unprecedented transverse and longitudinal segmentation for both electromagnetic (ECAL) and hadronic (HCAL) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The ECAL and a large fraction of HCAL will be based on hexagonal silicon sensors of 0.5-1 cm2 cell size, with the remainder of the HCAL based on highly-segmented scintillators with silicon photomultiplier (SiPM) readout. The intrinsic high-precision timing capabilities of the silicon sensors will add an extra dimension to event reconstruction, especially in terms of pileup rejection.

Upper limits to the annihilation radiation luminosity of Centaurus A

NASA Technical Reports Server (NTRS)

Gehrels, N.; Cline, T. L.; Paciesas, W. S.; Teegarden, B. J.; Tueller, J.; Dirouchoux, P.; Hameury, J. M.

1983-01-01

A high resolution observation of the active nucleus galaxy Centaurus A (NGC 5128) was made by the GSFC low energy gamma-ray spectrometer (LEGS) during a balloon flight on 1981 November 19. The measured spectrum between 70 and 500 keV is well represented by a power law of the form 1.05 x 10 (-4) (E/100 keV) (-1.59) ph/sq cm/s with no breaks or line features observed. The 98 percent confidence (2 sigma) flux upper limit for a narrow (3 keV) 511-keV positron annihilation line is 9.9 x 10 (-4) ph/sq cm/s. Using this upper limit, the ratio of the narrow-line annihilation radiation luminosity to the integral or = 511 keV luminosity is estimated to be 0.09 (2 sigma upper limit). This is compared with the measured value for our Galactic center in the Fall of 1979 of 0.10 to 0.13, indicating a difference in the emission regions in the nuclei of the two galaxies.

Upper Limits to the Annihilation Radiation Luminosity of Centaurus a

NASA Technical Reports Server (NTRS)

Gehrels, N.; Cline, T. L.; Paciesas, W. S.; Teegarden, B. J.; Tueller, J.; Dirouchoux, P.; Hameury, J. M.

1983-01-01

A high resolution observation of the active nucleus galaxy Centaurus A (NGC 5128) was made by the GSFC low energy gamma-ray spectrometer (LEGS) during a balloon flight on 1981 November 19. The measured spectrum between 70 and 500 keV is well represented by a power law of the form 1.05 x 10 (-4) (E/100 keV) (-1.59) ph/sq cm /s with no breaks or line features observed. The 98% confidence (2 sigma) flux upper limit for a narrow ( 3 keV) 511-keV positron annihilation line is 9.9 x 10 (-4) ph/ sq cm /s. Using this upper limit, the ratio of the narrow-line annihilation radiation luminosity to the integral or = 511 keV luminosity is estimated to be 0.09 (2 sigma upper limit). This is compared with the measured value for our galactic center in the Fall of 1979 of 0.10 to 0.13, indicating a difference in he emission regions in the nuclei of the two galaxies.

LFlGRB: Luminosity function of long gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-04-01

LFlGRB models the luminosity function (LF) of long Gamma Ray Bursts (lGRBs) by using a sample of Swift and Fermi lGRBs to re-derive the parameters of the Yonetoku correlation and self-consistently estimate pseudo-redshifts of all the bursts with unknown redshifts. The GRB formation rate is modeled as the product of the cosmic star formation rate and a GRB formation efficiency for a given stellar mass.

The Lag-Luminosity Relation in the GRB Source Frame: An Investigation with Swift BAT Bursts

NASA Technical Reports Server (NTRS)

Ukwatta, T. N.; Dhuga, K. S.; Stamatikos, M.; Dermer, C. D.; Sakamoto, T.; Sonbas, E.; Parke, W. C.; Maximon, L. C.; Linnemann, J. T.; Bhat, P. N.;

The Cool White Dwarf Luminosity Function and the Age of the Galactic Disk

NASA Astrophysics Data System (ADS)

Leggett, S. K.; Ruiz, Maria Teresa; Bergeron, P.

1998-04-01

We present new optical and infrared data for the cool white dwarfs in the proper motion sample of Liebert, Dahn, & Monet. Stellar properties--surface chemical composition, effective temperature, radius, surface gravity, mass, and luminosity--are determined from these data by using the model atmospheres of Bergeron, Saumon, & Wesemael. The space density contribution is calculated for each star and the luminosity function (LF) for cool white dwarfs is determined. Comparing the LF to the most recent cooling sequences by Wood implies that the age of the local region of the Galactic disk is 8 +/- 1.5 Gyr. This result is consistent with the younger ages now being derived for the globular clusters and the universe itself.

A Model for Protostellar Cluster Luminosities and the Impact on the CO–H2 Conversion Factor

NASA Astrophysics Data System (ADS)

Gaches, Brandt A. L.; Offner, Stella S. R.

2018-02-01

We construct a semianalytic model to study the effect of far-ultraviolet (FUV) radiation on gas chemistry from embedded protostars. We use the protostellar luminosity function (PLF) formalism of Offner & McKee to calculate the total, FUV, and ionizing cluster luminosity for various protostellar accretion histories and cluster sizes. We2 compare the model predictions with surveys of Gould Belt star-forming regions and find that the tapered turbulent core model matches best the mean luminosities and the spread in the data. We combine the cluster model with the photodissociation region astrochemistry code, 3D-PDR, to compute the impact of the FUV luminosity from embedded protostars on the CO-to-H2 conversion factor, X CO, as a function of cluster size, gas mass, and star formation efficiency. We find that X CO has a weak dependence on the FUV radiation from embedded sources for large clusters owing to high cloud optical depths. In smaller and more efficient clusters the embedded FUV increases X CO to levels consistent with the average Milky Way values. The internal physical and chemical structures of the cloud are significantly altered, and X CO depends strongly on the protostellar cluster mass for small efficient clouds.

Galaxies in ΛCDM with Halo Abundance Matching: Luminosity-Velocity Relation, Baryonic Mass-Velocity Relation, Velocity Function, and Clustering

NASA Astrophysics Data System (ADS)

Trujillo-Gomez, Sebastian; Klypin, Anatoly; Primack, Joel; Romanowsky, Aaron J.

2011-11-01

It has long been regarded as difficult if not impossible for a cosmological model to account simultaneously for the galaxy luminosity, mass, and velocity distributions. We revisit this issue using a modern compilation of observational data along with the best available large-scale cosmological simulation of dark matter (DM). We find that the standard cosmological model, used in conjunction with halo abundance matching (HAM) and simple dynamical corrections, fits—at least on average—all basic statistics of galaxies with circular velocities V circ > 80 km s-1 calculated at a radius of ~10 kpc. Our primary observational constraint is the luminosity-velocity (LV) relation—which generalizes the Tully-Fisher and Faber-Jackson relations in allowing all types of galaxies to be included, and provides a fundamental benchmark to be reproduced by any theory of galaxy formation. We have compiled data for a variety of galaxies ranging from dwarf irregulars to giant ellipticals. The data present a clear monotonic LV relation from ~50 km s-1 to ~500 km s-1, with a bend below ~80 km s-1 and a systematic offset between late- and early-type galaxies. For comparison to theory, we employ our new ΛCDM "Bolshoi" simulation of DM, which has unprecedented mass and force resolution over a large cosmological volume, while using an up-to-date set of cosmological parameters. We use HAM to assign rank-ordered galaxy luminosities to the DM halos, a procedure that automatically fits the empirical luminosity function and provides a predicted LV relation that can be checked against observations. The adiabatic contraction of DM halos in response to the infall of the baryons is included as an optional model ingredient. The resulting predictions for the LV relation are in excellent agreement with the available data on both early-type and late-type galaxies for the luminosity range from Mr = -14 to Mr = -22. We also compare our predictions for the "cold" baryon mass (i.e., stars and cold gas) of

The Coma Cluster Luminosity Function from Ultraviolet to Near-Infrared

NASA Astrophysics Data System (ADS)

Andreon, S.; Cuillandre, J.-C.; Pello, R.

The Coma cluster luminosity function (LF) from ultraviolet (2000 AA ) to the near-infrared (H band) is summarized. In the UV the LF is very steep, much steeper than in the optical. The steep Coma UV LF implies that faint and bright galaxies give similar contributions to the total UV flux and to the total metal production rate. The ComaUV LF is dominated in number and luminosity by blue galaxies, which are often faint in the optical. Therefore the Coma UV LF is dominated by star forming galaxies, not by massive and large galaxies. The optical Coma LF is relatively steep (alpha=-1.4) over the 11 magnitudes sampled, but its slope and shape depend on considered filter and magnitude. We found a clear steeping of the FL going from B to R bands, indicative of the presence of a large number of red dwarfs, as faint as three bright globular clusters. Furthermore, using Hubble Space Telescope images, we discover that blends of globular clusters, not resolved in individual components due to seeing, look like dwarf galaxies when observed from the ground and are numerous and bright. The existence of these fake extended sources increases the steepness of the LF at faint magnitudes, if not deal on. This concern affects previous deep probing of the luminosity function, but not the present work. The near-infrared LF wa s computed on a near-infrared selected sample of galaxies which photometry is complete down to the typical dwarf (M* +5) luminosity. The Coma LF can be described by a Schechter function with intermediate slope (alpha sim-1.3), plus a dip at MH~-22 mag. The shape of the Coma LF in H band is quite similar to th e one found in the B band. The similarity of the LF in the optical and H bands implies that in the central region of Coma there is no new population of galaxies which is too faint to be observed in the optical band (because dust enshrouded, for instance), down to the magnitudes of dwarfs. The exponential cut of the LF at the bright end is in good agreement with

Conceptual design of the cryostat for the new high luminosity (HL-LHC) triplet magnets

NASA Astrophysics Data System (ADS)

Ramos, D.; Parma, V.; Moretti, M.; Eymin, C.; Todesco, E.; Van Weelderen, R.; Prin, H.; Berkowitz Zamora, D.

2017-12-01

The High Luminosity LHC (HL-LHC) is a project to upgrade the LHC collider after 2020-2025 to increase the integrated luminosity by about one order of magnitude and extend the physics production until 2035. An upgrade of the focusing triplets insertion system for the ATLAS and CMS experiments is foreseen using superconducting magnets operating in a pressurised superfluid helium bath at 1.9 K. This will require the design and construction of four continuous cryostats, each about sixty meters in length and one meter in diameter, for the final beam focusing quadrupoles, corrector magnets and beam separation dipoles. The design is constrained by the dimensions of the existing tunnel and accessibility restrictions imposing the integration of cryogenic piping inside the cryostat, thus resulting in a very compact integration. As the alignment and position stability of the magnets is crucial for the luminosity performance of the machine, the magnet support system must be carefully designed in order to cope with parasitic forces and thermo-mechanical load cycles. In this paper, we present the conceptual design of the cryostat and discuss the approach to address the stringent and often conflicting requirements of alignment, integration and thermal aspects.

Coronal Heating and the Increase of Coronal Luminosity with Magnetic Flux

NASA Technical Reports Server (NTRS)

Moore, R. L.; Falconer, D. A.; Porter, J. G.; Hathaway, D. H.; Six, N. Frank (Technical Monitor)

2002-01-01

We present the observed scaling of coronal luminosity with magnetic flux in a set of quiet regions. Comparison of this with the observed scaling found for active regions suggests an underlying difference between coronal heating in active regions and quiet regions. From SOHO/EIT coronal images and SOHO/MDI magnetograms of four similar large quiet regions, we measure L(sub corona) and Phi(sub total) in random subregions ranging in area from about four supergranules [(70,000 km)(exp 2)] to about 100 supergranules [(0.5 R(sub sun))(exp 2)], where L(sub corona) is the luminosity of the corona in a subregion and Phi(sub total) is the flux content of the magnetic network in the subregion. This sampling of our quiet regions yields a correlation plot of Log L(sub corona) vs Log Phi(sub total) appropriate for comparison with the corresponding plot for active regions. For our quiet regions, the mean values of L(sub corona) and Phi(sub total) both increase linearly with area (simply because each set of subregions of the same area has very nearly the same mean coronal luminosity per unit area and mean magnetic flux per unit area), and in each constant-area set the values of L(sub corona) and Phi(sub total) 'scatter' about their means for that area. This results in the linear least-squares fit to the Log ((L (sub corona)), vs Log ((Phi (sub total)) plot having a slope somewhat less than one. If active regions mimicked our quiet regions in that all large sets of same-area active regions had the same mean coronal luminosity per unit area and same mean magnetic flux per unit area, then the least-squares fit to their Log((L (sub corona)) vs Log((Phi (sub total)) plot would also have a slope of less than one. Instead, the slope for active regions is 1.2. Given the observed factor of three scatter about the least-squares linear fit, this slope is consistent with Phi(sub total) on average increasing linearly with area (A) as in quiet regions, but L(sub corona) on average increasing as

Standard Model parton distributions at very high energies

DOE PAGES

Bauer, Christian W.; Ferland, Nicolas; Webber, Bryan R.

2017-08-09

We compute the leading-order evolution of parton distribution functions for all the Standard Model fermions and bosons up to energy scales far above the electroweak scale, where electroweak symmetry is restored. Our results include the 52 PDFs of the unpolarized proton, evolving according to the SU(3), SU(2), U(1), mixed SU(2)×U(1) and Yukawa interactions. We illustrate the numerical effects on parton distributions at large energies, and show that this can lead to important corrections to parton luminosities at a future 100 TeV collider.

Standard Model parton distributions at very high energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Christian W.; Ferland, Nicolas; Webber, Bryan R.

We compute the leading-order evolution of parton distribution functions for all the Standard Model fermions and bosons up to energy scales far above the electroweak scale, where electroweak symmetry is restored. Our results include the 52 PDFs of the unpolarized proton, evolving according to the SU(3), SU(2), U(1), mixed SU(2)×U(1) and Yukawa interactions. We illustrate the numerical effects on parton distributions at large energies, and show that this can lead to important corrections to parton luminosities at a future 100 TeV collider.

MUSE deep-fields: the Ly α luminosity function in the Hubble Deep Field-South at 2.91 < z < 6.64

NASA Astrophysics Data System (ADS)

Drake, Alyssa B.; Guiderdoni, Bruno; Blaizot, Jérémy; Wisotzki, Lutz; Herenz, Edmund Christian; Garel, Thibault; Richard, Johan; Bacon, Roland; Bina, David; Cantalupo, Sebastiano; Contini, Thierry; den Brok, Mark; Hashimoto, Takuya; Marino, Raffaella Anna; Pelló, Roser; Schaye, Joop; Schmidt, Kasper B.

2017-10-01

We present the first estimate of the Ly α luminosity function using blind spectroscopy from the Multi Unit Spectroscopic Explorer, MUSE, in the Hubble Deep Field-South. Using automatic source-detection software, we assemble a homogeneously detected sample of 59 Ly α emitters covering a flux range of -18.0 < log10 (F) < -16.3 (erg s-1 cm-2), corresponding to luminosities of 41.4 < log10 (L) < 42.8 (erg s-1). As recent studies have shown, Ly α fluxes can be underestimated by a factor of 2 or more via traditional methods, and so we undertake a careful assessment of each object's Ly α flux using a curve-of-growth analysis to account for extended emission. We describe our self-consistent method for determining the completeness of the sample, and present an estimate of the global Ly α luminosity function between redshifts 2.91 < z < 6.64 using the 1/Vmax estimator. We find that the luminosity function is higher than many number densities reported in the literature by a factor of 2-3, although our result is consistent at the 1σ level with most of these studies. Our observed luminosity function is also in good agreement with predictions from semi-analytic models, and shows no evidence for strong evolution between the high- and low-redshift halves of the data. We demonstrate that one's approach to Ly α flux estimation does alter the observed luminosity function, and caution that accurate flux assessments will be crucial in measurements of the faint-end slope. This is a pilot study for the Ly α luminosity function in the MUSE deep-fields, to be built on with data from the Hubble Ultra Deep Field that will increase the size of our sample by almost a factor of 10.

Is Episodic Accretion Necessary to Resolve the Luminosity Problem in Low-Mass Protostars?

NASA Astrophysics Data System (ADS)

Sevrinsky, Raymond Andrew; Dunham, Michael

2017-01-01

In this contribution, we compare the results of protostellar accretion simulations for scenarios both containing and lacking episodic accretion activity. We determine synthetic observational signatures for collapsing protostars by taking hydrodynamical simulations predicting highly variable episodic accretion events, filtering out the stochastic behavior by applying power law fits to the mass accretion rates onto the disk and central star, and using the filtered rates as inputs to two-dimensional radiative transfer calculations. The spectral energy distributions generated by these calculations are used to calculate standard observational signatures of Lbol and Tbol, and compared directly to a sample of 230 embedded protostars. We explore the degree to which these continually declining accretion models successfully reproduce the observed spread of protostellar luminosities, and examine their consistency with the prior variable models to investigate the degree to which episodic accretion bursts are necessary in protostellar formation theories to match observations of field protostars. The SAO REU program is funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851, and by the Smithsonian Institution.

Complete Hard X-Ray Surveys, AGN Luminosity Functions and the X-Ray Background

NASA Technical Reports Server (NTRS)

Tueller, Jack

2011-01-01

AGN are believed to make up most of the Cosmic X-Ray Background (CXB) above a few keV, but this background cannot be fully resolved at energies less than 10 keV due to absorption. The Swift/BAT and INTEGRAL missions are performing the first complete hard x-ray surveys with minimal bias due to absorption. The most recent results for both missions will be presented. Although the fraction of the CXB resolved by these surveys is small, it is possible to derive unbiased number counts and luminosity functions for AGN in the local universe. The survey energy range from 15-150 keV contains the important reflection and cutoff spectral features dominate the shape of the AGN contribution to the CXB. Average spectral characteristics of survey detected AGN will be presented and compared with model distributions. The numbers of hard x-ray blazars detected in these surveys are finally sufficient to estimate this important component's contribution the cosmic background. Constraints on CXB models and their significance will be discussed.

The near-infrared radius-luminosity relationship for active galactic nuclei

NASA Astrophysics Data System (ADS)

Landt, Hermine; Bentz, Misty C.; Peterson, Bradley M.; Elvis, Martin; Ward, Martin J.; Korista, Kirk T.; Karovska, Margarita

2011-05-01

Black hole masses for samples of active galactic nuclei (AGNs) are currently estimated from single-epoch optical spectra. In particular, the size of the broad-line emitting region needed to compute the black hole mass is derived from the optical or ultraviolet continuum luminosity. Here we consider the relationship between the broad-line region size, R, and the near-infrared (near-IR) AGN continuum luminosity, L, as the near-IR continuum suffers less dust extinction than at shorter wavelengths and the prospects for separating the AGN continuum from host-galaxy starlight are better in the near-IR than in the optical. For a relationship of the form R∝Lα, we obtain for a sample of 14 reverberation-mapped AGN a best-fitting slope of α= 0.5 ± 0.1, which is consistent with the slope of the relationship in the optical band and with the value of 0.5 naïvely expected from photoionization theory. Black hole masses can then be estimated from the near-IR virial product, which is calculated using the strong and unblended Paschen broad emission lines (Paα or Paβ).

Luminosity Limitations of Linear Colliders Based on Plasma Acceleration

DOE PAGES

Lebedev, Valeri; Burov, Alexey; Nagaitsev, Sergei

2016-01-01

Particle acceleration in plasma creates a possibility of exceptionally high accelerating gradients and appears as a very attractive option for future linear electron-positron and/or photon-photon colliders. These high accelerating gradients were already demonstrated in a number of experiments. Furthermore, a linear collider requires exceptionally high beam brightness which still needs to be demonstrated. In this article we discuss major phenomena which limit the beam brightness of accelerated beam and, consequently, the collider luminosity.

The Lag-Luminosity Relation in the GRB Source-Frame: An Investigation with Swift BAT Bursts

NASA Technical Reports Server (NTRS)

Ukwatta, T. N.; Dhuga, K. S.; Stamatikos, M.; Dermer, C. D.; Sakamoto, T.; Sonbas, E.; Parke, W. C.; Maximon, L. C.; Linnemann, J. T.; Bhat, P. N.;

The Herschel Virgo Cluster Survey. XIX. Physical properties of low luminosity FIR sources at z < 0.5

NASA Astrophysics Data System (ADS)

Pappalardo, Ciro; Bizzocchi, Luca; Fritz, Jacopo; Boselli, Alessandro; Boquien, Mederic; Boissier, Samuel; Baes, Maarten; Ciesla, Laure; Bianchi, Simone; Clemens, Marcel; Viaene, Sebastien; Bendo, George J.; De Looze, Ilse; Smith, Matthew W. L.; Davies, Jonathan

2016-05-01

Context. The star formation rate is a crucial parameter for the investigation galaxy evolution. At low redshift the cosmic star formation rate density declines smoothly, and massive active galaxies become passive, reducing their star formation activity. This implies that the bulk of the star formation rate density at low redshift is mainly driven by low mass objects. Aims: We investigate the properties of a sample of low luminosity far-infrared sources selected at 250 μm. We have collected data from ultraviolet to far-infrared in order to perform a multiwavelengths analysis. The main goal is to investigate the correlation between star formation rate, stellar mass, and dust mass for a galaxy population with a wide range in dust content and stellar mass, including the low mass regime that most probably dominates the star formation rate density at low redshift. Methods: We define a main sample of ~800 sources with full spectral energy distribution coverage between 0.15 <λ< 500 μm and an extended sample with ~5000 sources in which we remove the constraints on the ultraviolet and near-infrared bands. We analyze both samples with two different spectral energy distribution fitting methods: MAGPHYS and CIGALE, which interpret a galaxy spectral energy distribution as a combination of different simple stellar population libraries and dust emission templates. Results: In the star formation rate versus stellar mass plane our samples occupy a region included between local spirals and higher redshift star forming galaxies. These galaxies represent the population that at z< 0.5 quenches their star formation activity and reduces their contribution to the cosmic star formation rate density. The subsample of galaxies with the higher masses (M∗> 3 × 1010 M⊙) do not lie on the main sequence, but show a small offset as a consequence of the decreased star formation. Low mass galaxies (M∗< 1 × 1010 M⊙) settle in the main sequence with star formation rate and stellar mass

Radiological Environmental Protection for PEP-II Ring High Luminosity Operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, James C.; Nakao, Noriaki; /SLAC

2006-08-16

Stanford Linear Accelerator Center (SLAC) is located in northern California, USA. Radiological environmental protection is one of the main elements of the radiation protection program. One of SLAC's accelerator facilities is B-Factory, whose PEP-II accelerator ring has been operating since 1997 and is being upgraded to higher luminosity operation. Four radiological issues associated with high luminosity operation up to CY2008 are re-evaluated: (1) annual doses in IR halls, (2) annual skyshine doses at site boundaries, (3) potential radioactive air releases, and (4) potential groundwater activation. This paper presents the skyshine doses and air emission doses to the Maximally Exposed Individualmore » (MEI) at SLAC site boundaries. The normal beam loss scenarios around PEP-II ring are presented first. In CY2008, the luminosity is 2 x 10{sup 34} cm{sup -2} s{sup -1}, and the stored current is 4.0-A for low-energy ring (LER ) and 2.2-A for high-energy ring (HER). The beam losses around PEP-II ring include those near injection region in IR10 and IR8 and those at collimators (e.g., HER collimators in IR12, LER collimators in IR4 and IR6). The beam losses in IR8 and IR10 (where injection into ring occurs) are further divided into septum, BAD (beam abort dump) and TD (tune-up dump), as well as apertures. The skyshine prompt dose rate distributions as a function of distance from an IR hall at four directions were calculated using the MARS15 Monte Carlo code. For skyshine dose to the MEI, the annual dose (7200 h/y occupancy) is calculated to be 2.9 mrem/y at Sand Hill Road (from e{sup -} losses in IR12 HER collimators) and 1.2 mrem/y at Horse Track Offices near IR6 (from e{sup +} losses in IR8, IR6 and IR4). These are lower than the SLAC skyshine limit of 5 mrem/y for any single facility within SLAC. Radionuclide productions in the air at the PEP-II IR10 were calculated using MARS15. Beam losses of 9-GeV electrons were assumed in three target cases: the copper TD, septum

Pulsar gamma-rays: Spectra luminosities and efficiencies

NASA Technical Reports Server (NTRS)

Harding, A. K.

1980-01-01

The general characteristics of pulsar gamma ray spectra are presented for a model where the gamma rays are produced by curvature radiation from energetic particles above the polar cap and attenuated by pair production. The shape of the spectrum is found to depend on pulsar period, magnetic field strength, and primary particle energy. By a comparison of numerically calculated spectra with the observed spectra of the Crab and Vela pulsars, it is determined that primary particles must be accelerated to energies of about 3 x 10 to the 7th power mc sq. A genaral formula for pulsar gamma ray luminosity is determined and is found to depend on period and field strength.

Clustering, cosmology and a new era of black hole demographics- I. The conditional luminosity function of active galactic nuclei

NASA Astrophysics Data System (ADS)

Ballantyne, D. R.

2017-01-01

Deep X-ray surveys have provided a comprehensive and largely unbiased view of active galactic nuclei (AGN) evolution stretching back to z ˜ 5. However, it has been challenging to use the survey results to connect this evolution to the cosmological environment that AGN inhabit. Exploring this connection will be crucial to understanding the triggering mechanisms of AGN and how these processes manifest in observations at all wavelengths. In anticipation of upcoming wide-field X-ray surveys that will allow quantitative analysis of AGN environments, this paper presents a method to observationally constrain the conditional luminosity function (CLF) of AGN at a specific z. Once measured, the CLF allows the calculation of the AGN bias, mean dark matter halo mass, AGN lifetime, halo occupation number, and AGN correlation function- all as a function of luminosity. The CLF can be constrained using a measurement of the X-ray luminosity function and the correlation length at different luminosities. The method is illustrated at z ≈ 0 and 0.9 using the limited data that are currently available, and a clear luminosity dependence in the AGN bias and mean halo mass is predicted at both z, supporting the idea that there are at least two different modes of AGN triggering. In addition, the CLF predicts that z ≈ 0.9 quasars may be commonly hosted by haloes with Mh ˜ 1014 M⊙. These `young cluster' environments may provide the necessary interactions between gas-rich galaxies to fuel luminous accretion. The results derived from this method will be useful to populate AGN of different luminosities in cosmological simulations.

The Lick AGN Monitoring Project 2016: Extending Reverberation Mapping to Higher Luminosity AGNs

NASA Astrophysics Data System (ADS)

U, Vivian; LAMP2016 Collaboration

2017-01-01

The technique of reverberation mapping has been used to estimate virial black hole masses and, more fundamentally, to probe the broad line region structure in Seyfert I galaxies. Efforts from the previous Lick AGN Monitoring Project (LAMP) campaigns and other studies to date have culminated in a large sample of reverberation mapped AGNs and measurements of their black hole masses, which in turn enabled major improvement to various AGN scaling relations. However, the high-luminosity end of such relations remains poorly constrained; this is because of observational challenges presented by the weaker continuum flux variations and longer time dilation in these sources. To this end, we have initiated a new LAMP2016 campaign to target AGNs with luminosities of 10^44 erg/s, with predicted H-beta lags of ~20 - 60 days or black hole masses of 10^7 - 10^8.5 Msun. Designed to monitor ~20 AGNs biweekly from Spring 2016 through Winter 2017 with the Kast spectrograph on the 3-m Shane Telescope at Lick Observatory, we aim to probe luminosity-dependent trends in broad line region structure and dynamics, improve calibrations for single-epoch estimates of high-redshift quasar black hole masses, and test photoionization models for the radially-stratified structure of the broad line region. In this talk, I will present the overview and scope of LAMP2016 and show preliminary results from our ongoing campaign.

Resolving the faint end of the satellite luminosity function for the nearest elliptical Centaurus A

NASA Astrophysics Data System (ADS)

Crnojevic, Denija

2014-10-01

We request HST/ACS imaging to follow up 15 new faint candidate dwarfs around the nearest elliptical Centaurus A (3.8 Mpc). The dwarfs were found via a systematic ground-based (Magellan/Megacam) survey out to ~150 kpc, designed to directly confront the "missing satellites" problem in a wholly new environment. Current Cold Dark Matter models for structure formation fail to reproduce the shallow slope of the satellite luminosity function in spiral-dominated groups for which dwarfs fainter than M_V<-14 have been surveyed (the Local Group and the nearby, interacting M81 group). Clusters of galaxies show a better agreement with cosmological predictions, suggesting an environmental dependence of the (poorly-understood) physical processes acting on the evolution of low mass galaxies (e.g., reionization). However, the luminosity function completeness for these rich environments quickly drops due to the faintness of the satellites and to the difficult cluster membership determination. We target a yet unexplored "intermediate" environment, a nearby group dominated by an elliptical galaxy, ideal due to its proximity: accurate (10%) distance determinations for its members can be derived from resolved stellar populations. The proposed observations of the candidate dwarfs will confirm their nature, group membership, and constrain their luminosities, metallicities, and star formation histories. We will obtain the first complete census of dwarf satellites of an elliptical down to an unprecedented M_V<-9. Our results will crucially constrain cosmological predictions for the faint end of the satellite luminosity function to achieve a more complete picture of the galaxy formation process.

A Physical Model for the Evolving Ultraviolet Luminosity Function of High Redshift Galaxies and their Contribution to the Cosmic Reionization

NASA Astrophysics Data System (ADS)

Cai, Zhen-Yi; Lapi, Andrea; Bressan, Alessandro; De Zotti, Gianfranco; Negrello, Mattia; Danese, Luigi

2014-04-01

We present a physical model for the evolution of the ultraviolet (UV) luminosity function of high-redshift galaxies, taking into account in a self-consistent way their chemical evolution and the associated evolution of dust extinction. Dust extinction is found to increase fast with halo mass. A strong correlation between dust attenuation and halo/stellar mass for UV selected high-z galaxies is thus predicted. The model yields good fits of the UV and Lyman-α (Lyα) line luminosity functions at all redshifts at which they have been measured. The weak observed evolution of both luminosity functions between z = 2 and z = 6 is explained as the combined effect of the negative evolution of the halo mass function; of the increase with redshift of the star formation efficiency due to the faster gas cooling; and of dust extinction, differential with halo mass. The slope of the faint end of the UV luminosity function is found to steepen with increasing redshift, implying that low luminosity galaxies increasingly dominate the contribution to the UV background at higher and higher redshifts. The observed range of the UV luminosities at high z implies a minimum halo mass capable of hosting active star formation M crit <~ 109.8 M ⊙, which is consistent with the constraints from hydrodynamical simulations. From fits of Lyα line luminosity functions, plus data on the luminosity dependence of extinction, and from the measured ratios of non-ionizing UV to Lyman-continuum flux density for samples of z ~= 3 Lyman break galaxies and Lyα emitters, we derive a simple relationship between the escape fraction of ionizing photons and the star formation rate. It implies that the escape fraction is larger for low-mass galaxies, which are almost dust-free and have lower gas column densities. Galaxies already represented in the UV luminosity function (M UV <~ -18) can keep the universe fully ionized up to z ~= 6. This is consistent with (uncertain) data pointing to a rapid drop of the

THE CANADA-FRANCE HIGH-z QUASAR SURVEY: NINE NEW QUASARS AND THE LUMINOSITY FUNCTION AT REDSHIFT 6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willott, Chris J.; Crampton, David; Hutchings, John B.

2010-03-15

We present discovery imaging and spectroscopy for nine new z {approx} 6 quasars found in the Canada-France High-z Quasar Survey (CFHQS) bringing the total number of CFHQS quasars to 19. By combining the CFHQS with the more luminous Sloan Digital Sky Survey sample, we are able to derive the quasar luminosity function from a sample of 40 quasars at redshifts 5.74 < z < 6.42. Our binned luminosity function shows a slightly lower normalization and flatter slope than found in previous work. The binned data also suggest a break in the luminosity function at M {sub 1450} {approx} -25. Amore » double power-law maximum likelihood fit to the data is consistent with the binned results. The luminosity function is strongly constrained (1{sigma} uncertainty <0.1 dex) over the range -27.5 < M {sub 1450} < -24.7. The best-fit parameters are {phi}(M*{sub 1450}) = 1.14 x 10{sup -8} Mpc{sup -3} mag{sup -1}, break magnitude M*{sub 1450} = -25.13, and bright end slope {beta} = -2.81. However, the covariance between {beta} and M*{sub 1450} prevents strong constraints being placed on either parameter. For a break magnitude in the range -26 < M*{sub 1450} < -24, we find -3.8 < {beta} < -2.3 at 95% confidence. We calculate the z = 6 quasar intergalactic ionizing flux and show it is between 20 and 100 times lower than that necessary for reionization. Finally, we use the luminosity function to predict how many higher redshift quasars may be discovered in future near-IR imaging surveys.« less

CO luminosity function from Herschel-selected galaxies and the contribution of AGN

NASA Astrophysics Data System (ADS)

Vallini, L.; Gruppioni, C.; Pozzi, F.; Vignali, C.; Zamorani, G.

2016-02-01

We derive the carbon monoxide (CO) luminosity function (LF) for different rotational transitions [I.e. (1-0), (3-2), (5-4)] starting from the Herschel LF by Gruppioni et al. and using appropriate LCO-LIR conversions for different galaxy classes. Our predicted LFs fit the data so far available at z ≈ 0 and 2. We compare our results with those obtained by semi-analytical models (SAMs): while we find a good agreement over the whole range of luminosities at z ≈ 0, at z ≈ 1 and z ≈ 2, the tension between our LFs and SAMs in the faint and bright ends increases. We finally discuss the contribution of luminous active galactic nucleus (LX > 1044 erg s- 1) to the bright end of the CO LF concluding that they are too rare to reproduce the actual CO LF at z ≈ 2.

On the Disappearance of a Cold Molecular Torus around the Low-luminosity Active Galactic Nucleus of NGC 1097

NASA Astrophysics Data System (ADS)

Izumi, T.; Kohno, K.; Fathi, K.; Hatziminaoglou, E.; Davies, R. I.; Martín, S.; Matsushita, S.; Schinnerer, E.; Espada, D.; Aalto, S.; Onishi, K.; Turner, J. L.; Imanishi, M.; Nakanishi, K.; Meier, D. S.; Wada, K.; Kawakatu, N.; Nakajima, T.

