Science.gov

Sample records for pah luminous galaxies

  1. Evolution of luminous IRAS galaxies: Radio imaging

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Hutchings, J. B.

    1993-01-01

    In a recent study of IRAS galaxies' optical morphologies, we found that luminous IR sources lie in the IR color-luminosity plane in groups which separate out by optical spectroscopic type and also by degree of tidal disturbance. We found that the most luminous steep-IR-spectrum sources are generally galaxies in the initial stages of a major tidal interaction. Galaxies with active nuclei were generally found to have flatter IR spectra, to cover a range of IR luminosity, and to be in the later stages of a tidal interaction. We proposed a sequence of events by which luminous IR sources evolve: they start as interacting or merging galaxies, some develop active nuclei, and most undergo extensive star-formation in their central regions. Another way to study these objects and their individual evolution is to study their radio morphologies. Radio emission may arise at a detectable level from supernovae in star-forming regions and/or the appearance of an active nucleus can be accompanied by a nuclear radio source (which may develop extended structure). Therefore, the compact radio structure may trace the evolution of the inner regions of IRAS-luminous sources. If the radio sources are triggered by the interactions, we would expect to find the radio morphology related to the optical 'interactivity' of the systems. Here, we explore using the radio emission of IRAS galaxies as a possible tracer of galaxy evolution. We present and discuss observations of the compact radio morphology of 111 luminous IRAS-selected active galaxies covering a wide range of IR and optical properties.

  2. Orbital masses of nearby luminous galaxies

    SciTech Connect

    Karachentsev, Igor D.; Kudrya, Yuri N. E-mail: yukudrya@gmail.com

    2014-09-01

    We use observational properties of galaxies accumulated in the Updated Nearby Galaxy Catalog to derive a dark matter mass of luminous galaxies via motions of their companions. The data on orbital-to-stellar mass ratio are presented for 15 luminous galaxies situated within 11 Mpc from us: the Milky Way, M31, M81, NGC 5128, IC342, NGC 253, NGC 4736, NGC 5236, NGC 6946, M101, NGC 4258, NGC 4594, NGC 3115, NGC 3627, and NGC 3368, as well as for a composite suite around other nearby galaxies of moderate and low luminosity. The typical ratio for these galaxies is M {sub orb}/M {sub *} = 31, corresponding to the mean local density of matter Ω {sub m} = 0.09, i.e., one-third of the global cosmic density. This quantity seems to be rather an upper limit of dark matter density, since the peripheric population of the suites may suffer from the presence of fictitious unbound members. We note that the Milky Way and M31 halos have lower dimensions and lower stellar masses than those of the other 13 nearby luminous galaxies. However, the dark-to-stellar mass ratio for both the Milky Way and M31 is typical for other neighboring luminous galaxies. The distortion in the Hubble flow, observed around the Local Group and five other neighboring groups, yields their total masses within the radius of a zero velocity surface, R {sub 0}; these masses are slightly lower than the orbital and virial values. This difference may be due to the effect of dark energy producing a kind of 'mass defect' within R {sub 0}.

  3. Observations of Luminous Infrared Galaxies with Herschel

    NASA Astrophysics Data System (ADS)

    Armus, Lee

    2014-01-01

    A major result of the IRAS survey was the discovery of a large population of luminous infrared galaxies (LIRGs) which emit a significant fraction of their bolometric luminosity in the far-infrared. LIRGs cover the full range of morphologies from isolated disk galaxies, to advanced mergers, exhibiting enhanced star-formation rates and a higher fraction of Active Galactic Nuclei (AGN) compared to less luminous galaxies. A detailed study of low-redshift LIRGs is critical for our understanding of the cosmic evolution of galaxies and black holes, since LIRGs comprise the bulk of the cosmic far-infrared background and dominate the star-formation between 0.5 < z < 1. With ISO, it was possible to measure the full suite of infrared diagnostic lines in local normal and luminous infrared galaxies for the first time, but samples were small and observations challenging. With Herschel, we have been able to study large samples of low-redshift LIRGs, and even probe the physical conditions in poweful starburst galaxies out to significant redshifts. By combining the Herschel data with those from Spitzer, it is now possible to understand the heating and cooling of the dust and gas in complete samples of LIRGs for the first time. I will review recent results from a number of GTO, OTKP and GO programs in an attempt to summarize the advances we have made in understanding star formation and black hole accretion in LIRGs as a direct result of the Herschel mission.

  4. Galaxy Clustering Around Nearby Luminous Quasars

    NASA Technical Reports Server (NTRS)

    Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.

    1996-01-01

    We examine the clustering of galaxies around a sample of 20 luminous low redshift (z approx. less than 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope (HST). The HST resolution makes possible galaxy identification brighter than V = 24.5 and as close as 1 min or 2 min to the quasar. We find a significant enhancement of galaxies within a projected separation of approx. less than 100 1/h kpc of the quasars. If we model the QSO/galaxy correlation function as a power law with a slope given by the galaxy/galaxy correlation function, we find that the ratio of the QSO/galaxy to galaxy/galaxy correlation functions is 3.8 +/- 0.8. The galaxy counts within r less than 15 1/h kpc of the quasars are too high for the density profile to have an appreciable core radius (approx. greater than 100 1/h kpc). Our results reinforce the idea that low redshift quasars are located preferentially in groups of 10-20 galaxies rather than in rich clusters. We see no significant difference in the clustering amplitudes derived from radio-loud and radio-quiet subsamples.

  5. Over-Luminous Elliptical Galaxies

    NASA Technical Reports Server (NTRS)

    Forman, William; Mushotzky, Richard (Technical Monitor)

    2004-01-01

    The first paper from our work has been completed and accepted for publication. Another paper presents a study of the ESO 30601 70 galaxy group, combining Chandra, XMM-Newton, and optical observations. We find that the system is a true fossil galaxy group - a group whose optical light is dominated by a single galaxy. The group X-ray emission is composed of a central, dense, cool core (10 kpc in radius) and an isothermal medium beyond the central 10 kpc. The region between 10 and 50 kpc (the cooling radius) has the same temperature as the gas from 50 to 400 kpc, although the gas cooling time between 10 and 50 kpc (2-6 Gyr) is shorter than the Hubble time. Thus, the ESO 3060170 group does not have a group-sized cooling core. We suggest that the group cooling core may have been heated by a central active galactic nucleus (AGN) outburst in the past and that the small, dense, cool core is the truncated relic of a previous cooling core. The Chandra observations also reveal a variety of X-ray features in the central region, including a finger, an edge-like feature, and a small tail, all aligned along a north-south axis, as are the galaxy light and group galaxy distribution. The proposed AGN outburst may cause gas to slosh around the center and produce these asymmetric features. The observed flat temperature profile to 1/3rvir is not consistent with the predicted temperature profile in recent numerical simulations. We compare the entropy profile of the ESO 3060170 group with those of three other groups and find a flatter relation than that predicted by simulations involving only shock heating, S approximately r approximately 0.85. This is direct evidence of the importance of non-gravitational processes in group centers. We derive the mass profiles within 1/3rvir and find that the ESO 3060170 group is the most massive fossil group known.

  6. Evolution of local luminous compact blue galaxies

    NASA Astrophysics Data System (ADS)

    Rabidoux, Katherine; Pisano, Daniel J.

    2015-01-01

    Luminous compact blue galaxies (LCBGs) are a type of very blue, very compact star-forming galaxy that was common at z~1 but is rare in the local universe. While it is clear from this discrepancy that LCBGs must be a rapidly-evolving class of galaxy, it is not clear what type(s) of galaxy they become. Fortunately, since they are bright and nearby, the rare examples of z~0 LCBGs are easily studied across a large range of wavelengths. We have conducted a study of z~0 analogs to the z~1 LCBGs to investigate their galaxy-wide internal properties in order to determine what is triggering their current episode of star formation, for how long the star formation can continue, and what the galaxies may become once their star formation rates decrease from current levels. We have taken resolved H I observations of nine LCBGs and unresolved radio continuum observations of 35 LCBGs and combined this data with archival broad-band data to probe their global properties. We conclude that LCBGs are rotationally-supported, star-forming disk galaxies that, while they may be forming small central bulges or bars, are highly unlikely to evolve into dwarf elliptical, dwarf spheroidal, or elliptical galaxies on their own due to their masses and rotation velocities. LCBGs will likely fade to be spiral galaxies with lower surface brightnesses once their current episodes of star formation conclude. In addition, we have modeled the SEDs of the LCBGs in our sample to determine whether LCBGs' star formation is ramping up or winding down, and for how much longer their current active phase of star formation will last. We have begun to put together a picture of the current evolutionary stage of this class of galaxies, and have better constrained their future evolutionary paths.

  7. Luminous Stars in Galaxies Beyond 3 Mpc

    NASA Astrophysics Data System (ADS)

    Whitmore, B. C.; Wfc3 Science Oversight Committee

    2011-06-01

    I am mainly interested in the formation and destruction of young star clusters in nearby star forming galaxies such as the Antennae, M83, and M51. One of the first analysis steps is to throw out all those pesky stars that keep contaminating my young cluster samples. Recently, spurred on by our new Wide Field Camera 3 (WFC3) Early Release Science data of galaxies including M83, NGC 4214, M82, NGC 2841, and Cen A, we began taking a closer look at the stellar component. Questions we are addressing are: 1) what are the most luminous stars, 2) how can we use them to help study the destruction of star clusters and the population of the field, 3) what fraction of stars, at least the bright stars, are formed in the field, in associations, and in compact clusters. In this contribution we describe some of the beginning steps in this process. More specifically, we describe how we separate stars from clusters in our galaxies, and describe how candidate Luminous Blue Variables (LBVs) and "Single Star" HII (SSHII) regions have been identified.

  8. The Host Galaxies of Nearby, Optically Luminous, AGN

    NASA Astrophysics Data System (ADS)

    Petric, Andreea

    2016-01-01

    Coevolution of galaxies and their central black holes (BH) has been the central theme of much of recent extragalactic astronomical research. Observations of the dynamics of stars and gas in the nuclear regions of nearby galaxies suggest that the majority of spheroidal galaxies in the local Universe contain massive BHs and that the masses of those central BH correlate with the velocity dispersions of the stars in the spheroid and the bulge luminosity. Cold ISM is the basic fuel for star-formation and BH growth so its study is essential to understanding how galaxies evolve.I will present high sensitivity observations taken with the Herschel Space Observatory to measure the cold dust content in a sample of 85 nearby (z <= 0.5) QSOs chosen from the optically luminous broad-line PG QSOs sample (QSO1s) and in a complementary sample of 85 narrow-line QSOs (QSO2s) chosen to match the redshift and optical luminosity distribution of the broad-line targets. The FIR data are combined with NIR and MIR measurements from the Two Micron All Sky Survey and the Wide-Field Infrared Survey Explorer to determine their IR spectral energy distributions which we use to assess and compare the aggregate dust properties of QSO1s and QSO2s. I will also present NIR spectroscopy obtained with Gemini's Near-Infrared Spectrograph of a sub-sample of QSO2s and QSO1s which I use to compare the ratio of cold to warm H2 gas that emits in the NIR in the hosts of QSO1s and QSO2s.Finally I will present a comparison of star-formation in QSO1s and QSO2s. For both QSO1s and QSO2s 3stimates of star-formation rates that are based on the total IR continuum emission correlate with those based on the 11.3 micron PAH feature. However, for the QSO1s, star-formation rates estimated from the FIR continuum are higher than those estimated from the 11.3 micron PAH emission. This result can be attributed to a variety of factors including the possible destruction of the PAHs and that, in some sources, a fraction of the

  9. The Luminous Polycyclic Aromatic Hydrocarbon Emission Features: Applications to High Redshift Galaxies and Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Shipley, Heath; Papovich, Casey

    2015-08-01

    We provide a new robust star-formation rate (SFR) calibration using the luminosity from polycyclic aromatic hydrogen (PAH) molecules. The PAH features emit strongly in the mid-infrared (mid-IR; 3-19μm), mitigating dust extinction, and they are very luminous, containing 5-10% of the total IR luminosity in galaxies. We derive the calibration of the PAH luminosity as a SFR indicator using a sample of 105 star-forming galaxies covering a range of total IR luminosity, LIR = L(8-1000μm) = 109 - 1012 L⊙ and redshift 0 < z < 0.6. The PAH luminosity correlates linearly with the SFR as measured by the dust-corrected Hα luminosity (using the sum of the Hα and rest-frame 24μm luminosity from Kennicutt et al. 2009), with tight scatter of ~0.15 dex, comparable to the scatter in the dust-corrected Hα SFRs and Paα SFRs. We show this relation is sensitive to galaxy metallicity, where the PAH luminosity of galaxies with Z < 0.7 Z⊙ departs from the linear SFR relationship but in a behaved manor. We derive for this a correction to galaxies below solar metallicity. As a case study for observations with JWST, we apply the PAH SFR calibration to a sample of lensed galaxies at 1 < z < 3 with Spitzer Infrared Spectrograph (IRS) data, and we demonstrate the utility of PAHs to derive SFRs as accurate as those available from any other indicator. This new SFR indicator will be useful for probing the peak of the SFR density of the universe (1 < z < 3) and for studying the coevolution of star-formation and supermassive blackhole accretion contemporaneously in a galaxy.

  10. Spitzer Spectroscopy to Distinguish z>5 Sources of Reionization from z~2 Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Chary, Ranga-Ram; Dickinson, Mark; Lawrence, Charles; Teplitz, Harry

    2008-03-01

    Optical/near-infrared photometric redshifts of 13 red galaxies in GOODS favor z>5 redshift solutions which indicate that they are extremely massive galaxies with stellar masses exceeding 1E11 Msun. If true, these galaxies contribute the bulk of the stellar mass density at z~6 and the past star-formation in these galaxies is responsible for reionizing the intergalactic medium at z>>6. The majority of these galaxies have however found to be faint 24 micron sources which would instead suggest that they are luminous infrared galaxies (LIRGs) with L(IR)~3E11 Lsun at z~2. We propose ultradeep Spitzer/IRS LL spectroscopy which will measure the redshifts of two representative, optically invisible (i>27 mag) sources in this class and distinguish between these two widely disparate hypotheses. The detection of polycyclic aromatic hydrocarbons (PAH) in the spectra of these sources would imply that photometric redshifts of dusty infrared luminous galaxies are unreliable - a fundamental obstacle in estimating the comoving luminosity density of the Universe as a function of redshift. It would allow the shape of the dust extinction curve to be constrained and rule out the Balmer-'break' color selection as a reliable tracer of redshift. By virtue of being the deepest IRS/LL observations, it would yield the first measures of PAH line strengths in high redshift LIRGs. This will help refine the mid-infrared PAH templates that are used to estimate bolometric luminosities of galaxies detected in various mid-infrared surveys, including those which will be undertaken by WISE. The absence of PAH in the proposed spectra would imply the presence of Compton-thick AGN and/or confirm that we have identified the galaxies responsible for reionization without the need for changing the stellar initial mass function at high redshift. Spitzer offers the only opportunity to resolve this important conundrum until the James Webb Space Telescope.

  11. The Most Luminous Galaxies Found by WISE

    NASA Astrophysics Data System (ADS)

    Eisenhardt, Peter; Tsai, Chao-Wei; Wu, Jingwen; Griffith, Roger; Yan, Lin; Stern, Daniel; Stanford, Adam; Blain, Andrew; Benford, Dominic; Bridge, Carrie; Petty, Sara; Assef, Roberto; Donoso, Emilio; Lake, Sean

    2012-08-01

    NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 (micron) (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy shows that most of the sources have redshifts z>2. In combination with Herschel photometry, these redshifts lead to typical L_bol > 10^13 L_⊙, with ~10% exceeding 10^14 L_⊙. High resolution adaptive optics imaging shows these objects are typically unlensed. We request NOAO time to obtain redshifts and optical and near IR photometry of the complete all-sky sample of the brightest W12drops, all of which are in our Herschel program. This will fulfill the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

  12. Warm Molecular Gas in Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.; Zhao, Y.; Xu, C. K.; Gao, Y.; Armus, L.; Mazzarella, J. M.; Isaak, K. G.; Petric, A. O.; Charmandaris, V.; Díaz-Santos, T.; Evans, A. S.; Howell, J.; Appleton, P.; Inami, H.; Iwasawa, K.; Leech, J.; Lord, S.; Sanders, D. B.; Schulz, B.; Surace, J.; van der Werf, P. P.

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J-1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J <= 4 to a broad distribution peaking around J ~ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L IR, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 <~ J <~ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5-4), (6-5), (7-6), (8-7) and (10-9) transitions to L IR, log R midCO, remain largely independent of C(60/100), and show a mean value of -4.13 (\\equiv log R^SF_midCO) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R midCO higher and lower than R^SF_midCO, respectively. Based on Herschel observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  13. WARM MOLECULAR GAS IN LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Lu, N.; Zhao, Y.; Xu, C. K.; Mazzarella, J. M.; Howell, J.; Appleton, P.; Lord, S.; Schulz, B.; Gao, Y.; Armus, L.; Díaz-Santos, T.; Surace, J.; Isaak, K. G.; Petric, A. O.; Charmandaris, V.; Evans, A. S.; Inami, H.; Iwasawa, K.; Leech, J.; Sanders, D. B.; and others

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J–1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J ≤ 4 to a broad distribution peaking around J ∼ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L {sub IR}, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 ≲ J ≲ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5–4), (6–5), (7–6), (8–7) and (10–9) transitions to L {sub IR}, log R {sub midCO}, remain largely independent of C(60/100), and show a mean value of –4.13 (≡log R{sub midCO}{sup SF}) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R {sub midCO} higher and lower than R{sub midCO}{sup SF}, respectively.

  14. STAR FORMATION IN TWO LUMINOUS SPIRAL GALAXIES

    SciTech Connect

    Hunter, Deidre A.; Ashburn, Allison; Wright, Teresa; Elmegreen, Bruce G.; Rubin, Vera C.; Józsa, Gyula I. G.; Struve, Christian

    2013-10-01

    We examined star formation in two very luminous (M{sub V} = –22 to –23) Sc-type spiral galaxies, NGC 801 and UGC 2885, using ultra-deep Hα images. We combine these Hα images with UBV and Two-Micron All-Sky Survey JHK images and H I maps to explore the star formation characteristics of disk galaxies at high luminosity. Hα traces star formation in these galaxies to 4-6 disk scale lengths, but the lack of detection of Hα further out is likely due to the loss of Lyman continuum photons. Considering gravitational instabilities alone, we find that the gas and stars in the outer regions are marginally stable in an average sense, but considering dissipative gas and radial and azimuthal forcing, the outer regions are marginally unstable to forming spiral arms. Star formation is taking place in spiral arms, which are regions of locally higher gas densities. Furthermore, we have traced smooth exponential stellar disks over four magnitudes in V-band surface brightness and 4-6 disk scale lengths, in spite of a highly variable gravitational instability parameter. Thus, gravitational instability thresholds do not seem relevant to the stellar disk. One possibility for creating an exponential disk is that the molecular cloud densities and star formation rates have exponential profiles and this fact forces the stellar disk to build up such a profile. Another possibility is that the stellar disk is continuously adjusted to an exponential shape regardless of the star formation profile, for example, through global dynamical processes that scatter stars. However, such scattering processes are only known to operate in spiral systems, in which case they cannot explain the same dilemma of smooth exponential disks observed in dwarf irregular galaxies.

  15. Luminous red galaxies in hierarchical cosmologies

    NASA Astrophysics Data System (ADS)

    Almeida, C.; Baugh, C. M.; Wake, D. A.; Lacey, C. G.; Benson, A. J.; Bower, R. G.; Pimbblet, K.

    2008-06-01

    Luminous red galaxies (LRGs) are much rarer and more massive than L* galaxies. Coupled with their extreme colours, LRGs therefore provide a demanding testing ground for the physics of massive galaxy formation. We present the first self-consistent predictions for the abundance and properties of LRGs in hierarchical structure formation models. We test two published models which use quite different mechanisms to suppress the formation of massive galaxies: the Bower et al. model which invokes `active galactic nuclei (AGN) feedback' to prevent gas from cooling in massive haloes and the Baugh et al. model which relies upon a `superwind' to eject gas before it is turned into stars. Without adjusting any parameters, the Bower et al. model gives an excellent match to the observed luminosity function of LRGs in the Sloan Digital Sky Survey (with a median redshift of z = 0.24) and to their clustering; the Baugh et al. model is less successful in these respects. Both models fail to match the observed abundance of LRGs at z = 0.5 to better than a factor of ~2. In the models, LRGs are typically bulge-dominated systems with stellar masses of ~2 × 1011h-1Msolar and velocity dispersions of σ ~ 250kms-1. Around half of the stellar mass in the model LRGs is already formed by z ~ 2.2 and is assembled into one main progenitor by z ~ 1.5; on average, only 25 per cent of the mass of the main progenitor is added after z ~ 1. LRGs are predicted to be found in a wide range of halo masses, a conclusion which relies on properly taking into account the scatter in the formation histories of haloes. Remarkably, we find that the correlation function of LRGs is predicted to be a power law down to small pair separations, in excellent agreement with observational estimates. Neither the Bower et al. nor the Baugh et al. model is able to reproduce the observed radii of LRGs.

  16. The Luminous Polycyclic Aromatic Hydrocarbon Emission Features: Applications to High Redshift Galaxies and Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Shipley, Heath V.

    2016-01-01

    For decades, significant work has been applied to calibrating emission from the ultra-violet, nebular emission lines, far-infrared, X-ray and radio as tracers of the star-formation rate (SFR) in distant galaxies. Understanding the exact rate of star-formation and how it evolves with time and galaxy mass has deep implications for how galaxies form. The co-evolution of star-formation and supermassive black hole (SMBH) accretion is one of the key problems in galaxy formation theory. But, many of these SFR indicators are influenced by SMBH accretion in galaxies and result in unreliable SFRs. Utilizing the luminous polycyclic aromatic hydrocarbon (PAH) emission features, I provide a new robust SFR calibration using the luminosity emitted from the PAHs at 6.2μm, 7.7μm and 11.3μm to solve this. The PAH features emit strongly in the mid-infrared (mid-IR; 5-25μm) mitigating dust extinction, containing on average 5-10% of the total IR luminosity in galaxies. I use a sample of 105 star-forming galaxies covering a range of total IR luminosity, LIR = L(8-1000μm) = 109 - 1012 L⊙ and redshift 0 < z < 0.4, with mid-IR spectroscopy from the Spitzer Infrared Spectrograph (IRS), and data covering other SFR indicators (Hα emission and rest-frame 24μm continuum emission). The PAH luminosity correlates linearly with the SFR as measured by the Hα luminosity (corrected for attenuation using the mono-chromatic rest-frame 24μm emission), with a tight scatter of <0.15 dex. The scatter is comparable to that between SFRs derived from the Paα and dust-corrected Hα emission lines. We present a case study in advance of JWST, which will be capable of measuring SFRs (from 8μm rest-frame photometry, i.e. PAHs) in distant galaxies (z ≤ 2) with JWST/MIRI to SFRs as low as ~10 M⊙yr-1, because the PAH features are so bright. We use Spitzer/IRS observations of PAH features in lensed star-forming galaxies at 1 < z < 3 to demonstrate the utility of the PAHs to derive SFRs that agree with

  17. Compact radio sources in luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Parra, Rodrigo

    2007-08-01

    Radio interferometry is an observational technique of high sensitivity and incomparably high spatial resolution. Moreover, because radio waves can freely propagate through interstellar dust and gas, it allows the study of regions of the universe completely obscured at other wavelengths. This thesis reports the observational and theoretical results of my research during the past four years which are mostly based on interferometric radio data. The COLA sample is an infrared selected sample of active star forming galaxies. We conducted 6 cm VLA and VLBI snapshot observations of the northern half of this sample. The radio emission seen at VLA scales is consistent with being powered by star formation activity because it follows the far infrared to radio correlation. We detect 22% of the sample sources in our VLBI snapshots. Based on luminosity arguments, we argue that these sub-parsec VLBI sources are powered by AGN activity. Furthermore, we find that VLBI detections are preferentially found in sources whose VLA scale structures have the highest peak brightnesses suggesting a strong correlation between compact starburst and AGN activity. This observational result is consistent with the theoretical picture of an Eddington-limited nuclear starburst acting as the last valve in the pipeline transporting the gas from kiloparsec scales onto the accretion disc of a buried AGN. Arp 220 is the archetypical ultra luminous infrared galaxy. For many years this source has been known to harbour a compact (~100 pc) cluster of unresolved 18 cm bright sources believed to be bright core collapse supernovae. Using multiwavelength VLBI observations, we obtained for the first time radio spectra for 18 of these sources. We find that over a half of them have spectra consistent with young supernovae. The rest can be better explained as older supernova remnants interacting with the high density starburst ISM. This finding allowed us to constrain the number of possible scenarios for the Arp 220

  18. Morphological classification of local luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Psychogyios, A.; Charmandaris, V.; Diaz-Santos, T.; Armus, L.; Haan, S.; Howell, J.; Le Floc'h, E.; Petty, S. M.; Evans, A. S.

    2016-06-01

    We present analysis of the morphological classification of 89 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) sample, using non-parametric coefficients and compare their morphology as a function of wavelength. We rely on images that were obtained in the optical (B- and I-band) as well as in the infrared (H-band and 5.8 μm). Our classification is based on the calculation of Gini and the second order of light (M20) non-parametric coefficients, which we explore as a function of stellar mass (M⋆), infrared luminosity (LIR), and star formation rate (SFR). We investigate the relation between M20, the specific SFR (sSFR) and the dust temperature (Tdust) in our galaxy sample. We find that M20 is a better morphological tracer than Gini, as it allows us to distinguish systems that were formed by double systems from isolated and post-merger LIRGs. The effectiveness of M20 as a morphological tracer increases with increasing wavelength, from the B to H band. In fact, the multi-wavelength analysis allows us to identify a region in the Gini-M20 parameter space where ongoing mergers reside, regardless of the band used to calculate the coefficients. In particular, when measured in the H band, a region that can be used to identify ongoing mergers, with minimal contamination from LIRGs in other stages. We also find that, while the sSFR is positively correlated with M20 when measured in the mid-infrared, i.e. star-bursting galaxies show more compact emission, it is anti-correlated with the B-band-based M20. We interpret this as the spatial decoupling between obscured and unobscured star formation, whereby the ultraviolet/optical size of an LIRG experience an intense dust-enshrouded central starburst that is larger that in the mid-infrared since the contrast between the nuclear to the extended disk emission is smaller in the mid-infrared. This has important implications for high redshift surveys of dusty sources, where sizes of galaxies

  19. The Luminous Convolution Model for Galaxy Rotation Curves

    NASA Astrophysics Data System (ADS)

    Rubin, Shanon; Mucci, Maria; Sophia Cisneros Collaboration; Kennard Chng Collaboration; Meagan Crowley Collaboration

    2016-03-01

    The LCM takes as input only the observed luminous matter profile from galaxies, and allows us to confirm these observed data by considering frame-dependent effects from the luminous mass profile of the Milky Way. The LCM is useful when looking at galaxies that have similar total enclosed mass, but varying distributions. For example, variations in luminous matter profiles from a diffuse galaxy correlate to the LCM's five different Milky Way models equally well, but LCM fits for a centrally condensed galaxy distinguish between Milky Way models. In this presentation, we show how the rotation curve data of such galaxies can be used to constrain the Milky Way luminous mass modeling, by the physical characteristics of each galaxy used to interpret the fitting. Current Investigations will be presented showing how the convolved parameters of Keplerian predictions with rotation curve observations can be extracted with respect to the crossing location of the relative curvature versus the assumption of the luminous mass profiles from photometry. Since there currently exists no direct constraint to photometric estimates of the luminous mass in these systems, the LCM gives the first constraint based on the orthogonal measurement of Doppler shifted spectra from characteristic emitters.

  20. Spitzer Observations of Extraplanar PAH Emission from Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Lehner, N.; Howk, J.

    We present Spitzer/IRAC observations of polycylic aromatic hydrocarbon (PAH) emission from interstellar material in the thick disks of normal spiral galaxies. These data show PAHs to be a common constituent of extraplanar material in spirals. The processes that displace this material from the interstellar disks of these systems do not destroy these very small grains. The dust emission features are present far above the galactic planes, extended up to about 2-4 kpc above the midplanes of the galaxies presented in this work. The total extent for which dust can be traced is about half the extent of the DIG. If it is not a sensitivity effect, this suggests that PAHs may be associated with a cold neutral medium that can not be supported at high z.

  1. Ultraluminous Star-forming Galaxies and Extremely Luminous Warm Molecular Hydrogen Emission at z = 2.16 in the PKS 1138-26 Radio Galaxy Protocluster

    NASA Astrophysics Data System (ADS)

    Ogle, P.; Davies, J. E.; Appleton, P. N.; Bertincourt, B.; Seymour, N.; Helou, G.

    2012-05-01

    A deep Spitzer Infrared Spectrograph map of the PKS 1138-26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including Hα-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of ~500-1100 M ⊙ yr-1 are estimated from the 7.7 μm PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of Hα is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H2 0-0 S(3)) = 1.4 × 1044 erg s-1 (3.7 × 1010 L ⊙), ~20 times more luminous than any previously known H2 emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 × 106-2 × 109 M ⊙ of T > 300 K molecular gas, which may be heated by the PKS 1138-26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H2 at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected.

  2. Luminous red galaxies in the Sloan digital sky survey

    NASA Astrophysics Data System (ADS)

    Loh, Yeong-Shang

    2004-04-01

    We determine the luminosity function and evolution of 22,562 Luminous Red Galaxies (LRG) with 0.08 < z < 0.44 from the Sloan Digital Sky Survey (SDSS). The universal field galaxy luminosity function with a steep exponential bright end cut-off expected from a Schechter form is confirmed to z ˜ 0.4. We do not discern any evolution in the comoving number density of these luminous early-type galaxies, once biases due to photometric errors are taken into account. Using 2099 deg2 of SDSS imaging data, we search for bright early-type galaxies within 1 h-1 Mpc of LRG with 0.12 < z < 0.38 to study the bright end of the luminosity distribution at this scale. The brightest galaxies (nearly always an LRG) in LRG fields are too bright if other members in the same field are drawn from an exponentially decaying luminosity function. The luminosity gap between the brightest and the second brightest galaxy is large (˜0.8 mag). When the LRG fields were split into group-like and cluster- like environments, the former gives a larger gap. The gap shows little evolution with redshifts, putting stringent constraints on the scenario of the growth of Brightest Cluster (or Group) Galaxies by recent cannibalism of cluster members. We calibrate the observed color-magnitude-redshift relation for early-type galaxies. We use LRGs as spectroscopic references and measure the color of imaging galaxies that clustered around each LRG. We bin these galaxies in redshift and perform an optimal background subtraction to recover the color-magnitude relation. The observed scatter around this color-magnitude relation is also measured. We study the environments of LRG by counting the number of early-type galaxies brighter than M* within 1 h-1 Mpc of the LRG. LRGs are binned in redshift and treated as a single population to infer the evolution trend of their environments. Both the rich optical clusters and moderately X-ray bright clusters host at least one LRG. However, LRG are most common in group

  3. Temperature distribution of dust in luminous IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Carico, David P.

    1989-01-01

    Work is currently in progress to obtain temperature distributions of dust in the most infrared-luminous galaxies. The results presented are of a preliminary nature, representing a zeroth-order approximation. The objects which have been analyzed so far are all galaxies from the Infrared Astronomy Satellite (IRAS) Bright Galaxy Sample with infrared luminosities L sub IR greater than or equal to 10(exp 11) solar luminosity. They are: Arp 220, Mrk 231, Mrk 273, NGC 1614, NGC 3690, NGC 6285/6, and Zw 049.057. The analysis utilized 3.7 micron data from the Palomar 5 m Hale telescope, IRAS data at 12, 25, 60, and 100 microns, and 1 mm continuum data from the CalTech Submillimeter Observatory on Mauna Kea.

  4. The Fate of Luminous Compact Blue Galaxies: An Environmental Approach

    NASA Astrophysics Data System (ADS)

    Crawford, Steven

    2003-07-01

    Luminous Compact Blue Galaxies {LCBGs} are the most rapidly evolving galaxy population between 0.4 < z < 1.0. Despite their small sizes of 2-3 kpc, LCBGs are powerful engines of star formation that dominate the global SFR over that redshift regime. They appear to be a link between local, low-mass HII galaxies and high-z, high-luminosity Lyman Break galaxies. As such, LCBGs may provide an important test of hierarchical structure-formation scenarios. Currently, a debate rages over what LCBGs are: Are we seeing proto-spheroidals or the formation of spiral bulges? We propose to identify a sample of LCBGs in 10 intermediate-z clusters areas from Archive WFPC2 images through photometric structural measurements {e.g., surface brightness, size, and concentration}. These galaxies cannot be resolved in ground-based images. We then will measure the relative number densities and photometric properties of LCBGs in clusters and the field. By combining this comparison with what we know about the morphology-density relationship today, we will gain new insight on the ultimate fate of LCBGs and the differences between galaxy evolution in field and cluster environments. The WFPC2 data, combined with our deep multi-color, ground-based imaging from the WIYN 3.5m telescope will provide the largest data set of intermediate-z LCBGs to date.