2017-08-01

We used the Atacama Large Millimeter/Submillimeter Array to map the CO(3-2) and the underlying continuum emissions around the type-1 low-luminosity active galactic nucleus (LLAGN; bolometric luminosity ≲ {10}42 erg s-1) of NGC 1097 at ˜10 pc resolution. These observations revealed a detailed cold gas distribution within a ˜100 pc of this LLAGN. In contrast to the luminous Seyfert galaxy NGC 1068, where a ˜7 pc cold molecular torus was recently revealed, a distinctively dense and compact torus is missing in our CO(3-2) integrated intensity map of NGC 1097. Based on the CO(3-2) flux, the gas mass of the torus of NGC 1097 would be a factor of ≳2-3 less than that found for NGC 1068 by using the same CO-to-H2 conversion factor, which implies less active nuclear star formation and/or inflows in NGC 1097. Our dynamical modeling of the CO(3-2) velocity field implies that the cold molecular gas is concentrated in a thin layer as compared to the hot gas traced by the 2.12 μm H2 emission in and around the torus. Furthermore, we suggest that NGC 1097 hosts a geometrically thinner torus than NGC 1068. Although the physical origin of the torus thickness remains unclear, our observations support a theoretical prediction that geometrically thick tori with high opacity will become deficient as AGNs evolve from luminous Seyferts to LLAGNs.

Observed Luminosity Spread in Young Clusters and FU Ori Stars: A Unified Picture

NASA Astrophysics Data System (ADS)

Baraffe, I.; Vorobyov, E.; Chabrier, G.

2012-09-01

The idea that non-steady accretion during the embedded phase of protostar evolution can produce the observed luminosity spread in the Herzsprung-Russell diagram (HRD) of young clusters has recently been called into question. Observations of FU Ori, for instance, suggest an expansion of the star during strong accretion events, whereas the luminosity spread implies a contraction of the accreting objects, decreasing their radiating surface. In this paper, we present a global scenario based on calculations coupling episodic accretion histories derived from numerical simulations of collapsing cloud prestellar cores of various masses and subsequent protostar evolution. Our calculations show that, assuming an initial protostar mass Mi ~ 1 M Jup, typical of the second Larson's core, both the luminosity spread in the HRD and the inferred properties of FU Ori events (mass, radius, accretion rate) can be explained by this scenario, providing two conditions. First, there must be some variation within the fraction of accretion energy absorbed by the protostar during the accretion process. Second, the range of this variation should increase with increasing accretion burst intensity and thus with the initial core mass and final star mass. The numerical hydrodynamics simulations of collapsing cloud prestellar cores indeed show that the intensity of the accretion bursts correlates with the mass and initial angular momentum of the prestellar core. Massive prestellar cores with high initial angular momentum are found to produce intense bursts characteristic of FU Ori-like events. Our results thus suggest a link between the burst intensities and the fraction of accretion energy absorbed by the protostar, with some threshold in the accretion rate, of the order of 10-5 M ⊙ yr-1, delimitating the transition from "cold" to "hot" accretion. Such a transition might reflect a change in the accretion geometry with increasing accretion rate, i.e., a transition from magnetospheric or thin

The UV Luminosity Function at 6 < z < 10 from the Hubble Frontier Fields

NASA Astrophysics Data System (ADS)

Livermore, Rachael C.; Finkelstein, Steven L.; Lotz, Jennifer M.

2017-01-01

The Hubble Frontier Fields program has obtained deep optical and near-infrared Hubble Space Telescope imaging of six galaxy clusters and associated parallel fields. The depth of the imaging (m_AB ~ 29) means we can identify faint galaxies at z > 6, and those in the cluster fields also benefit from magnification due to strong gravitational lensing that allows us to reach intrinsic absolute magnitudes of M_UV ~ -12.5 at z ~ 6. Here, we present the UV luminosity functions at 6 < z < 10 from the complete Hubble Frontier Fields data, revealing a steep faint-end slope that extends to the limits of the data. The lack of any apparent turnover in the luminosity functions means that faint galaxies in the early Universe may have provided sufficient ionizing radiation to sustain reionization.

Does the evolution of the radio luminosity function of star-forming galaxies match that of the star formation rate function?

NASA Astrophysics Data System (ADS)

Bonato, Matteo; Negrello, Mattia; Mancuso, Claudia; De Zotti, Gianfranco; Ciliegi, Paolo; Cai, Zhen-Yi; Lapi, Andrea; Massardi, Marcella; Bonaldi, Anna; Sajina, Anna; Smolčić, Vernesa; Schinnerer, Eva

2017-08-01

The assessment of the relationship between radio continuum luminosity and star formation rate (SFR) is of crucial importance to make reliable predictions for the forthcoming ultra-deep radio surveys and to allow a full exploitation of their results to measure the cosmic star formation history. We have addressed this issue by matching recent accurate determinations of the SFR function up to high redshifts with literature estimates of the 1.4 GHz luminosity functions of star-forming galaxies (SFGs). This was done considering two options, proposed in the literature, for the relationship between the synchrotron emission (Lsynch), that dominates at 1.4 GHz, and the SFR: a linear relation with a decline of the Lsynch/SFR ratio at low luminosities or a mildly non-linear relation at all luminosities. In both cases, we get good agreement with the observed radio luminosity functions but, in the non-linear case, the deviation from linearity must be small. The luminosity function data are consistent with a moderate increase of the Lsynch/SFR ratio with increasing redshift, indicated by other data sets, although a constant ratio cannot be ruled out. A stronger indication of such increase is provided by recent deep 1.4-GHz counts, down to μJy levels. This is in contradiction with models predicting a decrease of that ratio due to inverse Compton cooling of relativistic electrons at high redshifts. Synchrotron losses appear to dominate up to z ≃ 5. We have also updated the Massardi et al. evolutionary model for radio loud AGNs.

Simulating the X-ray luminosity of Be X-ray binaries: the case for black holes versus neutron stars

NASA Astrophysics Data System (ADS)

Brown, R. O.; Ho, W. C. G.; Coe, M. J.; Okazaki, A. T.

2018-04-01

There are over 100 Be stars that are known to have neutron star companions but only one such system with a black hole. Previous theoretical work suggests this is not due to their formation but due to differences in X-ray luminosity. It has also been proposed that the truncation of the Be star's circumstellar disc is dependent on the mass of the compact object. Hence, Be star discs in black hole binaries are smaller. Since accretion onto the compact object from the Be star's disc is what powers the X-ray luminosity, a smaller disc in black hole systems leads to a lower luminosity. In this paper, simulations are performed with a range of eccentricities and compact object mass. The disc's size and density are shown to be dependent on both quantities. Mass capture and, in turn, X-ray luminosity are heavily dependent on the size and density of the disc. Be/black hole binaries are expected to be up to ˜10 times fainter than Be/neutron star binaries when both systems have the same eccentricity and can be 100 times fainter when comparing systems with different eccentricity.

COLA. III. Radio Detection of Active Galactic Nucleus in Compact Moderate Luminosity Infrared Galaxies

NASA Astrophysics Data System (ADS)

Parra, R.; Conway, J. E.; Aalto, S.; Appleton, P. N.; Norris, R. P.; Pihlström, Y. M.; Kewley, L. J.

2010-09-01

We present results from 4.8 GHz Very Large Array (VLA) and global very long baseline interferometry (VLBI) observations of the northern half of the moderate FIR luminosity (median L IR = 1011.01 L sun) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the galaxies observed. The radio luminosities of these cores (~1021 W Hz-1) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by active galactic nuclei (AGNs). These sub-parsec scale radio cores are preferentially detected toward galaxies whose VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star formation, we conclude that the AGN-powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central supermassive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity.

The period-luminosity and period-radius relations of Type II and anomalous Cepheids in the Large and Small Magellanic Clouds

NASA Astrophysics Data System (ADS)

Groenewegen, M. A. T.; Jurkovic, M. I.

2017-07-01

Context. Type II Cepheids (T2Cs) and anomalous Cepheids (ACs) are pulsating stars that follow separate period-luminosity relations. Aims: We study the period-luminosity (PL) and period-radius (PR) relations for T2Cs and ACs in the Magellanic Clouds. Methods: In an accompanying paper we determined the luminosities and effective temperatures for the 335 T2Cs and ACs in the LMC and SMC discovered in the OGLE-III survey, by constructing the spectral energy distribution (SED) and fitting this with model atmospheres and a dust radiative transfer model (in the case of dust excess). Building on these results we studied the PL and PR relations of these sources. Using existing pulsation models for RR Lyrae and classical Cepheids we derive the period-luminosity-mass-temperature-metallicity relations and then estimate the pulsation mass. Results: The PL relation for the T2Cs does not appear to depend on metallicity and is Mbol = + 0.12-1.78log P (for P < 50 days), excluding the dusty RV Tau stars. Relations for fundamental and first overtone LMC ACs are also presented. The PR relation for T2C also shows little or no dependence on metallicity or period. Our preferred relation combines SMC and LMC stars and all T2C subclasses and is log R = 0.846 + 0.521log P. Relations for fundamental and first overtone LMC ACs are also presented. The pulsation masses from the RR Lyrae and classical Cepheid pulsation models agree well for the short period T2Cs, the BL Her subtype, and ACs, and are consistent with estimates in the literature, I.e. MBLH 0.49M⊙ and MAC 1.3M⊙, respectively. The masses of the W Vir appear similar to the BL Her. The situation for the pWVir and RV Tau stars is less clear. For many RV Tau the masses are in conflict with the standard picture of (single-star) post-AGB evolution, where the masses are either too large (≳1 M⊙) or too small (≲0.4 M⊙). Full Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130

The Herschel* PEP-HERMES Luminosity Function- I. Probing the Evolution of PACS Selected Galaxies to z approx. equal to 4

NASA Technical Reports Server (NTRS)

Gruppioni, Carlotta; Pozzi, F.; Rodighiero, G.; Delvecchio, I.; Berta, S.; Pozzetti, L.; Zamorani, G.; Andreani, P.; Cimatti, A.; Ilbert, O.;

LoCuSS: the near-infrared luminosity and weak-lensing mass scaling relation of galaxy clusters

NASA Astrophysics Data System (ADS)

Mulroy, Sarah L.; Smith, Graham P.; Haines, Chris P.; Marrone, Daniel P.; Okabe, Nobuhiro; Pereira, Maria J.; Egami, Eiichi; Babul, Arif; Finoguenov, Alexis; Martino, Rossella

2014-10-01

We present the first scaling relation between weak-lensing galaxy cluster mass, MWL, and near-infrared luminosity, LK. Our results are based on 17 clusters observed with wide-field instruments on Subaru, the United Kingdom Infrared Telescope, the Mayall Telescope, and the MMT. We concentrate on the relation between projected 2D weak-lensing mass and spectroscopically confirmed luminosity within 1 Mpc, modelled as M_WL ∝ LK^b, obtaining a power-law slope of b=0.83^{+0.27}_{-0.24} and an intrinsic scatter of σ _{lnM_WL|LK}=10^{+8}_{-5} per cent. Intrinsic scatter of ˜10 per cent is a consistent feature of our results regardless of how we modify our approach to measuring the relationship between mass and light. For example, deprojecting the mass and measuring both quantities within r500, that is itself obtained from the lensing analysis, yields σ _{lnM_WL|LK}=10^{+7}_{-5} per cent and b=0.97^{+0.17}_{-0.17}. We also find that selecting members based on their (J - K) colours instead of spectroscopic redshifts neither increases the scatter nor modifies the slope. Overall our results indicate that near-infrared luminosity measured on scales comparable with r500 (typically 1 Mpc for our sample) is a low scatter and relatively inexpensive proxy for weak-lensing mass. Near-infrared luminosity may therefore be a useful mass proxy for cluster cosmology experiments.

Luminosity geometric reduction factor from colliding bunches with different lengths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verdu-Andres, S.

In the interaction point of the future electron-Ion collider eRHIC, the electron beam bunches are at least one order of magnitude shorter than the proton beam bunches. With the introduction of a crossing angle, the actual number of collisions resulting from the bunch collision gets reduced. Here we derive the expression for the luminosity geometric reduction factor when the bunches of the two incoming beams are not equal.

Supermassive black holes and their host galaxies. I. Bulge luminosities from dedicated near-infrared data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Läsker, Ronald; Van de Ven, Glenn; Ferrarese, Laura, E-mail: laesker@mpia.de

2014-01-01

In an effort to secure, refine, and supplement the relation between central supermassive black hole masses, M {sub •}, and the bulge luminosities of their host galaxies, L {sub bul}, we obtained deep, high spatial resolution K-band images of 35 nearby galaxies with securely measured M {sub •}, using the wide-field WIRCam imager at the Canada-France-Hawaii-Telescope. A dedicated data reduction and sky subtraction strategy was adopted to estimate the brightness and structure of the sky, a critical step when tracing the light distribution of extended objects in the near-infrared. From the final image product, bulge and total magnitudes were extractedmore » via two-dimensional profile fitting. As a first order approximation, all galaxies were modeled using a simple Sérsic-bulge+exponential-disk decomposition. However, we found that such models did not adequately describe the structure that we observed in a large fraction of our sample galaxies which often include cores, bars, nuclei, inner disks, spiral arms, rings, and envelopes. In such cases, we adopted profile modifications and/or more complex models with additional components. The derived bulge magnitudes are very sensitive to the details and number of components used in the models, although total magnitudes remain almost unaffected. Usually, but not always, the luminosities and sizes of the bulges are overestimated when a simple bulge+disk decomposition is adopted in lieu of a more complex model. Furthermore, we found that some spheroids are not well fit when the ellipticity of the Sérsic model is held fixed. This paper presents the details of the image processing and analysis, while we discuss how model-induced biases and systematics in bulge magnitudes impact the M {sub •}-L {sub bul} relation in a companion paper.« less

Line-driven disc wind model for ultrafast outflows in active galactic nuclei - scaling with luminosity

NASA Astrophysics Data System (ADS)

Nomura, M.; Ohsuga, K.

2017-03-01

In order to reveal the origin of the ultrafast outflows (UFOs) that are frequently observed in active galactic nuclei (AGNs), we perform two-dimensional radiation hydrodynamics simulations of the line-driven disc winds, which are accelerated by the radiation force due to the spectral lines. The line-driven winds are successfully launched for the range of MBH = 106-9 M⊙ and ε = 0.1-0.5, and the resulting mass outflow rate (dot{M_w}), momentum flux (dot{p_w}), and kinetic luminosity (dot{E_w}) are in the region containing 90 per cent of the posterior probability distribution in the dot{M}_w-Lbol plane, dot{p}_w-Lbol plane, and dot{E}_w-Lbol plane shown in Gofford et al., where MBH is the black hole mass, ε is the Eddington ratio, and Lbol is the bolometric luminosity. The best-fitting relations in Gofford et al., d log dot{M_w}/d log {L_bol}˜ 0.9, d log dot{p_w}/d log {L_bol}˜ 1.2, and d log dot{E_w}/d log {L_bol}˜ 1.5, are roughly consistent with our results, d log dot{M_w}/d log {L_bol}˜ 9/8, d log dot{p_w}/d log {L_bol}˜ 10/8, and d log dot{E_w}/d log {L_bol}˜ 11/8. In addition, our model predicts that no UFO features are detected for the AGNs with ε ≲ 0.01, since the winds do not appear. Also, only AGNs with MBH ≲ 108 M⊙ exhibit the UFOs when ε ∼ 0.025. These predictions nicely agree with the X-ray observations. These results support that the line-driven disc wind is the origin of the UFOs.

Supermassive Black Holes and Their Host Galaxies. I. Bulge Luminosities from Dedicated Near-infrared Data

NASA Astrophysics Data System (ADS)

Läsker, Ronald; Ferrarese, Laura; van de Ven, Glenn

2014-01-01

In an effort to secure, refine, and supplement the relation between central supermassive black hole masses, M •, and the bulge luminosities of their host galaxies, L bul, we obtained deep, high spatial resolution K-band images of 35 nearby galaxies with securely measured M •, using the wide-field WIRCam imager at the Canada-France-Hawaii-Telescope. A dedicated data reduction and sky subtraction strategy was adopted to estimate the brightness and structure of the sky, a critical step when tracing the light distribution of extended objects in the near-infrared. From the final image product, bulge and total magnitudes were extracted via two-dimensional profile fitting. As a first order approximation, all galaxies were modeled using a simple Sérsic-bulge+exponential-disk decomposition. However, we found that such models did not adequately describe the structure that we observed in a large fraction of our sample galaxies which often include cores, bars, nuclei, inner disks, spiral arms, rings, and envelopes. In such cases, we adopted profile modifications and/or more complex models with additional components. The derived bulge magnitudes are very sensitive to the details and number of components used in the models, although total magnitudes remain almost unaffected. Usually, but not always, the luminosities and sizes of the bulges are overestimated when a simple bulge+disk decomposition is adopted in lieu of a more complex model. Furthermore, we found that some spheroids are not well fit when the ellipticity of the Sérsic model is held fixed. This paper presents the details of the image processing and analysis, while we discuss how model-induced biases and systematics in bulge magnitudes impact the M •-L bul relation in a companion paper.

Mass to Luminosity Ratios of Some Clusters in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Sohn, Young-Jong; Chun, Mun-Suk

1990-12-01

Luminosity profiles and dynamical parameters of 12 globular clusters in the Large Magellanic Cloud(SB(s)m) are obtained from the concentric aperture photoelectric photometry of 3 different aged clusters and the collected photometric data of 9 clusters. The total masses of the globular clusters are the calculated using the equation M = Mrt3(4¥Ø2-k2), which is derived from the theoretical rotation curve for the exponential disk(Chun 1987). These masses lie between 0.3 x 104 and 15.8 x 104 M . From the determined total mass and luminosity ratios are also derived. The M/L ratio of a cluster increases with the cluster age; about 0.03 for the youngest clusters(SWB ¥°) and about 0.24 for the oldest clusters(SUB ¥¶). There is a difference in M/L by a factor of 10 between the galactic globular clusters and the old globular clusters in the LCM.

Discovery of 1-5 Hz Flaring at High Luminosity in SAX J1808.4-3658

NASA Astrophysics Data System (ADS)

Bult, Peter; van der Klis, Michiel

2014-07-01

We report the discovery of a 1-5 Hz X-ray flaring phenomenon observed at >30 mCrab near peak luminosity in the 2008 and 2011 outbursts of the accreting millisecond X-ray pulsar SAX J1808.4-3658 in observations with the Rossi X-ray Timing Explorer. In each of the two outbursts this high luminosity flaring is seen for ~3 continuous days and switches on and off on a timescale of 1-2 hr. The flaring can be seen directly in the light curve, where it shows sharp spikes of emission at quasi-regular separation. In the power spectrum it produces a broad noise component, which peaks at 1-5 Hz. The total 0.05-10 Hz variability has a fractional rms amplitude of 20%-45%, well in excess of the 8%-12% rms broadband noise usually seen in power spectra of SAX J1808.4-3658. We perform a detailed timing analysis of the flaring and study its relation to the 401 Hz pulsations. We find that the pulse amplitude varies proportionally with source flux through all phases of the flaring, indicating that the flaring is likely due to mass density variations created at or outside the magnetospheric boundary. We suggest that this 1-5 Hz flaring is a high mass accretion rate version of the 0.5-2 Hz flaring which is known to occur at low luminosity (<13 mCrab), late in the tail of outbursts of SAX J1808.4-3658. We propose the dead-disk instability, previously suggested as the mechanism for the 0.5-2 Hz flaring, as a likely mechanism for the high luminosity flaring reported here.

A finer view of the conditional galaxy luminosity function and magnitude-gap statistics

NASA Astrophysics Data System (ADS)

Trevisan, M.; Mamon, G. A.

2017-10-01

The gap between first- and second-ranked galaxy magnitudes in groups is often considered a tracer of their merger histories, which in turn may affect galaxy properties, and also serves to test galaxy luminosity functions (LFs). We remeasure the conditional luminosity function (CLF) of the Main Galaxy Sample of the SDSS in an appropriately cleaned subsample of groups from the Yang catalogue. We find that, at low group masses, our best-fitting CLF has steeper satellite high ends, yet higher ratios of characteristic satellite to central luminosities in comparison with the CLF of Yang et al. The observed fractions of groups with large and small magnitude gaps as well as the Tremaine & Richstone statistics are not compatible with either a single Schechter LF or with a Schechter-like satellite plus lognormal central LF. These gap statistics, which naturally depend on the size of the subsamples, and also on the maximum projected radius, Rmax, for defining the second brightest galaxy, can only be reproduced with two-component CLFs if we allow small gap groups to preferentially have two central galaxies, as expected when groups merge. Finally, we find that the trend of higher gap for higher group velocity dispersion, σv, at a given richness, discovered by Hearin et al., is strongly reduced when we consider σv in bins of richness, and virtually disappears when we use group mass instead of σv. This limits the applicability of gaps in refining cosmographic studies based on cluster counts.

UV TO FAR-IR CATALOG OF A GALAXY SAMPLE IN NEARBY CLUSTERS: SPECTRAL ENERGY DISTRIBUTIONS AND ENVIRONMENTAL TRENDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hernandez-Fernandez, Jonathan D.; Iglesias-Paramo, J.; Vilchez, J. M., E-mail: jonatan@iaa.es

2012-03-01

In this paper, we present a sample of cluster galaxies devoted to study the environmental influence on the star formation activity. This sample of galaxies inhabits in clusters showing a rich variety in their characteristics and have been observed by the SDSS-DR6 down to M{sub B} {approx} -18, and by the Galaxy Evolution Explorer AIS throughout sky regions corresponding to several megaparsecs. We assign the broadband and emission-line fluxes from ultraviolet to far-infrared to each galaxy performing an accurate spectral energy distribution for spectral fitting analysis. The clusters follow the general X-ray luminosity versus velocity dispersion trend of L{sub X}more » {proportional_to} {sigma}{sup 4.4}{sub c}. The analysis of the distributions of galaxy density counting up to the 5th nearest neighbor {Sigma}{sub 5} shows: (1) the virial regions and the cluster outskirts share a common range in the high density part of the distribution. This can be attributed to the presence of massive galaxy structures in the surroundings of virial regions. (2) The virial regions of massive clusters ({sigma}{sub c} > 550 km s{sup -1}) present a {Sigma}{sub 5} distribution statistically distinguishable ({approx}96%) from the corresponding distribution of low-mass clusters ({sigma}{sub c} < 550 km s{sup -1}). Both massive and low-mass clusters follow a similar density-radius trend, but the low-mass clusters avoid the high density extreme. We illustrate, with ABELL 1185, the environmental trends of galaxy populations. Maps of sky projected galaxy density show how low-luminosity star-forming galaxies appear distributed along more spread structures than their giant counterparts, whereas low-luminosity passive galaxies avoid the low-density environment. Giant passive and star-forming galaxies share rather similar sky regions with passive galaxies exhibiting more concentrated distributions.« less

An Empirical Planetesimal Belt Radius–Stellar Luminosity Relation

NASA Astrophysics Data System (ADS)

Matrà, L.; Marino, S.; Kennedy, G. M.; Wyatt, M. C.; Öberg, K. I.; Wilner, D. J.

2018-05-01

Resolved observations of millimeter-sized dust, tracing larger planetesimals, have pinpointed the location of 26 Edgeworth–Kuiper Belt analogs. We report that a belt’s distance R to its host star correlates with the star’s luminosity L ⋆, following R\\propto {L}\\star 0.19 with a low intrinsic scatter of ∼17%. Remarkably, our Edgeworth–Kuiper Belt in the solar system and the two CO snow lines imaged in protoplanetary disks lie close to this R–L ⋆ relation, suggestive of an intrinsic relationship between protoplanetary disk structures and belt locations. To test the effect of bias on the relation, we use a Monte Carlo approach and simulate uncorrelated model populations of belts. We find that observational bias could produce the slope and intercept of the R–L ⋆ relation but is unable to reproduce its low scatter. We then repeat the simulation taking into account the collisional evolution of belts, following the steady-state model that fits the belt population as observed through infrared excesses. This significantly improves the fit by lowering the scatter of the simulated R–L ⋆ relation; however, this scatter remains only marginally consistent with the one observed. The inability of observational bias and collisional evolution alone to reproduce the tight relationship between belt radius and stellar luminosity could indicate that planetesimal belts form at preferential locations within protoplanetary disks. The similar trend for CO snow line locations would then indicate that the formation of planetesimals or planets in the outer regions of planetary systems is linked to the volatility of their building blocks, as postulated by planet formation models.

IUE observations of blue halo high luminosity stars

NASA Technical Reports Server (NTRS)

Hack, M.; Franco, M. L.; Stalio, R.

1981-01-01

Two high luminosity population II blue stars of high galactic latitude, BD+33 deg 2642 and HD 137569 were observed at high resolution. The stellar spectra show the effect of mass loss in BD+33 deg 2642 and abnormally weak metallic lines in HD 137569. The interstellar lines in the direction of BD+33 deg 2642, which lies at a height z greater than or equal to 6.2 kpc from the galactic plane, are split into two components. No high ionization stages are found at the low velocity component; nor can they be detected in the higher velocity clouds because of mixing with the corresponding stellar/circumstellar lines.

The Intermediate Luminosity Optical Transient SN 2010da: The Progenitor, Eruption, and Aftermath of a Peculiar Supergiant High-mass X-Ray Binary

NASA Astrophysics Data System (ADS)

Villar, V. A.; Berger, E.; Chornock, R.; Margutti, R.; Laskar, T.; Brown, P. J.; Blanchard, P. K.; Czekala, I.; Lunnan, R.; Reynolds, M. T.

2016-10-01

We present optical spectroscopy, ultraviolet-to-infrared imaging, and X-ray observations of the intermediate luminosity optical transient (ILOT) SN 2010da in NGC 300 (d = 1.86 Mpc) spanning from -6 to +6 years relative to the time of outburst in 2010. Based on the light-curve and multi-epoch spectral energy distributions of SN 2010da, we conclude that the progenitor of SN 2010da is a ≈10-12 M ⊙ yellow supergiant possibly transitioning into a blue-loop phase. During outburst, SN 2010da had a peak absolute magnitude of M bol ≲ -10.4 mag, dimmer than other ILOTs and supernova impostors. We detect multi-component hydrogen Balmer, Paschen, and Ca II emission lines in our high-resolution spectra, which indicate a dusty and complex circumstellar environment. Since the 2010 eruption, the star has brightened by a factor of ≈5 and remains highly variable in the optical. Furthermore, we detect SN 2010da in archival Swift and Chandra observations as an ultraluminous X-ray source (L X ≈ 6 × 1039 erg s-1). We additionally attribute He II 4686 Å and coronal Fe emission lines in addition to a steady X-ray luminosity of ≈1037 erg s-1 to the presence of a compact companion.

The evolving far-IR galaxy luminosity function and dust-obscured star formation rate density out to z≃5.

NASA Astrophysics Data System (ADS)

Koprowski, M. P.; Dunlop, J. S.; Michałowski, M. J.; Coppin, K. E. K.; Geach, J. E.; McLure, R. J.; Scott, D.; van der Werf, P. P.

2017-11-01

We present a new measurement of the evolving galaxy far-IR luminosity function (LF) extending out to redshifts z ≃ 5, with resulting implications for the level of dust-obscured star formation density in the young Universe. To achieve this, we have exploited recent advances in sub-mm/mm imaging with SCUBA-2 on the James Clerk Maxwell Telescope and the Atacama Large Millimeter/Submillimeter Array, which together provide unconfused imaging with sufficient dynamic range to provide meaningful coverage of the luminosity-redshift plane out to z > 4. Our results support previous indications that the faint-end slope of the far-IR LF is sufficiently flat that comoving luminosity density is dominated by bright objects (≃L*). However, we find that the number density/luminosity of such sources at high redshifts has been severely overestimated by studies that have attempted to push the highly confused Herschel SPIRE surveys beyond z ≃ 2. Consequently, we confirm recent reports that cosmic star formation density is dominated by UV-visible star formation at z > 4. Using both direct (1/Vmax) and maximum likelihood determinations of the LF, we find that its high-redshift evolution is well characterized by continued positive luminosity evolution coupled with negative density evolution (with increasing redshift). This explains why bright sub-mm sources continue to be found at z > 5, even though their integrated contribution to cosmic star formation density at such early times is very small. The evolution of the far-IR galaxy LF thus appears similar in form to that already established for active galactic nuclei, possibly reflecting a similar dependence on the growth of galaxy mass.

Luminosity measurements for the R scan experiment at BESIII

DOE PAGES

Ablikim, M.; Achasov, M. N.; Ahmed, S.; ...

2017-02-08

By analyzing the large-angle Bhabha scattering events e +e - → (γ)e +e - and diphoton events e +e - → (γ)γγ for the data sets collected at center-of-mass (c.m.) energies between 2.2324 and 4.5900 GeV (131 energy points in total) with the upgraded Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider (BEPCII), the integrated luminosities have been measured at the different c.m. energies, individually. Finally, the results are important inputs for the R value and J/ψ resonance parameter measurements.

Quasar Spectral Energy Distributions As A Function Of Physical Property

NASA Astrophysics Data System (ADS)

Townsend, Shonda; Ganguly, R.; Stark, M. A.; Derseweh, J. A.; Richmond, J. M.

2012-05-01

Galaxy evolution models have shown that quasars are a crucial ingredient in the evolution of massive galaxies. Outflows play a key role in the story of quasars and their host galaxies, by helping regulate the accretion process, the star-formation rate and mass of the host galaxy (i.e., feedback). The prescription for modeling outflows as a contributor to feedback requires knowledge of the outflow velocity, geometry, and column density. In particular, we need to understand how these depend on physical parameters and how much is determined stochastically (and with what distribution). In turn, models of outflows have shown particular sensitivity to the shape of the spectral energy distribution (SED), depending on the UV luminosity to transfer momentum to the gas, the X-ray luminosity to regulate how efficiently that transfer can be, etc. To investigate how SED changes with physical properties, we follow up on Richards et al. (2006), who constructed SEDs with varying luminosity. Here, we construct SEDs as a function of redshift, and physical property (black hole mass, bolometric luminosity, Eddington ratio) for volume limited samples drawn from the Sloan Digital Sky Survey, with photometry supplemented from 2MASS, WISE, GALEX, ROSAT, and Chandra. To estimate black hole masses, we adopt the scaling relations from Greene & Ho (2005) based on the H-alpha emission line FWHM. This requires redshifts less than 0.4. To construct volume-limited subsamples, we begin by adopting g=19.8 as a nominal limiting magnitude over which we are guaranteed to detect z<0.4 quasars. At redshift 0.4, we are complete down to Mg=-21.8, which yields 3300 objects from Data Release 7. At z=0.1, we are complete down to Mg=-18.5. This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. 09-ADP09-0016 issued through the Astrophysics Data Analysis Program.

COLA. III. RADIO DETECTION OF ACTIVE GALACTIC NUCLEUS IN COMPACT MODERATE LUMINOSITY INFRARED GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parra, R.; Conway, J. E.; Aalto, S.

2010-09-01

We present results from 4.8 GHz Very Large Array (VLA) and global very long baseline interferometry (VLBI) observations of the northern half of the moderate FIR luminosity (median L{sub IR} = 10{sup 11.01} L{sub sun}) COLA sample of star-forming galaxies. VLBI sources are detected in a high fraction (20/90) of the galaxies observed. The radio luminosities of these cores ({approx}10{sup 21} W Hz{sup -1}) are too large to be explained by radio supernovae or supernova remnants and we argue that they are instead powered by active galactic nuclei (AGNs). These sub-parsec scale radio cores are preferentially detected toward galaxies whosemore » VLA maps show bright 100-500 parsec scale nuclear radio components. Since these latter structures tightly follow the FIR to radio-continuum correlation for star formation, we conclude that the AGN-powered VLBI sources are associated with compact nuclear starburst environments. The implications for possible starburst-AGN connections are discussed. The detected VLBI sources have a relatively narrow range of radio luminosity consistent with models in which intense compact Eddington-limited starbursts regulate the gas supply onto a central supermassive black hole. The high incidence of AGN radio cores in compact starbursts suggests little or no delay between the starburst phase and the onset of AGN activity.« less

V and K-band Mass-Luminosity Relations for M dwarf Stars

NASA Astrophysics Data System (ADS)

Benedict, G. Fritz; Henry, Todd J.; McArthur, Barbara; Franz, Otto G.; Wasserman, Lawrence H.; Dieterich, Sergio

2015-01-01

Applying Hubble Space Telescope Fine Guidance Sensor astrometric techniques developed to establish relative orbits for binary stars (Franz et al. 1998, AJ, 116, 1432), determine masses of binary components (Benedict et al. 2001, AJ, 121, 1607), and measure companion masses of exoplanet host stars (McArthur et al. 2010, ApJ, 715, 1203), we derive masses with an average 2.1% error for 24 components of 12 M dwarf binary star systems. Masses range 0.08 to 0.40 solar masses. With these we update the lower Main Sequence V-band Mass-Luminosity Relation first shown in Henry et al. (1999, ApJ, 512, 864). We demonstrate that a Mass-Luminosity Relation in the K-band has far less scatter than in the V-band. For the eight binary components for which we have component magnitude differences in the K-band the RMS residual drops from 0.5 magnitude in the V-band to 0.05 magnitude in the K-band. These relations can be used to estimate the masses of the ubiquitous red dwarfs that account for 75% of all stars, to an accuracy of 5%, which is much better than ever before.

The Seven Sisters DANCe. I. Empirical isochrones, luminosity, and mass functions of the Pleiades cluster

NASA Astrophysics Data System (ADS)

Bouy, H.; Bertin, E.; Sarro, L. M.; Barrado, D.; Moraux, E.; Bouvier, J.; Cuillandre, J.-C.; Berihuete, A.; Olivares, J.; Beletsky, Y.