  5. THE Mg II CROSS-SECTION OF LUMINOUS RED GALAXIES

    SciTech Connect

    Bowen, David V.; Chelouche, Doron

    2011-01-20

    We describe a search for Mg II {lambda}{lambda}2796, 2803 absorption lines in Sloan Digital Sky Survey (SDSS) spectra of QSOs whose lines of sight pass within impact parameters {rho} {approx} 200 kpc of galaxies with photometric redshifts of z = 0.46-0.6 and errors {Delta}z {approx} 0.05. The galaxies selected have the same colors and luminosities as the Luminous Red Galaxy (LRG) population previously selected from the SDSS. A search for Mg II lines within a redshift interval of {+-}0.1 of a galaxy's photometric redshift shows that absorption by these galaxies is rare: the covering fraction is f({rho}) {approx_equal} 10%-15% between {rho} = 20 kpcand{rho} = 100 kpc, for Mg II lines with rest equivalent widths of W{sub r} {>=} 0.6 A, falling to zero at larger {rho}. There is no evidence that W{sub r} correlates with impact parameter or galaxy luminosity. Our results are consistent with existing scenarios in which cool Mg II-absorbing clouds may be absent near LRGs because of the environment of the galaxies: if LRGs reside in high-mass groups and clusters, either their halos are too hot to retain or accrete cool gas, or the galaxies themselves-which have passively evolving old stellar populations-do not produce the rates of star formation and outflows of gas necessary to fill their halos with Mg II-absorbing clouds. In the rarer cases where Mg II is detected, however, the origin of the absorption is less clear. Absorption may arise from the little cool gas able to reach into cluster halos from the intergalactic medium, or from the few star-forming and/or AGN-like LRGs that are known to exist.

  6. Cosmological information in the intrinsic alignments of luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Chisari, Nora Elisa; Dvorkin, Cora

    2013-12-01

    The intrinsic alignments of galaxies are usually regarded as a contaminant to weak gravitational lensing observables. The alignment of Luminous Red Galaxies, detected unambiguously in observations from the Sloan Digital Sky Survey, can be reproduced by the linear tidal alignment model of Catelan, Kamionkowski & Blandford (2001) on large scales. In this work, we explore the cosmological information encoded in the intrinsic alignments of red galaxies. We make forecasts for the ability of current and future spectroscopic surveys to constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations (BAO) in the cross-correlation function of intrinsic alignments and the galaxy density field. For the Baryon Oscillation Spectroscopic Survey, we find that the BAO signal in the intrinsic alignments is marginally significant with a signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic survey following the EUCLID redshift selection function, we find signal-to-noise ratios of 12 and 15, respectively. Local type primordial non-Gaussianity, parametrized by fNL = 10, is only marginally significant in the intrinsic alignments signal with signal-to-noise ratios < 2 for the three surveys considered.

  7. Cosmological information in the intrinsic alignments of luminous red galaxies

    SciTech Connect

    Chisari, Nora Elisa; Dvorkin, Cora E-mail: cdvorkin@ias.edu

    2013-12-01

    The intrinsic alignments of galaxies are usually regarded as a contaminant to weak gravitational lensing observables. The alignment of Luminous Red Galaxies, detected unambiguously in observations from the Sloan Digital Sky Survey, can be reproduced by the linear tidal alignment model of Catelan, Kamionkowski and Blandford (2001) on large scales. In this work, we explore the cosmological information encoded in the intrinsic alignments of red galaxies. We make forecasts for the ability of current and future spectroscopic surveys to constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations (BAO) in the cross-correlation function of intrinsic alignments and the galaxy density field. For the Baryon Oscillation Spectroscopic Survey, we find that the BAO signal in the intrinsic alignments is marginally significant with a signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic survey following the EUCLID redshift selection function, we find signal-to-noise ratios of 12 and 15, respectively. Local type primordial non-Gaussianity, parametrized by f{sub NL} = 10, is only marginally significant in the intrinsic alignments signal with signal-to-noise ratios < 2 for the three surveys considered.

  8. Mid-infrared Properties of Luminous Infrared Galaxies. II. Probing the Dust and Gas Physics of the GOALS Sample

    NASA Astrophysics Data System (ADS)

    Stierwalt, S.; Armus, L.; Charmandaris, V.; Diaz-Santos, T.; Marshall, J.; Evans, A. S.; Haan, S.; Howell, J.; Iwasawa, K.; Kim, D. C.; Murphy, E. J.; Rich, J. A.; Spoon, H. W. W.; Inami, H.; Petric, A. O.; U, V.

    2014-08-01

    The Great Observatories All-sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here, we present the results of a multi-component, spectral decomposition analysis of the low-resolution mid-infrared (MIR) Spitzer Infrared Spectrograph spectra from 5-38 μm of 244 LIRG nuclei. The detailed fits and high-quality spectra allow for characterization of the individual polycyclic aromatic hydrocarbon (PAH) features, warm molecular hydrogen emission, and optical depths for both silicate dust grains and water ices. We find that starbursting LIRGs, which make up the majority of the GOALS sample, are very consistent in their MIR properties (i.e., τ9.7 μm, τice, neon line ratios, and PAH feature ratios). However, as their EQW6.2 μm decreases, usually an indicator of an increasingly dominant active galactic nucleus (AGN), LIRGs cover a larger spread in these MIR parameters. The contribution from PAH emission to the total IR luminosity (L(PAH)/L(IR)) in LIRGs varies from 2%-29% and LIRGs prior to their first encounter show significantly higher L(PAH)/L(IR) ratios on average. We observe a correlation between the strength of the starburst (represented by IR8 = L IR/L 8 μm) and the PAH fraction at 8 μm but no obvious link between IR8 and the 7.7 to 11.3 PAH ratio, suggesting that the fractional photodissociation region (PDR) emission, and not the overall grain properties, is associated with the rise in IR8 for galaxies off the starburst main sequence. We detect crystalline silicate features in ~6% of the sample but only in the most obscure sources (s 9.7 μm < -1.24). Ice absorption features are observed in ~11% (56%) of GOALS LIRGs (ULIRGs) in sources with a range of silicate depths. Most GOALS LIRGs have L(H2)/L(PAH) ratios elevated above those observed for normal star-forming galaxies and exhibit a trend for increasing L(H2)/L(PAH) ratio with increasing L(H2). While star formation appears to be the

  9. Mid-infrared properties of luminous infrared galaxies. II. Probing the dust and gas physics of the goals sample

    SciTech Connect

    Stierwalt, S.; Armus, L.; Diaz-Santos, T.; Marshall, J.; Haan, S.; Howell, J.; Murphy, E. J.; Inami, H.; Petric, A. O.; Charmandaris, V.; Evans, A. S.; Iwasawa, K.; Kim, D. C.; Rich, J. A.; Spoon, H. W. W.; U, V.

    2014-08-01

    The Great Observatories All-sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here, we present the results of a multi-component, spectral decomposition analysis of the low-resolution mid-infrared (MIR) Spitzer Infrared Spectrograph spectra from 5-38 μm of 244 LIRG nuclei. The detailed fits and high-quality spectra allow for characterization of the individual polycyclic aromatic hydrocarbon (PAH) features, warm molecular hydrogen emission, and optical depths for both silicate dust grains and water ices. We find that starbursting LIRGs, which make up the majority of the GOALS sample, are very consistent in their MIR properties (i.e., τ{sub 9.7μm}, τ{sub ice}, neon line ratios, and PAH feature ratios). However, as their EQW{sub 6.2{sub μm}} decreases, usually an indicator of an increasingly dominant active galactic nucleus (AGN), LIRGs cover a larger spread in these MIR parameters. The contribution from PAH emission to the total IR luminosity (L(PAH)/L(IR)) in LIRGs varies from 2%-29% and LIRGs prior to their first encounter show significantly higher L(PAH)/L(IR) ratios on average. We observe a correlation between the strength of the starburst (represented by IR8 = L{sub IR}/L{sub 8{sub μm}}) and the PAH fraction at 8 μm but no obvious link between IR8 and the 7.7 to 11.3 PAH ratio, suggesting that the fractional photodissociation region (PDR) emission, and not the overall grain properties, is associated with the rise in IR8 for galaxies off the starburst main sequence. We detect crystalline silicate features in ∼6% of the sample but only in the most obscure sources (s{sub 9.7{sub μm}} < –1.24). Ice absorption features are observed in ∼11% (56%) of GOALS LIRGs (ULIRGs) in sources with a range of silicate depths. Most GOALS LIRGs have L(H{sub 2})/L(PAH) ratios elevated above those observed for normal star-forming galaxies and exhibit a trend for increasing L(H{sub 2})/L(PAH

  10. X-raying the Winds of Luminous Active Galaxies

    NASA Astrophysics Data System (ADS)

    Brandt, W. N.; Chartas, G.; Gallagher, S. C.; Gibson, R. R.; Miller, B. P.

    2009-12-01

    We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback. Topics covered include (1) Relations between X-ray and UV absorption in Broad Absorption Line (BAL) and mini-BAL quasars; (2) X-ray absorption in radio-loud BAL quasars; and (3) Evidence for relativistic iron K BALs in the X-ray spectra of a few bright quasars. We also mention some key outstanding problems and prospects for future advances; e.g., with the International X-ray Observatory (IXO).

  11. Observing the First Stars in Luminous, Red Galaxies

    NASA Technical Reports Server (NTRS)

    Heap, Sally; Lindler, Don

    2010-01-01

    Modern cosmological simulations predict that the first stars are to be found today in luminous, red galaxies. Although observing such stars individually against a background of younger, metal-rich stars is impossible, the first stars should make their presence known by their strong, line-free ultraviolet flux. We have found evidence for a UV-bright stellar population in Sloan spectra of LRG's at z=0.4-0.5. We present arguments for interpreting this UV-bright stellar population as the oldest stars, rather than other types of stellar populations (e.g. young stars or blue straggler stars in the dominant, metal-rich stellar population

  12. Luminous Red Galaxies at Z=0.4-0.5

    NASA Technical Reports Server (NTRS)

    Heap, Sally; Lindler, Don

    2009-01-01

    We report on a study of approx.20,000 luminous red galaxies (LRG's) at z=0.4-0.5 observed by the Sloan Digital Sky Survey. In order to differentiate among them, we measured restframe magnitudes, u (3000-3500 A), b (4200-4800 A), and y (5700-6300 A) from the spectra themselves. The galaxies show a significant range in restframe colors and absolute magnitudes. We binned the spectra according to the restframe u-b color and y-band absolute magnitude in order to increase the S/N. We used 3 approaches to estimate the ages and metal content of these binned spectra: via their spectral energy distributions, from spectral-line indices, and by full spectral fitting. The three methods usually produce discordant results

  13. AKARI IRC INFRARED 2.5-5 {mu}m SPECTROSCOPY OF A LARGE SAMPLE OF LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Imanishi, Masatoshi; Nakagawa, Takao; Shirahata, Mai; Ohyama, Yoichi; Onaka, Takashi

    2010-10-01

    We present the results of our systematic infrared 2.5-5 {mu}m spectroscopy of 60 luminous infrared galaxies (LIRGs) with infrared luminosities L{sub IR} = 10{sup 11}-10{sup 12} L{sub sun} and 54 ultraluminous infrared galaxies (ULIRGs) with L{sub IR} {>=} 10{sup 12} L{sub sun}, using the AKARI Infrared Camera (IRC). AKARI IRC slit-less spectroscopy allows us to probe the full range of emission from these galaxies, including spatially extended components. The 3.3 {mu}m polycyclic aromatic hydrocarbon (PAH) emission features, hydrogen recombination emission lines, and various absorption features are detected and used to investigate the properties of these galaxies. Because of the relatively small effect of dust extinction in the infrared range, quantitative discussion of these dusty galaxy populations is possible. For sources with clearly detectable Br{beta} (2.63 {mu}m) and Br{alpha} (4.05 {mu}m) emission lines, the flux ratios are found to be similar to those predicted by case B theory. Starburst luminosities are estimated from both 3.3 {mu}m PAH and Br{alpha} emission, which roughly agree with each other. In addition to the detected starburst activity, a significant fraction of the observed sources display signatures of obscured active galactic nuclei (AGNs), such as low PAH equivalent widths, large optical depths of dust absorption features, and red continuum emission. The energetic importance of optically elusive buried AGNs in optically non-Seyfert galaxies tends to increase with increasing galaxy infrared luminosity, from LIRGs to ULIRGs.

  14. X-Ray Emission from Ultraviolet Luminous Galaxies and Lyman Break Galaxies

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann; Ptak, A. F.; Salim, S.; Heckman, T. P.; Overzier, R.; Mallery, R.; Rich, M.; Strickland, D.; Grimes, J.

    2009-01-01

    We present results from an XMM mini-survey of GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs) that appear to include an interesting subset that are analogs to the distant (3Galaxies (LBGs). The 2-10 kev X-ray emission of LBGs appear to be broadly similar to that of galaxies in the local Universe, possibly indicating similarity in the production of accreting binaries over large evolutionary timescales in the Universe. We have detected luminous X-ray emission from one UVLG that permits basic X-ray spectroscopic analysis, and have direct X-ray constraints on a total of 6 UVLGs. We find evidence for likely large scatter in the assumed X-ray/star-formation rate relation for LBGs.

  15. Optical Spectroscopy of Luminous Infrared Galaxies. I. Nuclear Data

    NASA Astrophysics Data System (ADS)

    Kim, D.-C.; Sanders, D. B.; Veilleux, S.; Mazzarella, J. M.; Soifer, B. T.

    1995-05-01

    A spectroscopic survey of a large sample of luminous infrared galaxies [log (L_ir_/L_sun_)^7^ ~ 10.5-12.5; H_0_ = 75 km s^-1^ Mpc^-1^] has been carried out using the Palomar 5 m telescope,, and the University of Hawaii 2.2 m telescope. Long-slit spectra covering 375o-8000 A at a resolution of ~10 A were obtained of 200 IRAS galaxies, including 114 objects from the IRAS Bright Galaxy Survey, and 86 objects with fainter infrared fluxes selected on the basis of their "warm" far-infrared (S_60_/S_100_) colors. The methods of observation and data reduction are discussed. An atlas of the spectra extracted from the nuclear region of these objects is presented along with a large number of parameters describing the properties of the emission lines, the stellar absorption lines, and the continuum emission that were measured from the spectra. An analysis of these data is presented in a companion paper (Veilleux et al. 1995) along with a discussion of the spatial variations of these parameters in a subsample of twenty-three objects.

  16. ULTRALUMINOUS STAR-FORMING GALAXIES AND EXTREMELY LUMINOUS WARM MOLECULAR HYDROGEN EMISSION AT z = 2.16 IN THE PKS 1138-26 RADIO GALAXY PROTOCLUSTER

    SciTech Connect

    Ogle, P.; Davies, J. E.; Helou, G.; Appleton, P. N.; Bertincourt, B.; Seymour, N.

    2012-05-20

    A deep Spitzer Infrared Spectrograph map of the PKS 1138-26 galaxy protocluster reveals ultraluminous polycyclic aromatic hydrocarbon (PAH) emission from obscured star formation in three protocluster galaxies, including H{alpha}-emitter (HAE) 229, HAE 131, and the central Spiderweb Galaxy. Star formation rates of {approx}500-1100 M{sub Sun} yr{sup -1} are estimated from the 7.7 {mu}m PAH feature. At such prodigious formation rates, the galaxy stellar masses will double in 0.6-1.1 Gyr. We are viewing the peak epoch of star formation for these protocluster galaxies. However, it appears that extinction of H{alpha} is much greater (up to a factor of 40) in the two ULIRG HAEs compared to the Spiderweb. This may be attributed to different spatial distributions of star formation-nuclear star formation in the HAEs versus extended star formation in accreting satellite galaxies in the Spiderweb. We find extremely luminous mid-IR rotational line emission from warm molecular hydrogen in the Spiderweb Galaxy, with L(H{sub 2} 0-0 S(3)) = 1.4 Multiplication-Sign 10{sup 44} erg s{sup -1} (3.7 Multiplication-Sign 10{sup 10} L{sub Sun }), {approx}20 times more luminous than any previously known H{sub 2} emission galaxy (MOHEG). Depending on the temperature, this corresponds to a very large mass of >9 Multiplication-Sign 10{sup 6}-2 Multiplication-Sign 10{sup 9} M{sub Sun} of T > 300 K molecular gas, which may be heated by the PKS 1138-26 radio jet, acting to quench nuclear star formation. There is >8 times more warm H{sub 2} at these temperatures in the Spiderweb than what has been seen in low-redshift (z < 0.2) radio galaxies, indicating that the Spiderweb may have a larger reservoir of molecular gas than more evolved radio galaxies. This is the highest redshift galaxy yet in which warm molecular hydrogen has been directly detected.

  17. LOCAL LUMINOUS INFRARED GALAXIES. III. CO-EVOLUTION OF BLACK HOLE GROWTH AND STAR FORMATION ACTIVITY?

    SciTech Connect

    Alonso-Herrero, Almudena; Hernan-Caballero, Antonio; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang Yiping; Rigopoulou, Dimitra

    2013-03-10

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 Multiplication-Sign 10{sup 7} M{sub Sun} using [Ne III] 15.56 {mu}m and optical [O III] {lambda}5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear {approx}1.5 kpc region, as estimated from the nuclear 11.3 {mu}m PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy.

  18. Local Luminous Infrared Galaxies. III. Co-evolution of Black Hole Growth and Star Formation Activity?

    NASA Astrophysics Data System (ADS)

    Alonso-Herrero, Almudena; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang, Yiping; Hernán-Caballero, Antonio; Rigopoulou, Dimitra

    2013-03-01

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 × 107 M ⊙ using [Ne III] 15.56 μm and optical [O III] λ5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear ~1.5 kpc region, as estimated from the nuclear 11.3 μm PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407.