2015-05-01

Context. The DANCe survey provides photometric and astrometric (position and proper motion) measurements for approximately 2 million unique sources in a region encompassing ~80 deg2 centered on the Pleiades cluster. Aims: We aim at deriving a complete census of the Pleiades and measure the mass and luminosity functions of the cluster. Methods: Using the probabilistic selection method previously described, we identified high probability members in the DANCe (i ≥ 14 mag) and Tycho-2 (V ≲ 12 mag) catalogues and studied the properties of the cluster over the corresponding luminosity range. Results: We find a total of 2109 high-probability members, of which 812 are new, making it the most extensive and complete census of the cluster to date. The luminosity and mass functions of the cluster are computed from the most massive members down to ~0.025 M⊙. The size, sensitivity, and quality of the sample result in the most precise luminosity and mass functions observed to date for a cluster. Conclusions: Our census supersedes previous studies of the Pleiades cluster populations, in terms of both sensitivity and accuracy. Based on service observations made with the William Herschel Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Table 1 and Appendices are available in electronic form at http://www.aanda.orgDANCe catalogs (Tables 6 and 7) and full Tables 2-5 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/577/A148

PRIMUS: Galaxy Clustering as a Function of Luminosity and Color at 0.2 < z < 1

NASA Astrophysics Data System (ADS)

Skibba, Ramin A.; Smith, M. Stephen M.; Coil, Alison L.; Moustakas, John; Aird, James; Blanton, Michael R.; Bray, Aaron D.; Cool, Richard J.; Eisenstein, Daniel J.; Mendez, Alexander J.; Wong, Kenneth C.; Zhu, Guangtun

2014-04-01

We present measurements of the luminosity and color-dependence of galaxy clustering at 0.2 < z < 1.0 in the Prism Multi-object Survey. We quantify the clustering with the redshift-space and projected two-point correlation functions, ξ(rp , π) and wp (rp ), using volume-limited samples constructed from a parent sample of over ~130, 000 galaxies with robust redshifts in seven independent fields covering 9 deg2 of sky. We quantify how the scale-dependent clustering amplitude increases with increasing luminosity and redder color, with relatively small errors over large volumes. We find that red galaxies have stronger small-scale (0.1 Mpc h -1 < rp < 1 Mpc h -1) clustering and steeper correlation functions compared to blue galaxies, as well as a strong color dependent clustering within the red sequence alone. We interpret our measured clustering trends in terms of galaxy bias and obtain values of b gal ≈ 0.9-2.5, quantifying how galaxies are biased tracers of dark matter depending on their luminosity and color. We also interpret the color dependence with mock catalogs, and find that the clustering of blue galaxies is nearly constant with color, while redder galaxies have stronger clustering in the one-halo term due to a higher satellite galaxy fraction. In addition, we measure the evolution of the clustering strength and bias, and we do not detect statistically significant departures from passive evolution. We argue that the luminosity- and color-environment (or halo mass) relations of galaxies have not significantly evolved since z ~ 1. Finally, using jackknife subsampling methods, we find that sampling fluctuations are important and that the COSMOS field is generally an outlier, due to having more overdense structures than other fields; we find that "cosmic variance" can be a significant source of uncertainty for high-redshift clustering measurements.

X-Ray Luminosity Functions of Normal Galaxies in the Great Observatories Origins Deep Survey

NASA Astrophysics Data System (ADS)

Ptak, Andrew; Mobasher, Bahram; Hornschemeier, Ann; Bauer, Franz; Norman, Colin

2007-10-01

We present soft (0.5-2 keV) X-ray luminosity functions (XLFs) in the Great Observatories Origins Deep Survey (GOODS) fields derived for galaxies at z~0.25 and 0.75. SED fitting was used to estimate photometric redshifts and separate galaxy types, resulting in a sample of 40 early-type galaxies and 46 late-type galaxies. We estimate k-corrections for both the X-ray/optical and X-ray/NIR flux ratios, which facilitates the separation of AGNs from the normal/starburst galaxies. We fit the XLFs with a power-law model using both traditional and Markov-Chain Monte Carlo (MCMC) procedures. A key advantage of the MCMC approach is that it explicitly takes into account upper limits and allows errors on ``derived'' quantities, such as luminosity densities, to be computed directly (i.e., without potentially questionable assumptions concerning the propagation of errors). The slopes of the early-type galaxy XLFs tend to be slightly flatter than the late-type galaxy XLFs, although the effect is significant at only the 90% and 97% levels for z~0.25 and 0.75. The XLFs differ between z<0.5 and z>0.5 at >99% significance levels for early-type, late-type, and all (early- and late-type) galaxies. We also fit Schechter and lognormal models to the XLFs, fitting the low- and high-redshift XLFs for a given sample simultaneously assuming only pure luminosity evolution. In the case of lognormal fits, the results of MCMC fitting of the local FIR luminosity function were used as priors for the faint- and bright-end slopes (similar to ``fixing'' these parameters at the FIR values, except here the FIR uncertainty is included). The best-fit values of the change in logL* with redshift were ΔlogL*=0.23+/-0.16 dex (for early-type galaxies) and 0.34+/-0.12 dex (for late-type galaxies), corresponding to (1+z)1.6 and (1+z)2.3. These results were insensitive to whether the Schechter or lognormal function was adopted.

THE OBSCURED FRACTION OF ACTIVE GALACTIC NUCLEI IN THE XMM-COSMOS SURVEY: A SPECTRAL ENERGY DISTRIBUTION PERSPECTIVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lusso, E.; Hennawi, J. F.; Richards, G. T.

2013-11-10

The fraction of active galactic nucleus (AGN) luminosity obscured by dust and re-emitted in the mid-IR is critical for understanding AGN evolution, unification, and parsec-scale AGN physics. For unobscured (Type 1) AGNs, where we have a direct view of the accretion disk, the dust covering factor can be measured by computing the ratio of re-processed mid-IR emission to intrinsic nuclear bolometric luminosity. We use this technique to estimate the obscured AGN fraction as a function of luminosity and redshift for 513 Type 1 AGNs from the XMM-COSMOS survey. The re-processed and intrinsic luminosities are computed by fitting the 18 bandmore » COSMOS photometry with a custom spectral energy distribution fitting code, which jointly models emission from hot dust in the AGN torus, from the accretion disk, and from the host galaxy. We find a relatively shallow decrease of the luminosity ratio as a function of L{sub bol}, which we interpret as a corresponding decrease in the obscured fraction. In the context of the receding torus model, where dust sublimation reduces the covering factor of more luminous AGNs, our measurements require a torus height that increases with luminosity as h ∝ L{sub bol}{sup 0.3-0.4}. Our obscured-fraction-luminosity relation agrees with determinations from Sloan Digital Sky Survey censuses of Type 1 and Type 2 quasars and favors a torus optically thin to mid-IR radiation. We find a much weaker dependence of the obscured fraction on 2-10 keV luminosity than previous determinations from X-ray surveys and argue that X-ray surveys miss a significant population of highly obscured Compton-thick AGNs. Our analysis shows no clear evidence for evolution of the obscured fraction with redshift.« less

A decades-long fast-rise-exponential-decay flare in low-luminosity AGN NGC 7213

NASA Astrophysics Data System (ADS)

Yan, Zhen; Xie, Fu-Guo

2018-03-01

We analysed the four-decades-long X-ray light curve of the low-luminosity active galactic nucleus (LLAGN) NGC 7213 and discovered a fast-rise-exponential-decay (FRED) pattern, i.e. the X-ray luminosity increased by a factor of ≈4 within 200 d, and then decreased exponentially with an e-folding time ≈8116 d (≈22.2 yr). For the theoretical understanding of the observations, we examined three variability models proposed in the literature: the thermal-viscous disc instability model, the radiation pressure instability model, and the TDE model. We find that a delayed tidal disruption of a main-sequence star is most favourable; either the thermal-viscous disc instability model or radiation pressure instability model fails to explain some key properties observed, thus we argue them unlikely.

Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs): New z > 6 Quasar Survey with Subaru/HSC

NASA Astrophysics Data System (ADS)

Matsuoka, Yoshiki; SHELLQs Collaboration

2017-01-01

Quasars at high redshift are an important and unique probe of the distant Universe, for understanding the origin and progress of cosmic reionization, the early growth of supermassive black holes, and the evolution of quasar host galaxies and their dark matter halos, among other topics. We are currently carrying out a new spectroscopic survey, called SHELLQs (Subaru High-z Exploration of Low-Luminosity Quasars), to search for low-luminosity quasars at z > 6. By exploiting the exquisite imaging data produced by the Subaru Hyper Suprime-Cam (HSC) survey, we aim to probe quasar luminosities down to M1450 ~ -22 mag, i.e., below the classical threshold between quasars and Seyfert galaxies. Candidate selection is performed by combining several photometric approaches including a Bayesian probabilistic algorithm. A large spectroscopic observing program is underway, using Subaru/FOCAS, GTC/OSIRIS, and Gemini/GMOS; in particular, SHELLQs has been approved as a Subaru intensive program to use 20 nights in the coming four semesters. As of August 2016, we have discovered ~40 quasars and bright galaxies at z ~ 6 and beyond, from the first 100 deg2 of the HSC survey (Matsuoka et al. 2016, ApJ, 828, 26). Surprisingly, we are starting to see the steep rise of the luminosity function of high-z galaxies, compared with that of quasars, at magnitudes fainter than M1450 ~ -22 mag or zAB ~ 24 mag. Multi-wavelength follow-up studies of the discovered objects as well as further survey observations are ongoing.

Heavily reddened type 1 quasars at z > 2 - I. Evidence for significant obscured black hole growth at the highest quasar luminosities

NASA Astrophysics Data System (ADS)

Banerji, Manda; Alaghband-Zadeh, S.; Hewett, Paul C.; McMahon, Richard G.

2015-03-01

We present a new population of z > 2 dust-reddened, type 1 quasars with 0.5 ≲ E(B - V) ≲ 1.5, selected using near-infrared (NIR) imaging data from the UKIDSS-LAS (Large Area Survey), ESO-VHS (European Southern Obseratory-VISTA Hemisphere Survey) and WISE surveys. NIR spectra obtained using the Very Large Telescope for 24 new objects bring our total sample of spectroscopically confirmed hyperluminous (>1013 L⊙), high-redshift dusty quasars to 38. There is no evidence for reddened quasars having significantly different Hα equivalent widths relative to unobscured quasars. The average black hole masses (˜109-1010 M⊙) and bolometric luminosities (˜1047 erg s-1) are comparable to the most luminous unobscured quasars at the same redshift, but with a tail extending to very high luminosities of ˜1048 erg s-1. 66 per cent of the reddened quasars are detected at >3σ at 22 μm by WISE. The average 6-μm rest-frame luminosity is log10(L6 μm/ erg s-1) = 47.1 ± 0.4, making the objects among the mid-infrared brightest active galactic nuclei (AGN) currently known. The extinction-corrected space density estimate now extends over three magnitudes (-30 < Mi < -27) and demonstrates that the reddened quasar luminosity function is significantly flatter than that of the unobscured quasar population at z = 2-3. At the brightest magnitudes, Mi ≲ -29, the space density of our dust-reddened population exceeds that of unobscured quasars. A model where the probability that a quasar becomes dust reddened increases at high luminosity is consistent with the observations and such a dependence could be explained by an increase in luminosity and extinction during AGN-fuelling phases. The properties of our obscured type 1 quasars are distinct from the heavily obscured, Compton-thick AGN that have been identified at much fainter luminosities and we conclude that they likely correspond to a brief evolutionary phase in massive galaxy formation.

ON THE DEPENDENCE OF TYPE Ia SNe LUMINOSITIES ON THE METALLICITY OF THEIR HOST GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreno-Raya, Manuel E.; Mollá, Mercedes; López-Sánchez, Ángel R.

The metallicity of the progenitor system producing a type Ia supernova (SN Ia) could play a role in its maximum luminosity, as suggested by theoretical predictions. We present an observational study to investigate if such a relationship exists. Using the 4.2 m William Herschel Telescope (WHT) we have obtained intermediate-resolution spectroscopy data of a sample of 28 local galaxies hosting SNe Ia, for which distances have been derived using methods independent of those based on SN Ia parameters. From the emission lines observed in their optical spectra, we derived the gas-phase oxygen abundance in the region where each SN Ia exploded. Our datamore » show a trend, with an 80% of chance not being due to random fluctuation, between SNe Ia absolute magnitudes and the oxygen abundances of the host galaxies, in the sense that luminosities tend to be higher for galaxies with lower metallicities. This result seems likely to be in agreement with both the theoretically expected behavior and with other observational results. This dependence M{sub B}–Z might induce systematic errors when it is not considered when deriving SNe Ia luminosities and then using them to derive cosmological distances.« less

The Faint End of the z = 5 Quasar Luminosity Function from the CFHTLS

NASA Astrophysics Data System (ADS)

McGreer, Ian D.; Fan, Xiaohui; Jiang, Linhua; Cai, Zheng

2018-03-01

We present results from a spectroscopic survey of z ∼ 5 quasars in the CFHT Legacy Survey. Using both optical color selection and a likelihood method, we select 97 candidates over an area of 105 deg2 to a limit of i AB < 23.2, and 7 candidates in the range 23.2 < i AB < 23.7 over an area of 18.5 deg2. Spectroscopic observations for 43 candidates were obtained with Gemini, MMT, and Large Binocular Telescope, of which 37 are z > 4 quasars. This sample extends measurements of the quasar luminosity function ∼1.5 mag fainter than our previous work in Sloan Digital Sky Survey Stripe 82. The resulting luminosity function is in good agreement with our previous results, and suggests that the faint end slope is not steep. We perform a detailed examination of our survey completeness, particularly the impact of the Lyα emission assumed in our quasar spectral models, and find hints that the observed Lyα emission from faint z ∼ 5 quasars is weaker than for z ∼ 3 quasars at a similar luminosity. Our results strongly disfavor a significant contribution of faint quasars to the hydrogen-ionizing background at z = 5.

SOLAR-LIKE OSCILLATIONS IN LOW-LUMINOSITY RED GIANTS: FIRST RESULTS FROM KEPLER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bedding, T. R.; Huber, D.; Stello, D.

2010-04-20

We have measured solar-like oscillations in red giants using time-series photometry from the first 34 days of science operations of the Kepler Mission. The light curves, obtained with 30 minute sampling, reveal clear oscillations in a large sample of G and K giants, extending in luminosity from the red clump down to the bottom of the giant branch. We confirm a strong correlation between the large separation of the oscillations ({delta}{nu}) and the frequency of maximum power ({nu}{sub max}). We focus on a sample of 50 low-luminosity stars ({nu}{sub max} > 100 {mu}Hz, L {approx}< 30 L {sub sun}) havingmore » high signal-to-noise ratios and showing the unambiguous signature of solar-like oscillations. These are H-shell-burning stars, whose oscillations should be valuable for testing models of stellar evolution and for constraining the star formation rate in the local disk. We use a new technique to compare stars on a single echelle diagram by scaling their frequencies and find well-defined ridges corresponding to radial and non-radial oscillations, including clear evidence for modes with angular degree l = 3. Measuring the small separation between l = 0 and l = 2 allows us to plot the so-called C-D diagram of {delta}{nu}{sub 02} versus {delta}{nu}. The small separation {delta}{nu}{sub 01} of l = 1 from the midpoint of adjacent l = 0 modes is negative, contrary to the Sun and solar-type stars. The ridge for l = 1 is notably broadened, which we attribute to mixed modes, confirming theoretical predictions for low-luminosity giants. Overall, the results demonstrate the tremendous potential of Kepler data for asteroseismology of red giants.« less

A Theoretical Study of the Luminosity-Temperature Relation for Clusters of Galaxies

NASA Astrophysics Data System (ADS)

Del Popolo, A.; Hiotelis, N.; Peñarrubia, J.

2005-07-01

A luminosity-temperature relation is derived for clusters of galaxies. The two models used take into account the angular momentum acquisition by the protostructures during their expansion and collapse. The first model is a modification of the self-similar model, while the second is a modification of the punctuated equilibria model of Cavaliere et al. In both models the mass-temperature relation (M-T) used is based on previous calculations of Del Popolo. We show that the above models lead, in X-rays, to a luminosity-temperature relation that scales as L~T5 at the scale of groups, flattening to L~T3 for rich clusters and converging to L~T2 at higher temperatures. However, a fundamental result of our paper is that the nonsimilarity in the L-T relation can be explained by a simple model that takes into account the amount of angular momentum of a protostructure. This result is in disagreement with the widely accepted idea that the nonsimilarity is due to nongravitating processes, such as heating and/or cooling.

Online Luminosity Measurement at CMS for Energy Frontier Physics after LS1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stickland, David P.

2015-09-20

This proposal was directed towards the measurement of Bunch-by-Bunch and Total Luminosity in the CMS experiment using Single-Crystal Diamond (sCVD) installed close to the Interaction Point - known as the Fast Beam Conditions Monitor, or BCM1F detector. The proposal was successfully carried out and in February 2015 CMS installed its upgraded BCM1F detector. At first collisions in June 2015 the BCM1F was used as the primary luminometer, then in August 2015 a Van De Meer scan has been carried out and the detailed luminometer calibration is under study. In all aspects of performance measurement the upgraded detector has satisfied itsmore » design parameters and as an overview of its performance in this report will show, we have high expectations that the detector will be a powerful addition to the luminosity measurement at CMS and LHC. The proposed upgrade of BCM1F was a collaboration of CMS Institutes in Germany (DESY-Zeuthen) and the USA (Princeton) and of CERN itself.« less

Stellar Populations in the Central 0.5 pc of the Galaxy. I. A New Method for Constructing Luminosity Functions and Surface-density Profiles

NASA Astrophysics Data System (ADS)

Do, T.; Lu, J. R.; Ghez, A. M.; Morris, M. R.; Yelda, S.; Martinez, G. D.; Wright, S. A.; Matthews, K.

2013-02-01

We present new high angular resolution near-infrared spectroscopic observations of the nuclear star cluster surrounding the Milky Way's central supermassive black hole. Using the integral-field spectrograph OSIRIS on Keck II behind the laser-guide-star adaptive optics system, this spectroscopic survey enables us to separate early-type (young, 4-6 Myr) and late-type (old, >1 Gyr) stars with a completeness of 50% down to K' = 15.5 mag, which corresponds to ~10 M ⊙ for the early-type stars. This work increases the radial extent of reported OSIRIS/Keck measurements by more than a factor of three from 4'' to 14'' (0.16 to 0.56 pc), along the projected disk of young stars. For our analysis, we implement a new method of completeness correction using a combination of star-planting simulations and Bayesian inference. We assign probabilities for the spectral type of every source detected in deep imaging down to K' = 15.5 mag using information from spectra, simulations, number counts, and the distribution of stars. The inferred radial surface-density profiles, Σ(R)vpropR -Γ, for the young stars and late-type giants are consistent with earlier results (Γearly = 0.93 ± 0.09, Γlate = 0.16 ± 0.07). The late-type surface-density profile is approximately flat out to the edge of the survey. While the late-type stellar luminosity function is consistent with the Galactic bulge, the completeness-corrected luminosity function of the early-type stars has significantly more young stars at faint magnitudes compared with previous surveys with similar depth. This luminosity function indicates that the corresponding mass function of the young stars is likely less top-heavy than that inferred from previous surveys.

New Evidence for a Substellar Luminosity Problem: Dynamical Mass for the Brown Dwarf Binary Gl 417BC

NASA Astrophysics Data System (ADS)

Dupuy, Trent J.; Liu, Michael C.; Ireland, Michael J.

2014-08-01

We present new evidence for a problem with cooling rates predicted by substellar evolutionary models that implies that model-derived masses in the literature for brown dwarfs and directly imaged planets may be too high. Based on our dynamical mass for Gl 417BC (L4.5+L6) and a gyrochronology system age from its young, solar-type host star, commonly used models predict luminosities 0.2-0.4 dex lower than we observe. This corroborates a similar luminosity-age discrepancy identified in our previous work on the L4+L4 binary HD 130948BC, which coincidentally has nearly identical component masses (≈50-55 M Jup) and age (≈800 Myr) as Gl 417BC. Such a luminosity offset would cause systematic errors of 15%-25% in model-derived masses at this age. After comparing different models, including cloudless models that should not be appropriate for mid-L dwarfs like Gl 417BC and HD 130948BC but actually match their luminosities better, we speculate the observed overluminosity could be caused by opacity holes (i.e., patchy clouds) in these objects. Moreover, from hybrid substellar evolutionary models that account for cloud disappearance, we infer the corresponding phase of overluminosity may extend from a few hundred million years up to a few gigayears and cause masses to be overestimated by up to 25%, even well after clouds disappear from view entirely. Thus, the range of ages and spectral types affected by this potential systematic shift in luminosity evolution would encompass most known directly imaged gas-giants and field brown dwarfs. Data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Jet or Shock Breakout? The Low-Luminosity GRB 060218

NASA Astrophysics Data System (ADS)

Irwin, Christopher; Chevalier, Roger

2016-01-01

We consider a model for the long-duration, low-luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The components of our model are: (1) a long-lived (tj ~ 3000 s) central engine and accompanying low-luminosity (Lj ~ 1045 erg s-1), mildly relativistic jet; (2) a low-mass (~ 10-2 Msun) envelope surrounding the progenitor star; and (3) a modest amount of dust (AV ~ 0.1) in the circumstellar or interstellar environment. Blackbody emission from the transparency radius in a low-power jet outflow can fit the prompt thermal X-ray emission, and the prompt nonthermal X-rays and γ-rays may be produced via Compton scattering of thermal photons from hot leptons in the jet interior or the external shocks. The later mildly relativistic phase of this outflow can produce the radio emission via synchrotron radiation from the forward shock. Meanwhile, interaction of the associated SN 2006aj with a circumstellar envelope extending to ~ 1013 cm can explain the early optical peak. The X-ray afterglow can be interpreted as a light echo of the prompt emission from dust at ~ 30 pc. Our model is a plausible alternative to that of Nakar, who recently proposed shock breakout of a jet smothered by an extended envelope as the source of prompt emission. Both our results and Nakar's suggest that ultra-long bursts such as GRB 060218 and GRB 100316D may originate from unusual progenitors with extended circumstellar envelopes, and that a jet is necessary to decouple the prompt high-energy emission from the supernova.

Jet or shock breakout? The low-luminosity GRB 060218

NASA Astrophysics Data System (ADS)

Irwin, Christopher M.; Chevalier, Roger A.

2016-08-01

We consider a model for the low-luminosity gamma-ray burst GRB 060218 that plausibly accounts for multiwavelength observations to day 20. The model components are: (1) a long-lived (tj ˜ 3000 s) central engine and accompanying low-luminosity (Lj ˜ 1047 erg s-1), mildly relativistic (γ ˜ 10) jet; (2) a low-mass (˜4 × 10-3 M⊙) envelope surrounding the progenitor star; and (3) a modest amount of dust (AV ˜ 0.1 mag) in the circumstellar or interstellar environment. Blackbody emission from the transparency radius in a low-power jet outflow can fit the prompt thermal X-ray emission, and the non-thermal X-rays and gamma-rays may be produced via Compton scattering of thermal photons from hot leptons in the jet interior or the external shocks. The later mildly relativistic phase of this outflow can produce the radio emission via synchrotron radiation from the forward shock. Meanwhile, interaction of the associated SN 2006aj with a circumstellar envelope extending to ˜1013 cm can explain the early optical emission. The X-ray afterglow can be interpreted as a light echo of the prompt emission from dust at ˜30 pc. Our model is a plausible alternative to that of Nakar, who recently proposed shock breakout of a jet smothered by an extended envelope as the source of prompt emission. Both our results and Nakar's suggest that bursts such as GRB 060218 may originate from unusual progenitors with extended circumstellar envelopes, and that a jet is necessary to decouple the prompt emission from the supernova.

Variable Stars in M13. II.The Red Variables and the Globular Cluster Period-Luminosity Relation

NASA Astrophysics Data System (ADS)

Osborn, W.; Layden, A.; Kopacki, G.; Smith, H.; Anderson, M.; Kelly, A.; McBride, K.; Pritzl, B.

2017-06-01

New CCD observations have been combined with archival data to investigate the nature of the red variables in the globular cluster M13. Mean magnitudes, colors and variation ranges on the UBVIC system have been determined for the 17 cataloged red variables. 15 of the stars are irregular or semi-regular variables that lie at the top of the red giant branch in the color-magnitude diagram. Two stars are not, including one with a well-defined period and a light curve shape indicating it is an ellipsoidal or eclipsing variable. All stars redder than (V-IC)0=1.38 mag vary, with the amplitudes being larger with increased stellar luminosity and with bluer filter passband. Searches of the data for periodicities yielded typical variability cycle times ranging from 30 d up to 92 d for the most luminous star. Several stars have evidence of multiple periods. The stars' period-luminosity diagram compared to those from microlensing survey data shows that most M13 red variables are overtone pulsators. Comparison with the diagrams for other globular clusters shows a correlation between red variable luminosity and cluster metallicity.

Period-luminosity relations for red supergiant variables - II. The distance to M101

NASA Astrophysics Data System (ADS)

Jurcevic, J. S.; Pierce, M. J.; Jacoby, G. H.

2000-04-01

We report the discovery of 42 red supergiant variables (RSVs) in the late-type spiral galaxy M101. Periods for the luminosity variation of these RSVs were determined from 20 epochs of ground-based CCD photometry in the Kron-Cousins R band obtained with the KPNO 2.1-m and WIYN 3.5-m telescopes over a span of three years. The periods found were in the range 200-1300days. Using the relationship between the RSV periods and their luminosity in the Kron-Cousins I band, we estimate a reddening-corrected distance modulus to M101 of 29.40+/-0.16mag (based on a distance modulus of 18.5+/-0.1mag for the Large Magellanic Cloud). This distance is consistent with the Hubble Space Telescope Key Project Cepheid distances of 29.34+/-0.17mag for the outer field of M101 and 29.21+/-0.17mag for the inner field.

MEASURING LENSING MAGNIFICATION OF QUASARS BY LARGE SCALE STRUCTURE USING THE VARIABILITY-LUMINOSITY RELATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bauer, Anne H.; Seitz, Stella; Jerke, Jonathan

2011-05-10

We introduce a technique to measure gravitational lensing magnification using the variability of type I quasars. Quasars' variability amplitudes and luminosities are tightly correlated, on average. Magnification due to gravitational lensing increases the quasars' apparent luminosity, while leaving the variability amplitude unchanged. Therefore, the mean magnification of an ensemble of quasars can be measured through the mean shift in the variability-luminosity relation. As a proof of principle, we use this technique to measure the magnification of quasars spectroscopically identified in the Sloan Digital Sky Survey (SDSS), due to gravitational lensing by galaxy clusters in the SDSS MaxBCG catalog. The Palomar-QUESTmore » Variability Survey, reduced using the DeepSky pipeline, provides variability data for the sources. We measure the average quasar magnification as a function of scaled distance (r/R{sub 200}) from the nearest cluster; our measurements are consistent with expectations assuming Navarro-Frenk-White cluster profiles, particularly after accounting for the known uncertainty in the clusters' centers. Variability-based lensing measurements are a valuable complement to shape-based techniques because their systematic errors are very different, and also because the variability measurements are amenable to photometric errors of a few percent and to depths seen in current wide-field surveys. Given the volume data of the expected from current and upcoming surveys, this new technique has the potential to be competitive with weak lensing shear measurements of large-scale structure.« less

Optical–Mid-infrared Period–Luminosity Relations for W UMa-type Contact Binaries Based on Gaia DR 1: 8% Distance Accuracy

NASA Astrophysics Data System (ADS)

Chen, Xiaodian; Deng, Licai; de Grijs, Richard; Wang, Shu; Feng, Yuting

2018-06-01

W Ursa Majoris (W UMa)-type contact binary systems (CBs) are useful statistical distance indicators because of their large numbers. Here, we establish (orbital) period–luminosity relations (PLRs) in 12 optical to mid-infrared bands (GBVRIJHK s W1W2W3W4) based on 183 nearby W UMa-type CBs with accurate Tycho–Gaia parallaxes. The 1σ dispersion of the PLRs decreases from optical to near- and mid-infrared wavelengths. The minimum scatter, 0.16 mag, implies that W UMa-type CBs can be used to recover distances to 7% precision. Applying our newly determined PLRs to 19 open clusters containing W UMa-type CBs demonstrates that the PLR and open cluster CB distance scales are mutually consistent to within 1%. Adopting our PLRs as secondary distance indicators, we compiled a catalog of 55,603 CB candidates, of which 80% have distance estimates based on a combination of optical, near-infrared, and mid-infrared photometry. Using Fourier decomposition, 27,318 high-probability W UMa-type CBs were selected. The resulting 8% distance accuracy implies that our sample encompasses the largest number of objects with accurate distances within a local volume with a radius of 3 kpc available to date. The distribution of W UMa-type CBs in the Galaxy suggests that in different environments, the CB luminosity function may be different: larger numbers of brighter (longer-period) W UMa-type CBs are found in younger environments.

Spectroscopy of luminous infrared galaxies at 2 microns: 1. The ultraluminous galaxies (L(sub IR) approximately greater than 10 (exp 12) solar luminosity)

NASA Technical Reports Server (NTRS)

Goldader, Jeffrey D.; Joseph, R. D.; Doyon, Rene; Sanders, D. B.

1995-01-01

We present high-quality spectra covering the K window at a resolving power of 340 for a sample of 13 ultraluminous (L(sub IR) approximately greater than 10(exp 12) solar luminosity) infrared-selected galaxies, and line fluxes for a comparison sample of 24 lower luminosity galaxies. The 2 micrometers spectra of 10 of the ultraluminous galaxies are characterized by emission and absorption features commonly associated with stars and star formation; two others have the red power-law spectra and Br gamma line widths of Seyfert 1 galaxies; the final galaxy has strong emission from hot dust. We have found no broad-line active nuclei not already known from optical observations, despite the fact that the extinction at 2 micrometers is 1/10 that at optical wavelengths; any putative Seyfert 1 nuclei must be deeply buried. Powerful continua and emission lines from H2 and Br gamma are detected in all the ultraluminous galaxies. Comparing the H2 1-0 S(1), Br gamma, and 2 micrometers and far-infrared luminosities to those of the lower luminosity galaxies yields several major results. First, the dereddened Br gamma emission, relative to the far-infrared luminosity is significantly depressed in the ultraluminous sample, when compared to the lower luminosity galaxies. Five of the ultraluminous galaxies have L(sub Br gamma)L(sub IR) ratios lower than for any of the comparison objects. Second, the H2 1-0 S(1) luminosity is also responsible, directly or indirectly, for producing the excited H2, and that the H2 apparently comes from optically thin regions in both classes of objects. Third, eight of the 13 ultraluminous systems have lower 2 micrometers/far-infrared luminosity ratios than any of the lower luminosity galaxies, and five of these are the galaxies also deficient in Br gamma. These three findings may be understood if the the H2, Br gamma, and 2 mircometers continua in the ultraluminous galaxies arise from spatially distinct regions, with the continuum and Br gamma largely

The detonation of a sub-Chandrasekhar-mass white dwarf at the origin of the low-luminosity Type Ia supernova 1999by

NASA Astrophysics Data System (ADS)

Blondin, Stéphane; Dessart, Luc; Hillier, D. John

2018-03-01

While Chandrasekhar-mass (MCh) models with a low 56Ni yield can match the peak luminosities of fast-declining, 91bg-like Type Ia supernovae (SNe Ia), they systematically fail to reproduce their faster light-curve evolution. Here, we illustrate the impact of a low ejecta mass on the radiative display of low-luminosity SNe Ia, by comparing a sub-MCh model resulting from the pure central detonation of a C-O white dwarf (WD) to an MCh delayed-detonation model with the same 56Ni yield of 0.12 M⊙. Our sub-MCh model from a 0.90 M⊙ WD progenitor has a ˜5 d shorter rise time in the integrated UV-optical-IR (uvoir) luminosity, as well as in the B band, and a ˜20 per cent higher peak uvoir luminosity (˜1 mag brighter peak MB). This sub-MCh model also displays bluer maximum-light colours due to the larger specific heating rate, and larger post-maximum uvoir and B-band decline rates. The luminosity decline at nebular times is also more pronounced, reflecting the enhanced escape of gamma rays resulting from the lower density of the progenitor WD. The deficit of stable nickel in the innermost ejecta leads to a notable absence of forbidden lines of [Ni II] in the nebular spectra. In contrast, the MCh model displays a strong line due to [Ni II] 1.939 μm, which could in principle serve to distinguish between different progenitor scenarios. Our sub-MCh model offers an unprecedented agreement with optical and near-infrared observations of the 91bg-like SN 1999by, making a strong case for a WD progenitor significantly below the Chandrasekhar-mass limit for this event and other low-luminosity SNe Ia.

The Faint End of the Quasar Luminosity Function at z ~ 4: Implications for Ionization of the Intergalactic Medium and Cosmic Downsizing

NASA Astrophysics Data System (ADS)

Glikman, Eilat; Djorgovski, S. G.; Stern, Daniel; Dey, Arjun; Jannuzi, Buell T.; Lee, Kyoung-Soo

2011-02-01

We present an updated determination of the z ~ 4 QSO luminosity function (QLF), improving the quality of the determination of the faint end of the QLF presented by Glikman et al. (2010). We have observed an additional 43 candidates from our survey sample, yielding one additional QSO at z = 4.23 and increasing the completeness of our spectroscopic follow-up to 48% for candidates brighter than R = 24 over our survey area of 3.76 deg2. We study the effect of using K-corrections to compute the rest-frame absolute magnitude at 1450 Å compared with measuring M 1450 directly from the object spectra. We find a luminosity-dependent bias: template-based K-corrections overestimate the luminosity of low-luminosity QSOs, likely due to their reliance on templates derived from higher luminosity QSOs. Combining our sample with bright quasars from the Sloan Digital Sky Survey and using spectrum-based M 1450 for all the quasars, we fit a double power law to the binned QLF. Our best fit has a bright-end slope, α = 3.3 ± 0.2, and faint-end slope, β = 1.6+0.8 -0.6. Our new data revise the faint-end slope of the QLF down to flatter values similar to those measured at z ~ 3. The break luminosity, though poorly constrained, is at M* = -24.1+0.7 -1.9, approximately 1-1.5 mag fainter than at z ~ 3. This QLF implies that QSOs account for about half the radiation needed to ionize the intergalactic medium at these redshifts. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Study of Swift/Bat Selected Low-luminosity Active Galactic Nuclei Observed with Suzaku

NASA Astrophysics Data System (ADS)

Kawamuro, Taiki; Ueda, Yoshihiro; Tazaki, Fumie; Terashima, Yuichi; Mushotzky, Richard

2016-11-01

We systematically analyze the broadband (0.5-200 keV) X-ray spectra of hard X-ray (>10 keV) selected local low-luminosity active galactic nuclei (LLAGNs) observed with Suzaku and Swift/BAT. The sample consists of 10 LLAGNs detected with Swift/BAT with intrinsic 14-195 keV luminosities smaller than 1042 erg s-1 available in the Suzaku archive, covering a wide range of the Eddington ratio from 10-5 to 10-2. The overall spectra can be reproduced with an absorbed cut-off power law, often accompanied by reflection components from distant cold matter, and/or optically thin thermal emission from the host galaxy. In all of the objects, relativistic reflection components from the innermost disk are not required. Eight objects show a significant narrow iron-Kα emission line. Comparing their observed equivalent widths with the predictions from the Monte-Carlo-based torus model by Ikeda et al. (2009), we constrain the column density in the equatorial plane to be {log} {N}{{H}}{{eq}}\\gt 22.7, or the torus half-opening angle θ oa < 70°. We infer that the Eddington ratio (λ Edd) is a key parameter that determines the torus structure of LLAGNs: the torus becomes large at λ Edd ≳ 2 × 10-4, whereas at lower accretion rates it is little developed. The luminosity correlation between the hard X-ray and mid-infrared (MIR) bands of the LLAGNs follows the same correlation as for more luminous AGNs. This implies that mechanisms other than AGN-heated dust are responsible for the MIR emission in low Eddington ratio LLAGNs.