  19. Resolved Molecular Gas Properties in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Sliwa, Kazimierz; Wilson, Christine

    2015-08-01

    Luminous infrared galaxies (LIRGs) in the local universe are mergers of gas-rich galaxies. The merger event funnels the molecular gas towards the central kiloparsec, compressing the gas, and triggering an extreme starburst, making LIRGs the perfect laboratory for studying extreme modes of star formation. We use the Submillimeter Array sample and observations of Wilson et al. (2008), supplemented with new CARMA and ALMA observations, to constrain the physical conditions such as temperature, density and column density of the molecular gas in the sample of 7 LIRGs. We use the radiative transfer code RADEX (van der Tak et al. 2007) and a Bayesian likelihood code to fit the most probable physical conditions. Comparison of the molecular gas physical conditions shows that earlier merger stage LIRGs such as Arp 299 and NGC 1614 have denser (> 103cm-1) molecular gas than a later stage merger such as VV 114 and NGC 2623. We measure the CO luminosity to H2 mass conversion factor, αCO, using the radiative transfer analysis results and find that the values are a factor of 4-10 times lower than the Galactic value of 4.3 M⊙ (K km s-1 pc2)-1. We also find unusually large 12CO-to-13CO abundance ratios (> 130), more than 2 times the local Galactic value.

  20. AKARI NEAR-INFRARED SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Lee, Jong Chul; Lee, Myung Gyoon; Hwang, Ho Seong

    2012-09-01

    We present the AKARI near-infrared (NIR; 2.5-5 {mu}m) spectroscopic study of 36 (ultra)luminous infrared galaxies ((U)LIRGs) at z = 0.01-0.4. We measure the NIR spectral features including the strengths of 3.3 {mu}m polycyclic aromatic hydrocarbon emission and hydrogen recombination lines (Br{alpha} and Br{beta}), optical depths at 3.1 and 3.4 {mu}m, and NIR continuum slope. These spectral features are used to identify optically elusive, buried active galactic nuclei (AGNs). We find that half of the (U)LIRGs optically classified as non-Seyferts show AGN signatures in their NIR spectra. Using a combined sample of (U)LIRGs with NIR spectra in the literature, we measure the contribution of buried AGNs to the infrared luminosity from the spectral energy distribution fitting to the IRAS photometry. The contribution of these buried AGNs to the infrared luminosity is 5%-10%, smaller than the typical AGN contribution of (U)LIRGs including Seyfert galaxies (10%-40%). We show that NIR continuum slopes correlate well with WISE [3.4]-[4.6] colors, which would be useful for identifying a large number of buried AGNs using the WISE data.

  1. VIBRATIONALLY EXCITED HCN IN THE LUMINOUS INFRARED GALAXY NGC 4418

    SciTech Connect

    Sakamoto, Kazushi; Aalto, Susanne; Evans, Aaron S.; Wiedner, Martina C.; Wilner, David J.

    2010-12-20

    Infrared pumping and its effect on the excitation of HCN molecules can be important when using rotational lines of HCN to probe dense molecular gas in galaxy nuclei. We report the first extragalactic detection of (sub)millimeter rotational lines of vibrationally excited HCN, in the dust-enshrouded nucleus of the luminous infrared galaxy NGC 4418. We estimate the excitation temperature of T{sub vib} {approx} 230 K between the vibrational ground and excited (v{sub 2} = 1) states. This excitation is most likely due to infrared radiation. At this high vibrational temperature the path through the v{sub 2} = 1 state must have a strong impact on the rotational excitation in the vibrational ground level, although it may not be dominant for all rotational levels. Our observations also revealed nearly confusion-limited lines of CO, HCN, HCO{sup +}, H{sup 13}CN, HC{sup 15}N, CS, N{sub 2}H{sup +}, and HC{sub 3}N at {lambda} {approx} 1 mm. Their relative intensities may also be affected by the infrared pumping.

  2. XMM-Newton observations of three interacting luminous infrared galaxies

    SciTech Connect

    Mudd, Dale; Mathur, Smita; Guainazzi, Matteo; Piconcelli, Enrico; Nicastro, Fabrizio; Bianchi, Stefano; Komossa, S.; Vignali, Cristian; Lanzuisi, Giorgio; Fiore, Fabrizio; Maiolino, Roberto

    2014-05-20

    We investigate the X-ray properties of three interacting luminous infrared galaxy systems. In one of these systems, IRAS 18329+5950, we resolve two separate sources. A second and third source, IRAS 19354+4559 and IRAS 20550+1656, have only a single X-ray source detected. We compare the observed emission to point-spread function (PSF) profiles and determine that they are all consistent with the PSF, albeit with large uncertainties for some of our sources. We then model the spectra to determine soft (0.5-2 keV) and hard (2-10 keV) luminosities for the resolved sources and compare these to relationships found in the literature between infrared and X-ray luminosities for starburst galaxies. We obtain luminosities (0.5-10 keV) ranging from 1.7 to 7.3 × 10{sup 41} erg s{sup –1} for our systems. These X-ray luminosities are consistent with predictions for star-formation-dominated sources and thus are most likely due to starbursts, but we cannot conclusively rule out active galactic nuclei.

  3. MODELING THE VERY SMALL SCALE CLUSTERING OF LUMINOUS RED GALAXIES

    SciTech Connect

    Watson, Douglas F.; Berlind, Andreas A.; McBride, Cameron K.; Masjedi, Morad

    2010-01-20

    We model the small-scale clustering of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey. Specifically, we use the halo occupation distribution formalism to model the projected two-point correlation function of LRGs on scales well within the sizes of their host halos (0.016 h {sup -1} Mpc <= r <= 0.42 h {sup -1} Mpc). We start by varying P(N|M), the probability distribution that a dark matter halo of mass M contains N LRGs, and assuming that the radial distribution of satellite LRGs within halos traces the Navarro-Frenk-White (NFW) dark matter density profile. We find that varying P(N|M) alone is not sufficient to match the small-scale data. We next allow the concentration of satellite LRG galaxies to differ from that of dark matter and find that this is also not sufficient. Finally, we relax the assumption of an NFW profile and allow the inner slope of the density profile to vary. We find that this model provides a good fit to the data and the resulting value of the slope is -2.17 +- 0.12. The radial density profile of satellite LRGs within halos is thus not compatible with that of the underlying dark matter, but rather is closer to an isothermal distribution.

  4. ULTRA-DEEP MID-INFRARED SPECTROSCOPY OF LUMINOUS INFRARED GALAXIES AT z{approx} 1 AND z {approx} 2

    SciTech Connect

    Fadda, Dario; Yan Lin; Frayer, David T.; Helou, George; Lagache, Guilaine; Marcillac, Delphine; Sajina, Anna; Lutz, Dieter; Wuyts, Stijn; Le Floc'h, Emeric; Caputi, Karina; Spoon, Henrik W. W.; Veilleux, Sylvain; Blain, Andrew E-mail: lyan@ipac.caltech.ed

    2010-08-10

    We present ultra-deep mid-infrared spectra of 48 infrared-luminous galaxies in the GOODS-south field obtained with the Infrared Spectrograph on the Spitzer Space Telescope. These galaxies are selected among faint infrared sources (0.14-0.5 mJy at 24 {mu}m) in two redshift bins (0.76-1.05 and 1.75-2.4) to sample the major contributors to the cosmic infrared background at the most active epochs. We estimate redshifts for 92% of the sample using polycyclic aromatic (PAH) and Si absorption features obtaining, in particular, eight new redshifts difficult to measure from ground-based observations. Only a few of these galaxies (5% at z {approx} 1 and 12% at z {approx} 2) have their total infrared luminosity dominated by emission from active galactic nuclei (AGNs). The averaged mid-IR spectrum of the z {approx} 1 luminous infrared galaxies (LIRGs) is a very good match to the averaged spectrum of local starbursts. The averaged spectrum of the z {approx} 2 ultra-luminous infrared galaxies (ULIRGs), because of a deeper Si absorption, is better fitted by the averaged spectrum of H II-like local ULIRGs. Combining this sample with other published data, we find that 6.2 {mu}m PAH equivalent widths (EW) reach a plateau of {approx} 1 {mu}m for L {sub 24{mu}m} {approx}< 10{sup 11} L{sub sun}. At higher luminosities, EW{sub 6.2{mu}m} anti-correlates with L{sub 24{mu}m}. Intriguingly, high-z ULIRGs and sub-millimeter galaxies (SMGs) lie above the local EW{sub 6.2{mu}m}-L{sub 24{mu}m} relationship suggesting that, at a given luminosity, high-z ULIRGs have AGN contributions to their dust emission lower than those of local counterparts. A quantitative analysis of their morphology shows that most of the luminous IR galaxies have morphologies similar to those of IR-quiet galaxies at the same redshift. All z {approx} 2 ULIRGs of our sample are IR-excess BzK galaxies and most of them have L{sub FIR}/L{sub 1600A} ratios higher than those of starburst galaxies at a given UV slope. The 'IR

  5. Ultra-deep Mid-infrared Spectroscopy of Luminous Infrared Galaxies at z ~ 1 and z ~ 2

    NASA Astrophysics Data System (ADS)

    Fadda, Dario; Yan, Lin; Lagache, Guilaine; Sajina, Anna; Lutz, Dieter; Wuyts, Stijn; Frayer, David T.; Marcillac, Delphine; Le Floc'h, Emeric; Caputi, Karina; Spoon, Henrik W. W.; Veilleux, Sylvain; Blain, Andrew; Helou, George

    2010-08-01

    We present ultra-deep mid-infrared spectra of 48 infrared-luminous galaxies in the GOODS-south field obtained with the Infrared Spectrograph on the Spitzer Space Telescope. These galaxies are selected among faint infrared sources (0.14-0.5 mJy at 24 μm) in two redshift bins (0.76-1.05 and 1.75-2.4) to sample the major contributors to the cosmic infrared background at the most active epochs. We estimate redshifts for 92% of the sample using polycyclic aromatic (PAH) and Si absorption features obtaining, in particular, eight new redshifts difficult to measure from ground-based observations. Only a few of these galaxies (5% at z ~ 1 and 12% at z ~ 2) have their total infrared luminosity dominated by emission from active galactic nuclei (AGNs). The averaged mid-IR spectrum of the z ~ 1 luminous infrared galaxies (LIRGs) is a very good match to the averaged spectrum of local starbursts. The averaged spectrum of the z ~ 2 ultra-luminous infrared galaxies (ULIRGs), because of a deeper Si absorption, is better fitted by the averaged spectrum of H II-like local ULIRGs. Combining this sample with other published data, we find that 6.2 μm PAH equivalent widths (EW) reach a plateau of ~ 1 μm for L 24 μm <~ 1011 L sun. At higher luminosities, EW6.2 μm anti-correlates with L 24 μm. Intriguingly, high-z ULIRGs and sub-millimeter galaxies (SMGs) lie above the local EW6.2 μm-L 24 μm relationship suggesting that, at a given luminosity, high-z ULIRGs have AGN contributions to their dust emission lower than those of local counterparts. A quantitative analysis of their morphology shows that most of the luminous IR galaxies have morphologies similar to those of IR-quiet galaxies at the same redshift. All z ~ 2 ULIRGs of our sample are IR-excess BzK galaxies and most of them have L FIR/L 1600 Å ratios higher than those of starburst galaxies at a given UV slope. The "IR excess" is mostly due to strong 7.7 μm PAH emission and underestimation of UV dust extinction. On the basis of

  6. BARYONS MATTER: WHY LUMINOUS SATELLITE GALAXIES HAVE REDUCED CENTRAL MASSES

    SciTech Connect

    Zolotov, Adi; Dekel, Avishai; Brooks, Alyson M.; Willman, Beth; Governato, Fabio; Quinn, Tom; Pontzen, Andrew; Christensen, Charlotte; Wadsley, James

    2012-12-10

    Using high-resolution cosmological hydrodynamical simulations of Milky Way-massed disk galaxies, we demonstrate that supernovae feedback and tidal stripping lower the central masses of bright (-15 < M{sub V} < -8) satellite galaxies. These simulations resolve high-density regions, comparable to giant molecular clouds, where stars form. This resolution allows us to adopt a prescription for H{sub 2} formation and destruction that ties star formation to the presence of shielded, molecular gas. Before infall, supernova feedback from the clumpy, bursty star formation captured by this physically motivated model leads to reduced dark matter (DM) densities and shallower inner density profiles in the massive satellite progenitors (M{sub vir} {>=} 10{sup 9} M{sub Sun }, M{sub *} {>=} 10{sup 7} M{sub Sun }) compared with DM-only simulations. The progenitors of the lower mass satellites are unable to maintain bursty star formation histories, due to both heating at reionization and gas loss from initial star-forming events, preserving the steep inner density profile predicted by DM-only simulations. After infall, gas stripping from satellites reduces the total central masses of satellites simulated with DM+baryons relative to DM-only satellites. Additionally, enhanced tidal stripping after infall due to the baryonic disk acts to further reduce the central DM densities of the luminous satellites. Satellites that enter with cored DM halos are particularly vulnerable to the tidal effects of the disk, exacerbating the discrepancy in the central masses predicted by baryon+DM and DM-only simulations. We show that DM-only simulations, which neglect the highly non-adiabatic evolution of baryons described in this work, produce denser satellites with larger central velocities. We provide a simple correction to the central DM mass predicted for satellites by DM-only simulations. We conclude that DM-only simulations should be used with great caution when interpreting kinematic observations

  7. Detection of stacked filament lensing between SDSS luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Clampitt, Joseph; Miyatake, Hironao; Jain, Bhuvnesh; Takada, Masahiro

    2016-04-01

    We search for the lensing signal of massive filaments between 135 000 pairs of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey. We develop a new estimator that cleanly removes the much larger shear signal of the neighbouring LRG haloes, relying only on the assumption of spherical symmetry. We consider two models: a `thick'-filament model constructed from ray-tracing simulations for Λ cold dark matter model, and a `thin'-filament model which models the filament by a string of haloes along the line connecting the two LRGs. We show that the filament lensing signal is in nice agreement with the thick simulation filament, while strongly disfavouring the thin model. The magnitude of the lensing shear due to the filament is below 10-4. Employing the likelihood ratio test, we find a 4.5σ significance for the detection of the filament lensing signal, corresponding to a null hypothesis fluctuation probability of 3 × 10-6. We also carried out several null tests to verify that the residual shear signal from neighbouring LRGs and other shear systematics are minimized.

  8. Stellar Evolutionary Effects on the Abundance of PAHS and SN-Condensed Dust in Galaxies

    NASA Technical Reports Server (NTRS)

    Dwek, Eli

    2007-01-01

    Spectral aid photometric observations of nearby galaxies show a correlation between the strength of their mid-IR aromatic features and their metal abundance, and a deficiency of these features in low-metallicity galaxies. The aromatic features are most commonly attributed to emission from PAH molecules. In this paper, we suggest that the observed correlation represents a trend of PAH abundance with galactic age, reflecting the delayed injection of PAHs and carbon dust into the ISM, by AGB stars in their final, post-AGB phase of their evolution. These AGB stars are the primary sources of PAHs and carbon dust in galaxies, and recycle their ejecta back to the interstellar medium only after a few hundred million years of evolution on the main sequence. In contrast, more massive stars that explode as Type II supernovae inject their metals and dust almost instantaneously after their formation. After determining the PAH abundances in 35 nearby galaxies, we use a chemical evolution model to show that the delayed injection of carbon dust by AGB stars provides a natural explanation to the dependence of the PAH content, in galaxies with metallicity. We also show that larger dust particles giving rise to the far-IR emission follow a distinct evolutionary trend closely related to the injection of dust by massive stars into the ISM.

  9. Host galaxies of luminous type II AGN: Winds, shocks, and comparisons to The SAMI Galaxy Survey

    NASA Astrophysics Data System (ADS)

    McElroy, Rebecca; Croom, Scott; Pracy, Michael; SAMI Galaxy Survey Team

    2016-01-01

    We present IFS observations of luminous (log(L[O III]/L⊙) > 8.7) local (z < 0.11) type II AGN, and demonstrate that winds are ubiquitous within this sample and have a direct influence on the ISM of the host galaxies. We use both non-parametric (e.g. line width and asymmetry) and multi-Gaussian fitting to decompose the complex emission profiles close to the AGN. We find line widths containing 80% flux in the range 400 - 1600 km/s with a mean of 790 ± 90 km/s, such high velocities are strongly suggestive that these AGN are driving ionized outflows. Additionally, multi-Gaussian fitting reveals that 14/17 of our targets require 3 separate kinematic components in the ionized gas in their central regions. The broadest components of these fits have FWHM = 530 - 2520 km/s, with a mean value of 920 ± 50 km/s. By simultaneously fitting both the Hβ/[O III] and Hα/[N II] complexes we construct ionization diagnostic diagrams for each component. 13/17 of our galaxies show a significant (> 95 %) correlation between the [N II]/Hα ratio and the velocity dispersion of the gas. Such a correlation is the natural consequence of a contribution to the ionization from shock excitation and we argue that this demonstrates that the outflows from these AGN are directly impacting the surrounding ISM within the galaxies. In addition, we use stellar absorption features to measure kinematics for these AGN host galaxies and those of a control sample selected from the SAMI Galaxy Survey to search for evidence of these luminous AGN being preferentially hosted by disturbed or merging systems.