Gaia luminosities of pulsating A-F stars in the Kepler field

NASA Astrophysics Data System (ADS)

Balona, L. A.

2018-06-01

All stars in the Kepler field brighter than 12.5 magnitude have been classified according to variability type. A catalogue of δ Scuti and γ Doradus stars is presented. The problem of low frequencies in δ Sct stars, which occurs in over 98 percent of these stars, is discussed. Gaia DR2 parallaxes were used to obtain precise luminosities, enabling the instability strips of the two classes of variable to be precisely defined. Surprisingly, it turns out that the instability region of the γ Dor stars is entirely within the δ Sct instability strip. Thus γDor stars should not be considered a separate class of variable. The observed red and blue edges of the instability strip do not agree with recent model calculations. Stellar pulsation occurs in less than half of the stars in the instability region and arguments are presented to show that this cannot be explained by assuming pulsation at a level too low to be detected. Precise Gaia DR2 luminosities of high-amplitude δ Sct stars (HADS) show that most of these are normal δ Sct stars and not transition objects. It is argued that current ideas on A star envelopes need to be revised.

Panchromatic spectral energy distributions of Herschel sources

NASA Astrophysics Data System (ADS)

Berta, S.; Lutz, D.; Santini, P.; Wuyts, S.; Rosario, D.; Brisbin, D.; Cooray, A.; Franceschini, A.; Gruppioni, C.; Hatziminaoglou, E.; Hwang, H. S.; Le Floc'h, E.; Magnelli, B.; Nordon, R.; Oliver, S.; Page, M. J.; Popesso, P.; Pozzetti, L.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Roseboom, I.; Scott, D.; Symeonidis, M.; Valtchanov, I.; Viero, M.; Wang, L.

2013-03-01

Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S, and COSMOS fields, it is possible to sample the 8-500 μm spectral energy distributions (SEDs) of galaxies with at least 7-10 bands. Extending to the UV, optical, and near-infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected restframe ten colors space, based on this rich data-set, using a superposition of multivariate Gaussian modes. We use this model to classify galaxies and build median SEDs of each class, which are then fitted with a modified version of the magphys code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an active galactic nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6-9 classes, spanning a large range of far- to near-infrared luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z ~ 1 Ly-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eightother popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10-20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of

Infrared Luminosities and Dust Properties of z ≈ 2 Dust-obscured Galaxies

NASA Astrophysics Data System (ADS)

Bussmann, R. S.; Dey, Arjun; Borys, C.; Desai, V.; Jannuzi, B. T.; Le Floc'h, E.; Melbourne, J.; Sheth, K.; Soifer, B. T.

2009-11-01

We present SHARC-II 350 μm imaging of twelve 24 μm bright (F 24 μm > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Boötes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 μm imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 μm flux density. The 350 μm upper limits for the 8 non-detected DOGs are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T dust > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of ≈3 × 108 M sun. In comparison to other dusty z ~ 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 × 1013 L sun versus 6 × 1012 L sun for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus ~30 K) and lower inferred dust masses (3 × 108 M sun versus 3 × 109 M sun). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 μm bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive galaxies at z ~ 2 involves a submillimeter bright, cold-dust, and star

INFRARED LUMINOSITIES AND DUST PROPERTIES OF z approx 2 DUST-OBSCURED GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bussmann, R. S.; Dey, Arjun; Jannuzi, B. T.

We present SHARC-II 350 mum imaging of twelve 24 mum bright (F{sub 24m}u{sub m} > 0.8 mJy) Dust-Obscured Galaxies (DOGs) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) 1 mm imaging of a subset of two DOGs. These objects are selected from the Booetes field of the NOAO Deep Wide-Field Survey. Detections of four DOGs at 350 mum imply infrared (IR) luminosities which are consistent to within a factor of 2 of expectations based on a warm-dust spectral energy distribution (SED) scaled to the observed 24 mum flux density. The 350 mum upper limits for the 8 non-detected DOGsmore » are consistent with both Mrk 231 and M82 (warm-dust SEDs), but exclude cold dust (Arp 220) SEDs. The two DOGs targeted at 1 mm were not detected in our CARMA observations, placing strong constraints on the dust temperature: T{sub dust} > 35-60 K. Assuming these dust properties apply to the entire sample, we find dust masses of approx3 x 10{sup 8} M{sub sun}. In comparison to other dusty z approx 2 galaxy populations such as submillimeter galaxies (SMGs) and other Spitzer-selected high-redshift sources, this sample of DOGs has higher IR luminosities (2 x 10{sup 13} L{sub sun} versus 6 x 10{sup 12} L{sub sun} for the other galaxy populations) that are driven by warmer dust temperatures (>35-60 K versus approx30 K) and lower inferred dust masses (3 x 10{sup 8} M{sub sun} versus 3 x 10{sup 9} M{sub sun}). Wide-field Herschel and Submillimeter Common-User Bolometer Array-2 surveys should be able to detect hundreds of these power-law-dominated DOGs. We use the existing Hubble Space Telescope and Spitzer/InfraRed Array Camera data to estimate stellar masses of these sources and find that the stellar to gas mass ratio may be higher in our 24 mum bright sample of DOGs than in SMGs and other Spitzer-selected sources. Although much larger sample sizes are needed to provide a definitive conclusion, the data are consistent with an evolutionary trend in which the formation of massive

Galactic bulge population II Cepheids in the VVV survey: period-luminosity relations and a distance to the Galactic centre

NASA Astrophysics Data System (ADS)

Bhardwaj, A.; Rejkuba, M.; Minniti, D.; Surot, F.; Valenti, E.; Zoccali, M.; Gonzalez, O. A.; Romaniello, M.; Kanbur, S. M.; Singh, H. P.

2017-09-01

spatial distribution, similar to metal-poor RR Lyrae variables. We do not find evidence of the inclined bar as traced by the metal-rich red-clump stars. Conclusions: Population II Cepheid and RR Lyrae variables follow similar period-luminosity relations and trace the same metal-poor old population in the Galactic bulge. The number density for population II Cepheids is more limited as compared to abundant RR Lyraes but they are bright and exhibit a wide range in period that provides a robust period-luminosity relation for an accurate estimate of the distance to the Galactic centre. The full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A100

PRIMUS: Galaxy clustering as a function of luminosity and color at 0.2 < z < 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skibba, Ramin A.; Smith, M. Stephen M.; Coil, Alison L.

2014-04-01

We present measurements of the luminosity and color-dependence of galaxy clustering at 0.2 < z < 1.0 in the Prism Multi-object Survey. We quantify the clustering with the redshift-space and projected two-point correlation functions, ξ(r{sub p} , π) and w{sub p} (r{sub p} ), using volume-limited samples constructed from a parent sample of over ∼130, 000 galaxies with robust redshifts in seven independent fields covering 9 deg{sup 2} of sky. We quantify how the scale-dependent clustering amplitude increases with increasing luminosity and redder color, with relatively small errors over large volumes. We find that red galaxies have stronger small-scale (0.1more » Mpc h {sup –1} < r{sub p} < 1 Mpc h {sup –1}) clustering and steeper correlation functions compared to blue galaxies, as well as a strong color dependent clustering within the red sequence alone. We interpret our measured clustering trends in terms of galaxy bias and obtain values of b {sub gal} ≈ 0.9-2.5, quantifying how galaxies are biased tracers of dark matter depending on their luminosity and color. We also interpret the color dependence with mock catalogs, and find that the clustering of blue galaxies is nearly constant with color, while redder galaxies have stronger clustering in the one-halo term due to a higher satellite galaxy fraction. In addition, we measure the evolution of the clustering strength and bias, and we do not detect statistically significant departures from passive evolution. We argue that the luminosity- and color-environment (or halo mass) relations of galaxies have not significantly evolved since z ∼ 1. Finally, using jackknife subsampling methods, we find that sampling fluctuations are important and that the COSMOS field is generally an outlier, due to having more overdense structures than other fields; we find that 'cosmic variance' can be a significant source of uncertainty for high-redshift clustering measurements.« less

A Catalog of Candidate Intermediate-Luminosity X-Ray Objects

NASA Astrophysics Data System (ADS)

Colbert, E. J. M.; Ptak, A. F.

2002-11-01

ROSAT, and now Chandra, X-ray images allow studies of extranuclear X-ray point sources in galaxies other than our own. X-ray observations of normal galaxies with ROSAT and Chandra have revealed that off-nuclear, compact, intermediate-luminosity (LX[2-10keV]>=1039.0 ergs s-1) X-ray objects (IXOs, a.k.a. ULXs [ultraluminous X-ray sources]) are quite common. Here we present a catalog and finding charts for 87 IXOs in 54 galaxies, derived from all of the ROSAT HRI imaging data for galaxies with cz<=5000 km s-1 from the Third Reference Catalog of Bright Galaxies. We have defined the cutoff LX for IXOs so that it is well above the Eddington luminosity of a 1.4 Msolar black hole (1038.3 ergs s-1), so as not to confuse IXOs with ``normal'' black hole X-ray binaries. This catalog is intended to provide a baseline for follow-up work with Chandra and XMM-Newton, and with space- and ground-based survey work at wavelengths other than X-ray. We demonstrate that elliptical galaxies with IXOs have a larger number of IXOs per galaxy than nonelliptical galaxies with IXOs and note that they are not likely to be merely high-mass X-ray binaries with beamed X-ray emission, as may be the case for IXOs in starburst galaxies. Approximately half of the IXOs with multiple observations show X-ray variability, and many (19) of the IXOs have faint optical counterparts in DSS optical B-band images. Follow-up observations of these objects should be helpful in identifying their nature.

Present limits for the luminosity, the beam current and the beam lifetime in Doris II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesemann, H.; Sarau, B.

1985-10-01

The e e storage ring DORIS II has been operating for high energy physics experiments in the region of the Y resonances around 2x5 GeV and as a source for synchrotron radiation near 3.7 GeV. A luminosity of nearly 3x10T cm Ssec or more than 1500 (nb) /day has been achieved. For synchrotron radiation e -currents of about 100 mA are stored in 4 bunches (out of 480 buckets). As long as the beam-beam interaction does not limit the luminosity the optimum performance of the ring is obtained for both modes of operation if the currents stored are large, themore » cross section of the beam is small and the lifetime is long. Thus we concentrate the discussion on these subjects.« less

Searching for intermediate-mass black holes in galaxies with low-luminosity AGN: a multiple-method approach

NASA Astrophysics Data System (ADS)

Koliopanos, F.; Ciambur, B.; Graham, A.; Webb, N.; Coriat, M.; Mutlu-Pakdil, B.; Davis, B.; Godet, O.; Barret, D.; Seigar, M.

2017-10-01

Intermediate Mass Black Holes (IMBHs) are predicted by a variety of models and are the likely seeds for super massive BHs (SMBHs). However, we have yet to establish their existence. One method, by which we can discover IMBHs, is by measuring the mass of an accreting BH, using X-ray and radio observations and drawing on the correlation between radio luminosity, X-ray luminosity and the BH mass, known as the fundamental plane of BH activity (FP-BH). Furthermore, the mass of BHs in the centers of galaxies, can be estimated using scaling relations between BH mass and galactic properties. We are initiating a campaign to search for IMBH candidates in dwarf galaxies with low-luminosity AGN, using - for the first time - three different scaling relations and the FP-BH, simultaneously. In this first stage of our campaign, we measure the mass of seven LLAGN, that have been previously suggested to host central IMBHs, investigate the consistency between the predictions of the BH scaling relations and the FP-BH, in the low mass regime and demonstrate that this multiple method approach provides a robust average mass prediction. In my talk, I will discuss our methodology, results and next steps of this campaign.

The Unbiased Velocity Distribution of Neutron Stars from a Simulation of Pulsar Surveys

NASA Astrophysics Data System (ADS)

Arzoumanian, Z.; Cordes, J. M.; Chernoff, D.

1997-12-01

We present the results of a new simulation of the Galactic population of neutron stars: their birthrate, velocity distribution, luminosities, beaming characteristics, and spin evolution. The many simulations in the literature differ from one another primarily in their treatment of the selection effects associated with pulsar detection. Our method, the most realistic to date, goes beyond earlier efforts by retaining the full kinematic, rotational, luminosity, and beaming evolution of each simulated star: ``Monte-Carlo'' neutron stars are created according to assumed distributions (at birth) in spatial coordinates, kick velocity, and magnitudes and orientations of the spin and magnetic field vectors. The neutron stars spin down following an assumed braking law, and their Galactic trajectories are traced to the present epoch. For each star, a pulse waveform is generated using a phenomenological radio-beam model, obviating the need for an arbitrary beaming fraction. Luminosity is assumed to be a parameterized function of period and spin-down rate, with no intrinsic spread, and a parameterized death-line is applied. Interstellar dispersion and scattering consistent with survey instrumentation and the galactic locales of the neutron stars are applied to the pulse waveforms, which are Fourier analyzed and tested for detection following the techniques of real-world surveys. A unique algorithm is used to compare the populations of simulated and known, non-millisecond, pulsars in the multi-dimensional space of observables (any subset of galactic coordinates, dispersion measure, period, spin-down rate, flux, and proper motion). Model parameters are varied, and statistically independent neutron star populations are created until a maximum likelihood model is found. The highlight of this effort is an unbiased determination of the velocity distribution of neutron stars. We discuss the implications of our results for supernova physics, binary evolution, and the nature of gamma

High-resolution observations of low-luminosity gigahertz-peaked spectrum and compact steep-spectrum sources

NASA Astrophysics Data System (ADS)

Collier, J. D.; Tingay, S. J.; Callingham, J. R.; Norris, R. P.; Filipović, M. D.; Galvin, T. J.; Huynh, M. T.; Intema, H. T.; Marvil, J.; O'Brien, A. N.; Roper, Q.; Sirothia, S.; Tothill, N. F. H.; Bell, M. E.; For, B.-Q.; Gaensler, B. M.; Hancock, P. J.; Hindson, L.; Hurley-Walker, N.; Johnston-Hollitt, M.; Kapińska, A. D.; Lenc, E.; Morgan, J.; Procopio, P.; Staveley-Smith, L.; Wayth, R. B.; Wu, C.; Zheng, Q.; Heywood, I.; Popping, A.

2018-06-01

We present very long baseline interferometry observations of a faint and low-luminosity (L1.4 GHz < 1027 W Hz-1) gigahertz-peaked spectrum (GPS) and compact steep-spectrum (CSS) sample. We select eight sources from deep radio observations that have radio spectra characteristic of a GPS or CSS source and an angular size of θ ≲ 2 arcsec, and detect six of them with the Australian Long Baseline Array. We determine their linear sizes, and model their radio spectra using synchrotron self-absorption (SSA) and free-free absorption (FFA) models. We derive statistical model ages, based on a fitted scaling relation, and spectral ages, based on the radio spectrum, which are generally consistent with the hypothesis that GPS and CSS sources are young and evolving. We resolve the morphology of one CSS source with a radio luminosity of 10^{25} W Hz^{-1}, and find what appear to be two hotspots spanning 1.7 kpc. We find that our sources follow the turnover-linear size relation, and that both homogeneous SSA and an inhomogeneous FFA model can account for the spectra with observable turnovers. All but one of the FFA models do not require a spectral break to account for the radio spectrum, while all but one of the alternative SSA and power-law models do require a spectral break to account for the radio spectrum. We conclude that our low-luminosity sample is similar to brighter samples in terms of their spectral shape, turnover frequencies, linear sizes, and ages, but cannot test for a difference in morphology.

The infrared luminosity function of AKARI 90 μm galaxies in the local Universe

NASA Astrophysics Data System (ADS)

Kilerci Eser, Ece; Goto, Tomotsugu

2018-03-01

Local infrared (IR) luminosity functions (LFs) are necessary benchmarks for high-redshift IR galaxy evolution studies. Any accurate IR LF evolution studies require accordingly accurate local IR LFs. We present IR galaxy LFs at redshifts of z ≤ 0.3 from AKARI space telescope, which performed an all-sky survey in six IR bands (9, 18, 65, 90, 140, and 160 μm) with 10 times better sensitivity than its precursor Infrared Astronomical Satellite. Availability of 160 μm filter is critically important in accurately measuring total IR luminosity of galaxies, covering across the peak of the dust emission. By combining data from Wide-field Infrared Survey Explorer (WISE), Sloan Digital Sky Survey (SDSS) Data Release 13 (DR 13), six-degree Field Galaxy Survey and the 2MASS Redshift Survey, we created a sample of 15 638 local IR galaxies with spectroscopic redshifts, factor of 7 larger compared to previously studied AKARI-SDSS sample. After carefully correcting for volume effects in both IR and optical, the obtained IR LFs agree well with previous studies, but comes with much smaller errors. Measured local IR luminosity density is ΩIR = 1.19 ± 0.05 × 108L⊙ Mpc-3. The contributions from luminous IR galaxies and ultraluminous IR galaxies to ΩIR are very small, 9.3 per cent and 0.9 per cent, respectively. There exists no future all-sky survey in far-IR wavelengths in the foreseeable future. The IR LFs obtained in this work will therefore remain an important benchmark for high-redshift studies for decades.

Differential evolution of the UV luminosity function of Lyman break galaxies from z ~ 5 to 3

NASA Astrophysics Data System (ADS)

Iwata, I.; Ohta, K.; Tamura, N.; Akiyama, M.; Aoki, K.; Ando, M.; Kiuchi, G.; Sawicki, M.

2007-04-01

We report the ultraviolet luminosity function (UVLF) of Lyman break galaxies at z ~ 5 derived from a deep and wide survey using the prime focus camera of the 8.2 m Subaru telescope (Suprime-Cam). Target fields consist of two blank regions of the sky, namely, the region including the Hubble Deep Field-North and the J0053+1234 region, and the total effective surveyed area is 1290 arcmin2. Applications of carefully determined colour selection criteria in V - Ic and Ic - z' yield a detection of 853 z ~ 5 candidates with z'AB < 26.5 mag. The UVLF at z ~ 5 based on this sample shows no significant change in the number density of bright (L >~ L*z=3) LBGs from that at z ~ 3, while there is a significant decline in the LF's faint end with increasing look-back time. This result means that the evolution of the number densities is differential with UV luminosity: the number density of UV luminous objects remains almost constant from z ~ 5 to 3 (the cosmic age is about 1.2 to 2.1 Gyr) while the number density of fainter objects gradually increases with cosmic time. This trend becomes apparent thanks to the small uncertainties in number densities both in the bright and faint parts of LFs at different epochs that are made possible by the deep and wide surveys we use. We discuss the origins of this differential evolution of the UVLF along the cosmic time and suggest that our observational findings are consistent with the biased galaxy evolution scenario: a galaxy population hosted by massive dark haloes starts active star formation preferentially at early cosmic time, while less massive galaxies increase their number density later. We also calculated the UV luminosity density by integrating the UVLF and at z ~ 5 found it to be 38.8+6.7-4.1 per cent of that at z ~ 3 for the luminosity range L > 0.1L*z=3. By combining our results with those from the literature, we find that the cosmic UV luminosity density marks its peak at and then slowly declines towards higher redshift. Based on

Calibrating the Decline Rate - Peak Luminosity Relation for Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Rust, Bert W.; Pruzhinskaya, Maria V.; Thijsse, Barend J.

2015-08-01

The correlation between peak luminosity and rate of decline in luminosity for Type I supernovae was first studied by B. W. Rust [Ph.D. thesis, Univ. of Illinois (1974) ORNL-4953] and Yu. P. Pskovskii [Sov. Astron., 21 (1977) 675] in the 1970s. Their work was little-noted until Phillips rediscovered the correlation in 1993 [ApJ, 413 (1993) L105] and attempted to derive a calibration relation using a difference quotient approximation Δm15(B) to the decline rate after peak luminosity Mmax(B). Numerical differentiation of data containing measuring errors is a notoriously unstable calculation, but Δm15(B) remains the parameter of choice for most calibration methods developed since 1993. To succeed, it should be computed from good functional fits to the lightcurves, but most workers never exhibit their fits. In the few instances where they have, the fits are not very good. Some of the 9 supernovae in the Phillips study required extinction corrections in their estimates of the Mmax(B), and so were not appropriate for establishing a calibration relation. Although the relative uncertainties in his Δm15(B) estimates were comparable to those in his Mmax(B) estimates, he nevertheless used simple linear regression of the latter on the former, rather than major-axis regression (total least squares) which would have been more appropriate.Here we determine some new calibration relations using a sample of nearby "pure" supernovae suggested by M. V. Pruzhinskaya [Astron. Lett., 37 (2011) 663]. Their parent galaxies are all in the NED collection, with good distance estimates obtained by several different methods. We fit each lightcurve with an optimal regression spline obtained by B. J. Thijsse's spline2 [Comp. in Sci. & Eng., 10 (2008) 49]. The fits, which explain more that 99% of the variance in each case, are better than anything heretofore obtained by stretching "template" lightcurves or fitting combinations of standard lightcurves. We use the fits to compute estimates of �

Dependence of the Broad Absorption Line Quasar Fraction on Radio Luminosity

NASA Astrophysics Data System (ADS)

Shankar, Francesco; Dai, Xinyu; Sivakoff, Gregory R.

2008-11-01

We find that the fraction of classical broad absorption line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5+ 7.3-5.9% at the faintest radio powers detected (L1.4 GHz ~ 1032 erg s-1), and rapidly drops to lesssim8% at L1.4 GHz ~ 3 × 1033 erg s-1. Similarly, adopting the broader absorption index (AI) definition of Trump et al., we find the fraction of radio BALQSOs to be 44+ 8.1-7.8%, reducing to 23.1+ 7.3-6.1% at high luminosities. While the high fraction at low radio power is consistent with the recent near-IR estimates by Dai et al., the lower fraction at high radio powers is intriguing and confirms previous claims based on smaller samples. The trend is independent of the redshift range, the optical and radio flux selection limits, or the exact definition of a radio match. We also find that at fixed optical magnitude, the highest bins of radio luminosity are preferentially populated by non-BALQSOs, consistent with the overall trend. We do find, however, that those quasars identified as AI-BALQSOs but not under the classical definition do not show a significant drop in their fraction as a function of radio power, further supporting independent claims that these sources, characterized by lower equivalent width, may represent an independent class from the classical BALQSOs. We find the balnicity index, a measure of the absorption trough in BALQSOs, and the mean maximum wind velocity to be roughly constant at all radio powers. We discuss several plausible physical models which may explain the observed fast drop in the fraction of the classical BALQSOs with increasing radio power, although none is entirely satisfactory. A strictly evolutionary model for the BALQSO and radio emission phases requires a strong fine-tuning to work, while a simple geometric model, although still not capable of explaining polar BALQSOs and the paucity of FRII BALQSOs, is statistically successful in matching the data if part of the apparent radio

Anti-correlation between X-ray luminosity and pulsed fraction in the Small Magellanic Cloud pulsar SXP 1323

NASA Astrophysics Data System (ADS)

Yang, Jun; Zezas, Andreas; Coe, Malcolm J.; Drake, Jeremy J.; Hong, JaeSub; Laycock, Silas G. T.; Wik, Daniel R.

2018-05-01

We report the evidence for the anti-correlation between pulsed fraction (PF) and luminosity of the X-ray pulsar SXP 1323, found for the first time in a luminosity range 1035-1037 erg s-1 from observations spanning 15 years. The phenomenon of a decrease in X-ray PF when the source flux increases has been observed in our pipeline analysis of other X-ray pulsars in the Small Magellanic Cloud (SMC). It is expected that the luminosity under a certain value decreases as the PF decreases due to the propeller effect. Above the propeller region, an anti-correlation between the PF and flux might occur either as a result of an increase in the un-pulsed component of the total emission or a decrease of the pulsed component. Additional modes of accretion may also be possible, such as spherical accretion and a change in emission geometry. At higher mass accretion rates, the accretion disk could also extend closer to the neutron star (NS) surface, where a reduced inner radius leads to hotter inner disk emission. These modes of plasma accretion may affect the change in the beam configuration to fan-beam dominant emission.

X-ray View of Four High-Luminosity Swift-BAT AGN: Unveiling Obscuration and Reflection with Suzaku

NASA Technical Reports Server (NTRS)

Fiorettil, V.; Angelini, L.; Mushotzky, R. F.; Koss, M.; Malaguti, G.

2013-01-01

Aims. A complete census of obscured Active Galactic Nuclei (AGN) is necessary to reveal the history of the super massive black hole (SMBH) growth and galaxy evolution in the Universe given the complex feedback processes and the fact that much of this growth occurs in an obscured phase. In this context, hard X-ray surveys and dedicated follow-up observations represent a unique tool for selecting highly absorbed AGN and for characterizing the obscuring matter surrounding the SMBH. Here we focus on the absorption and reflection occurring in highly luminous, quasar-like AGN, to study the relation between the geometry of the absorbing matter and the AGN nature (e.g. X-ray, optical, and radio properties), and to help to determine the column density dependency on the AGN luminosity. Methods. The Swift/BAT nine-month survey observed 153 AGN, all with ultra-hard X-ray BAT fluxes in excess of 10(exp -11) erg per square centimeter and an average redshift of 0.03. Among them, four of the most luminous BAT AGN (44.73 less than LogLBAT less than 45.31) were selected as targets of Suzaku follow-up observations: J2246.0+3941 (3C 452), J0407.4+0339 (3C 105), J0318.7+6828, and J0918.5+0425. The column density, scattered/reflected emission, the properties of the Fe K line, and a possible variability are fully analyzed. For the latter, the spectral properties from Chandra, XMM-Newton and Swift/XRT public observations were compared with the present Suzaku analysis, adding an original spectral analysis when non was available from the literature. Results. Of our sample, 3C 452 is the only certain Compton-thick AGN candidate because of i) the high absorption (N(sub H) approximately 4 × 10(exp 23) per square centimeter) and strong Compton reflection; ii) the lack of variability; iii) the "buried" nature, i.e. the low scattering fraction (less than 0.5%) and the extremely low relative [OIII] luminosity. In contrast 3C 105 is not reflection-dominated, despite the comparable column density

Optical Variability Properties of High Luminosity AGN Classes

NASA Astrophysics Data System (ADS)

Stalin, C. S.; Gopal Krishna; Sagar, Ram; Wiita, Paul J.

2004-03-01

We present the results of a comparative study of the intranight optical variability (INOV) characteristics of radio-loud and radioquiet quasars, which involves a systematic intra-night optical monitoring of seven sets of high luminosity AGNs covering the redshift range z ' 0:2 to z ' 2:2. The sample, matched in the optical luminosity - redshift .MB?z/ plane, consists of seven radio-quiet quasars (RQQs), eight radio lobedominated quasars (LDQs), five radio core-dominated quasars (CDQs) and six BL Lac objects (BLs). Systematic CCD observations, aided by a careful data analysis procedure, have allowed us to detect INOV with amplitudes as low as about 1%. Present observations cover a total of 113 nights (720 hours) with only a single quasar monitored as continuously as possible on a given night. Considering the cases of only unambiguous detections of INOV we have estimated duty cycles (DCs) of 17%, 12%, 20% and 61% for RQQs, LDQs, CDQs, and BLs, respectively. The much lower amplitude and DC of INOV shown by RQQs compared to BLs may be understood in terms of their having optical synchrotron jets which are modestly misdirected from us. From our fairly extensive dataset, no general trend of a correlation between the INOVamplitude and the apparent optical brightness of the quasar is noticed. This suggests that the physical mechanisms of INOV and long term optical variability (LTOV) do not have a one-to-one relationship and different factors are involved. Also, the absence of a clear negative correlation between the INOV and LTOV characteristics of blazars of our sample points toward an inconspicuous contribution of accretion disk fluctuations to the observed INOV. The INOVduty cycle of theAGNs observed in this program suggests that INOV is associated predominantly with the highly polarized optical emission components. We also report new VLA imaging of two RQQs .1029C329&1252C020/ in our sample which has yielded a 5 GHz detection in one of them .1252 C 020I S5 GHz ' 1 mJy/.

YOUNG STELLAR CLUSTERS WITH A SCHUSTER MASS DISTRIBUTION. I. STATIONARY WINDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palous, Jan; Wuensch, Richard; Hueyotl-Zahuantitla, Filiberto

2013-08-01

Hydrodynamic models for spherically symmetric winds driven by young stellar clusters with a generalized Schuster stellar density profile are explored. For this we use both semi-analytic models and one-dimensional numerical simulations. We determine the properties of quasi-adiabatic and radiative stationary winds and define the radius at which the flow turns from subsonic to supersonic for all stellar density distributions. Strongly radiative winds significantly diminish their terminal speed and thus their mechanical luminosity is strongly reduced. This also reduces their potential negative feedback into their host galaxy interstellar medium. The critical luminosity above which radiative cooling becomes dominant within the clusters,more » leading to thermal instabilities which make the winds non-stationary, is determined, and its dependence on the star cluster density profile, core radius, and half-mass radius is discussed.« less

Model-dependence of neutrino emissivities and neutrino luminosities of neutron stars from the direct Urca processes and the modified Urca processes

NASA Astrophysics Data System (ADS)

Yin, Peng; Fan, Xiaohua; Dong, Jianmin; Guo, Wenmei; Zuo, Wei

2017-05-01

The neutrino emissivities in β-stable neutron star matter from the direct Urca (DU) processes and the modified Urca (MU) processes have been investigated by adopting 26 Skyrme interactions. Several physical quantities related to the MU processes and the DU processes have been calculated and discussed. The model-dependence of the neutrino emissivities from the DU processes is found to stem mainly from the model-dependence of the effective mass, while the neutrino emissivities from the MU processes are determined by the competition between the effects of the symmetry energy and the effective mass. Besides, we have investigated the total neutrino luminosities of neutron stars, with the masses of 1.2 , 1.4 , 1.6 and 1.8M⊙, from the DU processes and the MU processes. The neutrino luminosity of a neutron star is found to be primarily determined by whether the electron DU process is allowed or not. As long as the electron DU process can occur, the total luminosity turns out to be 5 to 8 orders of magnitude larger as compared with the case that the DU process is forbidden, which indicates that the strongest model-dependence of the neutrino luminosity comes from that of the symmetry energy and the equation of state (EOS) of neutron star matter. In the case that the DU processes are allowed, the discrepancy of the calculated neutrino luminosity using various Skyrme interactions remains noticeable, which is essentially attributed to the model-dependence of the symmetry energy, the EOS of NS matter and the effective masses.

Support Structure Design of the $$\\hbox{Nb}_{3}\\hbox{Sn}$$ Quadrupole for the High Luminosity LHC

DOE PAGES

Juchno, M.; Ambrosio, G.; Anerella, M.; ...

2014-10-31

New low-β quadrupole magnets are being developed within the scope of the High Luminosity LHC (HL-LHC) project in collaboration with the US LARP program. The aim of the HLLHC project is to study and implement machine upgrades necessary for increasing the luminosity of the LHC. The new quadrupoles, which are based on the Nb₃Sn superconducting technology, will be installed in the LHC Interaction Regions and will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. In this paper, we describe the design of the short model magnet support structure and discuss results of themore » detailed 3D numerical analysis performed in preparation for the first short model test.« less

Integral luminosities of radio pulsars

NASA Astrophysics Data System (ADS)

Malov, I.; Malov, O.

The integral radio luminosities L for 311 normal pulsars and for 27 ones with the rotation period P<0.1 s (fast pulsars) are calculated using new data on their compilated spectra. The values of L lie in the range 10^27-10^30 erg/s for 88% of the normal pulsars and in the range 10^28-10^31 erg/s for 88% of the fast objects. The high correlation between L and estimates l=S x d^2 from the known catalogues is detected. It is shown that the coefficient K of a transformation of the neutron star rotation energy into radio emission increases when P grows for normal pulsars and falls for fast ones. The mean values of K are -3.73 and -4.85 for normal and fast pulsars, respectively. There are no changes of L with the kinematic age T = z/V, where z is the pulsar height over the Galactic plane and V = 300 km/s is its mean velocity. The correlation between L and the rate of the rotation energy losses E is detected for both pulsar groups under consideration. It is shown that L= A E^(1/3) for the whole sample. The total number of pulsars in the Galaxy and their birth rate are in agreement with data on the rate of supernova explosions.

The luminosity function at the end of the main sequence: Results of a deep, large-area, CCD survey for cool dwarfs

NASA Technical Reports Server (NTRS)

Kirkpatrick, J. Davy; Mcgraw, John T.; Hess, Thomas R.; Liebert, James; Mccarthy, Donald W., Jr.

1994-01-01

The luminosity function at the end of the main sequence is determined from V, R, and I data taken by the charge coupled devices (CCD)/Transit Instrument, a dedicated telescope surveying an 8.25 min wide strip of sky centered at delta = +28 deg, thus sampling Galactic latitudes of +90 deg down to -35 deg. A selection of 133 objects chosen via R - I and V - I colors has been observed spectroscopically at the 4.5 m Multiple Mirror Telescope to assess contributions by giants and subdwarfs and to verify that the reddest targets are objects of extremely late spectral class. Eighteen dwarfs of type M6 or later have been discovered, with the latest being of type M8.5. Data used for the determination of the luminosity function cover 27.3 sq. deg down to a completeness limit of R = 19.0. This luminosity function, computed at V, I, and bolometric magnitudes, shows an increase at the lowest luminosities, corresponding to spectral types later than M6- an effect suggested in earlier work by Reid & Gilmore and Legget & Hawkins. When the luminosity function is segregated into north Galactic and south Galactic portions, it is found that the upturn at faint magnitudes exists only in the southern sample. In fact, no dwarfs with M(sub I) is greater than or equal to 12.0 are found within the limiting volume of the 19.4 sq deg northern sample, in stark contrast to the smaller 7.9 sq deg area at southerly latitudes where seven such dwarfs are found. This fact, combined with the fact that the Sun is located approximately 10-40 pc north of the midplane, suggests that the latest dwarfs are part of a young population with a scale height much smaller than the 350 pc value generally adopted for other M dwarfs. These objects comprise a young population either because the lower metallicities prevelant at earlier epochs inhibited the formation of late M dwarfs or because the older counterparts of this population have cooled beyond current detection limits. The latter scenario would hold if these

Impact of beam-beam effects on precision luminosity measurements at the ILC

NASA Astrophysics Data System (ADS)

Rimbault, C.; Bambade, P.; Mönig, K.; Schulte, D.

2007-09-01

In this paper, the impact of beam-beam effects on the precision luminosity measurement at the International Linear Collider is investigated quantitatively for the first time. GUINEA-PIG, a beam-beam interaction simulation tool, is adapted to treat the space charge effects affecting the Bhabha events used in this measurement. The biases due to the resulting changes in kinematics are evaluated for different center-of-mass energies and beam parameters.

Color Retinal Image Enhancement Based on Luminosity and Contrast Adjustment.

PubMed

Zhou, Mei; Jin, Kai; Wang, Shaoze; Ye, Juan; Qian, Dahong

2018-03-01

Many common eye diseases and cardiovascular diseases can be diagnosed through retinal imaging. However, due to uneven illumination, image blurring, and low contrast, retinal images with poor quality are not useful for diagnosis, especially in automated image analyzing systems. Here, we propose a new image enhancement method to improve color retinal image luminosity and contrast. A luminance gain matrix, which is obtained by gamma correction of the value channel in the HSV (hue, saturation, and value) color space, is used to enhance the R, G, and B (red, green and blue) channels, respectively. Contrast is then enhanced in the luminosity channel of L * a * b * color space by CLAHE (contrast-limited adaptive histogram equalization). Image enhancement by the proposed method is compared to other methods by evaluating quality scores of the enhanced images. The performance of the method is mainly validated on a dataset of 961 poor-quality retinal images. Quality assessment (range 0-1) of image enhancement of this poor dataset indicated that our method improved color retinal image quality from an average of 0.0404 (standard deviation 0.0291) up to an average of 0.4565 (standard deviation 0.1000). The proposed method is shown to achieve superior image enhancement compared to contrast enhancement in other color spaces or by other related methods, while simultaneously preserving image naturalness. This method of color retinal image enhancement may be employed to assist ophthalmologists in more efficient screening of retinal diseases and in development of improved automated image analysis for clinical diagnosis.

Evaluation of GPUs as a level-1 track trigger for the High-Luminosity LHC

NASA Astrophysics Data System (ADS)

Mohr, H.; Dritschler, T.; Ardila, L. E.; Balzer, M.; Caselle, M.; Chilingaryan, S.; Kopmann, A.; Rota, L.; Schuh, T.; Vogelgesang, M.; Weber, M.

2017-04-01

In this work, we investigate the use of GPUs as a way of realizing a low-latency, high-throughput track trigger, using CMS as a showcase example. The CMS detector at the Large Hadron Collider (LHC) will undergo a major upgrade after the long shutdown from 2024 to 2026 when it will enter the high luminosity era. During this upgrade, the silicon tracker will have to be completely replaced. In the High Luminosity operation mode, luminosities of 5-7 × 1034 cm-2s-1 and pileups averaging at 140 events, with a maximum of up to 200 events, will be reached. These changes will require a major update of the triggering system. The demonstrated systems rely on dedicated hardware such as associative memory ASICs and FPGAs. We investigate the use of GPUs as an alternative way of realizing the requirements of the L1 track trigger. To this end we implemeted a Hough transformation track finding step on GPUs and established a low-latency RDMA connection using the PCIe bus. To showcase the benefits of floating point operations, made possible by the use of GPUs, we present a modified algorithm. It uses hexagonal bins for the parameter space and leads to a more truthful representation of the possible track parameters of the individual hits in Hough space. This leads to fewer duplicate candidates and reduces fake track candidates compared to the regular approach. With data-transfer latencies of 2 μs and processing times for the Hough transformation as low as 3.6 μs, we can show that latencies are not as critical as expected. However, computing throughput proves to be challenging due to hardware limitations.

The Dragonfly Nearby Galaxies Survey. III. The Luminosity Function of the M101 Group

NASA Astrophysics Data System (ADS)

Danieli, Shany; van Dokkum, Pieter; Merritt, Allison; Abraham, Roberto; Zhang, Jielai; Karachentsev, I. D.; Makarova, L. N.

2017-03-01

We obtained follow-up HST observations of the seven low surface brightness galaxies discovered with the Dragonfly Telephoto Array in the field of the massive spiral galaxy M101. Out of the seven galaxies, only three were resolved into stars and are potentially associated with the M101 group at D = 7 Mpc. Based on HST ACS photometry in the broad F606W and F814W filters, we use a maximum likelihood algorithm to locate the Tip of the Red Giant Branch in galaxy color-magnitude diagrams. Distances are {6.38}-0.35+0.35,{6.87}-0.30+0.21 and {6.52}-0.27+0.25 {Mpc} and we confirm that they are members of the M101 group. Combining the three confirmed low-luminosity satellites with previous results for brighter group members, we find the M101 galaxy group to be a sparsely populated galaxy group consisting of seven group members, down to M V = -9.2 mag. We compare the M101 cumulative luminosity function to that of the Milky Way and M31. We find that they are remarkably similar; in fact, the cumulative luminosity function of the M101 group gets even flatter for fainter magnitudes, and we show that the M101 group might exhibit the two known small-scale flaws in the ΛCDM model, namely “the missing satellite” problem and the “too big to fail” problem. Kinematic measurements of M101's satellite galaxies are required to determine whether the “too big to fail” problem does in fact exist in the M101 group.

Evolution of jets driven by relativistic radiation hydrodynamics as Long and Low Luminosity GRBs

NASA Astrophysics Data System (ADS)

Rivera-Paleo, F. J.; Guzmán, F. S.

2018-06-01

We present numerical simulations of jets modeled with Relativistic Radiation Hydrodynamics (RRH), that evolve across two environments: i) a stratified surrounding medium and ii) a 16TI progenitor model. We consider opacities consistent with various processes of interaction between the fluid and radiation, specifically, free-free, bound-free, bound-bound and electron scattering. We explore various initial conditions, with different radiation energy densities of the beam in hydrodynamical and radiation pressure dominated scenarios, considering only highly-relativistic jets. In order to investigate the impact of the radiation field on the evolution of the jets, we compare our results with purely hydrodynamical jets. Comparing among jets driven by RRH, we find that radiation pressure dominated jets propagate slightly faster than gas pressure dominated ones. Finally, we construct the luminosity Light Curves (LCs) associated with the two cases. The construction of LCs uses the fluxes of the radiation field which is fully coupled to the hydrodynamics equations during the evolution. The main properties of the jets propagating on the stratified surrounding medium are that the LCs show the same order of magnitude as the gamma-ray luminosity of typical Long Gamma-Ray Bursts 1050 - 1054erg/s and the difference between the radiation and gas temperatures is of nearly one order of magnitude. The properties of jets breaking out from the progenitor star model are that the LCs are of the order of magnitude of low-luminosity GRBs 1046 - 1049 erg/s, and in this scenario the difference between the gas and radiation temperature is of four orders of magnitude, which is a case far from thermal equilibrium.

Cosmological perturbation effects on gravitational-wave luminosity distance estimates

NASA Astrophysics Data System (ADS)

Bertacca, Daniele; Raccanelli, Alvise; Bartolo, Nicola; Matarrese, Sabino

2018-06-01

Waveforms of gravitational waves provide information about a variety of parameters for the binary system merging. However, standard calculations have been performed assuming a FLRW universe with no perturbations. In reality this assumption should be dropped: we show that the inclusion of cosmological perturbations translates into corrections to the estimate of astrophysical parameters derived for the merging binary systems. We compute corrections to the estimate of the luminosity distance due to velocity, volume, lensing and gravitational potential effects. Our results show that the amplitude of the corrections will be negligible for current instruments, mildly important for experiments like the planned DECIGO, and very important for future ones such as the Big Bang Observer.

Hard X-ray luminosity function of tidal disruption events: First results from the MAXI extragalactic survey

NASA Astrophysics Data System (ADS)

Kawamuro, Taiki; Ueda, Yoshihiro; Shidatsu, Megumi; Hori, Takafumi; Kawai, Nobuyuki; Negoro, Hitoshi; Mihara, Tatehiro

2016-08-01

We derive the first hard X-ray luminosity function (XLF) of stellar tidal disruption events (TDEs) by supermassive black holes (SMBHs), which gives an occurrence rate of TDEs per unit volume as a function of peak luminosity and redshift, utilizing an unbiased sample observed by the Monitor of All-sky X-ray Image (MAXI). On the basis of the light curves characterized by a power-law decay with an index of -5/3, a systematic search using the MAXI data detected four TDEs in the first 37 months of observations, all of which have been found in the literature. To formulate the TDE XLF, we consider the mass function of SMBHs, that of disrupted stars, the specific TDE rate as a function of SMBH mass, and the fraction of TDEs with relativistic jets. We perform an unbinned maximum likelihood fit to the MAXI TDE list and check the consistency with the observed TDE rate in the ROSAT all-sky survey. The results suggest that the intrinsic fraction of the jet-accompanying events is 0.0007%-34%. We confirm that at z ≲ 1.5 the contamination of the hard X-ray luminosity functions of active galactic nuclei by TDEs is not significant and hence that their contribution to the growth of SMBHs is negligible at the redshifts.

Detector Developments for the High Luminosity LHC Era (2/4)

ScienceCinema

Straessner, Arno

2018-04-16

Calorimetry and Muon Spectromers - Part II: When upgrading the LHC to higher luminosities, the detector and trigger performance shall be preserved - if not improved - with respect to the nominal performance. The ongoing R&D; for new radiation tolerant front-end electronics for calorimeters with higher read-out bandwidth are summarized and new possibilities for the trigger systems are presented. Similar developments are foreseen for the muon spectrometers, where also radiation tolerance of the muon detectors and functioning at high background rates is important. The corresponding plans and research work for the calorimeter and muon detectors at a LHC with highest luminsity are presented.

The stellar population and luminosity function in M31 bulge and Inner Disk Fields

NASA Technical Reports Server (NTRS)

Rich, R. Michael; Mould, J. R.; Graham, James R.

1993-01-01

We report infrared photometry and stellar identifications for stars in five fields in the M31 bulge located from 2 to 11 arcmin from the nucleus. These fields have been chosen such that the bulge/disk star ratio predicted from Kent's (1989) small bulge model varies from 7:1 to 1:5, allowing a study of near pure disk and near pure bulge stellar populations. We reject the hypothesis of Davies et al. (1991) that luminous stars found within 500 pc of the nucleus are due to a contaminating disk population. We find that the bulge contains stars in excess of M(sub bol) = -5 mag and that the bulge luminosity function has a distinct shape different from the disk fields. We find many stars redder than (J-K) = 2 mag, and suggest that these stars may be the counterparts of the IRAS-selected Galactic bulge Miras studied by Whitelock et at. (1991). The number of bright stars (M(sub bol) is less than -5 mag) falls off more rapidly than the r band surface brightness. By building model fields out of a bulge luminosity function and artificial stars, we are able to show that the change in the luminosity function toward the center cannot be explained simply by the mismeasurement of overcrowded star images. However, these tests also raise the possibility that the asymptotic giant branch (AGB) tip may be approximately equal to 1 mag fainter than actually measured in our most crowded field, reaching only M(sub bol) = -5. We compare observed counts of AGB stars with those predicted from theoretical lifetimes using a technique of general interest for this problem, the Fuel Consumption Theorem of Renzini & Buzzoni (1986) Spectral Evolution of Galaxies (Reidel, Dordrecht). Our methodology is generally applicable to the study of other resolved extragalactic stellar populations. The number of observed stars per magnitude up to a luminosity of M(bol) = -5.5 mag is consistent with AGB evolution of the whole population of the innermost bulge field with the standard lifetime on the AGB of 1.3 Myr

Galaxy And Mass Assembly: evolution of the Hα luminosity function and star formation rate density up to z < 0.35

NASA Astrophysics Data System (ADS)

Gunawardhana, M. L. P.; Hopkins, A. M.; Bland-Hawthorn, J.; Brough, S.; Sharp, R.; Loveday, J.; Taylor, E.; Jones, D. H.; Lara-López, M. A.; Bauer, A. E.; Colless, M.; Owers, M.; Baldry, I. K.; López-Sánchez, A. R.; Foster, C.; Bamford, S.; Brown, M. J. I.; Driver, S. P.; Drinkwater, M. J.; Liske, J.; Meyer, M.; Norberg, P.; Robotham, A. S. G.; Ching, J. H. Y.; Cluver, M. E.; Croom, S.; Kelvin, L.; Prescott, M.; Steele, O.; Thomas, D.; Wang, L.

2013-08-01

Measurements of the low-z Hα luminosity function, Φ, have a large dispersion in the local number density of sources (˜0.5-1 Mpc-3 dex-1), and correspondingly in the star formation rate density (SFRD). The possible causes for these discrepancies include limited volume sampling, biases arising from survey sample selection, different methods of correcting for dust obscuration and active galactic nucleus contamination. The Galaxy And Mass Assembly (GAMA) survey and Sloan Digital Sky Survey (SDSS) provide deep spectroscopic observations over a wide sky area enabling detection of a large sample of star-forming galaxies spanning 0.001 < SFRHα (M⊙ yr- 1) < 100 with which to robustly measure the evolution of the SFRD in the low-z Universe. The large number of high-SFR galaxies present in our sample allow an improved measurement of the bright end of the luminosity function, indicating that the decrease in Φ at bright luminosities is best described by a Saunders functional form rather than the traditional Schechter function. This result is consistent with other published luminosity functions in the far-infrared and radio. For GAMA and SDSS, we find the r-band apparent magnitude limit, combined with the subsequent requirement for Hα detection leads to an incompleteness due to missing bright Hα sources with faint r-band magnitudes.

Measurement of the integrated Luminosities of cross-section scan data samples around the {\\rm{\\psi }}(3770) mass region

NASA Astrophysics Data System (ADS)

Ablikim, M.; Achasov, M. N.; Ahmed, S.; Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, Y.; Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Begzsuren, K.; Bennett, D. W.; Bennett, J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chai, J.; Chang, J. F.; Chang, W. L.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, P. L.; Chen, S. J.; Chen, X. R.; Chen, Y. B.; Chu, X. K.; Cibinetto, G.; Cossio, F.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fang, J.; Fang, S. S.; Fang, Y.; Farinelli, R.; Fava, L.; Fegan, S.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garillon, B.; Garzia, I.; Gilman, A.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, L. M.; Gu, M. H.; Gu, Y. T.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y. P.; Guskov, A.; Haddadi, Z.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; He, X. Q.; Heinsius, F. H.; Held, T.; Heng, Y. K.; Holtmann, T.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.; Hussain, T.; Ikegami Andersson, W.; Irshad, M.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin, Y.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Khan, T.; Khoukaz, A.; Kiese, P.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kuemmel, M.; Kuessner, M.; Kupsc, A.; Kurth, M.; Kühn, W.; Lange, J. S.; Lara, M.; Larin, P.; Lavezzi, L.; Leiber, S.; Leithoff, H.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, J. W.; Li, K. J.; Li, Kang; Li, Ke; Li, Lei; Li, P. L.; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Liao, L. Z.; Libby, J.; Lin, C. X.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, D. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. L.; Liu, H. M.; Liu, Huanhuan; Liu, Huihui; Liu, J. B.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, Ke; Liu, L. D.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, X. L.; Lusso, S.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Malik, Q. A.; Mangoni, A.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.; Morello, G.; Muchnoi, N. Yu; Muramatsu, H.; Mustafa, A.; Nakhoul, S.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.; Patteri, P.; Pelizaeus, M.; Pellegrino, J.; Peng, H. P.; Peng, Z. Y.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Pitka, A.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qi, T. Y.; Qian, S.; Qiao, C. F.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Richter, M.; Ripka, M.; Rolo, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Sarantsev, A.; Savrié, M.; Schnier, C.; Schoenning, K.; Shan, W.; Shan, X. Y.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, X.; Song, J. J.; Song, W. M.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tan, Y. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Tapan, I.; Tiemens, M.; Tsednee, B.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, C. W.; Wang, D.; Wang, D. Y.; Wang, Dan; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, Meng; Wang, P.; Wang, P. L.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. Y.; Wang, Zongyuan; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, X.; Xia, Y.; Xiao, D.; Xiao, Y. J.; Xiao, Z. J.; Xie, Y. G.; Xie, Y. H.; Xiong, X. A.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, F.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, S. L.; Yang, Y. H.; Yang, Y. X.; Yang, Yifan; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. F.; Zhang, T. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. T.; Zhang, Yang; Zhang, Yao; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, Q.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, A. N.; Zhu, J.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.; BESIII Collaboration

2018-05-01

To investigate the nature of the {{\\psi }}(3770) resonance and to measure the cross section for {{{e}}}+{{{e}}}-\\to {{D}}\\bar{{{D}}}, a cross-section scan data sample, distributed among 41 center-of-mass energy points from 3.73 to 3.89 GeV, was taken with the BESIII detector operated at the BEPCII collider in the year 2010. By analyzing the large angle Bhabha scattering events, we measure the integrated luminosity of the data sample at each center-of-mass energy point. The total integrated luminosity of the data sample is 76.16+/- 0.04+/- 0.61 {pb}}-1, where the first uncertainty is statistical and the second systematic. Supported by National Key Basic Research Program of China (2015CB856700), National Natural Science Foundation of China (NSFC) (11235011, 11335008, 11425524, 11625523, 11635010), the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program, the CAS Center for Excellence in Particle Physics (CCEPP), Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1332201, U1532257, U1532258), CAS Key Research Program of Frontier Sciences (QYZDJ-SSW-SLH003, QYZDJ-SSW-SLH040), 100 Talents Program of CAS, National 1000 Talents Program of China, INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology, German Research Foundation DFG under Contracts Nos. Collaborative Research Center CRC 1044, FOR 2359, Istituto Nazionale di Fisica Nucleare, Italy, Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) (530-4CDP03), Ministry of Development of Turkey (DPT2006K-120470), National Science and Technology fund, The Swedish Research Council, U. S. Department of Energy (DE-FG02-05ER41374, DE-SC-0010118, DE-SC-0010504, DE-SC-0012069), University of Groningen (RuG) and the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), Darmstadt, WCU Program of National Research Foundation of Korea (R32-2008-000-10155-0)

Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC

NASA Astrophysics Data System (ADS)

Tortajada, Ignacio Asensi

2018-01-01

The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. The Tile Calorimeter (TileCal) will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and then transferred directly to the off-detector electronics, where the signals will be reconstructed, stored, and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the reliability and redundancy of the system. Three different front-end options are presently being investigated for the upgrade, two of them based on ASICs, and a final solution will be chosen after extensive laboratory and test beam studies that are in progress. A hybrid demonstrator module is being developed using the new electronics while conserving compatibility with the current system. The status of the developments will be presented, including results from the several tests with particle beams.

THE INTERMEDIATE LUMINOSITY OPTICAL TRANSIENT SN 2010DA: THE PROGENITOR, ERUPTION, AND AFTERMATH OF A PECULIAR SUPERGIANT HIGH-MASS X-RAY BINARY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villar, V. A.; Berger, E.; Blanchard, P. K.

We present optical spectroscopy, ultraviolet-to-infrared imaging, and X-ray observations of the intermediate luminosity optical transient (ILOT) SN 2010da in NGC 300 ( d = 1.86 Mpc) spanning from −6 to +6 years relative to the time of outburst in 2010. Based on the light-curve and multi-epoch spectral energy distributions of SN 2010da, we conclude that the progenitor of SN 2010da is a ≈10–12 M {sub ⊙} yellow supergiant possibly transitioning into a blue-loop phase. During outburst, SN 2010da had a peak absolute magnitude of M {sub bol} ≲ −10.4 mag, dimmer than other ILOTs and supernova impostors. We detect multi-componentmore » hydrogen Balmer, Paschen, and Ca ii emission lines in our high-resolution spectra, which indicate a dusty and complex circumstellar environment. Since the 2010 eruption, the star has brightened by a factor of ≈5 and remains highly variable in the optical. Furthermore, we detect SN 2010da in archival Swift and Chandra observations as an ultraluminous X-ray source ( L {sub X} ≈ 6 × 10{sup 39} erg s{sup −1}). We additionally attribute He ii 4686 Å and coronal Fe emission lines in addition to a steady X-ray luminosity of ≈10{sup 37} erg s{sup −1} to the presence of a compact companion.« less

The Luminosity Function of Star Clusters in 20 Star-Forming Galaxies Based on Hubble Legacy Archive Photometry

NASA Astrophysics Data System (ADS)

Bowers, Ariel; Whitmore, B. C.; Chandar, R.; Larsen, S. S.

2014-01-01

Luminosity functions have been determined for star cluster populations in 20 nearby (4 - 30 Mpc), star-forming galaxies based on ACS source lists generated by the Hubble Legacy Archive (http://hla.stsci.edu). These cluster catalogs provide one of the largest sets of uniform, automatically-generated cluster candidates available in the literature at present. Comparisons are made with other recently generated cluster catalogs demonstrating that the HLA-generated catalogs are of similar quality, but in general do not go as deep. A typical cluster luminosity function can be approximated by a power-law, dN/dL ∝ Lα, with an average value for α of -2.37 and rms scatter = 0.18. A comparison of fitting results based on methods which use binned and unbinned data shows good agreement, although there may be a systematic tendency for the unbinned (maximum-likelihood) method to give slightly more negative values of α for galaxies with steper luminosity functions. Our uniform database results in a small scatter (0.5 magnitude) in the correlation between the magnitude of the brightest cluster (Mbrightest) and Log of the number of clusters brighter than MI = -9 (Log N). We also examine the magnitude of the brightest cluster vs. Log SFR for a sample including LIRGS and ULIRGS.

The K-Band Quasar Luminosity Function from an SDSS and UKIDSS Matched Catalog

NASA Astrophysics Data System (ADS)

Peth, Michael; Ross, N. P.; Schneider, D. P.

2010-01-01

We match the 1,015,082 quasars from the Sloan Digital Sky Survey (SDSS) DR6 Photometric Quasar catalog to the UKIRT Infrared Digital Sky Survey (UKIDSS) Large Area Survey (LAS) DR3 to produce a catalog of 130,827 objects with optical (ugriz) and infrared (YJHK) measurements over an area of 1,200 sq. deg. A matching radius of 1'’ is used; the positional standard deviations of SDSS DR6 quasars and UKIDSS LAS is δRA = 0.137'’ and δDec = 0.131''. The catalog contains 74,351 K-band detections and 42,133 objects have coverage in all four NIR bands. In addition to the catalog, we present optical and NIR color-redshift and color-color plots. The photometric vs. spectroscopic redshift plots demonstrate how unreliable high reported photometric redshifts can be. This forces us to focus on z4.6 quasars are compared to our highest redshift objects. The giK color-color plot demonstrates that stellar contamination only affects a small sample of the objects. Distributions for Y,J,H,K and i-bands reveal insights into the flux limits in each magnitude. We investigate the distribution of redshifts from different data sets and investigate the legitimacy of certain measured photometric redshift regions. For in-depth analysis, we focus on the 300 sq. deg area equatorial SDSS region designated as Stripe 82. We measure the observed K-band quasar luminosity function (QLF) for a subset of 9,872, z<2.2 objects. We find the shape of the K-band QLF is very similar to that of the optical QLF, over the considered redshift ranges. Our calculated K-Band QLFs broadly match previous optical QLFs calculated from the SDSS and 2SLAQ QSO surveys and should provide important constraints linking unobscured optical quasars to Mid-Infrared detected, dusty and obscured AGNs at high-redshift.

Clustering of moderate luminosity X-ray-selected type 1 and type 2 AGNs at z ∼ 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allevato, V.; Finoguenov, A.; Civano, F.

2014-11-20

We investigate, for the first time at z ∼ 3, the clustering properties of 189 Type 1 and 157 Type 2 X-ray active galactic nuclei (AGNs) of moderate luminosity ((L {sub bol}) = 10{sup 45.3} erg s{sup –1}), with photometric or spectroscopic redshifts in the range 2.2 < z < 6.8. These samples are based on Chandra and XMM-Newton data in COSMOS. We find that Type 1 and Type 2 COSMOS AGNs at z ∼ 3 inhabit DMHs with typical mass of log M{sub h} = 12.84{sub −0.11}{sup +0.10} and 11.73{sub −0.45}{sup +0.39} h {sup –1} M {sub ☉}, respectively.more » This result requires a drop in the halo masses of Type 1 and 2 COSMOS AGNs at z ∼ 3 compared to z ≲ 2 XMM-COSMOS AGNs with similar luminosities. Additionally, we infer that unobscured COSMOS AGNs at z ∼ 3 reside in 10 times more massive halos compared to obscured COSMOS AGNs, at the 2.6σ level. This result extends to z ∼ 3 the results found in COSMOS at z ≲ 2, and rules out the picture in which obscuration is purely an orientation effect. A model which assumes that the AGNs activity is triggered by major mergers is quite successful in predicting both the low halo mass of COSMOS AGNs and the typical mass of luminous SDSS quasars at z ∼ 3, with the latter inhabiting more massive halos respect to moderate luminosity AGNs. Alternatively we can argue, at least for Type 1 COSMOS AGNs, that they are possibly representative of an early phase of fast (i.e., Eddington limited) BH growth induced by cosmic cold flows or disk instabilities. Given the moderate luminosity, these new fast growing BHs have masses of ∼10{sup 7-8} M {sub ☉} at z ∼ 3 which might evolve into ∼10{sup 8.5-9} M {sub ☉} mass BHs at z = 0. Following our clustering measurements, we argue that this fast BH growth at z ∼ 3 in AGNs with moderate luminosity occurs in DMHs with typical mass of ∼ 6× 10{sup 12} h {sup –1} M {sub ☉}.« less

1.0 Mm Maps and Radial Density Distributions of Southern Hii/molecular Cloud Complexes

NASA Technical Reports Server (NTRS)

Cheung, L. H.; Frogel, J. A.; Gezar, D. Y.; Hauser, M. G.

1980-01-01

Several 1.0 continuum mapping observations were made of seven southern hemisphere h12/molecular cloud complexes with 65 arcsec resolution. The radial density distribution of the clouds with central luminosity sources was determined observationally. Strong similarities in morphology and general physical conditions were found to exist among all of the southern clouds in the sample.

The galaxy NGC 1566 - Distribution and kinematics of the ionized gas

NASA Astrophysics Data System (ADS)

Comte, G.; Duquennoy, A.

1982-10-01

H-alpha narrowband observations are the basis of a study of ionized hydrogen in the large spiral galaxy NGC 1566 which has yielded a catalog of 418 H II regions covering the main body of the galaxy, supplemented by 59 positions and estimated H-alpha luminosities for regions located in the pseudo-outer ring where no H-alpha plate is available. A discussion of luminosity function, diameter distribution and spiral structure notes evidence for a double two-armed spiral pattern. The plane of the galaxy appears warped, and the efficiency of the two different spiral patterns in star formation is different. A preliminary radial velocity field is determined from three interferograms in H-alpha light, and is found to be acceptably fitted by a simple bulge-plus-disk dynamical model in which the apparent disk mass-to-light ratio sharply increases from center to edge.

The Faint End of the Quasar Luminosity Function at z ~ 4

NASA Astrophysics Data System (ADS)

Glikman, Eilat; Bogosavljević, Milan; Djorgovski, S. G.; Stern, Daniel; Dey, Arjun; Jannuzi, Buell T.; Mahabal, Ashish

2010-02-01

The evolution of the quasar luminosity function (QLF) is one of the basic cosmological measures providing insight into structure formation and mass assembly in the universe. We have conducted a spectroscopic survey to find faint quasars (-26.0 < M 1450 < -22.0) at redshifts z = 3.8-5.2 in order to measure the faint end of the QLF at these early times. Using available optical imaging data from portions of the NOAO Deep Wide-Field Survey and the Deep Lens Survey, we have color-selected quasar candidates in a total area of 3.76 deg2. Thirty candidates have R <= 23 mag. We conducted spectroscopic follow-up for 28 of our candidates and found 23 QSOs, 21 of which are reported here for the first time, in the 3.74 < z < 5.06 redshift range. We estimate our survey completeness through detailed Monte Carlo simulations and derive the first measurement of the density of quasars in this magnitude and redshift interval. We find that the binned luminosity function (LF) is somewhat affected by the K-correction used to compute the rest-frame absolute magnitude at 1450 Å. Considering only our R <= 23 sample, the best-fit single power law (Φ vprop L β) gives a faint-end slope β = -1.6 ± 0.2. If we consider our larger, but highly incomplete sample going 1 mag fainter, we measure a steeper faint-end slope -2 < β < -2.5. In all cases, we consistently find faint-end slopes that are steeper than expected based on measurements at z ~ 3. We combine our sample with bright quasars from the Sloan Digital Sky Survey to derive parameters for a double-power-law LF. Our best fit finds a bright-end slope, α = -2.4 ± 0.2, and faint-end slope, β = -2.3 ± 0.2, without a well-constrained break luminosity. This is effectively a single power law, with β = -2.7 ± 0.1. We use these results to place limits on the amount of ultraviolet radiation produced by quasars and find that quasars are able to ionize the intergalactic medium at these redshifts. The data presented herein were obtained at the

Matching into the Helical Bunch Coalescing Channel for a High Luminosity Muon Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sy, Amy; Ankenbrandt, Charles; Derbenev, Yaroslav

2015-09-01

For high luminosity in a muon collider, muon bunches that have been cooled in the six-dimensional helical cooling channel (HCC) must be merged into a single bunch and further cooled in preparation for acceleration and transport to the collider ring. The helical bunch coalescing channel has been previously simulated and provides the most natural match from helical upstream and downstream subsystems. This work focuses on the matching from the exit of the multiple bunch HCC into the start of the helical bunch coalescing channel. The simulated helical matching section simultaneously matches the helical spatial period lambda in addition to providingmore » the necessary acceleration for efficient bunch coalescing. Previous studies assumed that the acceleration of muon bunches from p=209.15 MeV/c to 286.816 MeV/c and matching of lambda from 0.5 m to 1.0 m could be accomplished with zero particle losses and zero emittance growth in the individual bunches. This study demonstrates nonzero values for both particle loss and emittance growth, and provides considerations for reducing these adverse effects to best preserve high luminosity.« less

X-ray Pulsars Across the Parameter Space of Luminosity, Accretion Mode, and Spin

NASA Astrophysics Data System (ADS)

Laycock, Silas; Yang, Jun; Christodoulou, Dimitris; Coe, Malcolm; Cappallo, Rigel; Zezas, Andreas; Ho, Wynn C. G.; Hong, JaeSub; Fingerman, Samuel; Drake, Jeremy J.; Kretschmar, Peter; Antoniou, Vallia

2017-08-01

We present our multi-satellite library of X-ray Pulsar observations to the community, and highlight recent science results. Available at www.xraypulsars.space the library provides a range of high-level data products, including: activity histories, pulse-profiles, phased event files, and a unique pulse-profile modeling interface. The initial release (v1.0) contains some 15 years of RXTE-PCA, Chandra ACIS-I, and XMM-PN observations of the Small Magellanic Cloud, creating a valuable record of pulsar behavior. Our library is intended to enable new progress on fundamental NS parameters and accretion physics. The major motivations are (1) Assemble a large homogeneous sample to enable population statistics. This has so far been used to map the propeller transition, and explore the role of retrograde and pro-grade accretion disks. (2) Obtain pulse-profiles for the same pulsars on many different occasions, at different luminosities and states in order to break model degeneracies. This effort has led to preliminary measurements of the offsets between magnetic and spin axes. With the addition of other satellites, and Galactic pulsars, the library will cover the entire available range of luminosity, variability timescales and accretion regimes.