  10. On the Cusp around Central Black Holes in Luminous Elliptical Galaxies.

    PubMed

    Nakano; Makino

    1999-11-10

    In this Letter, we show that a massive black hole (MBH) that falls into the center of a galaxy on the dynamical timescale leaves a weak cusp (rho~r-1&solm0;2) around it, which is in good agreement with the recent observations of luminous elliptical galaxies by the Hubble Space Telescope. Such an event is a natural outcome of the merging of two galaxies that have central MBHs. This is the only known mechanism for forming weak cusps in luminous elliptical galaxies. Therefore, the existence of the weak cusps indicates that the central black holes of luminous elliptical galaxies have fallen to the center from outside, most likely during a major merger event. PMID:10525458

  11. The Luminosity-Metallicity relation of distant luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Liang, Y. C.; Hammer, F.; Flores, H.; Elbaz, D.; Marcillac, D.; Cesarsky, C. J.

    2004-09-01

    One hundred and five 15 \\mum-selected objects in three ISO (Infrared Space Observatory) deep survey fields (CFRS 3h, UDSR and UDSF) are studied on the basis of their high-quality optical spectra with resolution R>1000 from VLT/FORS2. ˜92 objects (88%) have secure redshifts, ranging from 0 to 1.16 with a median value of z_med=0.587. Considerable care is taken in estimating the extinction properties of individual galaxy, which can seriously affect diagnostic diagrams and estimates of star formation rates (SFRs) and of metal abundances. Two independent estimates of the extinction have been made, e.g. Balmer line ratio and energy balance between infrared (IR) and H\\beta luminosities. For most of the sources, we find a good agreement between the two extinction coefficients (within ±0.64 rms in AV, the extinction in V band), with median values of A_V(IR) = 2.36 and A_V(Balmer)= 1.82 for z>0.4 luminous IR galaxies (LIRGs). At z >0.4, our sample show many properties (IR luminosity, continuum color, ionization and extinction) strikingly in common with those of local (IRAS) LIRGs studied by Veilleux et al. (\\cite{Veilleux1995}). Thus, our sample can provide a good representation of LIRGs in the distant Universe. We confirm that most (>77%) ISO 15 μm-selected galaxies are dominated by star formation. Oxygen abundances in interstellar medium in the galaxies are estimated from the extinction-corrected ``strong'' emission line ratios (e.g. \\ion{[O}{ii]}/Hβ, \\ion{[O}{iii]}/Hβ and \\ion{[O}{iii]}/\\ion{[O}{ii]}). The derived 12+log(O/H) values range from 8.36 to 8.93 for the z>0.4 galaxies with a median value of 8.67. Distant LIRGs present a metal content less than half of that of the local bright disks (i.e. L*). Their properties can be reproduced with infall models although one has to limit the infall time to avoid overproduction of metals at late times. The models predict that total masses (gas + stars) of the distant LIRGs are from 1011 M⊙ to ≤1012 M⊙. A

  12. Cosmological constraints from the SDSS luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Tegmark, Max; Eisenstein, Daniel J.; Strauss, Michael A.; Weinberg, David H.; Blanton, Michael R.; Frieman, Joshua A.; Fukugita, Masataka; Gunn, James E.; Hamilton, Andrew J. S.; Knapp, Gillian R.; Nichol, Robert C.; Ostriker, Jeremiah P.; Padmanabhan, Nikhil; Percival, Will J.; Schlegel, David J.; Schneider, Donald P.; Scoccimarro, Roman; Seljak, Uroš; Seo, Hee-Jong; Swanson, Molly; Szalay, Alexander S.; Vogeley, Michael S.; Yoo, Jaiyul; Zehavi, Idit; Abazajian, Kevork; Anderson, Scott F.; Annis, James; Bahcall, Neta A.; Bassett, Bruce; Berlind, Andreas; Brinkmann, Jon; Budavari, Tamás; Castander, Francisco; Connolly, Andrew; Csabai, Istvan; Doi, Mamoru; Finkbeiner, Douglas P.; Gillespie, Bruce; Glazebrook, Karl; Hennessy, Gregory S.; Hogg, David W.; Ivezić, Željko; Jain, Bhuvnesh; Johnston, David; Kent, Stephen; Lamb, Donald Q.; Lee, Brian C.; Lin, Huan; Loveday, Jon; Lupton, Robert H.; Munn, Jeffrey A.; Pan, Kaike; Park, Changbom; Peoples, John; Pier, Jeffrey R.; Pope, Adrian; Richmond, Michael; Rockosi, Constance; Scranton, Ryan; Sheth, Ravi K.; Stebbins, Albert; Stoughton, Christopher; Szapudi, István; Tucker, Douglas L.; vanden Berk, Daniel E.; Yanny, Brian; York, Donald G.

    2006-12-01

    We measure the large-scale real-space power spectrum P(k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loève eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01h/Mpcgalaxy samples are consistent, with the former providing higher signal-to-noise. Our results are robust to omitting angular and radial density fluctuations and are consistent between different parts of the sky. They provide a striking confirmation of the predicted large-scale ΛCDM power spectrum. Combining only SDSS LRG and WMAP data places robust constraints on many cosmological parameters that complement prior analyses of multiple data sets. The LRGs provide independent cross-checks on Ωm and the baryon fraction in good agreement with WMAP. Within the context of flat ΛCDM models, our LRG measurements complement WMAP by sharpening the constraints on the matter density, the neutrino density and the tensor amplitude by about a factor of 2, giving Ωm=0.24±0.02 (1σ), ∑mν≲0.9eV (95%) and r<0.3 (95%). Baryon oscillations are clearly detected and provide a robust measurement of the comoving distance to the median survey redshift z=0.35 independent of curvature and dark energy properties. Within the ΛCDM framework, our power spectrum measurement improves the evidence for spatial flatness, sharpening the curvature constraint Ωtot=1.05±0.05 from WMAP alone to Ωtot=1.003±0.010. Assuming Ωtot=1, the equation of state parameter is constrained to w=-0.94±0.09, indicating the potential for more ambitious future LRG measurements to provide precision

  13. WISE: From the Dimmest Stars to the most Luminous Galaxies!

    NASA Astrophysics Data System (ADS)

    Craig, N.; Mendez, B. J.; Wright, E. L.

    2004-12-01

    The Wide-field Infrared Survey Explorer (WISE) Mission, led by UCLA PI Dr. Edward L. Wright is a newly selected MIDEX Mission, scheduled to launch in Summer 2008. WISE will conduct a survey of the entire sky in the infrared (3.5 - 23 microns) with far greater sensitivity than any previous program or mission. WISE will catalogue more than 100,000 asteroids, discover the coolest, dimmest, and nearest stars to the Sun, and determine which are the most luminous galaxies in the Universe. The WISE survey will consist of over a million images, from which hundreds of millions of astronomical objects will be catalogued, providing a vast storehouse of knowledge about the Solar System, the Milky Way, and the Universe. We will discuss our plans for an Education and Public Outreach (E/PO) program for WISE, including how our program will leverage resources from other IR mission E/PO programs such as Spitzer and SOFIA. We will also discuss our plans to partner with the amateur astronomer community to reach out to the K-12 education community, including underserved communities. The University of California, Berkeley's SEGway group from the Space Sciences Laboratory will lead the E/PO efforts of the WISE Mission with formal and informal education partners such as NOAO, Hands-On-Universe, the American Museum of Natural History, Space Science Institute, Space Dynamics Laboratory, the Astronomical Society of the Pacific, and Cornerstone Evaluations. The outreach program of WISE will captivate a wide range of audiences in the formal and informal science education communities with beautiful imagery and engaging science.

  14. The First Hyper-Luminous Infrared Galaxy Discovered by WISE

    NASA Technical Reports Server (NTRS)

    Eisenhardt, Peter R.; Wu, Jingwen; Tsai, Chao-Wei; Assef, Roberto; Benford, Dominic; Blain, Andrew; Bridge, Carrie; Condon, J. J.; Cushing, Michael C.; Cutri, Roc; Evans, Neal J., III; Gelino, Chris; Griffith, Roger L.; Grillmair, Carl J.; Jarrett, Tom; Lonsdale, Carol J.; Masci, Frank J.; Mason, Brian S.; Petty, Sara; Sayers, Jack; Stanford, S. Adam; Stern, Daniel; Wright, Edward L.; Yan, Lin

    2012-01-01

    We report the discovery by the Wide-field Infrared Survey Explorer of the z = 2.452 source WISEJ181417.29+341224.9, the first hyperluminous source found in the WISE survey. WISE 1814+3412 is also the prototype for an all-sky sample of approximately 1000 extremely luminous "W1W2-dropouts" (sources faint or undetected by WISE at 3.4 and 4.6 micrometers and well detected at 12 or 22 micrometers). The WISE data and a 350 micrometers detection give a minimum bolometric luminosity of 3.7 x 10(exp 13) solar luminosity, with approximately 10(exp 14) solar luminosity plausible. Followup images reveal four nearby sources: a QSO and two Lyman Break Galaxies (LBGs) at z = 2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission. Gravitational lensing is unlikely given the source locations and their different spectra and colors. The dominant LBG spectrum indicates a star formation rate approximately 300 solar mass yr(exp -1), accounting for less than or equal to 10 percent of the bolometric luminosity. Strong 22 micrometer emission relative to 350 micrometer implies that warm dust contributes significantly to the luminosity, while cooler dust normally associated with starbursts is constrained by an upper limit at 1.1 mm. Radio emission is approximately 10? above the far-infrared/radio correlation, indicating an active galactic nucleus is present. An obscured AGN combined with starburst and evolved stellar components can account for the observations. If the black hole mass follows the local MBH-bulge mass relation, the implied Eddington ratio is approximately greater than 4. WISE 1814+3412 may be a heavily obscured object where the peak AGN activity occurred prior to the peak era of star formation.

  15. The luminous polycyclic aromatic hydrocarbon emission features: Applications to high redshift galaxies and active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Shipley, Heath Vernon

    The co-evolution of star-formation and supermassive black hole (SMBH) accretion in galaxies is one of the key problems in galaxy formation theory. Understanding the formation of galaxies, and their subsequent evolution, will be coupled to intensive study of the evolution of SMBHs. This thesis focuses on studying diagnostics of star-formation and SMBH accretion to develop tools to study this co-evolution. Chapter 2 consists of using mid-infrared (mid-IR) spectroscopy from the Spitzer Infrared Spectrograph (IRS) to study the nature of star-formation and SMBH accretion. The mid-IR spectra cover wavelengths 5-38mum, spanning the polycyclic aromatic hydrocarbon (PAH) features and important atomic diagnostic lines. We divide our sample into a subsample of galaxies with Spitzer IRAC colors indicative of warm dust heated by an AGN (IRAGN) and those galaxies whose colors indicate star-formation processes (non-IRAGN). In both the IRAGN and star-forming samples, the luminosity in the PAH features correlates strongly with [Ne II]lambda12.8&mum emission line, from which we conclude that the PAH luminosity directly traces the instantaneous star-formation rate (SFR) in both the IRAGN and star-forming galaxies. There is no measurable difference between the PAH luminosity ratios of L11:3/L7:7 and L6:2/L7:7 for the IRAGN and non-IRAGN, suggesting that AGN do not significantly excite or destroy PAH molecules on galaxy-wide scales. In chapter 3, I calibrate the PAH luminosity as a SFR indicator. We provide a new robust SFR calibration using the luminosity emitted from PAH molecules at 6.2mum, 7.7mum and 11.3mum. The PAH features emit strongly in the mid-IR mitigating dust extinction, containing on average 5--10% of the total IR luminosity in galaxies. We use mid-IR spectroscopy from the Spitzer/IRS, and data covering other SFR indicators (Halpha emission and rest-frame 24mum continuum emission). The PAH luminosity correlates linearly with the SFR as measured by the Halpha luminosity

  16. OBSERVATIONS OF DARK AND LUMINOUS MATTER: THE RADIAL DISTRIBUTION OF SATELLITE GALAXIES AROUND MASSIVE RED GALAXIES

    SciTech Connect

    Tal, Tomer; Wake, David A.; Van Dokkum, Pieter G.

    2012-05-20

    We study the projected radial distribution of satellite galaxies around more than 28,000 luminous red galaxies (LRGs) at 0.28 < z < 0.40 and trace the gravitational potential of LRG groups in the range 15 < r/kpc < 700. We show that at large radii the satellite number-density profile is well fitted by a projected Navarro-Frenk-White (NFW) profile with r{sub s} {approx} 270 kpc and that at small radii this model underestimates the number of satellite galaxies. Utilizing the previously measured stellar light distribution of LRGs from deep imaging stacks, we demonstrate that this small-scale excess is consistent with a non-negligible baryonic mass contribution to the gravitational potential of massive groups and clusters. The combined NFW+scaled stellar profile provides an excellent fit to the satellite number-density profile all the way from 15 kpc to 700 kpc. Dark matter dominates the total mass profile of LRG halos at r > 25 kpc whereas baryons account for more than 50% of the mass at smaller radii. We calculate the total dark-to-baryonic mass ratio and show that it is consistent with measurements from weak lensing for environments dominated by massive early-type galaxies. Finally, we divide the satellite galaxies in our sample into three luminosity bins and show that the satellite light profiles of all brightness levels are consistent with each other outside of roughly 25 kpc. At smaller radii we find evidence for a mild mass segregation with an increasing fraction of bright satellites close to the central LRG.

  17. Stellar Evolutionary Effects on the Abundances of PAH and SN-Condensed Dust in Galaxies

    NASA Technical Reports Server (NTRS)

    Dwek, Eliahu

    2007-01-01

    Spectral and photometric observations of nearby galaxies show a correlation between the strength of their mid-IR aromatic features, attributed to PAH molecules, and their metal abundance, leading to a deficiency of these features in low-metallicity galaxies. We suggest that the observed correlation represents a trend of PAH abundance with galactic age, reflecting the delayed injection of carbon dust into the ISM by AGB stars in the final post-AGB phase of their evolution. We also show that larger dust particles giving rise to the far-IR emission follow a distinct evolutionary trend closely related to the injection of dust by massive stars into the ISM.

  18. Unveiling the hearts of luminous and ultra-luminous infrared galaxy mergers with laser guide star adaptive optics

    NASA Astrophysics Data System (ADS)

    Medling, Anne M.

    2013-03-01

    Gas-rich galaxies across cosmic time exhibit one or both of two phenomena: ongoing star formation and an active galactic nucleus indicating current black hole accretion. These two processes are important mechanisms through which galaxies evolve and grow, but their effects are difficult to disentangle. Both will use up some available gas, and both are capable of producing winds strong enough to eject remaining gas from the galaxy. One must look at high spatial resolutions in order to separate the dynamical effects of star formation going on near the nucleus of a galaxy from the black hole growth going on in the nucleus. We present high spatial resolution integral field spectroscopy of fifteen nearby luminous and ultra-luminous infrared galaxies. These systems are extremely bright in the infrared exactly because they host powerful starbursts and active nuclei, which in turn heat the surrounding dust. Our data provide resolved stellar and gaseous kinematics of the central kiloparsec of each of these systems by removing atmospheric blurring with adaptive optics, an observing technique that measures the turbulence in the Earth's atmosphere and then uses a deformable mirror to correct the resulting distortions. Our kinematic maps reveal nuclear disks of gas and stars with radii ˜ a few hundred parsecs surrounding the central black holes. Because the stellar and gas kinematics match well, we conclude that the stars are forming in situ from the gas in the disks. These disks may be the progenitors of kinematically decoupled cores seen in many isolated elliptical galaxies, and may have a significant effect on the merger rate of binary black holes. Additionally, these disks may be used to measure black hole masses which, when combined with host galaxy properties and placed on scaling relations, indicate that black holes grow as or more quickly than their host galaxies during a merger. This suggests that a sudden burst of black hole growth at in the final stages of the merger

  19. MID-INFRARED PROPERTIES OF NEARBY LUMINOUS INFRARED GALAXIES. I. SPITZER INFRARED SPECTROGRAPH SPECTRA FOR THE GOALS SAMPLE

    SciTech Connect

    Stierwalt, S.; Armus, L.; Surace, J. A.; Inami, H.; Petric, A. O.; Diaz-Santos, T.; Haan, S.; Howell, J.; Marshall, J.; Charmandaris, V.; Kim, D. C.; Mazzarella, J. M.; Chan, B.; Spoon, H. W. W.; Veilleux, S.; Evans, A.; Sanders, D. B.; Appleton, P.; Bothun, G.; Bridge, C. R.; and others

    2013-05-01

    The Great Observatories All-Sky LIRG Survey (GOALS) is a comprehensive, multiwavelength study of luminous infrared galaxies (LIRGs) in the local universe. Here we present low resolution Spitzer Infrared Spectrograph spectra covering 5-38 {mu}m and provide a basic analysis of the mid-IR spectral properties observed for nearby LIRGs. In a companion paper, we discuss detailed fits to the spectra and compare the LIRGs to other classes of galaxies. The GOALS sample of 244 nuclei in 180 luminous (10{sup 11} {<=} L {sub IR}/L {sub Sun} < 10{sup 12}) and 22 ultraluminous (L {sub IR}/L {sub Sun} {>=} 10{sup 12}) IR galaxies represents a complete subset of the IRAS Revised Bright Galaxy Sample and covers a range of merger stages, morphologies, and spectral types. The majority (>60%) of the GOALS LIRGs have high 6.2 {mu}m polycyclic aromatic hydrocarbon (PAH) equivalent widths (EQW{sub 6.2{mu}m} > 0.4 {mu}m) and low levels of silicate absorption (s {sub 9.7{mu}m} > -1.0). There is a general trend among the U/LIRGs for both silicate depth and mid-infrared (MIR) slope to increase with increasing L {sub IR}. U/LIRGs in the late to final stages of a merger also have, on average, steeper MIR slopes and higher levels of dust obscuration. Together, these trends suggest that as gas and dust is funneled toward the center of a coalescing merger, the nuclei become more compact and more obscured. As a result, the dust temperature increases also leading to a steeper MIR slope. The sources that depart from these correlations have very low PAH equivalent width (EQW{sub 6.2{mu}m} < 0.1 {mu}m) consistent with their emission being dominated by an active galactic nucleus (AGN) in the MIR. These extremely low PAH EQW sources separate into two distinct types: relatively unobscured sources with a very hot dust component (and thus very shallow MIR slopes) and heavily dust obscured nuclei with a steep temperature gradient. The most heavily dust obscured sources are also the most compact in their MIR

  20. Rapid evolution of the most luminous galaxies during the first 900 million years.

    PubMed

    Bouwens, Rychard J; Illingworth, Garth D

    2006-09-14

    The first 900 million years (Myr) to redshift z approximately 6 (the first seven per cent of the age of the Universe) remains largely unexplored for the formation of galaxies. Large samples of galaxies have been found at z approximately 6 (refs 1-4) but detections at earlier times are uncertain and unreliable. It is not at all clear how galaxies built up from the first stars when the Universe was about 300 Myr old (z approximately 12-15) to z approximately 6, just 600 Myr later. Here we report the results of a search for galaxies at z approximately 7-8, about 700 Myr after the Big Bang, using the deepest near-infrared and optical images ever taken. Under conservative selection criteria we find only one candidate galaxy at z approximately 7-8, where ten would be expected if there were no evolution in the galaxy population between z approximately 7-8 and z approximately 6. Using less conservative criteria, there are four candidates, where 17 would be expected with no evolution. This demonstrates that very luminous galaxies are quite rare 700 Myr after the Big Bang. The simplest explanation is that the Universe is just too young to have built up many luminous galaxies at z approximately 7-8 by the hierarchical merging of small galaxies. PMID:16971943

  1. Nebular Line Emission in z 1 Spitzer Infrared-Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Krause, John; Papovich, C.; Finkelstein, S.; Willmer, C.; Egami, E.; Conselice, C.; Huang, J.; Koo, D.; Laird, E.; Le Floc'h, E.; Lotz, J.; Maia, M.; Marcillac, D.; Nandra, K.; Webb, T.; Weiner, B.

    2010-01-01

    We present near-infrared (IR) spectroscopic observations from the Multi-Object IR Camera and Spectrograph (MOIRCS) on the Subaru telescope of a sample of 21 IR-luminous galaxies in the approximate range 1 < z < 1.5. These galaxies were selected based on their Spitzer 24-micron flux densities (S(24 micron) > 0.1 mJy) and known spectroscopic redshifts from the All-Wavelength Extended Groth Strip International Survey (AEGIS). We measure rest-frame optical emission line fluxes for H-alpha and [NII], and also [OIII] and H-beta, where available. We use emission-line diagnostics to constrain the origin of the ionization in these objects: processes associated with star formation or AGN (including Seyferts and LINERs). The high-redshift galaxies in our sample have similar [NII] / H-alpha flux ratios compared to low-redshift (z 0.1) IR-luminous galaxies (Kim et al., 1995; Veilleux et al., 1995) for galaxies with implied IR luminosities of 11 < Log L(8-1000 micron) / L sol < 12. However, we find evidence that the IR-luminous galaxies in our sample with implied Log L(8-1000 micron) / L sol > 12 have lower [NII] / H-alpha ratios than low-redshift galaxies with comparable IR luminosity, implying the higher redshift IR-luminous galaxies may have a higher fraction of systems dominated by star formation. We also study the relation of our rest-frame optical emission-line diagnostics to other indicators of AGN activity, including the mid-IR colors and X-ray luminosities. In addition, we compare star-formation-rate indicators from our dust-corrected H-alpha emission line luminosities to those from the mid-to-far IR and compare these as a function of IR luminosity against the low-redshift sample.

  2. Radio continuum properties of luminous infrared galaxies. Identifying the presence of an AGN in the radio

    NASA Astrophysics Data System (ADS)

    Vardoulaki, E.; Charmandaris, V.; Murphy, E. J.; Diaz-Santos, T.; Armus, L.; Evans, A. S.; Mazzarella, J. M.; Privon, G. C.; Stierwalt, S.; Barcos-Muñoz, L.

    2015-02-01

    Context. Luminous infrared galaxies (LIRGs) are systems enshrouded in dust, which absorbs most of their optical/UV emission and radiates it again in the mid- and far-infrared. Radio observations are largely unaffected by dust obscuration, enabling us to study the central regions of LIRGs in an unbiased manner. Aims: The main goal of this project is to examine how the radio properties of local LIRGs relate to their infrared spectral characteristics. Here we present an analysis of the radio continuum properties of a subset of the Great Observatories All-sky LIRG Survey (GOALS), which consists of 202 nearby systems (z< 0.088). Our radio sample consists of 35 systems, containing 46 individual galaxies, that were observed at both 1.49 and 8.44 GHz with the VLA with a resolution of about 1 arcsec (FWHM). The aim of the project is to use the radio imagery to probe the central kpc of these LIRGs in search of active galactic nuclei (AGN). Methods: We used the archival data at 1.49 and 8.44 GHz to create radio-spectral-index maps using the standard relation between flux density Sν and frequency ν, Sν ~ ν- α, where α is the radio spectral index. By studying the spatial variations in α, we classified the objects as radio-AGN, radio-SB, and AGN/SB (a mixture). We identified the presence of an active nucleus using the radio morphology, deviations from the radio/infrared correlation, and spatially resolved spectral index maps, and then correlated this to the usual mid-infrared ([NeV]/[NeII] and [OIV]/[NeII] line ratios and equivalent width of the 6.2 μm PAH feature) and optical (BPT diagram) AGN diagnostics. Results: We find that 21 out of the 46 objects in our sample (~45%) are radio-AGN, 9 out of the 46 (~20%) are classified as starbursts (SB) based on the radio analysis, and 16 (~35%) are AGN/SB. After comparing to other AGN diagnostics we find 3 objects out of the 46 (~7%) that are identified as AGN based on the radio analysis, but are not classified as such based on

  3. DARK AND LUMINOUS MATTER IN THINGS DWARF GALAXIES

    SciTech Connect

    Oh, Se-Heon; De Blok, W. J. G.; Brinks, Elias; Walter, Fabian; Kennicutt, Robert C. Jr. E-mail: edeblok@ast.uct.ac.za E-mail: walter@mpia.de

    2011-06-15

    We present mass models for the dark matter component of seven dwarf galaxies taken from 'The H I Nearby Galaxy Survey' (THINGS) and compare these with those taken from numerical {Lambda} cold dark matter ({Lambda}CDM) simulations. The THINGS high-resolution data significantly reduce observational uncertainties and thus allow us to derive accurate dark matter distributions in these systems. We here use the bulk velocity fields when deriving the rotation curves of the galaxies. Compared to other types of velocity fields, the bulk velocity field minimizes the effect of small-scale random motions more effectively and traces the underlying kinematics of a galaxy more properly. The 'Spitzer Infrared Nearby Galaxies Survey' 3.6 {mu}m and ancillary optical data are used for separating the baryons from their total matter content in the galaxies. The sample dwarf galaxies are found to be dark matter dominated over most radii. The relation between total baryonic (stars + gas) mass and maximum rotation velocity of the galaxies is roughly consistent with the baryonic Tully-Fisher relation calibrated from a larger sample of gas-dominated low-mass galaxies. We find discrepancies between the derived dark matter distributions of the galaxies and those of {Lambda}CDM simulations, even after corrections for non-circular motions have been applied. The observed solid body-like rotation curves of the galaxies rise too slowly to reflect the cusp-like dark matter distribution in cold dark matter halos. Instead, they are better described by core-like models such as pseudo-isothermal halo models dominated by a central constant-density core. The mean value of the logarithmic inner slopes of the mass density profiles is {alpha} = -0.29 {+-} 0.07. They are significantly different from the steep slope of {approx} - 1.0 inferred from previous dark-matter-only simulations, and are more consistent with shallower slopes found in recent {Lambda}CDM simulations of dwarf galaxies in which the effects

  4. Spectroscopic Confirmation of the Dragonfish Association: The Galaxy's Most Luminous OB Association

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Moon, Dae-Sik; Matzner, Christopher D.

    2011-12-01

    Young OB associations with masses greater than 104 M ⊙ have been inferred to exist in the Galaxy but have largely evaded detection. Recently, a candidate OB association has been identified within the most luminous star-forming complex in the Galaxy, the Dragonfish Nebula. We identify 18 young, massive stars with near-infrared spectroscopy from a sample of 50 members within the candidate OB association, including 15 O-type and 3 luminous blue variables or Wolf-Rayet stars. This number matches the expected yield of massive stars from the candidate association, confirming its existence and ability to power the parent star-forming complex. These results demonstrate the existence of a 105 M ⊙ OB association, more powerful than any previously known in the Galaxy, comparable in mass only to Westerlund 1. Further, the results also validate the color selection method used to identify the association, adding credence to others discovered in the same way.

  5. STUDYING LARGE- AND SMALL-SCALE ENVIRONMENTS OF ULTRAVIOLET LUMINOUS GALAXIES

    SciTech Connect

    Basu-Zych, Antara R.; Schiminovich, David; Heinis, Sebastien; Heckman, Tim; Bianchi, Luciana; Overzier, Roderik; Zamojski, Michel; Barlow, Tom A.; Conrow, Tim; Forster, Karl G.; Friedman, Peter G.; Martin, D. Christopher; Morrissey, Patrick; Ilbert, Olivier; Koekemoer, Anton M.; Donas, Jose; Milliard, Bruno; Lee, Young-Wook; Madore, Barry F.; Neff, Susan G.

    2009-07-10

    Studying the environments of 0.4 < z < 1.2 ultraviolet (UV)-selected galaxies, as examples of extreme star-forming galaxies (with star formation rates (SFRs) in the range of 3-30 M{sub sun} yr{sup -1}), we explore the relationship between high rates of star formation, host halo mass, and pair fractions. We study the large- and small-scale environments of local ultraviolet luminous galaxies (UVLGs) by measuring angular correlation functions. We cross-correlate these systems with other galaxy samples: a volume-limited sample (ALL), a blue luminous galaxy sample, and a luminous red galaxy (LRG) sample. We determine the UVLG comoving correlation length to be r{sub 0} = 4.8{sup +11.6}{sub -2.4} h {sup -1} Mpc at (z) = 1.0, which is unable to constrain the halo mass for this sample. However, we find that UVLGs form close (separation <30 kpc) pairs with the ALL sample, but do not frequently form pairs with LRGs. A rare subset of UVLGs, those with the highest FUV surface brightnesses, are believed to be local analogs of high-redshift Lyman break galaxies (LBGs) and are called Lyman break analogs (LBAs). LBGs and LBAs share similar characteristics (i.e., color, size, surface brightness, specific SFRs, metallicities, and dust content). Recent Hubble Space Telescope images of z {approx} 0.2 LBAs show disturbed morphologies, signs of mergers and interactions. UVLGs may be influenced by interactions with other galaxies and we discuss this result in terms of other high star-forming, merging systems.

  6. Distribution of dark and luminous mass in galaxies

    SciTech Connect

    Lovas, Stephen; Kielkopf, John F.

    2014-06-01

    A uniform scale relation between dark and baryonic matter is observed in galaxies over a broad range of physical parameter space. The ratio of dark to baryonic mass is found to increase proportionately with radial distance in observational data spanning a wide dynamic range of morphological type, rotation velocity, radius, surface density, and mass. This close relation between dark and baryonic mass poses a fine-tuning problem for galaxy formation models. Such a uniform scale relation, extending from the inner galactic region to the outermost kinematic data point, may play a role in clarifying the dark matter phenomenon.

  7. Morphological Properties and AGN Content of High Redshift Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Kartaltepe, Jeyhan S.; CANDELS Collaboration

    2013-01-01

    We explore the evolution of the morphological properties of (Ultra) Luminous Infrared Galaxies ((U)LIRGs) over cosmic time using a large sample of galaxies from Herschel observations of the CANDELS fields (including GOODS, COSMOS, and UDS). In particular, we investigate whether the role of galaxy mergers has changed between 2 and now using the extensive visual classification catalogs produced by the CANDELS team. The combination of a selection from Herschel, near the peak of IR emission, and rest-frame optical morphologies from CANDELS, provides the ideal comparison to nearby (U)LIRGs. We then study the how role of galaxy mergers and the presence of AGN activity correspond to the galaxy's position in the star formation rate - stellar mass plane.

  8. Submillimeter Imaging of the Luminous Infrared Galaxy Pair VV114

    NASA Technical Reports Server (NTRS)

    Frayer, D.; Ivison, R. J.; Smail, I.; Yun, M. S.; Armus, L.

    1999-01-01

    We report on 450 and 850 mue observations of the interacting galaxy pair, VV114E+W (IC 1623), taken with the SCUBA camera on the James Clerk Maxwell Telescope, and near-infrared observations taken with UFTI on the UK Infrared Telescope.

  9. IUE observations of luminous blue star associations in irregular galaxies

    NASA Technical Reports Server (NTRS)

    Lamb, S. A.; Hunter, D. A.; Gallagher, J. S., III

    1987-01-01

    Two regions of recent star formation in blue irregular galaxies were observed with the IUE in the short wavelength, low dispersion mode. The spectra indicate that the massive star content is similar in these regions and is best fit by massive stars formed in a burst and now approximately 2.5 to 3.0 million years old.

  10. Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

    SciTech Connect

    Laag, E A; Canalizo, G; van Breugel, W; Gates, E L; de Vries, W; Stanford, S A

    2006-03-13

    We present high resolution imaging observations of a sample of previously unidentified far-infrared galaxies at z < 0.3. The objects were selected by cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and the HST Guide Star Catalog to allow for adaptive optics observations. We found two new ULIGs (with L{sub FIR} {ge} 10{sup 12} L{sub {circle_dot}}) and 19 new LIGs (with L{sub FIR} {ge} 10{sup 11} L{sub {circle_dot}}). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K{prime}. Galaxy morphologies were determined using the two dimensional fitting program GALFIT and the residuals examined to look for interesting structure. The morphologies reveal that at least 30% are involved in tidal interactions, with 20% being clear mergers. An additional 50% show signs of possible interaction. Line ratios were used to determine powering mechanism; of the 17 objects in the sample showing clear emission lines--four are active galactic nuclei and seven are starburst galaxies. The rest exhibit a combination of both phenomena.

  11. Green Pea Galaxies and Cohorts: Luminous Compact Emission-line Galaxies in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Izotov, Yuri I.; Guseva, Natalia G.; Thuan, Trinh X.

    2011-02-01

    We present a large sample of 803 star-forming luminous compact galaxies (LCGs) in the redshift range z = 0.02-0.63, selected from Data Release 7 of the Sloan Digital Sky Survey (SDSS). The global properties of these galaxies are similar to those of the so-called green pea star-forming galaxies in the redshift range z = 0.112-0.360 and selected from the SDSS on the basis of their green color and compact structure. In contrast to green pea galaxies, our LCGs are selected on the basis of both their spectroscopic and photometric properties, resulting in a ~10 times larger sample, with galaxies spanning a redshift range gsim2 times larger. We find that the oxygen abundances and the heavy element abundance ratios in LCGs do not differ from those of nearby low-metallicity blue compact dwarf galaxies. The median stellar mass of LCGs is ~109 M sun. However, for galaxies with high EW(Hβ), >= 100 Å, it is only ~7 × 108 M sun. The star formation rate in LCGs varies in the large range of 0.7-60 M sun yr-1, with a median value of ~4 M sun yr-1, a factor of ~3 lower than in high-redshift star-forming galaxies at z >~ 3. The specific star formation rates in LCGs are extremely high and vary in the range ~10-9-10-7 yr-1, comparable to those derived in high-redshift galaxies.

  12. Outflows in infrared-luminous galaxies: Absorption-line spectroscopy of starbursts and AGN

    NASA Astrophysics Data System (ADS)

    Rupke, David S.