Distributions of topological observables in inclusive three- and four-jet events in pp collisions at

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Randle-conde, A.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Júnior, W. L. Aldá; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Martins, T. Dos Reis; Mora Herrera, C.; Pol, M. E.; Rebello Teles, P.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Bontenackels, M.; Edelhoff, M.; Feld, L.; Heister, A.; Hindrichs, O.; Klein, K.; Ostapchuk, A.; Raupach, F.; Sammet, J.; Schael, S.; Schulte, J. F.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Erdmann, M.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Reithler, H.; Schmitz, S. A.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Weber, M.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nowack, A.; Nugent, I. M.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behr, J.; Behrens, U.; Bell, A. J.; Bethani, A.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Garcia, J. Garay; Geiser, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, l.; Krücker, D.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Lutz, B.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Ron, E.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Vargas Trevino, A. D. R.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Kirschenmann, H.; Klanner, R.; Kogler, R.; Lange, J.; Lapsien, T.; Lenz, T.; Marchesini, I.; Ott, J.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Poehlsen, T.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Hauth, T.; Husemann, U.; Katkov, I.; Kornmayer, A.; Kuznetsova, E.; Lobelle Pardo, P.; Mozer, M. U.; Müller, T.; Müller, Th.; Nürnberg, A.; Quast, G.; Rabbertz, K.; Röcker, S.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Markou, C.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Stiliaris, E.; Aslanoglou, X.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Palinkas, J.; Szillasi, Z.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Swain, S. K.; Beri, S. B.; Bhatnagar, V.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, M.; Kumar, R.; Mittal, M.; Nishu, N.; Singh, J. B.; Kumar, Ashok; Kumar, Arun; Ahuja, S.; Bhardwaj, A.; Choudhary, B. C.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dutta, S.; Gomber, B.; Jain, Sa.; Jain, Sh.; Khurana, R.; Modak, A.; Mukherjee, S.; Roy, D.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Dutta, D.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Mohanty, G. B.; Parida, B.; Sudhakar, K.; Wickramage, N.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Chhibra, S. S.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Primavera, F.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Albergo, S.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gallo, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Ferretti, R.; Ferro, F.; Lo Vetere, M.; Robutti, E.; Tosi, S.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Lucchini, M. T.; Malvezzi, S.; Manzoni, R. A.; Martelli, A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Fabozzi, F.; Iorio, A. O. M.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Azzi, P.; Bacchetta, N.; Bellato, M.; Biasotto, M.; Dall'Osso, M.; Dorigo, T.; Galanti, M.; Giubilato, P.; Gonella, F.; Gozzelino, A.; Kanishchev, K.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Montecassiano, F.; Passaseo, M.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Vanini, S.; Ventura, S.; Zotto, P.; Zucchetta, A.; Gabusi, M.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vitulo, P.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Fiori, F.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Moon, C. S.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Vernieri, C.; Barone, L.; Cavallari, F.; D'imperio, G.; Del Re, D.; Diemoz, M.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Micheli, F.; Nourbakhsh, S.; Organtini, G.; Paramatti, R.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Soffi, L.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Casasso, S.; Costa, M.; Degano, A.; Demaria, N.; Finco, L.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Musich, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Potenza, A.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Tamponi, U.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Umer, T.; Zanetti, A.; Chang, S.; Kropivnitskaya, T. A.; Nam, S. K.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Kim, M. S.; Kong, D. J.; Lee, S.; Oh, Y. D.; Park, H.; Sakharov, A.; Son, D. C.; Kim, T. J.; Kim, J. Y.; Song, S.; Choi, S.; Gyun, D.; Hong, B.; Jo, M.; Kim, H.; Kim, Y.; Lee, B.; Lee, K. S.; Park, S. K.; Roh, Y.; Yoo, H. D.; Choi, M.; Kim, J. H.; Park, I. C.; Ryu, G.; Ryu, M. S.; Choi, Y.; Choi, Y. K.; Goh, J.; Kim, D.; Kwon, E.; Lee, J.; Yu, I.; Juodagalvis, A.; Komaragiri, J. R.; Md Ali, M. A. B.; Casimiro Linares, E.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-de La Cruz, I.; Hernandez-Almada, A.; Lopez-Fernandez, R.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Vazquez Valencia, F.; Pedraza, I.; Salazar Ibarguen, H. A.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Reucroft, S.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Khan, W. A.; Khurshid, T.; Shoaib, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Brona, G.; Bunkowski, K.; Cwiok, M.; Dominik, W.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Wolszczak, W.; Bargassa, P.; Da Cruz E Silva, C. Beir ao; Faccioli, P.; Parracho, P. G. Ferreira; Gallinaro, M.; Lloret Iglesias, L.; Nguyen, F.; Rodrigues Antunes, J.; Seixas, J.; Varela, J.; Vischia, P.; Afanasiev, S.; Bunin, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Kamenev, A.; Karjavin, V.; Konoplyanikov, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Moisenz, P.; Palichik, V.; Perelygin, V.; Shmatov, S.; Skatchkov, N.; Smirnov, V.; Zarubin, A.; Golovtsov, V.; Ivanov, Y.; Kim, V.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Vorobyev, An.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, l.; Safronov, G.; Semenov, S.; Spiridonov, A.; Stolin, V.; Vlasov, E.; Zhokin, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Mesyats, G.; Rusakov, S. V.; Vinogradov, A.; Belyaev, A.; Boos, E.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Tourtchanovitch, L.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Ekmedzic, M.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Battilana, C.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Domínguez Vázquez, D.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Ramos, J. P. Fernández; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro De Martino, E.; Yzquierdo, A. Pérez-Calero; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Soares, M. S.; Albajar, C.; de Trocóniz, J. F.; Missiroli, M.; Moran, D.; Brun, H.; Cuevas, J.; Fernandez Menendez, J.; Folgueras, S.; Gonzalez Caballero, I.; Brochero Cifuentes, J. A.; Cabrillo, I. J.; Calderon, A.; Duarte Campderros, J.; Fernandez, M.; Gomez, G.; Graziano, A.; Lopez Virto, A.; Marco, J.; Marco, R.; Martinez Rivero, C.; Matorras, F.; Munoz Sanchez, F. J.; Piedra Gomez, J.; Rodrigo, T.; Rodríguez-Marrero, A. Y.; Ruiz-Jimeno, A.; Scodellaro, L.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Auffray, E.; Auzinger, G.; Bachtis, M.; Baillon, P.; Ball, A. H.; Barney, D.; Benaglia, A.; Bendavid, J.; Benhabib, L.; Benitez, J. F.; Bernet, C.; Bloch, P.; Bocci, A.; Bonato, A.; Bondu, O.; Botta, C.; Breuker, H.; Camporesi, T.; Cerminara, G.; Colafranceschi, S.; D'Alfonso, M.; d'Enterria, D.; Dabrowski, A.; David, A.; De Guio, F.; De Roeck, A.; De Visscher, S.; Di Marco, E.; Dobson, M.; Dordevic, M.; Dorney, B.; Dupont-Sagorin, N.; Elliott-Peisert, A.; Franzoni, G.; Funk, W.; Gigi, D.; Gill, K.; Giordano, D.; Girone, M.; Glege, F.; Guida, R.; Gundacker, S.; Guthoff, M.; Hammer, J.; Hansen, M.; Harris, P.; Hegeman, J.; Innocente, V.; Janot, P.; Kousouris, K.; Krajczar, K.; Lecoq, P.; Lourenço, C.; Magini, N.; Malgeri, L.; Mannelli, M.; Marrouche, J.; Masetti, L.; Meijers, F.; Mersi, S.; Meschi, E.; Moortgat, F.; Morovic, S.; Mulders, M.; Orsini, L.; Pape, L.; Perez, E.; Perrozzi, L.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pimiä, M.; Piparo, D.; Plagge, M.; Racz, A.; Rolandi, G.; Rovere, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Sharma, A.; Siegrist, P.; Silva, P.; Simon, M.; Sphicas, P.; Spiga, D.; Steggemann, J.; Stieger, B.; Stoye, M.; Takahashi, Y.; Treille, D.; Tsirou, A.; Veres, G. I.; Wardle, N.; Wöhri, H. K.; Wollny, H.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Renker, D.; Rohe, T.; Bachmair, F.; Bäni, L.; Bianchini, L.; Buchmann, M. A.; Casal, B.; Chanon, N.; Dissertori, G.; Dittmar, M.; Donegà, M.; Dünser, M.; Eller, P.; Grab, C.; Hits, D.; Hoss, J.; Lustermann, W.; Mangano, B.; Marini, A. C.; Marionneau, M.; Martinez Ruiz del Arbol, P.; Masciovecchio, M.; Meister, D.; Mohr, N.; Musella, P.; Nägeli, C.; Nessi-Tedaldi, F.; Pandolfi, F.; Pauss, F.; Peruzzi, M.; Quittnat, M.; Rebane, L.; Rossini, M.; Starodumov, A.; Takahashi, M.; Theofilatos, K.; Wallny, R.; Weber, H. A.; Amsler, C.; Canelli, M. F.; Chiochia, V.; De Cosa, A.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Lange, C.; Millan Mejias, B.; Ngadiuba, J.; Pinna, D.; Robmann, P.; Ronga, F. J.; Taroni, S.; Verzetti, M.; Yang, Y.; Cardaci, M.; Chen, K. H.; Ferro, C.; Kuo, C. M.; Lin, W.; Lu, Y. J.; Volpe, R.; Yu, S. S.; Chang, P.; Chang, Y. H.; Chang, Y. W.; Chao, Y.; Chen, K. F.; Chen, P. H.; Dietz, C.; Grundler, U.; Hou, W.-S.; Kao, K. Y.; Liu, Y. F.; Lu, R.-S.; Majumder, D.; Petrakou, E.; Tzeng, Y. M.; Wilken, R.; Asavapibhop, B.; Singh, G.; Srimanobhas, N.; Suwonjandee, N.; Adiguzel, A.; Bakirci, M. N.; Cerci, S.; Dozen, C.; Dumanoglu, I.; Eskut, E.; Girgis, S.; Gokbulut, G.; Gurpinar, E.; Hos, I.; Kangal, E. E.; Kayis Topaksu, A.; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Tali, B.; Topakli, H.; Vergili, M.; Akin, I. V.; Bilin, B.; Bilmis, S.; Gamsizkan, H.; Isildak, B.; Karapinar, G.; Ocalan, K.; Sekmen, S.; Surat, U. E.; Yalvac, M.; Zeyrek, M.; Albayrak, A.; Gülmez, E.; Kaya, M.; Kaya, O.; Yetkin, T.; Cankocak, K.; Vardarlı, F. I.; Levchuk, L.; Sorokin, P.; Brooke, J. J.; Clement, E.; Cussans, D.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Meng, Z.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Sakuma, T.; Senkin, S.; Smith, V. J.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Womersley, W. J.; Worm, S. D.; Baber, M.; Bainbridge, R.; Buchmuller, O.; Burton, D.; Colling, D.; Cripps, N.; Dauncey, P.; Davies, G.; Della Negra, M.; Dunne, P.; Ferguson, W.; Fulcher, J.; Futyan, D.; Hall, G.; Iles, G.; Jarvis, M.; Karapostoli, G.; Kenzie, M.; Lane, R.; Lucas, R.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mathias, B.; Nash, J.; Nikitenko, A.; Pela, J.; Pesaresi, M.; Petridis, K.; Raymond, D. M.; Rogerson, S.; Rose, A.; Seez, C.; Sharp, P.; Tapper, A.; Vazquez Acosta, M.; Virdee, T.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Leggat, D.; Leslie, D.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Dittmann, J.; Hatakeyama, K.; Kasmi, A.; Liu, H.; Scarborough, T.; Charaf, O.; Cooper, S. I.; Henderson, C.; Rumerio, P.; Avetisyan, A.; Bose, T.; Fantasia, C.; Lawson, P.; Richardson, C.; Rohlf, J.; St. John, J.; Sulak, L.; Alimena, J.; Berry, E.; Bhattacharya, S.; Christopher, G.; Cutts, D.; Demiragli, Z.; Dhingra, N.; Ferapontov, A.; Garabedian, A.; Heintz, U.; Kukartsev, G.; Laird, E.; Landsberg, G.; Luk, M.; Narain, M.; Segala, M.; Sinthuprasith, T.; Speer, T.; Swanson, J.; Breedon, R.; Breto, G.; De La Barca Sanchez, M. Calderon; Chauhan, S.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Gardner, M.; Ko, W.; Lander, R.; Mulhearn, M.; Pellett, D.; Pilot, J.; Ricci-Tam, F.; Shalhout, S.; Smith, J.; Squires, M.; Stolp, D.; Tripathi, M.; Wilbur, S.; Yohay, R.; Cousins, R.; Everaerts, P.; Farrell, C.; Hauser, J.; Ignatenko, M.; Rakness, G.; Takasugi, E.; Valuev, V.; Weber, M.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Hanson, G.; Heilman, J.; Ivova Rikova, M.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Luthra, A.; Malberti, M.; Negrete, M. Olmedo; Shrinivas, A.; Sumowidagdo, S.; Wimpenny, S.; Branson, J. G.; Cerati, G. B.; Cittolin, S.; D'Agnolo, R. T.; Holzner, A.; Kelley, R.; Klein, D.; Letts, J.; Macneill, I.; Olivito, D.; Padhi, S.; Palmer, C.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Tu, Y.; Vartak, A.; Welke, C.; Würthwein, F.; Yagil, A.; Barge, D.; Bradmiller-Feld, J.; Campagnari, C.; Danielson, T.; Dishaw, A.; Dutta, V.; Flowers, K.; Franco Sevilla, M.; Geffert, P.; George, C.; Golf, F.; Gouskos, L.; Incandela, J.; Justus, C.; Mccoll, N.; Richman, J.; Stuart, D.; To, W.; West, C.; Yoo, J.; Apresyan, A.; Bornheim, A.; Bunn, J.; Chen, Y.; Duarte, J.; Mott, A.; Newman, H. B.; Pena, C.; Pierini, M.; Spiropulu, M.; Vlimant, J. R.; Wilkinson, R.; Xie, S.; Zhu, R. Y.; Azzolini, V.; Calamba, A.; Carlson, B.; Ferguson, T.; Iiyama, Y.; Paulini, M.; Russ, J.; Vogel, H.; Vorobiev, I.; Cumalat, J. P.; Ford, W. T.; Gaz, A.; Krohn, M.; Luiggi Lopez, E.; Nauenberg, U.; Smith, J. G.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chatterjee, A.; Chaves, J.; Chu, J.; Dittmer, S.; Eggert, N.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Ryd, A.; Salvati, E.; Skinnari, L.; Sun, W.; Teo, W. D.; Thom, J.; Thompson, J.; Tucker, J.; Weng, Y.; Winstrom, L.; Wittich, P.; Winn, D.; Abdullin, S.; Albrow, M.; Anderson, J.; Apollinari, G.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gao, Y.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Hare, D.; Harris, R. M.; Hirschauer, J.; Hooberman, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Kaadze, K.; Klima, B.; Kreis, B.; Kwan, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Martinez Outschoorn, V. I.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mishra, K.; Mrenna, S.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Prokofyev, O.; Sexton-Kennedy, E.; Sharma, S.; Soha, A.; Spalding, W. J.; Spiegel, L.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vidal, R.; Whitbeck, A.; Whitmore, J.; Yang, F.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Carver, M.; Curry, D.; Das, S.; De Gruttola, M.; Di Giovanni, G. P.; Field, R. D.; Fisher, M.; Furic, I. K.; Hugon, J.; Konigsberg, J.; Korytov, A.; Kypreos, T.; Low, J. F.; Matchev, K.; Mei, H.; Milenovic, P.; Mitselmakher, G.; Muniz, L.; Rinkevicius, A.; Shchutska, L.; Snowball, M.; Sperka, D.; Yelton, J.; Zakaria, M.; Hewamanage, S.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Adams, T.; Askew, A.; Bochenek, J.; Diamond, B.; Haas, J.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Prosper, H.; Veeraraghavan, V.; Weinberg, M.; Baarmand, M. M.; Hohlmann, M.; Kalakhety, H.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Kurt, P.; Moon, D. H.; O'Brien, C.; Sandoval Gonzalez, l. D.; Silkworth, C.; Turner, P.; Varelas, N.; Bilki, B.; Clarida, W.; Dilsiz, K.; Haytmyradov, M.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Rahmat, R.; Sen, S.; Tan, P.; Tiras, E.; Wetzel, J.; Yi, K.; Barnett, B. A.; Blumenfeld, B.; Bolognesi, S.; Fehling, D.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Swartz, M.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Kenny, R. P.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Sekaric, J.; Stringer, R.; Wang, Q.; Wood, J. S.; Chakaberia, I.; Ivanov, A.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Skhirtladze, N.; Svintradze, I.; Gronberg, J.; Lange, D.; Rebassoo, F.; Wright, D.; Baden, A.; Belloni, A.; Calvert, B.; Eno, S. C.; Gomez, J. A.; Hadley, N. J.; Kellogg, R. G.; Kolberg, T.; Lu, Y.; Mignerey, A. C.; Pedro, K.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Busza, W.; Cali, I. A.; Chan, M.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Klute, M.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Sumorok, K.; Velicanu, D.; Veverka, J.; Wyslouch, B.; Yang, M.; Zanetti, M.; Zhukova, V.; Dahmes, B.; Gude, A.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Pastika, N.; Rusack, R.; Singovsky, A.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Gonzalez Suarez, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Ratnikov, F.; Snow, G. R.; Zvada, M.; Dolen, J.; Godshalk, A.; Iashvili, I.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Trocino, D.; Wang, R. J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Velasco, M.; Won, S.; Brinkerhoff, A.; Chan, K. M.; Drozdetskiy, A.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Musienko, Y.; Pearson, T.; Planer, M.; Ruchti, R.; Smith, G.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wolfe, H.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Hunt, A.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Brownson, E.; Malik, S.; Mendez, H.; Ramirez Vargas, J. E.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; De Mattia, M.; Gutay, L.; Hu, Z.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Michlin, B.; Padley, B. P.; Redjimi, R.; Roberts, J.; Zabel, J.; Betchart, B.; Bodek, A.; Covarelli, R.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Khukhunaishvili, A.; Korjenevski, S.; Petrillo, G.; Vishnevskiy, D.; Ciesielski, R.; Demortier, L.; Goulianos, K.; Mesropian, C.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Kaplan, S.; Lath, A.; Panwalkar, S.; Park, M.; Patel, R.; Salur, S.; Schnetzer, S.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Khotilovich, V.; Krutelyov, V.; Montalvo, R.; Osipenkov, I.; Pakhotin, Y.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Suarez, I.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kovitanggoon, K.; Kunori, S.; Lee, S. W.; Libeiro, T.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sharma, M.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wood, J.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Lazaridis, C.; Levine, A.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Sarangi, T.; Savin, A.; Smith, W. H.; Taylor, D.; Vuosalo, C.; Woods, N.

2015-07-01

This paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7 with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1. The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with pythia6 displays the overall best agreement with data.

Dust temperature distributions in star-forming condensations

NASA Technical Reports Server (NTRS)

Xie, Taoling; Goldsmith, Paul F.; Snell, Ronald L.; Zhou, Weimin

1993-01-01

The FIR spectra of the central IR condensations in the dense cores of molecular clouds AFGL 2591. B335, L1551, Mon R2, and Sgr B2 are reanalyzed here in terms of the distribution of dust mass as a function of temperature. FIR spectra of these objects can be characterized reasonably well by a given functional form. The general shapes of the dust temperature distributions of these objects are similar and closely resemble the theoretical computations of de Muizon and Rouan (1985) for a sample of 'hot centered' clouds with active star formation. Specifically, the model yields a 'cutoff' temperature below which essentially no dust is needed to interpret the dust emission spectra, and most of the dust mass is distributed in a broad temperature range of a few tens of degrees above the cutoff temperature. Mass, luminosity, average temperature, and column density are obtained, and it is found that the physical quantities differ considerably from source to source in a meaningful way.

Influence of the Solar Luminosity on the Glaciations, sea Level Changes and Resulting Earthquakes.

NASA Astrophysics Data System (ADS)

Shopov, Y. Y.; Stoykova, D. A.; Tsankov, L. T.; Sanabria, M. E.; Georgieva, D. I.; Ford, D. C.; Georgiev, L. N.

2002-12-01

Glaciations were attributed to variations of the Earth's orbit (Milankovitch cycles). But the best ever dated paleoclimatic record (from Devils Hole, Nevada) demonstrated that the end of the last glacial period (termination II) happened 10 000 years before the one suggested by the orbital variations, i.e. the result appeared before the reason. This fact suggests that there is something wrong in the theory. Calcite speleothems luminescence of organics depends exponentially upon soil temperatures that are determined primarily by the solar radiation. So the microzonality of luminescence of speleothems may be used as an indirect Solar Insolation (radiation) proxy index. We obtained luminescence solar insolation proxy records in speleothems (from Jewel Cave, South Dakota, US and Duhlata cave, Bulgaria). These records exhibit very rapid increasing of the solar insolation at 139 kyrs BP responsible for the termination II (the end of the last glaciation) and demonstrate that solar luminosity variations contribute to Earth's heating almost as much as the orbital variations of the Earth's orbit (Milankovitch cycles). The most powerful cycle of the solar luminosity (11500 yrs) is responsible for almost 1/2 of the variations in solar insolation experimental records. Changes in the speed of Earth's rotation during glacial- interglacial transitions produce fracturing of the Earth's crust and major earthquakes along the fractures. The intensity of this process is as higher as faster is the change of the sea level and as higher is its amplitude. Glaciations and deglaciations drive changes of the sea level. Much higher dimensions of this process should be caused by eruptive increasing of solar luminosity, which may be caused only by collision of large asteroids with the Sun. We demonstrate that such collision may cause "Bible Deluge" type of event.

Supernovae in Early-Type Galaxies: Directly Connecting Age and Metallicity with Type Ia Luminosity

NASA Astrophysics Data System (ADS)

Gallagher, Joseph S.; Garnavich, Peter M.; Caldwell, Nelson; Kirshner, Robert P.; Jha, Saurabh W.; Li, Weidong; Ganeshalingam, Mohan; Filippenko, Alexei V.

2008-10-01

We have obtained optical spectra of 29 early-type (E/S0) galaxies that hosted Type Ia supernovae (SNe Ia). We have measured absorption-line strengths and compared them to a grid of models to extract the relations between the supernova properties and the luminosity-weighted age/composition of the host galaxies. Such a direct measurement is a marked improvement over existing analyses that tend to rely on general correlations between the properties of stellar populations and morphology. We find a strong correlation suggesting that SNe Ia in galaxies whose populations have a characteristic age greater than 5 Gyr are ~1 mag fainter at Vmax than those found in galaxies with younger populations. We find that SN Ia distance residuals in the Hubble diagram are correlated with host-galaxy metal abundance with higher iron abundance galaxies hosting less-luminous supernovae. We thus conclude that the time since progenitor formation primarily determines the radioactive Ni production while progenitor metal abundance has a weaker influence on peak luminosity, but one not fully corrected by light-curve shape and color fitters. This result, particularly the secondary dependence on metallicity, has significant implications for the determination of the equation-of-state parameter, w = P/(ρ c2) , and could impact planning for future dark-energy missions such as JDEM. Assuming no selection effects in discovering SNe Ia in local early-type galaxies, we find a higher specific SN Ia rate in E/S0 galaxies with ages below 3 Gyr than in older hosts. The higher rate and brighter luminosities seen in the youngest E/S0 hosts may be a result of recent star formation and represents a tail of the "prompt" SN Ia progenitors.

Transverse emittance growth due to rf noise in the high-luminosity LHC crab cavities

NASA Astrophysics Data System (ADS)

Baudrenghien, P.; Mastoridis, T.

2015-10-01

The high-luminosity LHC (HiLumi LHC) upgrade with planned operation from 2025 onward has a goal of achieving a tenfold increase in the number of recorded collisions thanks to a doubling of the intensity per bunch (2.2e11 protons) and a reduction of β* to 15 cm. Such an increase would significantly expedite new discoveries and exploration. To avoid detrimental effects from long-range beam-beam interactions, the half crossing angle must be increased to 295 microrad. Without bunch crabbing, this large crossing angle and small transverse beam size would result in a luminosity reduction factor of 0.3 (Piwinski angle). Therefore, crab cavities are an important component of the LHC upgrade, and will contribute strongly to achieving an increase in the number of recorded collisions. The proposed crab cavities are electromagnetic devices with a resonance in the radio frequency (rf) region of the spectrum (400.789 MHz). They cause a kick perpendicular to the direction of motion (transverse kick) to restore an effective head-on collision between the particle beams, thereby restoring the geometric factor to 0.8 [K. Oide and K. Yokoya, Phys. Rev. A 40, 315 (1989).]. Noise injected through the rf/low level rf (llrf) system could cause significant transverse emittance growth and limit luminosity lifetime. In this work, a theoretical relationship between the phase and amplitude rf noise spectrum and the transverse emittance growth rate is derived, for a hadron machine assuming zero synchrotron radiation damping and broadband rf noise, excluding infinitely narrow spectral lines. This derivation is for a single beam. Both amplitude and phase noise are investigated. The potential improvement in the presence of the transverse damper is also investigated.

Star formation relations and CO spectral line energy distributions across the J-ladder and redshift

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greve, T. R.; Leonidaki, I.; Xilouris, E. M.

2014-10-20

We present FIR [50-300 μm]–CO luminosity relations (i.e., log L{sub FIR}=αlog L{sub CO}{sup ′}+β) for the full CO rotational ladder from J = 1-0 up to J = 13-12 for a sample of 62 local (z ≤ 0.1) (Ultra) Luminous Infrared Galaxies (LIRGs; L {sub IR[8-1000} {sub μm]} > 10{sup 11} L {sub ☉}) using data from Herschel SPIRE-FTS and ground-based telescopes. We extend our sample to high redshifts (z > 1) by including 35 submillimeter selected dusty star forming galaxies from the literature with robust CO observations, and sufficiently well-sampled FIR/submillimeter spectral energy distributions (SEDs), so that accurate FIRmore » luminosities can be determined. The addition of luminous starbursts at high redshifts enlarge the range of the FIR–CO luminosity relations toward the high-IR-luminosity end, while also significantly increasing the small amount of mid-J/high-J CO line data (J = 5-4 and higher) that was available prior to Herschel. This new data set (both in terms of IR luminosity and J-ladder) reveals linear FIR–CO luminosity relations (i.e., α ≅ 1) for J = 1-0 up to J = 5-4, with a nearly constant normalization (β ∼ 2). In the simplest physical scenario, this is expected from the (also) linear FIR–(molecular line) relations recently found for the dense gas tracer lines (HCN and CS), as long as the dense gas mass fraction does not vary strongly within our (merger/starburst)-dominated sample. However, from J = 6-5 and up to the J = 13-12 transition, we find an increasingly sublinear slope and higher normalization constant with increasing J. We argue that these are caused by a warm (∼100 K) and dense (>10{sup 4} cm{sup –3}) gas component whose thermal state is unlikely to be maintained by star-formation-powered far-UV radiation fields (and thus is no longer directly tied to the star formation rate). We suggest that mechanical heating (e.g., supernova-driven turbulence and shocks), and not cosmic rays, is the more likely source of energy

THE INFLUENCE OF RED SPIRAL GALAXIES ON THE SHAPE OF THE LOCAL K-BAND LUMINOSITY FUNCTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonne, Nicolas J.; Brown, Michael J. I.; Jones, Heath

2015-02-01

We have determined K-band luminosity functions for 13,325 local universe galaxies as a function of morphology and color (for K {sub tot} ≤ 10.75). Our sample is drawn from the Two Micron All Sky Survey Extended Source Catalog, with all sample galaxies having measured morphologies and distances (including 4219 archival redshift-independent distances). The luminosity function for our total sample is in good agreement with previous works, but is relatively smooth at faint magnitudes (due to bulk flow distance corrections). We investigated the differences due to morphological and color selection using 5417 sample galaxies with NASA Sloan Atlas optical colors and find thatmore » red spirals comprise 20%-50% of all spirals with –25 ≤ M{sub K}  < –20. Fainter than M{sub K} = –24, red spirals are as common as early types, explaining the different faint end slopes (α = –0.87 and –1.00 for red and early-types, respectively). While we find red spirals comprise more than 50% of all M{sub K}  < –25 spiral galaxies, they do not dominate the bright end of the overall red galaxy luminosity function, which is dominated by early-type galaxies. The brightest red spirals have ongoing star formation and those without are frequently misclassified as early-types. The faintest ones have an appearance and Sérsic indices consistent with faded disks, rather than true bulge-dominated galaxies.« less

A study of the discrepant QSO X-ray luminosity function from the HEAO-2 data archive

NASA Technical Reports Server (NTRS)

Margon, B.

1984-01-01

An in-progress investigation aimed at characterizing the X-ray luminosity of very faint QSOs is described. More than 100 faint, previously uncataloged QSOs which lie in areas imaged in X rays at very high sensitivity were discovered.

HIFLUGCS: X-ray luminosity-dynamical mass relation and its implications for mass calibrations with the SPIDERS and 4MOST surveys

NASA Astrophysics Data System (ADS)

Zhang, Yu-Ying; Reiprich, Thomas H.; Schneider, Peter; Clerc, Nicolas; Merloni, Andrea; Schwope, Axel; Borm, Katharina; Andernach, Heinz; Caretta, César A.; Wu, Xiang-Ping

2017-03-01

We present the relation of X-ray luminosity versus dynamical mass for 63 nearby clusters of galaxies in a flux-limited sample, the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS, consisting of 64 clusters). The luminosity measurements are obtained based on 1.3 Ms of clean XMM-Newton data and ROSAT pointed observations. The masses are estimated using optical spectroscopic redshifts of 13647 cluster galaxies in total. We classify clusters into disturbed and undisturbed based on a combination of the X-ray luminosity concentration and the offset between the brightest cluster galaxy and X-ray flux-weighted center. Given sufficient numbers (I.e., ≥45) of member galaxies when the dynamical masses are computed, the luminosity versus mass relations agree between the disturbed and undisturbed clusters. The cool-core clusters still dominate the scatter in the luminosity versus mass relation even when a core-corrected X-ray luminosity is used, which indicates that the scatter of this scaling relation mainly reflects the structure formation history of the clusters. As shown by the clusters with only few spectroscopically confirmed members, the dynamical masses can be underestimated and thus lead to a biased scaling relation. To investigate the potential of spectroscopic surveys to follow up high-redshift galaxy clusters or groups observed in X-ray surveys for the identifications and mass calibrations, we carried out Monte Carlo resampling of the cluster galaxy redshifts and calibrated the uncertainties of the redshift and dynamical mass estimates when only reduced numbers of galaxy redshifts per cluster are available. The resampling considers the SPIDERS and 4MOST configurations, designed for the follow-up of the eROSITA clusters, and was carried out for each cluster in the sample at the actual cluster redshift as well as at the assigned input cluster redshifts of 0.2, 0.4, 0.6, and 0.8. To follow up very distant clusters or groups, we also carried out the mass

Luminosity and redshift dependence of the covering factor of active galactic nuclei viewed with WISE and Sloan digital sky survey

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toba, Y.; Matsuhara, H.; Oyabu, S.

2014-06-10

In this work, we investigate the dependence of the covering factor (CF) of active galactic nuclei (AGNs) on the mid-infrared (MIR) luminosity and the redshift. We constructed 12 and 22 μm luminosity functions (LFs) at 0.006 ≤z ≤ 0.3 using Wide-field Infrared Survey Explorer (WISE) data. Combining the WISE catalog with Sloan Digital Sky Survey (SDSS) spectroscopic data, we selected 223,982 galaxies at 12 μm and 25,721 galaxies at 22 μm for spectroscopic classification. We then identified 16,355 AGNs at 12 μm and 4683 AGNs at 22 μm by their optical emission lines and cataloged classifications in the SDSS. Followingmore » that, we estimated the CF as the fraction of Type 2 AGN in all AGNs whose MIR emissions are dominated by the active nucleus (not their host galaxies) based on their MIR colors. We found that the CF decreased with increasing MIR luminosity, regardless of the choice of Type 2 AGN classification criteria, and the CF did not change significantly with redshift for z ≤ 0.2. Furthermore, we carried out various tests to determine the influence of selection bias and confirmed that similar dependences exist, even when taking these uncertainties into account. The luminosity dependence of the CF can be explained by the receding torus model, but the 'modified' receding torus model gives a slightly better fit, as suggested by Simpson.« less

Determining Black Hole Mass of AGN using FWHM of H-beta Emission Line and Luminosity Relations

NASA Astrophysics Data System (ADS)

Cameron, Thomas Jacob; Burris, Debra L.

2017-01-01

At the center of some active galaxies are super-massive black holes and for some time the accepted method of measuring the mass of such galaxies has been the method used by Vestergaard and Peterson, among others. By using the luminosity function which is related to H-β emission spectra from these black holes, both for cosmic redshift and for Fe-II emissions using IRAF. From there, H-β can accurately measure the full width half max of the H-beta line in these spectrum as well as the luminosity and these paired with the O-III lines give us an estimate on the mass of the black hole. The purpose of this is to compare it to the values obtained from the Mass-Pitch Angle relation being proposed by Kennefick et al. (2016 in preparation)

The gamma-ray luminosity function of millisecond pulsars and implications for the GeV excess

DOE PAGES

Hooper, Dan; Mohlabeng, Gopolang

2016-03-29

It has been proposed that a large population of unresolved millisecond pulsars (MSPs) could potentially account for the excess of GeV-scale gamma-rays observed from the region surrounding the Galactic Center. The viability of this scenario depends critically on the gamma-ray luminosity function of this source population, which determines how many MSPs Fermi should have already detected as resolved point sources. In this paper, we revisit the gamma-ray luminosity function of MSPs, without relying on uncertain distance measurements. Our determination, based on a comparison of models with the observed characteristics of the MSP population, suggests that Fermi should have already detectedmore » a significant number of sources associated with such a hypothesized Inner Galaxy population. As a result, we cannot rule out a scenario in which the MSPs residing near the Galactic Center are systematically less luminous than those present in the Galactic Plane or within globular clusters.« less

A Globular Cluster Luminosity Function Distance to NGC 4993 Hosting a Binary Neutron Star Merger GW170817/GRB 170817A

NASA Astrophysics Data System (ADS)

Lee, Myung Gyoon; Kang, Jisu; Im, Myungshin

2018-05-01

NGC 4993 hosts a binary neutron star merger, GW170817/GRB 170817A, emitting gravitational waves and electromagnetic waves. The distance to this galaxy is not well established. We select the globular cluster candidates from the Hubble Space Telescope (HST)/ACS F606W images of NGC 4993 in the archive, using the structural parameters of the detected sources. The radial number density distribution of these candidates shows a significant central concentration around the galaxy center at the galactocentric distance r < 50″, showing that they are mostly the members of NGC 4993. Also, the luminosity function of these candidates is fit well by a Gaussian function. Therefore, the selected candidates at r < 50″ are mostly considered to be globular clusters in NGC 4993. We derive an extinction-corrected turnover Vega magnitude in the luminosity function of the globular clusters at 20″ < r < 50″, F606W (max)0 = 25.36 ± 0.08 (V 0 = 25.52 ± 0.11) mag. Adopting the calibration of the turnover magnitudes of the globular clusters, M V (max) = ‑7.58 ± 0.11, we derive a distance to NGC 4993, d = 41.65 ± 3.00 Mpc ({(m-M)}0 = 33.10+/- 0.16). The systematic error of this method can be as large as ±0.3 mag. This value is consistent with the previous distance estimates based on the fundamental plane relation and the gravitational wave method in the literature. The distance in this study can be used to constrain the values of the parameters including the inclination angle of the binary system in the models of gravitational wave analysis.

Galaxy luminosity function: evolution at high redshift

NASA Astrophysics Data System (ADS)

Martinet, N.; Durret, F.; Guennou, L.; Adami, C.

2014-12-01

There are some disagreements about the abundance of faint galaxies in high redshift clusters. DAFT/FADA (Dark energy American French Team) is a medium redshift (0.4luminosity functions (GLFs) based on photometric redshifts for 30 clusters in B, V, R and I restframe bands. We show that completeness is a key parameter to understand the different observed behaviors when fitting the GLFs. We also investigate the evolution of GLFs with redshift for red and blue galaxy populations separately. We find a drop of the faint end of red GLFs which is more important at higher redshift while the blue GLF faint end remains flat in our redshift range. These results can be interpreted in terms of galaxy quenching. Faint blue galaxies transform into red ones which enrich the red sequence from high to low redshifts in clusters while some blue galaxies are still accreted from the environment, compensating for this evolution so that the global GLF does not seem to evolve.