    Large-scale galactic outflows, better known as superwinds, are driven by the powerful energy reservoirs in star forming and active galaxies. They play a significant role in galaxy formation, galaxy evolution, and the evolution of the intergalactic medium. We have performed a survey of over 100 infrared-luminous galaxies in order to address the exact frequency with which they occur in different galaxy types, the dependence of their properties on those of their host galaxies, and their properties in the most luminous starburst and active galaxies. Most of our sample consists of ultraluminous infrared galaxies (ULIRGs), and we use moderate- resolution spectroscopy of the Na I D interstellar absorption feature (which directly probes the neutral gas phase). We find superwinds in the majority of these galaxies at typical maximum, deprojected velocities of 500 700 km s-1. The detection rate increases with star formation rate (SFR) in starbursts, while the mass outflow rate appears constant with SFR, contrary to theoretical expectations. The resulting mass entrainment efficiencies in ULIRGs are quite low, of order a few percent of the star formation rate. There is some dependence of outflow velocity on host galaxy properties; the outflow velocities in LINERs are higher than those in H II galaxies, and the highest column density gas in each galaxy may have an upper envelope in velocity that increases with SFR. Outflows in most galaxies hosting a dominant AGN have very similar properties to those in starbursts, so discerning their power source is difficult. The velocities in Seyfert 2 outflows may be slightly higher than those in starbursts, and the fraction of neutral gas escaping Seyfert 2s is higher than that in starbursts (˜50% vs. ≲ 20%). The outflows in our Seyfert 1 galaxies have extreme velocities of up to ˜104 km s-1, and two of three Seyfert is with outflows possess broad absorption lines. Finally, we find that spectroscopy of a few galaxies at very high

  13. Star-formation histories of local luminous infrared galaxies

    NASA Astrophysics Data System (ADS)

    Pereira-Santaella, Miguel; Alonso-Herrero, Almudena; Colina, Luis; Miralles-Caballero, Daniel; Pérez-González, Pablo G.; Arribas, Santiago; Bellocchi, Enrica; Cazzoli, Sara; Díaz-Santos, Tanio; Piqueras López, Javier

    2015-05-01

    We present analysis of the integrated spectral energy distribution (SED) from the ultraviolet (UV) to the far-infrared and Hα of a sample of 29 local systems and individual galaxies with infrared (IR) luminosities between 1011L⊙ and 1011.8L⊙. We combined new narrow-band Hα + [N ii] and broad-band g, r optical imaging taken with the Nordic Optical Telescope (NOT), with archival GALEX, 2MASS, Spitzer, and Herschel data. Their SEDs(photometry and integrated Hα flux) were fitted simultaneously with a modified version of the magphys code using stellar population synthesis models for the UV-near-IR range and thermal emission models for the IR emission taking the energy balance between the absorbed and re-emitted radiation into account. From the SED fits, we derive the star-formation histories (SFH) of these galaxies. For nearly half of them, the star-formation rate appears to be approximately constant during the last few Gyr. In the other half, the current star-formation rate seems to be enhanced by a factor of 3-20 with respect to what occurred ~1 Gyr ago. Objects with constant SFH tend to be more massive than starbursts, and they are compatible with the expected properties of a main-sequence (M-S) galaxy. Likewise, the derived SFHs show that all our objects were M-S galaxies ~1 Gyr ago with stellar masses between 1010.1 and 1011.5 M⊙. We also derived the average extinction (Av = 0.6-3 mag) and the polycyclic aromatic hydrocarbon luminosity to LIR ratio (0.03-0.16) from our fits. We combined the Av with the total IR and Hα luminosities into a diagramthat can be used to identify objects with rapidly changing (increasing or decreasing) SFR during the past 100 Myr. Appendices are available in electronic form at http://www.aanda.orgFITS files for all the reduced images 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/A78

  14. The Milky Way's Most Luminous Star Clusters: Engines of Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Matzner, C. D.; Moon, D.

    2012-01-01

    Massive young star clusters and OB associations (M > 104 Msun) dominate the energetic feedback from stars into the interstellar medium. They contain the most massive and luminous stars in the Galaxy, which shape their environments through winds, ionizing flux, radiation pressure, and eventually supernovae, destroying their natal molecular clouds and inflating superbubbles. Few such clusters have been identified in our Galaxy. We systematically investigate the most luminous H II regions, which we identify using the WMAP foreground maps. We find that the 13 most luminous sources produce one-third of the Galaxy's total ionizing luminosity, all with expected powering populations of M > 4×104 Msun. These populations are grouped in small numbers of clusters or associations for each WMAP source. The emission from these regions is dominated by the diffuse component at large radii ( 10-70 pc) indicating a high leaking fraction of ionizing photons. Using 8 micron maps from Spitzer GLIMPSE and published radio recombination line observations, we resolve the large (>1°) WMAP sources into 40 star forming complexes (SFCs) exhibiting shell morphology with evidence of expansion due to a central powering source. We develop a method, based on differential extinction of the galactic disk, to identify the SFC's powering cluster candidates with 2MASS. We identify 25 candidate clusters within the 40 SFCs having extinctions consistent with their distances. With near-infrared spectroscopy from the New Technology Telescope, we have confirmed the existence of the most massive of these associations, the Dragonfish Association, with M = 105 Msun. Of the 50 sampled stars, we identify 2 Luminous Blue Variable candidates, a Wolf-Rayet, and 15 O-type stars, consistent with the yield expected from the candidate contamination rate, verifying the candidate cluster identification method. This investigation produces the most complete picture of the upper-end of the Galaxy's cluster mass function to

  15. Host Galaxies of Luminous Quasars: Structural Properties and the Fundamental Plane

    NASA Astrophysics Data System (ADS)

    Wolf, Marsha J.; Sheinis, Andrew I.

    2008-10-01

    We present stellar velocity dispersion measurements in the host galaxies of ten luminous quasars (MV < -23) using the Ca H&K lines in off-nuclear spectra. We combine these data with effective radii and magnitudes from the literature to place the host galaxies on the fundamental plane (FP) where their properties are compared with other types of galaxies. We find that the radio-loud (RL) QSO hosts have similar properties to massive elliptical galaxies, while the radio-quiet (RQ) hosts are more similar to intermediate-mass galaxies. The RL hosts lie at the upper extreme of the FP due to their large velocity dispersions (langσ*rang = 321 km s-1), low surface brightness (langμ e (r)rang = 20.8 mag arcsec-2), and large effective radii (langRe rang = 11.4 kpc), and have langM *rang = 1.5 × 1012 M sun and langM/Lrang = 12.4. In contrast, properties of the RQ hosts are langσ*rang = 241 km s-1, langM *rang = 4.4 × 1011 M sun, and M/L ~ 5.3. The distinction between these galaxies occurs at σ*~ 300 km s-1, Re ~ 6 kpc, and corresponding M * ~ 5.9 ± 3.5 × 1011 M sun. Our data support previous results that Palomar-Green QSOs are related to gas-rich galaxy mergers that form intermediate-mass galaxies, while RL QSOs reside in massive early-type galaxies, most of which also show signs of recent mergers or interactions. Previous authors have drawn these conclusions by using estimates of the black hole mass and inferring host galaxy properties from that, while here we have relied purely on directly measured host galaxy properties.

  16. EXTENDED [C II] EMISSION IN LOCAL LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Díaz-Santos, T.; Armus, L.; Surace, J. A.; Charmandaris, V.; Stacey, G.; Murphy, E. J.; Haan, S.; Stierwalt, S.; Evans, A. S.; Malhotra, S.; Appleton, P.; Inami, H.; Magdis, G. E.; Elbaz, D.; Van der Werf, P. P.; Meijerink, R.; and others

    2014-06-10

    We present Herschel/PACS observations of extended [C II] 157.7 μm line emission detected on ∼1-10 kpc scales in 60 local luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey. We find that most of the extra-nuclear emission show [C II]/FIR ratios ≥4 × 10{sup –3}, larger than the mean ratio seen in the nuclei, and similar to those found in the extended disks of normal star-forming galaxies and the diffuse interstellar medium of our Galaxy. The [C II] ''deficits'' found in the most luminous local LIRGs are therefore restricted to their nuclei. There is a trend for LIRGs with warmer nuclei to show larger differences between their nuclear and extra-nuclear [C II]/FIR ratios. We find an anti-correlation between [C II]/FIR and the luminosity surface density, Σ{sub IR}, for the extended emission in the spatially resolved galaxies. However, there is an offset between this trend and that found for the LIRG nuclei. We use this offset to derive a beam filling-factor for the star-forming regions within the LIRG disks of ∼6% relative to their nuclei. We confront the observed trend to photo-dissociation region models and find that the slope of the correlation is much shallower than the model predictions. Finally, we compare the correlation found between [C II]/FIR and Σ{sub IR} with measurements of high-redshift starbursting IR-luminous galaxies.

  17. IR Fine-Structure Line Signatures of Central Dust-Bounded Nebulae in Luminous Infrared Galaxies

    NASA Technical Reports Server (NTRS)

    Fischer, J.; Allen, R.; Dudley, C. C.; Satyapal, S.; Luhman, M.; Wolfire, M.; Smith, H. A.

    2004-01-01

    To date, the only far-infrared spectroscopic observations of ultraluminous infrared galaxies have been obtained with the European Space Agency s Infrared Space Observatory Long Wavelength Spectrometer. The spectra of these galaxies are characterized by molecular absorption lines and weak emission lines from photodissociation regions (PDRs), but no far-infrared (greater than 40 microns) lines from ionized regions have been detected. ESA s Herschel Space Observatory, slated for launch in 2007, will likely be able to detect these lines in samples of local and moderate redshift ultra luminous galaxies and to enable measurement of the ionization parameters, the slope of the ionizing continuum, and densities present in the ionized regions of these galaxies. The higher spatial resolution of proposed observatories discussed in this workshop will enable isolation of the central regions of local galaxies and detection of these lines in high-redshift galaxies for study of the evolution of galaxies. Here we discuss evidence for the e.ects of absorption by dust within ionized regions and present the spectroscopic signatures predicted by photoionization modeling of dust-bounded regions.

  18. Discovery of GeV emission from the direction of the luminous infrared galaxy NGC 2146

    SciTech Connect

    Tang, Qing-Wen; Wang, Xiang-Yu; Thomas Tam, Pak-Hin E-mail: phtam@phys.nthu.edu.tw

    2014-10-10

    Recent detections of high-energy gamma-ray emission from starburst galaxies M82 and NGC 253 suggest that starburst galaxies are huge reservoirs of cosmic rays and these cosmic rays convert a significant fraction of their energy into gamma-rays by colliding with the dense interstellar medium. In this paper, we report the search for high-energy gamma-ray emission from several nearby star-forming and starburst galaxies using the 68 month data obtained with the Fermi Large Area Telescope. We found a ∼5.5σ detection of gamma-ray emission above 200 MeV from a source spatially coincident with the location of the luminous infrared galaxy NGC 2146. Also taking into account the temporal and spectral properties of the gamma-ray emission, we suggest that the gamma-ray source is likely to be the counterpart of NGC 2146. The gamma-ray luminosity suggests that cosmic rays in NGC 2146 convert most of their energy into secondary pions, so NGC 2146 is a 'proton calorimeter'. It is also found that NGC 2146 obeys the quasi-linear scaling relation between gamma-ray luminosity and total infrared luminosity for star-forming galaxies, strengthening the connection between massive star formation and gamma-ray emission of star-forming galaxies. Possible TeV emission from NGC 2146 is predicted and the implications for high-energy neutrino emission from starburst galaxies are discussed.

  19. Luminous compact blue galaxies in the local Universe: A key reference for high-redshift studies

    NASA Astrophysics Data System (ADS)

    Pérez Gallego, J.; Guzmán, R.; Castander, F. J.; Garland, C. A.; Pisano, D. J.

    2005-05-01

    Luminous Compact Blue Galaxies (LCBGs) are high surface brightness starburst galaxies, bluer than a typical Sbc and brighter than ˜0.25Lstar. LCBGs have evolved more than any other galaxy class in the last ˜8 Gyr, and are a major contributor to the observed enhancement of the UV luminosity density of the Universe at z≤1. Despite the key role LCBGs may play in galaxy evolution, their statistical properties are still largely unknown. We have selected a complete sample of ˜25 LCBGs within 100 Mpc, after investigating over 106 nearby galaxies from the DR1 of the SDSS database. This sample, although small, provides an excellent reference for comparison with current and future surveys of similar galaxies at high redshift, including the population of Lyman-break galaxies. We present preliminary results of this study using 3D spectroscopic observations obtained over a very wide range in wavelength, using WIYN/DENSEPAK in the optical, FISICA in the infrared, and the VLA at cm wavelengths.

  20. THE WHIQII SURVEY: METALLICITIES AND SPECTROSCOPIC PROPERTIES OF LUMINOUS COMPACT BLUE GALAXIES

    SciTech Connect

    Tollerud, Erik J.; Barton, Elizabeth J.; Cooke, Jeff; Van Zee, Liese

    2010-01-10

    As part of the WIYN High Image Quality Indiana-Irvine (WHIQII) survey, we present 123 spectra of faint emission-line galaxies, selected to focus on intermediate redshift (0.4 approx< z approx< 0.8) galaxies with blue colors that appear physically compact on the sky. The sample includes 15 true Luminous Compact Blue Galaxies (LCBGs) and an additional 27 slightly less extreme emission-line systems. These galaxies represent a highly evolving class that may play an important role in the decline of star formation since z approx 1, but their exact nature and evolutionary pathways remain a mystery. Here, we use emission lines to determine metallicities and ionization parameters, constraining their intrinsic properties and state of star formation. Some LCBG metallicities are consistent with a 'bursting dwarf' scenario, while a substantial fraction of others are not, further confirming that LCBGs are a highly heterogeneous population but are broadly consistent with the intermediate redshift field. In agreement with previous studies, we observe overall evolution in the luminosity-metallicity relation at intermediate redshift. Our sample, and particularly the LCBGs, occupies a region in the empirical R{sub 23}-O{sub 32} plane that differs from luminous local galaxies and is more consistent with dwarf irregulars at the present epoch, suggesting that cosmic 'downsizing' is observable in even the most fundamental parameters that describe star formation. These properties for our sample are also generally consistent with lying between local galaxies and those at high redshift, as expected by this scenario. Surprisingly, our sample exhibits no detectable correlation between compactness and metallicity, strongly suggesting that at these epochs of rapid star formation, the morphology of compact star-forming galaxies is largely transient.

  1. ULTRA-LUMINOUS X-RAY SOURCES IN THE MOST METAL POOR GALAXIES

    SciTech Connect

    Prestwich, A. H.; Zezas, A.; Jackson, F.; Tsantaki, Maria; Roberts, T. P.; Foltz, R.; Linden, T.; Kalogera, V.

    2013-06-01

    Ultra-luminous X-ray sources (ULX) are X-ray binaries with L{sub x} >10{sup 39} erg s{sup -1}. The most spectacular examples of ULX occur in starburst galaxies and are now understood to be young, luminous high mass X-ray binaries. The conditions under which ULX form are poorly understood, but recent evidence suggests they may be more common in low metallicity systems. Here we investigate the hypothesis that ULX form preferentially in low metallicity galaxies by searching for ULX in a sample of extremely metal poor galaxies (XMPG) observed with the Chandra X-Ray Observatory. XMPG are defined as galaxies with log(O/H) + 12 < 7.65, or less than 5% solar. These are the most metal-deficient galaxies known, and a logical place to find ULX if they favor metal poor systems. We compare the number of ULX (corrected for background contamination) per unit of star formation (N{sub ULX}(SFR)) in the XMPG sample with N{sub ULX}(SFR) in a comparison sample of galaxies with higher metallicities taken from the Spitzer Infrared Galaxy Sample. We find that ULX occur preferentially in the metal poor sample with a formal statistical significance of 2.3{sigma}. We do not see strong evidence for a trend in the formation of ULX in the high metallicity sample: above 12+log(O/H) {approx} 8.0 the efficiency of ULX production appears to be flat. The effect we see is strongest in the lowest metallicity bin. We discuss briefly the implications of these results for the formation of black holes in low metallicity gas.

  2. Buried Quasars in Ultra-luminous Infrared Galaxies

    NASA Technical Reports Server (NTRS)

    2004-01-01

    We were awarded l00kS of INTEGRAL spacecraft time (Priority A) to observe the ultraluminous infrared galaxy (ULIG) Mrk 2273 in order to measure the integrated flux of the 20-1003 KeV gamma-Ray emission, and to use this information to search for the presence of an highly obscured active galactic nucleus (AGN). With this observation we hope to be able to better assess the role of AGN in the complete class of ULIGs and therefore to better constrain their contribution to the hard X-ray and soft gamma-ray backgrounds. Our Priority A 100 kS observation of Mrk 273 was successfully carried out during revolution #73 using 4 separate exposures with the IBIS camera during May, 2003. Our IBIS observations of Mrk 273 were successfully executed, and the source was properly centered in the Field-of-view of the detectors. We are still in the process of interpreting the IBIS gamma-ray data.

  3. The Fate of Luminous Compact Blue Galaxies: Identification of Cluster LCBGs

    NASA Astrophysics Data System (ADS)

    Crawford, S. M.; Bershady, M. A.; Glenn, A. D.; Hoessel, J. G.