VARIATIONS OF MID- AND FAR-INFRARED LUMINOSITIES AMONG EARLY-TYPE GALAXIES: RELATION TO STELLAR METALLICITY AND COLD DUST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mathews, William G.; Brighenti, Fabrizio; Temi, Pasquale

The Hubble morphological sequence from early to late galaxies corresponds to an increasing rate of specific star formation. The Hubble sequence also follows a banana-shaped correlation between 24 and 70 {mu}m luminosities, both normalized with the K-band luminosity. We show that this correlation is significantly tightened if galaxies with central active galactic nucleus (AGN) emission are removed, but the cosmic scatter of elliptical galaxies in both 24 and 70 {mu}m luminosities remains significant along the correlation. We find that the 24 {mu}m variation among ellipticals correlates with stellar metallicity, reflecting emission from hot dust in winds from asymptotic giant branchmore » stars of varying metallicity. Infrared surface brightness variations in elliptical galaxies indicate that the K - 24 color profile is U-shaped for reasons that are unclear. In some elliptical galaxies, cold interstellar dust emitting at 70 and 160 {mu}m may arise from recent gas-rich mergers. However, we argue that most of the large range of 70 {mu}m luminosity in elliptical galaxies is due to dust transported from galactic cores by feedback events in (currently IR-quiet) AGNs. Cooler dusty gas naturally accumulates in the cores of elliptical galaxies due to dust-cooled local stellar mass loss and may accrete onto the central black hole, releasing energy. AGN-heated gas can transport dust in cores 5-10 kpc out into the hot gas atmospheres where it radiates extended 70 {mu}m emission but is eventually destroyed by sputtering. This, and some modest star formation, defines a cycle of dust creation and destruction. Elliptical galaxies evidently undergo large transient excursions in the banana plot in times comparable to the sputtering time or AGN duty cycle, 10 Myr. Normally regarded as passive, elliptical galaxies are the most active galaxies in the IR color-color correlation.« less

DA white dwarfs from the LSS-GAC survey DR1: the preliminary luminosity and mass functions and formation rate

NASA Astrophysics Data System (ADS)

Rebassa-Mansergas, A.; Liu, X.-W.; Cojocaru, R.; Yuan, H.-B.; Torres, S.; García-Berro, E.; Xiang, M.-X.; Huang, Y.; Koester, D.; Hou, Y.; Li, G.; Zhang, Y.

2015-06-01

Modern large-scale surveys have allowed the identification of large numbers of white dwarfs. However, these surveys are subject to complicated target selection algorithms, which make it almost impossible to quantify to what extent the observational biases affect the observed populations. The LAMOST (Large Sky Area Multi-Object Fiber Spectroscopic Telescope) Spectroscopic Survey of the Galactic anticentre (LSS-GAC) follows a well-defined set of criteria for selecting targets for observations. This advantage over previous surveys has been fully exploited here to identify a small yet well-characterized magnitude-limited sample of hydrogen-rich (DA) white dwarfs. We derive preliminary LSS-GAC DA white dwarf luminosity and mass functions. The space density and average formation rate of DA white dwarfs we derive are 0.83 ± 0.16 × 10-3 pc-3 and 5.42 ± 0.08 × 10-13 pc-3 yr-1, respectively. Additionally, using an existing Monte Carlo population synthesis code we simulate the population of single DA white dwarfs in the Galactic anticentre, under various assumptions. The synthetic populations are passed through the LSS-GAC selection criteria, taking into account all possible observational biases. This allows us to perform a meaningful comparison of the observed and simulated distributions. We find that the LSS-GAC set of criteria is highly efficient in selecting white dwarfs for spectroscopic observations (80-85 per cent) and that, overall, our simulations reproduce well the observed luminosity function. However, they fail at reproducing an excess of massive white dwarfs present in the observed mass function. A plausible explanation for this is that a sizable fraction of massive white dwarfs in the Galaxy are the product of white dwarf-white dwarf mergers.

Variability Selected Low-Luminosity Active Galactic Nuclei in the 4 Ms Chandra Deep Field-South

NASA Technical Reports Server (NTRS)

Young, M.; Brandt, W. N.; Xue, Y. Q.; Paolillo, D. M.; Alexander, F. E.; Bauer, F. E.; Lehmer, B. D.; Luo, B.; Shemmer, O.; Schneider, D. P.;

A Deep Proper Motion Catalog Within the Sloan Digital Sky Survey Footprint. II. The White Dwarf Luminosity Function

NASA Astrophysics Data System (ADS)

Munn, Jeffrey A.; Harris, Hugh C.; von Hippel, Ted; Kilic, Mukremin; Liebert, James W.; Williams, Kurtis A.; DeGennaro, Steven; Jeffery, Elizabeth; Dame, Kyra; Gianninas, A.; Brown, Warren R.

2017-01-01

A catalog of 8472 white dwarf (WD) candidates is presented, selected using reduced proper motions from the deep proper motion catalog of Munn et al. Candidates are selected in the magnitude range 16< r< 21.5 over 980 square degrees, and 16< r< 21.3 over an additional 1276 square degrees, within the Sloan Digital Sky Survey (SDSS) imaging footprint. Distances, bolometric luminosities, and atmospheric compositions are derived by fitting SDSS ugriz photometry to pure hydrogen and helium model atmospheres (assuming surface gravities {log} {\\text{}}g=8). The disk white dwarf luminosity function (WDLF) is constructed using a sample of 2839 stars with 5.5< {M}{bol}< 17, with statistically significant numbers of stars cooler than the turnover in the luminosity function. The WDLF for the halo is also constructed, using a sample of 135 halo WDs with 5< {M}{bol}< 16. We find space densities of disk and halo WDs in the solar neighborhood of 5.5+/- 0.1× {10}-3 {{pc}}-3 and 3.5+/- 0.7× {10}-5 {{pc}}-3, respectively. We resolve the bump in the disk WDLF due to the onset of fully convective envelopes in WDs, and see indications of it in the halo WDLF as well.

Measuring the stellar luminosity function and spatial density profile of the inner 0.5 pc of the Milky Way nuclear star cluster

NASA Astrophysics Data System (ADS)

Do, Tuan; Ghez, Andrea; Lu, Jessica R.; Morris, Mark R.; Yelda, Sylvana; Martinez, Gregory D.; Peter, Annika H. G.; Wright, Shelley; Bullock, James; Kaplinghat, Manoj; Matthews, K.

2012-07-01

We report on measurements of the luminosity function of early (young) and late-type (old) stars in the central 0.5 pc of the Milky Way nuclear star cluster as well as the density profiles of both components. The young (~ 6 Myr) and old stars (> 1 Gyr) in this region provide different physical probes of the environment around a supermassive black hole; the luminosity function of the young stars offers us a way to measure the initial mass function from star formation in an extreme environment, while the density profile of the old stars offers us a probe of the dynamical interaction of a star cluster with a massive black hole. The two stellar populations are separated through a near-infrared spectroscopic survey using the integral-field spectrograph OSIRIS on Keck II behind the laser guide star adaptive optics system. This spectroscopic survey is able to separate early-type (young) and late-type (old) stars with a completeness of 50% at K' = 15.5. We describe our method of completeness correction using a combination of star planting simulations and Bayesian inference. The completeness corrected luminosity function of the early-type stars contains significantly more young stars at faint magnitudes compared to previous surveys with similar depth. In addition, by using proper motion and radial velocity measurements along with anisotropic spherical Jeans modeling of the cluster, it is possible to measure the spatial density profile of the old stars, which has been difficult to constrain with number counts alone. The most probable model shows that the spatial density profile, n(r) propto r-γ, to be shallow with γ = 0.4 ± 0.2, which is much flatter than the dynamically relaxed case of γ = 3/2 to 7/4, but does rule out a 'hole' in the distribution of old stars. We show, for the first time, that the spatial density profile, the black hole mass, and velocity anisotropy can be fit simultaneously to obtain a black hole mass that is consistent with that derived from

The seven sisters DANCe. III. Projected spatial distribution

NASA Astrophysics Data System (ADS)

Olivares, J.; Moraux, E.; Sarro, L. M.; Bouy, H.; Berihuete, A.; Barrado, D.; Huelamo, N.; Bertin, E.; Bouvier, J.

2018-04-01

Context. Membership analyses of the DANCe and Tycho + DANCe data sets provide the largest and least contaminated sample of Pleiades candidate members to date. Aims: We aim at reassessing the different proposals for the number surface density of the Pleiades in the light of the new and most complete list of candidate members, and inferring the parameters of the most adequate model. Methods: We compute the Bayesian evidence and Bayes Factors for variations of the classical radial models. These include elliptical symmetry, and luminosity segregation. As a by-product of the model comparison, we obtain posterior distributions for each set of model parameters. Results: We find that the model comparison results depend on the spatial extent of the region used for the analysis. For a circle of 11.5 parsecs around the cluster centre (the most homogeneous and complete region), we find no compelling reason to abandon King's model, although the Generalised King model introduced here has slightly better fitting properties. Furthermore, we find strong evidence against radially symmetric models when compared to the elliptic extensions. Finally, we find that including mass segregation in the form of luminosity segregation in the J band is strongly supported in all our models. Conclusions: We have put the question of the projected spatial distribution of the Pleiades cluster on a solid probabilistic framework, and inferred its properties using the most exhaustive and least contaminated list of Pleiades candidate members available to date. Our results suggest however that this sample may still lack about 20% of the expected number of cluster members. Therefore, this study should be revised when the completeness and homogeneity of the data can be extended beyond the 11.5 parsecs limit. Such a study will allow for more precise determination of the Pleiades spatial distribution, its tidal radius, ellipticity, number of objects and total mass.

The CALYMHA survey: Lyα luminosity function and global escape fraction of Lyα photons at z = 2.23

NASA Astrophysics Data System (ADS)

Sobral, David; Matthee, Jorryt; Best, Philip; Stroe, Andra; Röttgering, Huub; Oteo, Iván; Smail, Ian; Morabito, Leah; Paulino-Afonso, Ana

2017-04-01

We present the CAlibrating LYMan-α with Hα (CALYMHA) pilot survey and new results on Lyman α (Lyα) selected galaxies at z ˜ 2. We use a custom-built Lyα narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z = 2.23 Hα HiZELS survey. Here, we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3σ line flux limit of ˜4 × 10-17 erg s-1 cm-2, and a Lyα luminosity limit of ˜1042.3 erg s-1. We find 188 Lyα emitters over 7.3 × 105 Mpc3, but also find significant numbers of other line-emitting sources corresponding to He II, C III] and C IV emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lyα luminosity function at z = 2.23 is very well described by a Schechter function up to LLy α ≈ 1043 erg s-1 with L^{ast }=10^{42.59^{+0.16}_{-0.08}} erg s-1, φ ^{ast }=10^{-3.09^{+0.14}_{-0.34}} Mpc-3 and α = -1.75 ± 0.25. Above LLy α ≈ 1043 erg s-1, the Lyα luminosity function becomes power-law like, driven by X-ray AGN. We find that Lyα-selected emitters have a high escape fraction of 37 ± 7 per cent, anticorrelated with Lyα luminosity and correlated with Lyα equivalent width. Lyα emitters have ubiquitous large (≈40 kpc) Lyα haloes, ˜2 times larger than their Hα extents. By directly comparing our Lyα and Hα luminosity functions, we find that the global/overall escape fraction of Lyα photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1 ± 0.2 per cent at the peak of the star formation history. An extra 3.3 ± 0.3 per cent of Lyα photons likely still escape, but at larger radii.

An X-ray/SDSS sample. I. Multi-phase outflow incidence and dependence on AGN luminosity

NASA Astrophysics Data System (ADS)

Perna, M.; Lanzuisi, G.; Brusa, M.; Mignoli, M.; Cresci, G.

2017-07-01

Aims: The connection between the growth of super-massive black holes (SMBHs) and the evolution of their host galaxies is nowadays well established, although the underlying mechanisms explaining their mutual relations are still debated. Multi-phase fast, massive outflows have been postulated to play a crucial role in this process. The aim of this work is to constrain the nature and the fraction of outflowing gas in active galactic nuclei (AGNs) as well as the nuclear conditions possibly at the origin of such phenomena. Methods: We present a large spectroscopic sample of X-ray detected SDSS AGNs at z< 0.8 with a high signal-to-noise ratio in the [O III]λ5007 line to unveil the faint wings of the emission profile associated with AGN-driven outflows. We used X-ray and optical flux ratio diagnostics to select the sample. We derived physical and kinematic characterization by re-analysing optical (and X-ray) spectra. Results: We derive the incidence of ionized ( 40%) and atomic (<1%) outflows covering a wide range of AGN bolometric luminosity from 1042 to 1046 erg/s. We also derive bolometric luminosities and X-ray bolometric corrections to test whether the presence of outflows is associated with an X-ray loudness, as suggested by our recent results obtained by studying high-z QSOs. Conclusions: We study the relations between the outflow velocity inferred from [O III] kinematic analysis and different AGN power tracers, such as black hole mass (MBH), [O III], and X-ray luminosity. We show a well-defined positive trend between outflow velocity and LX, for the first time, over a range of 5 order of magnitudes. Overall, we find that in the QSO-luminosity regime and at MBH> 108M⊙ the fraction of AGNs with outflows becomes >50%. Finally, we discuss our results about X-ray bolometric corrections and outflow incidence in cold and ionized phases in the context of an evolutionary sequence allowing two distinct stages for the feedback phase: first, an initial stage characterized

CAN THE SUBSONIC ACCRETION MODEL EXPLAIN THE SPIN PERIOD DISTRIBUTION OF WIND-FED X-RAY PULSARS?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Tao; Shao, Yong; Li, Xiang-Dong, E-mail: lixd@nju.edu.cn

Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently, Shakura et al. suggested a subsonic accretion model for low-luminosity (<4 × 10{sup 36} erg s{sup −1}), wind-fed X-ray pulsars. To test the feasibility of this model, we investigate the spin period distribution of wind-fed X-ray pulsars with a supergiant companion star, using a population synthesis method. We find that the modeled distribution of supergiant HMXBs in the spin period–orbital period diagram is consistent with observations, provided that the winds from the donor stars have relatively low terminal velocities (≲1000 kmmore » s{sup −1}). The measured wind velocities in several supergiant HMXBs seem to favor this viewpoint. The predicted number ratio of wind-fed X-ray pulsars with persistent X-ray luminosities that are higher and lower than 4 × 10{sup 36} erg s{sup −1} is about 1:10.« less

Simple luminosity normalization of greenness, yellowness and redness/greenness for comparison of leaf spectral profiles in multi-temporally acquired remote sensing images.

PubMed

Doi, Ryoichi

2012-09-01

Observation of leaf colour (spectral profiles) through remote sensing is an effective method of identifying the spatial distribution patterns of abnormalities in leaf colour, which enables appropriate plant management measures to be taken. However, because the brightness of remote sensing images varies with acquisition time, in the observation of leaf spectral profiles in multi-temporally acquired remote sensing images, changes in brightness must be taken into account. This study identified a simple luminosity normalization technique that enables leaf colours to be compared in remote sensing images over time. The intensity values of green and yellow (green+red) exhibited strong linear relationships with luminosity (R2 greater than 0.926) when various invariant rooftops in Bangkok or Tokyo were spectralprofiled using remote sensing images acquired at different time points. The values of the coefficient and constant or the coefficient of the formulae describing the intensity of green or yellow were comparable among the single Bangkok site and the two Tokyo sites, indicating the technique's general applicability. For single rooftops, the values of the coefficient of variation for green, yellow, and red/green were 16% or less (n=6-11), indicating an accuracy not less than those of well-established remote sensing measures such as the normalized difference vegetation index. After obtaining the above linear relationships, raw intensity values were normalized and a temporal comparison of the spectral profiles of the canopies of evergreen and deciduous tree species in Tokyo was made to highlight the changes in the canopies' spectral profiles. Future aspects of this technique are discussed herein.

The SDSS u-band Galaxy Survey: Luminosity functions and evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldry, Ivan K.; Glazebrook, K.; Budavari, T.

2005-01-01

We construct and analyze a u-band selected galaxy sample from the SDSS Southern Survey, which covers 275 deg{sup 2}. The sample includes 43223 galaxies with spectroscopic redshifts in the range 0.005 < z < 0.3 and with 14.5 < u < 20.5. The S/N in the u-band Petrosian aperture is improved by coadding multiple epochs of imaging data and by including sky-subtraction corrections. Luminosity functions for the near-UV {sup 0.1}u band ({lambda} {approx} 322 {+-} 26 nm) are determined in redshift slices of width 0.02, which show a highly significant evolution in M* of -0.8 {+-} 0.1 mag between zmore » = 0 and 0.3; with M* - 5 log h{sub 70} = -18.84 {+-} 0.05 (AB mag), log {phi}* = -2.06 {+-} 0.03 (h{sub 70}{sup 3} Mpc{sup -3}) and log {rho}{sub L} = 19.11 {+-} 0.02 (h{sub 70} W Hz{sup -1}Mpc{sup -3}) at z = 0.1. The faint-end slope determined for z < 0.06 is given by {alpha} = -1.05 {+-} 0.08. This is in agreement with recent determinations from GALEX at shorter wavelengths. Comparing our z < 0.3 luminosity density measurements with 0.2 < z < 1.2 from COMBO-17, we find that the 280-nm density evolves as {rho}{sub L} {proportional_to} (1+z){sup {beta}} with {beta} = 2.1 {+-} 0.2; and find no evidence for any change in slope over this redshift range. By comparing with other measurements of cosmic star formation history, we estimate that the effective dust attenuation at 280 nm has increased by 0.8 {+-} 0.3 mag between z = 0 and 1.« less

Characterizing Quasar Outflows III: SEDs, and Bolometric Luminosity Estimates

NASA Astrophysics Data System (ADS)

Richmond, Joseph; Robbins, J. M.; Ganguly, R.; Stark, M. A.; Christenson, D. H.; Derseweh, J. A.; Townsend, S. L.

2012-05-01

Galaxy evolution models have shown that quasars are a crucial ingredient in the evolution of massive galaxies. Outflows play a key role in the story of quasars and their host galaxies, by helping regulate the accretion process, the star-formation rate and mass of the host galaxy (i.e., feedback). The prescription for modeling outflows as a contributor to feedback requires knowledge of the outflow velocity, geometry, and column density. In particular, we need to understand how these depend on physical parameters and how much is determined stochastically (and with what distribution). For this purpose, we are examining a sample of 11000 z=1.7-2.0 quasars from the Sloan Digital Sky Survey. This redshift range permits the following from the SDSS spectra: (1) separation of objects that do and do not exhibit outflows; (2) classification/measurement of outflow properties (ionization, velocity, velocity width); and (3) measurements of UV emission line and continuum parameters. In this poster, we add photometry from both the Two Micron All-Sky Survey (2MASS) and from the Wide-Field Infrared Survey Explorer (WISE). 2MASS photometry covers the rest-frame optical regime of these qusars, while the WISE W1, W2, and W3 bands cover the rest-frame wavelength ranges 0.9-1.27 micron, 1.35-1.75 micron, and 2.52-5.51 micron, respectively. The preliminary release of WISE data cover 3800 of our quasars. In an accompnying poster, we have subjectively divided these quasars into four categories: broad absorption-line quasars (2700 objects), associated absorption-line quasars (1700 objects), reddened quasars (160 objects), and unabsorbed/unreddened quasars (6300 objects). Here, we present average SEDs for these subsamples, estimates of bolometric luminosity, and explore changes in SED based on both outflow properties and quasar physical properties. This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. 09-ADP09-0016 issued through the

Effect of luminosity on color discrimination of dichromatic marmosets (Callithrix jacchus).

PubMed

Freitag, Fabio Batista; Pessoa, Daniel Marques Almeida

2012-02-01

Psychophysical data have shown that under mesopic conditions cones and rods can interact, improving color vision. Since electrophysiological data have suggested that rods of dichromatic marmosets appear to be active at higher luminance, we aimed to investigate the effect of different levels of sunlight on the foraging abilities of male dichromatic marmosets. Captive marmosets were observed under three different conditions, with respect to their performance in detecting colored food items against a green background. Compared to high and low light intensities, intermediate luminosities significantly increased detection of orange targets by male dichromats, an indication of rod intrusion. © 2012 Optical Society of America

The HELLAS2XMM survey. IV. Optical identifications and the evolution of the accretion luminosity in the Universe

NASA Astrophysics Data System (ADS)

Fiore, F.; Brusa, M.; Cocchia, F.; Baldi, A.; Carangelo, N.; Ciliegi, P.; Comastri, A.; La Franca, F.; Maiolino, R.; Matt, G.; Molendi, S.; Mignoli, M.; Perola, G. C.; Severgnini, P.; Vignali, C.

2003-10-01

We present results from the photometric and spectroscopic identification of 122 X-ray sources recently discovered by XMM-Newton in the 2-10 keV band (the HELLAS2XMM 1dF sample). Their flux cover the range 8*E-15-4*E-13 erg cm-2 s-1 and the total area surveyed is 0.9 square degrees. One of the most interesting results (which is found also in deeper sourveys) is that about 20% of the hard X-ray selected sources have an X-ray to optical flux ratio (X/O) ten times or more higher than that of optically selected AGN. Unlike the faint sources found in the ultra-deep Chandra and XMM-Newton surveys, which reach X-ray (and optical) fluxes more than one order of magnitude lower than the HELLAS2XMM survey sources, many of the extreme X/O sources in our sample have Rprotect la25 and are therefore accessible to optical spectroscopy. We report the identification of 13 sources with X/Oprotect ga10 (to be compared with 9 sources known from the deeper, pencil-beam surveys). Eight of them are narrow line QSO (seemingly the extension to very high luminosity of the type 2 Seyfert galaxies), four are broad line QSO. The results from our survey are also used to make reliable predictions about the luminosity of the sources not yet spectroscopically identified, both in our sample and in deeper Chandra and XMM-Newton samples. We then use a combined sample of 317 hard X-ray selected sources (HELLAS2XMM 1dF, Chandra Deep Field North 1Msec, Chandra SSA13 and XMM-Newton Lockman Hole flux limited samples), 221 with measured redshifts, to evaluate the cosmological evolution of the hard X-ray source's number and luminosity densities. Looking backward in time, the low luminosity sources (log L2-10 keV=43-44 erg s-1) increase in number at a much slower rate than the very high luminosity sources (log L2-10 keV >44.5 erg s-1), reaching a maximum around z=1 and then levelling off beyond z=2. This translates into an accretion driven luminosity density which is dominated by sources with log L2-10 keV <44

Archival Investigation of Outburst Sites and Progenitors of Extragalactic Intermediate-Luminosity Mid-IR Transients

NASA Astrophysics Data System (ADS)

Bond, Howard

2017-08-01

Our team is using Spitzer in a long-term search for extragalactic mid-infrared (MIR) variable stars and transients-the SPIRITS project (SPitzer InfraRed Intensive Transients Survey). In this first exploration of luminous astrophysical transients in the infrared, we have discovered a puzzling new class. We call them SPRITEs: eSPecially Red Intermediate-luminosity Transient Events. They have maximum MIR luminosities between supernovae and classical novae, but are not detected in the optical to deep limits. To date, we have discovered more than 50 SPRITEs in galaxies out to 17 Mpc. In this Archival Research proposal, we request support in order to investigate the pre-eruption sites in HST images of some 3 dozen SPRITEs discovered to date, and an additional 2 dozen that we are likely to find until the end of Spitzer observing in late 2018. Our aims are (1) characterize the pre-outburst environments at HST resolution in the visible and near-IR, to understand the stellar populations, stellar ages and masses, and interstellar medium at the outburst sites; (2) search for progenitors; (3) help prepare the way for a better understanding of the nature of extragalactic IR transients that will be investigated by JWST.

The massive end of the luminosity and stellar mass functions and clustering from CMASS to SDSS: evidence for and against passive evolution

NASA Astrophysics Data System (ADS)

Bernardi, M.; Meert, A.; Sheth, R. K.; Huertas-Company, M.; Maraston, C.; Shankar, F.; Vikram, V.

2016-02-01

We describe the luminosity function, based on Sérsic fits to the light profiles, of CMASS galaxies at z ˜ 0.55. Compared to previous estimates, our Sérsic-based reductions imply more luminous, massive galaxies, consistent with the effects of Sérsic- rather than Petrosian or de Vaucouleur-based photometry on the Sloan Digital Sky Survey (SDSS) main galaxy sample at z ˜ 0.1. This implies a significant revision of the high-mass end of the correlation between stellar and halo mass. Inferences about the evolution of the luminosity and stellar mass functions depend strongly on the assumed, and uncertain, k + e corrections. In turn, these depend on the assumed age of the population. Applying k + e corrections taken from fitting the models of Maraston et al. to the colours of both SDSS and CMASS galaxies, the evolution of the luminosity and stellar mass functions appears impressively passive, provided that the fits are required to return old ages. However, when matched in comoving number- or luminosity-density, the SDSS galaxies are less strongly clustered compared to their counterparts in CMASS. This rules out the passive evolution scenario, and, indeed, any minor merger scenarios which preserve the rank ordering in stellar mass of the population. Potential incompletenesses in the CMASS sample would further enhance this mismatch. Our analysis highlights the virtue of combining clustering measurements with number counts.

Bayesian inference of galaxy formation from the K-band luminosity function of galaxies: tensions between theory and observation

NASA Astrophysics Data System (ADS)

Lu, Yu; Mo, H. J.; Katz, Neal; Weinberg, Martin D.

2012-04-01

We conduct Bayesian model inferences from the observed K-band luminosity function of galaxies in the local Universe, using the semi-analytic model (SAM) of galaxy formation introduced in Lu et al. The prior distributions for the 14 free parameters include a large range of possible models. We find that some of the free parameters, e.g. the characteristic scales for quenching star formation in both high-mass and low-mass haloes, are already tightly constrained by the single data set. The posterior distribution includes the model parameters adopted in other SAMs. By marginalizing over the posterior distribution, we make predictions that include the full inferential uncertainties for the colour-magnitude relation, the Tully-Fisher relation, the conditional stellar mass function of galaxies in haloes of different masses, the H I mass function, the redshift evolution of the stellar mass function of galaxies and the global star formation history. Using posterior predictive checking with the available observational results, we find that the model family (i) predicts a Tully-Fisher relation that is curved; (ii) significantly overpredicts the satellite fraction; (iii) vastly overpredicts the H I mass function; (iv) predicts high-z stellar mass functions that have too many low-mass galaxies and too few high-mass ones and (v) predicts a redshift evolution of the stellar mass density and the star formation history that are in moderate disagreement. These results suggest that some important processes are still missing in the current model family, and we discuss a number of possible solutions to solve the discrepancies, such as interactions between galaxies and dark matter haloes, tidal stripping, the bimodal accretion of gas, preheating and a redshift-dependent initial mass function.

ROSAT X-ray observations of late-type evolved stars: On the relationship between coronal temperatures and luminosities

NASA Technical Reports Server (NTRS)

Maggio, A.; Sciortino, S.; Harnden, F. R., Jr.

1994-01-01

We present ROSAT Position Sensitive Proportional Counters (PSPC) X-ray observations of three near-solar-mass stars, in different evolutionary phases beyond the main sequence: eta Sco (F3 III-IV), iota Vir (F6 III), and HD 74772 (G5 III). All three of these nearby, presumably single stars have been detected, and we have collected enough counts to perform a detailed analysis of their soft X-ray spectra. While the X-ray spectra of eta Sco and HD 74772 can be fitted with Raymond-Smith thermal models with temperatures around 2 x 10(exp 6) K, the high signal-to-noise spectrum of iota Vir provides unambiguous evidence of a multitemperature plasma, with a two-temperature best-fit model with components at approximately 2 x 10(exp 6) K and 8 x 10(exp 6) K. Evidence of some hot plasma (T approximately 10(exp 7) K) has been also found for HD 74772. The present data, compared with spectral fitting results for other late-type stars observed with the Einstein Observatory, indicate that the low X-ray luminosity giants (L(sub x) is less than 5 x 10(exp 28) ergs/s) do not share with the higher X-ray luminosity stars of the same class the property of having substantial amount of 10(exp 7) K plasma. Moreover, our results confirm the trend of increasing X-ray luminosities with increasing coronal temperatures.

Star Formation Rate Distribution in the Galaxy NGC 1232

NASA Astrophysics Data System (ADS)

Araújo de Souza, Alexandre; Martins, Lucimara P.; Rodríguez-Ardila, Alberto; Fraga, Luciano

2018-06-01

NGC 1232 is a face-on spiral galaxy and a great laboratory for the study of star formation due to its proximity. We obtained high spatial resolution Hα images of this galaxy, with adaptive optics, using the SAM instrument at the SOAR telescope, and used these images to study its H II regions. These observations allowed us to produce the most complete H II region catalog for it to date, with a total of 976 sources. This doubles the number of H II regions previously found for this object. We used these data to construct the H II luminosity function, and obtained a power-law index lower than the typical values found for Sc galaxies. This shallower slope is related to the presence of a significant number of high-luminosity H II regions (log L > 39 dex). We also constructed the size distribution function, verifying that, as for most galaxies, NGC 1232 follows an exponential law. We also used the Hα luminosity to calculate the star formation rate. An extremely interesting fact about this galaxy is that X-ray diffuse observations suggest that NGC 1232 recently suffered a collision with a dwarf galaxy. We found an absence of star formation around the region where the X-ray emission is more intense, which we interpret as a star formation quenching due to the collision. Along with that, we found an excess of star-forming regions in the northeast part of the galaxy, where the X-ray emission is less intense.

Modelling galaxy clustering: halo occupation distribution versus subhalo matching.

PubMed

Guo, Hong; Zheng, Zheng; Behroozi, Peter S; Zehavi, Idit; Chuang, Chia-Hsun; Comparat, Johan; Favole, Ginevra; Gottloeber, Stefan; Klypin, Anatoly; Prada, Francisco; Rodríguez-Torres, Sergio A; Weinberg, David H; Yepes, Gustavo

2016-07-01

We model the luminosity-dependent projected and redshift-space two-point correlation functions (2PCFs) of the Sloan Digital Sky Survey (SDSS) Data Release 7 Main galaxy sample, using the halo occupation distribution (HOD) model and the subhalo abundance matching (SHAM) model and its extension. All the models are built on the same high-resolution N -body simulations. We find that the HOD model generally provides the best performance in reproducing the clustering measurements in both projected and redshift spaces. The SHAM model with the same halo-galaxy relation for central and satellite galaxies (or distinct haloes and subhaloes), when including scatters, has a best-fitting χ 2 /dof around 2-3. We therefore extend the SHAM model to the subhalo clustering and abundance matching (SCAM) by allowing the central and satellite galaxies to have different galaxy-halo relations. We infer the corresponding halo/subhalo parameters by jointly fitting the galaxy 2PCFs and abundances and consider subhaloes selected based on three properties, the mass M acc at the time of accretion, the maximum circular velocity V acc at the time of accretion, and the peak maximum circular velocity V peak over the history of the subhaloes. The three subhalo models work well for luminous galaxy samples (with luminosity above L * ). For low-luminosity samples, the V acc model stands out in reproducing the data, with the V peak model slightly worse, while the M acc model fails to fit the data. We discuss the implications of the modelling results.

Confirmation of a Steep Luminosity Function for Ly alpha Emitters at z 5.7: a Major Component of Reionization

NASA Technical Reports Server (NTRS)

Dressler, Alan; Henry, Alaina L.; Martin, Crystal L.; Sawicki, Marcin; McCarthy, Patrick; Villaneuva, Edward

2014-01-01

We report the first direct and robust measurement of the faint-end slope of the Ly-alpha emitter (LAE) luminosity function at z = 5.7. Candidate LAEs from a low-spectral-resolution blind search with IMACS on Magellan- Baade were targeted at higher resolution to distinguish high redshift LAEs from foreground galaxies. All but 2 of our 42 single-emission-line systems are fainter than F = 2.0×10(exp-17) ergs s(exp-1) cm(exp-2), making these the faintest emission-lines observed for a z = 5.7 sample with known completeness, an essential property for determining the faint end slope of the LAE luminosity function. We find 13 LAEs as compared to 29 foreground galaxies, in very good agreement with the modeled foreground counts predicted in Dressler et al. (2011a) that had been used to estimate a faint-end slope of alpha = -2.0 for the LAE luminosity function. A 32% LAE fraction, LAE/(LAE+foreground) within the flux interval F = 2-20 × 10(exp-18) ergs s(exp-1) cm(exp-2) constrains the faint end slope of the luminosity function to -1.95 greater than alpha greater than -2.35 (1 delta). We show how this steep LF should provide, to the limit of our observations, more than 20% of the flux necessary to maintain ionization at z = 5.7, with a factor-of-ten extrapolation in flux reaching more than 55%. We suggest that this bodes well for a comparable contribution by similar, low-mass star forming galaxies at higher-redshift - within the reionization epoch at z greater than approximately 7, only 250 Myr earlier - and that such systems provide a substantial, if not dominant, contribution to the late-stage reionization of the IGM.

THE CENTRAL MOLECULAR GAS STRUCTURE IN LINERS WITH LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI: EVIDENCE FOR GRADUAL DISAPPEARANCE OF THE TORUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mueller-Sanchez, F.; Prieto, M. A.; Mezcua, M.

2013-01-20

We present observations of the molecular gas in the nuclear environment of three prototypical low-luminosity active galactic nuclei (LLAGNs), based on VLT/SINFONI AO-assisted integral-field spectroscopy of H{sub 2} 1-0 S(1) emission at angular resolutions of {approx}0.''17. On scales of 50-150 pc, the spatial distribution and kinematics of the molecular gas are consistent with a rotating thin disk, where the ratio of rotation (V) to dispersion ({sigma}) exceeds unity. However, in the central 50 pc, the observations reveal a geometrically and optically thick structure of molecular gas (V/{sigma} < 1 and N{sub H} > 10{sup 23} cm{sup -2}) that is likelymore » to be associated with the outer extent of any smaller scale obscuring structure. In contrast to Seyfert galaxies, the molecular gas in LLAGNs has a V/{sigma} < 1 over an area that is {approx}9 times smaller and column densities that are on average {approx}3 times smaller. We interpret these results as evidence for a gradual disappearance of the nuclear obscuring structure. While a disk wind may not be able to maintain a thick rotating structure at these luminosities, inflow of material into the nuclear region could provide sufficient energy to sustain it. In this context, LLAGNs may represent the final phase of accretion in current theories of torus evolution. While the inflow rate is considerable during the Seyfert phase, it is slowly decreasing, and the collisional disk is gradually transitioning to become geometrically thin. Furthermore, the nuclear region of these LLAGNs is dominated by intermediate-age/old stellar populations (with little or no ongoing star formation), consistent with a late stage of evolution.« less

Wind Variability in Intermediate Luminosity B Supergiants

NASA Technical Reports Server (NTRS)

Massa, Derck

1996-01-01

This study used the unique spectroscopic diagnostics of intermediate luminosity B supergiants to determine the ubiquity and nature of wind variability. Specifically, (1) A detailed analysis of HD 64760 demonstrated massive ejections into its wind, provided the first clear demonstration of a 'photospheric connection' and ionization shifts in a stellar wind; (2) The international 'IUE MEGA campaign' obtained unprecedented temporal coverage of wind variability in rapidly rotating stars and demonstrated regularly repeating wind features originating in the photosphere; (3) A detailed analysis of wind variability in the rapidly rotating B1 Ib, gamma Ara demonstrated a two component wind with distinctly different mean states at different epochs; (4) A follow-on campaign to the MEGA project to study slowly rotating stars was organized and deemed a key project by ESA/NASA, and will obtain 30 days of IUE observations in May-June 1996; and (5) A global survey of archival IUE time series identified recurring spectroscopic signatures, identified with different physical phenomena. Items 4 and 5 above are still in progress and will be completed this summer in collaboration with Raman Prinja at University College, London.

The Luminosity Function and Star Formation Rate Between Redshifts of 0.07 and 1.47 for Narrow-band Emitters in the Subaru Deep Field

NASA Astrophysics Data System (ADS)

Ly, Chun; Malkan, M.; Kashikawa, N.; Shimasaku, K.; Doi, M.; Nagao, T.; Iye, M.; Kodama, T.; Morokuma, T.; Motohara, K.

2006-06-01

Subaru Deep Field line-emitting galaxies in four narrow-band filters at low and intermediate redshifts are presented. Broad-band colors, follow-up optical spectroscopy, and multiple narrow-band filters are used to distinguish Hα, [OII], and [OIII] emitters between redshifts of 0.07 and 1.47 to construct their averaged rest-frame optical-to-UV SED and luminosity functions. These luminosity functions are derived down to faint magnitudes, which allows for a more accurate determination of the faint end slope. With a large (N 200-900) sample for each redshift interval, a Schechter profile is fitted to each luminosity function. Prior to dust extinction corrections, the [OIII] and [OII] luminosity functions reported in this paper agree reasonably well with those of Hippelein et al (2003). The z=0.066-0.092 Hα LF agrees with those of Jones & Bland-Hawthorn (2001), but for z=0.24 and 0.40, their number density is higher by a factor of two or more. The z=0.08 Hα LF, which reaches two orders of magnitude fainter than Gallego et al. (1995), is steeper by 25%. This indicates that there are more low luminosity star-forming galaxies for z<0.1 than predicted. The faint end slope α and φ* show a strong evolution with redshift while L* show little evolution. The evolution in α indicates that low-luminosity galaxies have a stronger evolution compared to brighter ones. Integrated star formation rate densities are derived via Hα for 0.07

VizieR Online Data Catalog: Be star rotational velocities distribution (Zorec+, 2016)

NASA Astrophysics Data System (ADS)

Zorec, J.; Fremat, Y.; Domiciano de Souza, A.; Royer, F.; Cidale, L.; Hubert, A.-M.; Semaan, T.; Martayan, C.; Cochetti, Y. R.; Arias, M. L.; Aidelman, Y.; Stee, P.

2016-06-01

Table 1 contains apparent fundamental parameters of the 233 Galactic Be stars. For each Be star is given the HD number, the effective temperature, effective surface gravity and bolometric luminosity. They correspond to the parameters of a plan parallel model of stellar atmosphere that fits the energy distribution of the stellar apparent hemisphere rotationally deformed. In Table 1 are also given the color excess E(B-V) and the vsini rotation parameter determined with model atmospheres of rigidly rotating stars. For each parameter is given the 1sigma uncertainty. In the notes are given the authors that produced some reported the data or the methods used to obtain the data. Table 4 contains parent-non-rotating-counterpart fundamental parameters of 233 Be stars: effective temperature, effective surface gravity, bolometric luminosity in solar units, stellar mass in solar units, fractional main-sequence stellar age, pnrc-apparent rotational velocity, critical velocity, ratio of centrifugal-force to gravity in the equator, inclination angle of the rotational axis. (2 data files).

Exploration of a High Luminosity 100 TeV Proton Antiproton Collider

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oliveros, Sandra J.; Summers, Don; Cremaldi, Lucien

New physics is being explored with the Large Hadron Collider at CERN and with Intensity Frontier programs at Fermilab and KEK. The energy scale for new physics is known to be in the multi-TeV range, signaling the need for a future collider which well surpasses this energy scale. We explore a 10more » $$^{\\,34}$$ cm$$^{-2}$$ s$$^{-1}$$ luminosity, 100 TeV $$p\\bar{p}$$ collider with 7$$\\times$$ the energy of the LHC but only 2$$\\times$$ as much NbTi superconductor, motivating the choice of 4.5 T single bore dipoles. The cross section for many high mass states is 10 times higher in $$p\\bar{p}$$ than $pp$ collisions. Antiquarks for production can come directly from an antiproton rather than indirectly from gluon splitting. The higher cross sections reduce the synchrotron radiation in superconducting magnets and the number of events per beam crossing, because lower beam currents can produce the same rare event rates. Events are more centrally produced, allowing a more compact detector with less space between quadrupole triplets and a smaller $$\\beta^{*}$$ for higher luminosity. A Fermilab-like $$\\bar p$$ source would disperse the beam into 12 momentum channels to capture more antiprotons. Because stochastic cooling time scales as the number of particles, 12 cooling ring sets would be used. Each set would include phase rotation to lower momentum spreads, equalize all momentum channels, and stochastically cool. One electron cooling ring would follow the stochastic cooling rings. Finally antiprotons would be recycled during runs without leaving the collider ring by joining them to new bunches with synchrotron damping.« less

The X-Ray Luminosity-Mass Relation for Local Clusters of Galaxies

NASA Astrophysics Data System (ADS)

Stanek, Rebecca; Evrard, A.; Boehringer, H.; Schuecker, P.; Nord, B.

2006-12-01

My thesis is centered on investigating scaling relations of galaxy clusters. Focusing on the relationship between soft X-ray luminosity and mass (L-M) for low-redshift clusters of galaxies, I have determined the mean parameters to 5%, and calculated a formal measure of the scatter in the L-M relation. I model the L-M relation with a conditional probability function including a mean power-law scaling relation, L Mpρsc(z), and log-normal scatter in mass at fixed luminosity, σlnM. Convolving with the halo mass function, I compute expected counts in redshift and flux that, after appropriate survey effects are included, are compared to REFLEX survey data. Combining the likelihood analysis with the measured variance in L-T relation from HIFLUGCS, I obtain fit parameters p=1.59+/-0.05, lnL15,0=1.34+/-0.09, and σlnM=0.37+/-0.05 for self-similar redshift evolution (s = 7/6) in a concordance (Ωm=0.3, ΩΛ=0.7, σ8=0.9) universe. I find a substantially (factor 2) dimmer intercept and slightly steeper slope than the values published using hydrostatic mass estimates of the HIFLUGCS sample and show that a Malmquist bias of the X-ray flux-limited sample accounts for this effect. I accommodate the new WMAP constraints with a compromise model with Ωm=0.24, σ8=0.85, and somewhat lower scatter σlnM=0.25. I will also present work in progress from galaxy cluster population statistics in the Millennium Simulation with Gas (MSG), specifically focusing on the scatter and covariance between cluster properties at a fixed epoch.

PHOTOMETRIC PROPERTIES AND LUMINOSITY FUNCTION OF NEARBY MASSIVE EARLY-TYPE GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Y. Q.; Xia, X. Y.; Hao, C. N.

We perform photometric analyses of a bright early-type galaxy sample with 2949 galaxies (M{sub r} < -22.5 mag) in the redshift range of 0.05-0.15, drawn from the Sloan Digital Sky Survey (SDSS) DR7 with morphological classification from Galaxy Zoo 1. We measure the Petrosian and isophotal magnitudes, as well as the corresponding half-light radius for each galaxy. We find that for the brightest galaxies (M{sub r} < -23 mag), our Petrosian magnitudes and isophotal magnitudes to 25 mag arcsec{sup -2} and 1% of the sky brightness are on average 0.16 mag, 0.20 mag, and 0.26 mag brighter than the SDSSmore » Petrosian values, respectively. In the first case, the underestimations are caused by overestimations in the sky background by the SDSS PHOTO algorithm, while the latter two are also due to deeper photometry. Similarly, the typical half-light radii (r{sub 50}) measured by the SDSS algorithm are smaller than our measurements. As a result, the bright end of the r-band luminosity function is found to decline more slowly than previous works. Our measured luminosity densities at the bright end are more than one order of magnitude higher than those of Blanton et al., and the stellar mass densities at M{sub *} {approx} 5 Multiplication-Sign 10{sup 11} M{sub Sun} and M{sub *} {approx} 10{sup 12} M{sub Sun} are a few tenths and a factor of a few higher than those of Bernardi et al. These results may significantly alleviate the tension in the assembly of massive galaxies between observations and predictions of the hierarchical structure formation model.« less

High-precision QCD at hadron colliders:electroweak gauge boson rapidity distributions at NNLO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anastasiou, C.

2004-01-05

We compute the rapidity distributions of W and Z bosons produced at the Tevatron and the LHC through next-to-next-to leading order in QCD. Our results demonstrate remarkable stability with respect to variations of the factorization and renormalization scales for all values of rapidity accessible in current and future experiments. These processes are therefore ''gold-plated'': current theoretical knowledge yields QCD predictions accurate to better than one percent. These results strengthen the proposal to use $W$ and $Z$ production to determine parton-parton luminosities and constrain parton distribution functions at the LHC. For example, LHC data should easily be able to distinguish themore » central parton distribution fit obtained by MRST from that obtained by Alekhin.« less

The Radio Spectral Energy Distribution and Star-formation Rate Calibration in Galaxies

NASA Astrophysics Data System (ADS)

Tabatabaei, F. S.; Schinnerer, E.; Krause, M.; Dumas, G.; Meidt, S.; Damas-Segovia, A.; Beck, R.; Murphy, E. J.; Mulcahy, D. D.; Groves, B.; Bolatto, A.; Dale, D.; Galametz, M.; Sandstrom, K.; Boquien, M.; Calzetti, D.; Kennicutt, R. C.; Hunt, L. K.; De Looze, I.; Pellegrini, E. W.

2017-02-01

We study the spectral energy distribution (SED) of the radio continuum (RC) emission from the Key Insight in Nearby Galaxies Emitting in Radio (KINGFISHER) sample of nearby galaxies to understand the energetics and origin of this emission. Effelsberg multi-wavelength observations at 1.4, 4.8, 8.4, and 10.5 GHz combined with archive data allow us, for the first time, to determine the mid-RC (1-10 GHz, MRC) bolometric luminosities and further present calibration relations versus the monochromatic radio luminosities. The 1-10 GHz radio SED is fitted using a Bayesian Markov Chain Monte Carlo technique leading to measurements for the nonthermal spectral index ({S}ν ˜ {ν }-{α {nt}}) and the thermal fraction ({f}{th}) with mean values of {α }{nt}=0.97 +/- 0.16(0.79 +/- 0.15 for the total spectral index) and {f}{th} = (10 ± 9)% at 1.4 GHz. The MRC luminosity changes over ˜3 orders of magnitude in the sample, 4.3× {10}2 {L}⊙ < MRC < 3.9× {10}5 {L}⊙ . The thermal emission is responsible for ˜23% of the MRC on average. We also compare the extinction-corrected diagnostics of the star-formation rate (SFR) with the thermal and nonthermal radio tracers and derive the first star-formation calibration relations using the MRC radio luminosity. The nonthermal spectral index flattens with increasing SFR surface density, indicating the effect of the star-formation feedback on the cosmic-ray electron population in galaxies. Comparing the radio and IR SEDs, we find that the FIR-to-MRC ratio could decrease with SFR, due to the amplification of the magnetic fields in star-forming regions. This particularly implies a decrease in the ratio at high redshifts, where mostly luminous/star-forming galaxies are detected.

Low-radiative efficiency accretion: Microphysics and applications to low-luminosity AGN

NASA Astrophysics Data System (ADS)

Quataert, Eliot James Leo

There is growing dynamical evidence that most nearby galaxies contain central ``massive dark objects,'' most likely supermassive black holes. Accretion onto a supermassive black hole may therefore be commonplace, and not just restricted to quasars and active galactic nuclei (AGN). This hypothesis is supported by observational surveys which show that the majority of nearby galaxies have nuclear emission properties reminiscent of AGN. Their emission-line and bolometric luminosities are, however, ~102 - 105 times smaller than typical AGN. In this thesis I explore several issues related to the physics of these low luminosity active galactic nuclei (LLAGN). In particular, it has been proposed that LLAGN are supermassive black holes accreting mass via a radiatively inefficient advection-dominated accretion flow, in which most of the energy dissipated by turbulence is carried with the gas through the event horizon rather than being radiated. This requires that turbulence dissipate most of its energy into the protons, rather than the electrons. I calculate the heating of electrons and protons by the collisionless dissipation of magneto-hydrodynamic turbulence and argue that preferential proton heating can only be achieved for relatively subthermal magnetic fields (roughly β >~ 10, where β is the average ratio of the gas pressure to the magnetic pressure in the accretion flow). For stronger, near equipartition, magnetic fields (β ~ 1), the electrons receive most of the turbulent energy. I give an independent argument, based on a fluid model for the radial evolution of the magnetic energy density in the accretion flow, that magnetic fields in advection- dominated accretion flows may be somewhat subthermal. An alternative explanation for LLAGN is that they accrete mass at very low rates. This is, however, inconsistent with accretion rate estimates (based on Bondi's method) in nearby massive elliptical galaxies and the center of our Galaxy. I give a detailed discussion of

60 micron luminosity evolution of rich clusters of galaxies

NASA Technical Reports Server (NTRS)

Kelly, Douglas M.; Rieke, George H.

1990-01-01

The average 60-micron flux has been determined for a collection of optically selected galaxy clusters at redshifts ranging from 0.30 to 0.92. The result, 26 mJy per cluster, represents the faintest flux determination known of using the IRAS data base. The flux from this set of clusters has been compared to the 60-micron flux from a sample of nearby galaxy clusters. It is found that the far-infrared luminosity evolution in cluster galaxies can be no more than a factor of 1.7 from z = 0.4 to the present epoch. This upper limit is close to the evolution predicted for simple aging of the stellar populations. Additional processes such as mergers, cannibalism, or enhanced rates of starbursts appear to occur at a low enough level that they have little influence on the far-infrared emission from clusters over this redshift range.

GRS 1739-278 Observed at Very Low Luminosity with XMM-Newton and NuSTAR

NASA Astrophysics Data System (ADS)

Fürst, F.; Tomsick, J. A.; Yamaoka, K.; Dauser, T.; Miller, J. M.; Clavel, M.; Corbel, S.; Fabian, A.; García, J.; Harrison, F. A.; Loh, A.; Kaaret, P.; Kalemci, E.; Migliari, S.; Miller-Jones, J. C. A.; Pottschmidt, K.; Rahoui, F.; Rodriguez, J.; Stern, D.; Stuhlinger, M.; Walton, D. J.; Wilms, J.

2016-12-01

We present a detailed spectral analysis of XMM-Newton and NuSTAR observations of the accreting transient black hole GRS 1739-278 during a very faint low hard state at ˜0.02% of the Eddington luminosity (for a distance of 8.5 kpc and a mass of 10 {M}⊙ ). The broadband X-ray spectrum between 0.5 and 60 keV can be well-described by a power-law continuum with an exponential cutoff. The continuum is unusually hard for such a low luminosity, with a photon index of Γ = 1.39 ± 0.04. We find evidence for an additional reflection component from an optically thick accretion disk at the 98% likelihood level. The reflection fraction is low, with {{ R }}{refl}={0.043}-0.023+0.033. In combination with measurements of the spin and inclination parameters made with NuSTAR during a brighter hard state by Miller et al., we seek to constrain the accretion disk geometry. Depending on the assumed emissivity profile of the accretion disk, we find a truncation radius of 15-35 {R}{{g}} (5-12 {R}{ISCO}) at the 90% confidence limit. These values depend strongly on the assumptions and we discuss possible systematic uncertainties.

Infrared Spectral Energy Distribution Decomposition of WISE-selected, Hyperluminous Hot Dust-obscured Galaxies

NASA Astrophysics Data System (ADS)

Fan, Lulu; Han, Yunkun; Nikutta, Robert; Drouart, Guillaume; Knudsen, Kirsten K.

2016-06-01

We utilize a Bayesian approach to fit the observed mid-IR-to-submillimeter/millimeter spectral energy distributions (SEDs) of 22 WISE-selected and submillimeter-detected, hyperluminous hot dust-obscured galaxies (Hot DOGs), with spectroscopic redshift ranging from 1.7 to 4.6. We compare the Bayesian evidence of a torus plusgraybody (Torus+GB) model with that of a torus-only (Torus) model and find that the Torus+GB model has higher Bayesian evidence for all 22 Hot DOGs than the torus-only model, which presents strong evidence in favor of the Torus+GB model. By adopting the Torus+GB model, we decompose the observed IR SEDs of Hot DOGs into torus and cold dust components. The main results are as follows. (1) Hot DOGs in our submillimeter-detected sample are hyperluminous ({L}{IR}≥slant {10}13{L}⊙ ), with torus emission dominating the IR energy output. However, cold dust emission is non-negligible, contributing on average ˜ 24% of total IR luminosity. (2) Compared to QSO and starburst SED templates, the median SED of Hot DOGs shows the highest luminosity ratio between mid-IR and submillimeter at rest frame, while it is very similar to that of QSOs at ˜ 10{--}50 μ {{m}}, suggesting that the heating sources of Hot DOGs should be buried AGNs. (3) Hot DOGs have high dust temperatures ({T}{dust}˜ 72 K) and high IR luminosity of cold dust. The {T}{dust}{--}{L}{IR} relation of Hot DOGs suggests that the increase in IR luminosity for Hot DOGs is mostly due to the increase of the dust temperature, rather than dust mass. Hot DOGs have lower dust masses than submillimeter galaxies (SMGs) and QSOs within a similar redshift range. Both high IR luminosity of cold dust and relatively low dust mass in Hot DOGs can be expected by their relatively high dust temperatures. (4) Hot DOGs have high dust-covering factors (CFs), which deviate from the previously proposed trend of the dust CF decreasing with increasing bolometric luminosity. Finally, we can reproduce the observed

Cosmic Star Formation History and Evolution of the Galaxy UV Luminosity Function for z < 1

NASA Astrophysics Data System (ADS)

Zhang, Keming; Schiminovich, David

2018-01-01

We present the latest constraints on the evolution of the far-ultraviolet luminosity function of galaxies (1500 Å, UVLF hereafter) for 0 < z < 1 based on GALEX photometry, with redshift measurements from four spectroscopic and photometric-redshift catalogs: NSA, GAMA, VIPERS, and COSMOS photo-z. Our final sample consists of ~170000 galaxies, which represents the largest sample used in such studies. By integrating wide NSA and GAMA data and deep VIPERS and COSMOS photo-z data, we have been able to constrain both the bright end and the faint end of the luminosity function with high accuracy over the entire redshift range. We fit a Schechter function to our measurements of the UVLF, both to parameterize its evolution, and to integrate for SFR densities. From z~1 to z~0, the characteristic absolute magnitude of the UVLF increases linearly by ~1.5 magnitudes, while the faint end slope remains shallow (alpha < 1.5). However, the Schechter function fit exhibits an excess of galaxies at the bright end, which is accounted for by contributions from AGN. We also describe our methodology, which can be applied more generally to any combination of wide-shallow and deep-narrow surveys.

An intermediate luminosity optical transient (ILOTs) model for the young stellar object ASASSN-15qi

NASA Astrophysics Data System (ADS)

Kashi, Amit; Soker, Noam

2017-07-01

We construct a scenario where the outburst of the young stellar object ASASSN-15qi is an intermediate luminosity optical transient (ILOT). In this scenario, a sub-Jupiter young planet was tidally destructed on to a young main-sequence (MS) star. The system is young, and therefore the radius of the planet is larger than its final value; consequently, its density is smaller. The lower density allows the tidal destruction of the young Saturn-like planet on to the MS star of mass ≈2.4 M⊙, resulting in the formation of a disc and a gravitationally powered ILOT. Unlike the case of the more energetic ILOT V838 Mon, the mass of the destructed planet is too low to inflate a giant envelope, and hence the merger remnant remains hot. If our suggested model holds, this ILOT possesses two interesting properties: (I) its luminosity and total energy are below those of novae; (II) it is not as red as other ILOTs. The unusual outburst of ASASSN-15qi - if indeed is an ILOT - further increases the diversity of the already heterogeneous group of ILOTs. We mark the region on the energy-time diagram occupied by such young ILOTs.

The 2.4 μm Galaxy Luminosity Function As Measured Using WISE. I. Measurement Techniques

NASA Astrophysics Data System (ADS)

Lake, S. E.; Wright, E. L.; Tsai, C.-W.; Lam, A.

2017-04-01

The astronomy community has at its disposal a large back catalog of public spectroscopic galaxy redshift surveys that can be used for the measurement of luminosity functions (LFs). Utilizing the back catalog with new photometric surveys to maximum efficiency requires modeling the color selection bias imposed on the selection of target galaxies by flux limits at multiple wavelengths. The likelihood derived herein can address, in principle, all possible color selection biases through the use of a generalization of the LF, {{Φ }}(L), over the space of all spectra: the spectro-luminosity functional, {{\\Psi }}[{L}ν ]. It is, therefore, the first estimator capable of simultaneously analyzing multiple redshift surveys in a consistent way. We also propose a new way of parametrizing the evolution of the classic Schechter function parameters, L ⋆ and ϕ ⋆, that improves both the physical realism and statistical performance of the model. The techniques derived in this paper are used in a companion paper by Lake et al. to measure the LF of galaxies at the rest-frame wavelength of 2.4 μ {{m}} using the Widefield Infrared Survey Explorer (WISE).

A study of the luminosity function for field galaxies. [non-rich-cluster galaxies

NASA Technical Reports Server (NTRS)

Felten, J. E.

1977-01-01

Nine determinations of the luminosity function (LF) for field galaxies are analyzed and compared. Corrections for differences in Hubble constants, magnitude systems, galactic absorption functions, and definitions of the LF are necessary prior to comparison. Errors in previous comparisons are pointed out. After these corrections, eight of the nine determinations are in fairly good agreement. The discrepancy in the ninth appears to be mainly an incompleteness effect. The LF data suggest that there is little if any distinction between field galaxies and those in small groups.

Masses and luminosities for 342 stars from the PennState-Toruń Centre for Astronomy Planet Search

NASA Astrophysics Data System (ADS)

Adamczyk, M.; Deka-Szymankiewicz, B.; Niedzielski, A.

2016-03-01

Aims: We present revised basic astrophysical stellar parameters: the masses, luminosities, ages, and radii for 342 stars from the PennState-Toruń Centre for Astronomy Planet Search. For 327 stars the atmospheric parameters were already available in the literature. For the other 15 objects we also present spectroscopic atmospheric parameters: the effective temperatures, surface gravities, and iron abundances. Methods: Spectroscopic atmospheric parameters were obtained with a standard spectroscopic analysis procedure, using ARES and MOOG, or TGVIT codes. To refine the stellar masses, ages, and luminosities, we applied a Bayesian method. Results: The revised stellar masses for 342 stars and their uncertainties are generally lower than previous estimates. Atmospheric parameters for 13 objects are determined here for the first time. Table 3 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A119

A lower limit to the accretion disc radius in the low-luminosity AGNNGC 1052 derived from high-angular resolution data

NASA Astrophysics Data System (ADS)

Reb, Lennart; Fernández-Ontiveros, Juan A.; Prieto, M. Almudena; Dolag, Klaus

2018-07-01

We investigate the central sub-arcsec region of the low-luminosity active galactic nucleusNGC 1052, using a high-angular resolution data set that covers 10 orders of magnitude in frequency. This allows us to infer the continuum emission within the innermost ˜17 pc around the black hole to be of non-thermal, synchrotron origin and to set a limit to the maximum contribution of a standard accretion disc. Assuming the canonical 10 per cent mass-light conversion efficiency for the standard accretion disc, its inferred accretion power would be too low by one order of magnitude to account for the observed continuum luminosity. We thus introduce a truncated accretion disc and derive a truncation radius to mass-light conversion efficiency relation, which we use to reconcile the inferred accretion power with the continuum luminosity. As a result we find that a disc providing the necessary accretion power must be truncated at rtr ≳ 26 rg, consistent with the inner radius derived from the observations of the Fe Kα line in the X-ray spectrum of this nucleus. This is the first time to derive a limit on the truncation radius of the accretion disc from high-angular resolution data only.

Measurement of charged-particle distributions sensitive to the underlying event in $$ \\sqrt{s}=13 $$ TeV proton-proton collisions with the ATLAS detector at the LHC

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2017-03-29

We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb –1. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function ofmore » both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.« less

Measurement of charged-particle distributions sensitive to the underlying event in $$ \\sqrt{s}=13 $$ TeV proton-proton collisions with the ATLAS detector at the LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aaboud, M.; Aad, G.; Abbott, B.

We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb –1. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function ofmore » both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.« less

Clustering, cosmology and a new era of black hole demographics- II. The conditional luminosity functions of Type 2 and Type 1 active galactic nuclei

NASA Astrophysics Data System (ADS)

Ballantyne, D. R.

2017-01-01

The orientation-based unification model of active galactic nuclei (AGNs) posits that the principle difference between obscured (Type 2) and unobscured (Type 1) AGNs is the line of sight into the central engine. If this model is correct then there should be no difference in many of the properties of AGN host galaxies (e.g. the mass of the surrounding dark matter haloes). However, recent clustering analyses of Type 1 and Type 2 AGNs have provided some evidence for a difference in the halo mass, in conflict with the orientation-based unified model. In this work, a method to compute the conditional luminosity function (CLF) of Type 2 and Type 1 AGNs is presented. The CLF allows many fundamental halo properties to be computed as a function of AGN luminosity, which we apply to the question of the host halo masses of Type 1 and 2 AGNs. By making use of the total AGN CLF, the Type 1 X-ray luminosity function, and the luminosity-dependent Type 2 AGN fraction, the CLFs of Type 1 and 2 AGNs are calculated at z ≈ 0 and 0.9. At both z, there is no statistically significant difference in the mean halo mass of Type 2 and 1 AGNs at any luminosity. There is marginal evidence that Type 1 AGNs may have larger halo masses than Type 2s, which would be consistent with an evolutionary picture where quasars are initially obscured and then subsequently reveal themselves as Type 1s. As the Type 1 lifetime is longer, the host halo will increase somewhat in mass during the Type 1 phase. The CLF technique will be a powerful way to study the properties of many AGNs subsets (e.g. radio-loud, Compton-thick) as future wide-area X-ray and optical surveys substantially increase our ability to place AGNs in their cosmological context.

Extending pure luminosity evolution models into the mid-infrared, far-infrared and submillimetre

NASA Astrophysics Data System (ADS)

Hill, Michael D.; Shanks, Tom

2011-07-01

Simple pure luminosity evolution (PLE) models, in which galaxies brighten at high redshift due to increased star formation rates (SFRs), are known to provide a good fit to the colours and number counts of galaxies throughout the optical and near-infrared. We show that optically defined PLE models, where dust reradiates absorbed optical light into infrared spectra composed of local galaxy templates, fit galaxy counts and colours out to 8 μm and to at least z≈ 2.5. At 24-70 μm, the model is able to reproduce the observed source counts with reasonable success if 16 per cent of spiral galaxies show an excess in mid-IR flux due to a warmer dust component and a higher SFR, in line with observations of local starburst galaxies. There remains an underprediction of the number of faint-flux, high-z sources at 24 μm, so we explore how the evolution may be altered to correct this. At 160 μm and longer wavelengths, the model fails, with our model of normal galaxies accounting for only a few percent of sources in these bands. However, we show that a PLE model of obscured AGN, which we have previously shown to give a good fit to observations at 850 μm, also provides a reasonable fit to the Herschel/BLAST number counts and redshift distributions at 250-500 μm. In the context of a ΛCDM cosmology, an AGN contribution at 250-870 μm would remove the need to invoke a top-heavy IMF for high-redshift starburst galaxies.

Towards A Complete Census of Compton-thick AGN and N_H Distribution in the Local Universe

NASA Astrophysics Data System (ADS)

Annuar, A.; Gandhi, P.; Alexander, D.; Asmus, D.; Goulding, A.; Harrison, C.; Lansbury, G.

2014-07-01

Many studies have shown that Compton-thick AGNs (CTAGNs) provide important contribution to the cosmic X-ray background spectrum (˜25% at 20keV). They are expected to dominate the Seyfert 2 population in the local universe, yet only ˜20 bona fide CTAGNs are known. We present an updated census of CTAGN population in the local universe using a volume-limited AGN sample complete to D=15Mpc. Intrinsic relations between 2-10keV X-ray luminosity and mid-IR emission at 12μm, [OIV]λ25.68μm and [NeV]λ14.32μm are investigated, and it is found that the emission at 12μm has the tightest correlation with the X-ray luminosity.Candidates for CTAGN are then selected using this relation and by comparing their 12μm luminosity with the observed X-ray luminosity.We also investigate the Compton-thick nature of these sources using the optical [OIII]λ5007{A}:X-ray diagnostic for comparison, and find that 35-50% of the sample are Compton-thick,of which 10-20% would be missed with the optical approach.Finally, we estimate the intrinsic N_{H} distribution of AGN population in the local universe from this analysis, and show that up to 70% of the sources are heavily obscured (N_{H}>10^{23} cm^{-2}), with ≥50% lying in the Compton-thick regime (N_{H}>10^{24} cm^{-2}).This work provides a well-defined local benchmark for AGN obscuration studies.

The MUSE Hubble Ultra Deep Field Survey. VI. The faint-end of the Lyα luminosity function at 2.91 < z < 6.64 and implications for reionisation

NASA Astrophysics Data System (ADS)

Drake, A. B.; Garel, T.; Wisotzki, L.; Leclercq, F.; Hashimoto, T.; Richard, J.; Bacon, R.; Blaizot, J.; Caruana, J.; Conseil, S.; Contini, T.; Guiderdoni, B.; Herenz, E. C.; Inami, H.; Lewis, J.; Mahler, G.; Marino, R. A.; Pello, R.; Schaye, J.; Verhamme, A.; Ventou, E.; Weilbacher, P. M.

2017-11-01

We present the deepest study to date of the Lyα luminosity function in a blank field using blind integral field spectroscopy from MUSE. We constructed a sample of 604 Lyα emitters (LAEs) across the redshift range 2.91 < z < 6.64 using automatic detection software in the Hubble Ultra Deep Field. The deep data cubes allowed us to calculate accurate total Lyα fluxes capturing low surface-brightness extended Lyα emission now known to be a generic property of high-redshift star-forming galaxies. We simulated realistic extended LAEs to fully characterise the selection function of our samples, and performed flux-recovery experiments to test and correct for bias in our determination of total Lyα fluxes. We find that an accurate completeness correction accounting for extended emission reveals a very steep faint-end slope of the luminosity function, α, down to luminosities of log10L erg s-1< 41.5, applying both the 1 /Vmax and maximum likelihood estimators. Splitting the sample into three broad redshift bins, we see the faint-end slope increasing from -2.03-0.07+ 1.42 at z ≈ 3.44 to -2.86-∞+0.76 at z ≈ 5.48, however no strong evolution is seen between the 68% confidence regions in L∗-α parameter space. Using the Lyα line flux as a proxy for star formation activity, and integrating the observed luminosity functions, we find that LAEs' contribution to the cosmic star formation rate density rises with redshift until it is comparable to that from continuum-selected samples by z ≈ 6. This implies that LAEs may contribute more to the star-formation activity of the early Universe than previously thought, as any additional intergalactic medium (IGM) correction would act to further boost the Lyα luminosities. Finally, assuming fiducial values for the escape of Lyα and LyC radiation, and the clumpiness of the IGM, we integrated the maximum likelihood luminosity function at 5.00

Deep CFHT Y-band Imaging of VVDS-F22 Field. II. Quasar Selection and Quasar Luminosity Function

NASA Astrophysics Data System (ADS)

Yang, Jinyi; Wu, Xue-Bing; Liu, Dezi; Fan, Xiaohui; Yang, Qian; Wang, Feige; McGreer, Ian D.; Fan, Zuhui; Yuan, Shuo; Shan, Huanyuan

2018-03-01

We report the results of a faint quasar survey in a one-square-degree field. The aim is to test the Y-K/g-z and J-K/i-Y color selection criteria for quasars at faint magnitudes to obtain a complete sample of quasars based on deep optical and near-infrared color–color selection and to measure the faint end of the quasar luminosity function (QLF) over a wide redshift range. We carried out a quasar survey based on the Y-K/g-z and J-K/i-Y quasar selection criteria, using the deep Y-band data obtained from our CFHT/WIRCam Y-band images in a two-degree field within the F22 field of the VIMOS VLT deep survey, optical co-added data from Sloan Digital Sky Survey Stripe 82 and deep near-infrared data from the UKIDSS Deep Extragalactic Survey in the same field. We discovered 25 new quasars at 0.5< z< 4.5 and i< 22.5 mag within one-square-degree field. The survey significantly increases the number of faint quasars in this field, especially at z∼ 2{--}3. It confirms that our color selections are highly complete in a wide redshift range (z< 4.5), especially over the quasar number density peak at z∼ 2{--}3, even for faint quasars. Combining all previous known quasars and new discoveries, we construct a sample with 109 quasars and measure the binned QLF and parametric QLF. Although the sample is small, our results agree with a pure luminosity evolution at lower redshift and luminosity evolution and density evolution model at redshift z> 2.5.