    2004-12-01

    Luminous Compact Blue Galaxies (LCBGs) appear to form a link between local, low mass HII galaxies and high-z, high luminosity Lyman Break Galaxies. Accounting for the majority of the star formation at intermediate redshifts (0.3 < z < 0.9), they represent a dominant phase of galaxy evolution; yet the identity of their present-day counterparts is an open question. We have undertaken a major survey of intermediate redshift galaxy clusters in search of LCBGs in order to connect this population of small, but powerful star forming galaxies to their present-day descendants through the morphology-density relationship. In this paper, we present the identification of LCBGs in two galaxy clusters, MS0451-0305 (z=0.538) and CL1604+4304 (z=0.90), and compare the photometric characteristics of cluster LCBGs to field LCBGs and other galaxy types. The LCBGs are identified through their broad and narrow band colors measured from deep imaging with the Mini-Mosaic camera on the WIYN 3.5m telescope. We use photometric redshifts and rest-frame [OII] λ 3727 emission in the narrow band images to identify star-burst galaxies associated with each galaxy clusters. LCBGs are too small for any detailed structural analysis from ground-based data, therefore we derived photometric characteristics (size, surface brightness, concentration, ellipticity, and asymmetry) from Archive HST WFPC2 and ACS imaging of the clusters. This work was supported by HST Archive grant #9917, NSF / AST-0307417, and an award from the Wisconsin Space Grant Corporation.

  4. The Ultra-Luminous X-ray Source Population from the Chandra Archive of Galaxies

    NASA Technical Reports Server (NTRS)

    Swartz, Douglas A.; Ghosh, Kajal K.; Tennant, Allen F.; Wu, Kinwah

    2004-01-01

    One hundred fifty-four discrete non-nuclear Ultra-Luminous X-ray (ULX) sources, with spectroscopically-determined intrinsic X-ray luminosities greater than 1 e39 ergs/s, are identified in 82 galaxies observed with Chandra's Advanced CCD Imaging Spectrometer. Source positions, X-ray luminosities, and spectral and timing characteristics are tabulated. Statistical comparisons between these X-ray properties and those of the weaker discrete sources in the same fields (mainly neutron star and stellar-mass black hole binaries) are made. Sources above approximately le38 ergs per second display similar spatial, spectral, color, and variability distributions. In particular, there is no compelling evidence in the sample for a new and distinct class of X-ray object such as the intermediate-mass black holes. 83% of ULX candidates have spectra that can be described as absorbed power laws with index = 1.74 and column density = 2.24e21 l per square centimeter, or approximately 5 times the average Galactic column. About 20% of the ULX's have much steeper indices indicative of a soft, and likely thermal, spectrum. The locations of ULXs in their host galaxies are strongly peaked towards their galaxy centers. The deprojected radial distribution of the ULX candidates is somewhat steeper than an exponential disk, indistinguishable from that of the weaker sources. About 5--15% of ULX candidates are variable during the Chandra observations (which average 39.5 ks). Comparison of the cumulative X-ray luminosity functions of the ULXs to Chandra Deep Field results suggests approximately 25% of the sources may be background objects including 14% of the ULX candidates in the sample of spiral galaxies and 44% of those in elliptical galaxies implying the elliptical galaxy ULX population is severely compromised by background active galactic nuclei. Correlations with host galaxy properties confirm the number and total X-ray luminosity of the ULXs are associated with recent star formation

  5. Galaxy evolution. Black hole feedback in the luminous quasar PDS 456.

    PubMed

    Nardini, E; Reeves, J N; Gofford, J; Harrison, F A; Risaliti, G; Braito, V; Costa, M T; Matzeu, G A; Walton, D J; Behar, E; Boggs, S E; Christensen, F E; Craig, W W; Hailey, C J; Matt, G; Miller, J M; O'Brien, P T; Stern, D; Turner, T J; Ward, M J

    2015-02-20

    The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband x-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10(46) ergs per second is enough to provide the feedback required by models of black hole and host galaxy coevolution. PMID:25700515

  6. Cold Galaxies on FIRE: Modeling the Most Luminous Starbursts in the Universe with Cosmological Zoom Simulations

    NASA Astrophysics Data System (ADS)

    Narayanan, Desika

    2014-10-01

    As the most luminous, heavily star-forming galaxies in the Universe, Submillimeter Galaxies at z 2-4 are key players in galaxy evolution. Since their discovery, SMGs have received significant attention from HST in characterizing their physical morphology, stellar masses, and star formation histories. Unfortunately, these physical constraints have been difficult for theorists to reconcile with galaxy formation simulations. Previous generations of simulations have all either {a} neglected baryons; {b} neglected radiative transfer {and connecting to observations}; or {c} neglected cosmological conditions. Here, we propose to conduct the first ever cosmological hydrodynamic simulations of Submillimeter Galaxy formation that couple with bona fide 3D dust radiative transfer calculations. These ultra-high resolution simulations {parsec-scale} will be the first to resolve the sites of dust obscuration, the cosmic growth history of SMGs, and their evolutionary destiny. Our proposal has two principle goals: {1} Develop the first ever model for SMG formation from cosmological simulations that include both baryons and dust radiative transfer; {2} Capitalize on our parsec-scale resolution to understand the connection between the physical properties of star-forming regions in high-z starbursts, and recent IMF constraints from present-epoch massive galaxies.

  7. A CANDIDATE FOR THE MOST LUMINOUS OB ASSOCIATION IN THE GALAXY

    SciTech Connect

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-02-20

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray and Rahman, which, at {approx}9.7 kpc, has a recombination rate of {approx}7 x 10{sup 51} s{sup -1}. Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 < A{sub K} < 1.2, and they are sufficiently numerous (406 {+-} 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  8. A Candidate for the Most Luminous OB Association in the Galaxy

    NASA Astrophysics Data System (ADS)

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-02-01

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray & Rahman, which, at ~9.7 kpc, has a recombination rate of ~7 × 1051 s-1. Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 < AK < 1.2, and they are sufficiently numerous (406 ± 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  9. WISE Discovery of Hyper Luminous Galaxies at z=2-4 and Their Implications for Galaxy and AGN Evolution

    NASA Technical Reports Server (NTRS)

    Tsai, Chao Wei; Eisenhardt, Peter; Wu, Jingwen; Bridge, Carrie; Assef, Roberto; Benford, Dominic; Blain, Andrew; Cutri, Roc; Griffith, Robert L.; Jarrett, Thomas; Lonsdale, Carol; Petty, Sara; Sayers, Jack; Stanford, Adam; Stern, Daniel; Wright, Edward L.; Yan, Lin

    2014-01-01

    On behalf of the WISE Science team, we present the discovery of a class of distant dust-enshrouded galaxies with extremely high luminosity. These galaxies are selected to have extreme red colors in the mid-IR using NASA's Wide-field Infrared Survey Explorer (WISE). They are faint in the optical and near-IR, predominantly at zeta = 2-4, and with IR luminosity > 10(exp 13) Solar Luminosity, making them Hyper-Luminous Infrared Galaxies (HyLIRGs). SEDs incorporating the WISE, Spitzer, and Herschel PACS and SPIRE photometry indicate hot dust dominates the bolometric luminosity, presumably powered by AGN. Preliminary multi-wavelength follow-up suggests that they are different from normal populations in the local M-sigma relation. Their low source density implies that these objects are either intrinsically rare, or a short-lived phase in a more numerous population. If the latter is the case, these hot, dust-enshrouded galaxies may be an early stage in the interplay between AGN and galaxies.

  10. Search for Obscured Nucleus in a Luminous IRAS Galaxy NGC 6240

    NASA Technical Reports Server (NTRS)

    Leighly, Karen

    1999-01-01

    IRAS discovered very luminous objects which emit the vast majority of their radiation in the infrared wavelength. The energy source of such a tremendous amount of emission is not understood. Starburst and active galactic nuclei (AGN) are thought to be the origin of their power. X-ray observations are expected to be able to reveal the characteristics of the AGN component. However, some are very X-ray quiet, because the AGN is thought to be obscured by a large column density. In order to determine the primary luminosity of the nucleus, we need an X-ray observation with a wide energy band at least up to several tens of keV. We propose to observe NGC 6240, one of the luminous IRAS galaxies, to investigate the characteristics of its AGN, which must be obscured by large column density.

  11. SPECTROSCOPIC CONFIRMATION OF THE DRAGONFISH ASSOCIATION: THE GALAXY'S MOST LUMINOUS OB ASSOCIATION

    SciTech Connect

    Rahman, Mubdi; Moon, Dae-Sik; Matzner, Christopher D.

    2011-12-20

    Young OB associations with masses greater than 10{sup 4} M{sub Sun} have been inferred to exist in the Galaxy but have largely evaded detection. Recently, a candidate OB association has been identified within the most luminous star-forming complex in the Galaxy, the Dragonfish Nebula. We identify 18 young, massive stars with near-infrared spectroscopy from a sample of 50 members within the candidate OB association, including 15 O-type and 3 luminous blue variables or Wolf-Rayet stars. This number matches the expected yield of massive stars from the candidate association, confirming its existence and ability to power the parent star-forming complex. These results demonstrate the existence of a 10{sup 5} M{sub Sun} OB association, more powerful than any previously known in the Galaxy, comparable in mass only to Westerlund 1. Further, the results also validate the color selection method used to identify the association, adding credence to others discovered in the same way.

  12. Photometric Redshift Survey Forecast for Luminous Red Galaxies at z 1.0

    NASA Astrophysics Data System (ADS)

    Huang, Xiaosheng; Schlegel, D. J.

    2006-12-01

    We analyzed the data from the DEEP2 Redshift Survey to obtain the number densities for luminous red galaxies between z=0.4 and 1.2. Based on the DEEP photometric data in B, R and I bands and the spectroscopic redshift we synthesized spectrophotometry for the 4000 DEEP galaxies in the extended groth strip (EGS) field, using templates from the Kinney-Calzetti catalog and Coleman, Wu and Weedman. We determined the number densities in the redshift ranges of 0.4luminous red galaxy survey, the sound horizon scale can be measured to an accuracy of 1.2-2% and w to 6-10%. This work has been supported by the Office of Science, U.S. Department of Energy, through contract DE-AC02-05CH11231.

  13. LUMINOUS RED GALAXY HALO DENSITY FIELD RECONSTRUCTION AND APPLICATION TO LARGE-SCALE STRUCTURE MEASUREMENTS

    SciTech Connect

    Reid, Beth A.; Spergel, David N.; Bode, Paul E-mail: dns@astro.princeton.edu

    2009-09-01

    The nontrivial relationship between observations of galaxy positions in redshift space and the underlying matter field complicates our ability to determine the linear theory power spectrum and extract cosmological information from galaxy surveys. The Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) catalog has the potential to place powerful constraints on cosmological parameters. LRGs are bright, highly biased tracers of large-scale structure. However, because they are highly biased, the nonlinear contribution of satellite galaxies to the galaxy power spectrum is large and fingers-of-God (FOGs) are significant. The combination of these effects leads to a {approx}10% correction in the underlying power spectrum at k = 0.1 h Mpc{sup -1} and {approx}40% correction at k = 0.2 h Mpc{sup -1} in the LRG P(k) analysis of Tegmark et al., thereby compromising the cosmological constraints when this potentially large correction is left as a free parameter. We propose an alternative approach to recovering the matter field from galaxy observations. Our approach is to use halos rather than galaxies to trace the underlying mass distribution. We identify FOGs and replace each FOG with a single halo object. This removes the nonlinear contribution of satellite galaxies, the one-halo term. We test our method on a large set of high-fidelity mock SDSS LRG catalogs and find that the power spectrum of the reconstructed halo density field deviates from the underlying matter power spectrum at the {<=}1% level for k {<=} 0.1 h Mpc{sup -1} and {<=}4% at k = 0.2 h Mpc{sup -1}. The reconstructed halo density field also removes the bias in the measurement of the redshift space distortion parameter {beta} induced by the FOG smearing of the linear redshift space distortions.

  14. CO Spectral Line Energy Distributions of Infrared-Luminous Galaxies and Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Padeli P.; van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M.

    2010-06-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L IR(8-1000 μm) >~ 1011 L sun), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L IR>1012 L sun), and two powerful local active galactic nuclei (AGNs)—the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293—using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C+ line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these high-redshift starbursts, with genuinely low

  15. Alma observations of nearby luminous infrared galaxies with various agn energetic contributions using dense gas tracers

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2014-07-01

    We present the results of our ALMA Cycle 0 observations, using HCN/HCO{sup +}/HNC J = 4-3 lines, of six nearby luminous infrared galaxies with various energetic contributions from active galactic nuclei (AGNs) estimated from previous infrared spectroscopy. These lines are very effective for probing the physical properties of high-density molecular gas around the hidden energy sources in the nuclear regions of these galaxies. We find that HCN to HCO{sup +} J = 4-3 flux ratios tend to be higher in AGN-important galaxies than in starburst-dominated regions, as was seen at the J = 1-0 transition, while there is no clear difference in the HCN-to-HNC J = 4-3 flux ratios among observed sources. A galaxy with a starburst-type infrared spectral shape and very large molecular line widths shows a high HCN-to-HCO{sup +} J = 4-3 flux ratio, which could be due to turbulence-induced heating. We propose that enhanced HCN J = 4-3 emission relative to HCO{sup +} J = 4-3 could be used to detect more energetic activity than normal starbursts, including deeply buried AGNs, in dusty galaxy populations.

  16. An ALMA Spectral Scan of the Obscured Luminous Infrared Galaxy NGC 4418

    NASA Astrophysics Data System (ADS)

    Costagliola, F.; Sakamoto, K.; Aalto, S.; Muller, S.; Martín, S.

    2015-12-01

    Until recently, the study of the molecular interstellar medium of galaxies has been mostly focused on a few, relatively abundant, molecular species. Recent attempts at modeling the molecular emission of active galaxies have shown that standard high-density tracers do not provide univocal results and are not able to discriminate between different relevant environments (e.g., star-formation vs AGN). Spectral lines surveys allow us to explore the richness of the molecular spectrum of galaxies, provide tighter constrains to astrochemical models, and find new more sensitive tracers of specific gas properties. What started as a time-consuming pioneering work has become now routinely accessible with the advent of ALMA. Here we report the results of the first ALMA spectral scan of an obscured luminous infrared galaxy (LIRG), NGC 4418. The galaxy has a very compact IR core and narrow emission lines that make it the perfect target for the study of vibrationally excited molecules. More than 300 emission lines from 45 molecular species were identified and modeled via an LTE and NLTE analysis. The molecular excitation and abundances derived offer a unique insight into the chemistry of obscured LIRGs.

  17. Structural Properties and Evidence for Interactions in a Sample of Luminous Blue Compact Galaxies

    NASA Astrophysics Data System (ADS)

    Newton, Cassidy L.; Fanelli, M.; Marcum, P.

    2010-01-01

    Understanding the life cycles of galaxies over cosmic time is a primary effort in modern astrophysics. Here we explore the nature of luminous blue compact galaxies (LBCGs), a class of galaxy in the local (z < 0.05) universe exhibiting blue optical colors [(B-V) < 0.5], high luminosity (MB < -19), one or more high surface brightness regions, and moderate to high star formation rates [> 5 M(sun) per year]. LBCGs appear to be similar in their global properties to the early evolutionary phases of most galaxies, but are more amenable to detailed analysis due to their low redshifts. We describe an ultraviolet and optical investigation of a sample of 50 LBCGs using UBVR & Hα imagery obtained at McDonald Observatory, ultraviolet photometry from GALEX, and correlative data from IRAS, 2MASS, and SDSS. Using these data, we explore the evolutionary state of LBCGs. In particular, we determine the radial and azimuthal light distributions, explore the spatial extent of ionized gas (e.g., centrally- concentrated versus spatially diffuse), compare multiwavelength measures of the high-mass star formation rate, and quantify the interaction strength using a variety of merger diagnostics. Although selected independent of their environment, most systems display either a close companion or the signature of an interaction such as tails, bridges, and possible polar rings. Interpretation of the assembly history of LBCGs provides insight on massive galaxy evolution at earlier epochs.

  18. The Most Luminous Object in the Universe: Shrouded Quasar or Proto-Galaxy

    NASA Technical Reports Server (NTRS)

    Heckman, Timothy M.

    1999-01-01

    We have used ASCA to observe the IRAS source FSC 10214+4724, which is identified with a galaxy at a redshift of 2.286. When first discovered, it was believed to be the most luminous object in the universe. Subsequent HST images have established that it is gravitationally-lensed by a foreground cluster. It is still a very powerful object, but not extraordinarily so. Observations at other wavebands have not established whether it is a dust-shrouded quasar or a young, massive galaxy in the process of formation. Since quasars are strong emitters of hard X-rays, while proto-galaxies would not be, and since the opacity of gas and dust is relatively small in the energy regime probed by ASCA (3 to 30 keV in the galaxy rest frame), we undertook these observations to search for a heavily shrouded quasar that might be invisible at lower energies. However, the observations did not detect any emission from this object. This either means that the galaxy is in fact powered by a starburst or that the putative quasar is located behind a very high column density of absorbing gas (N_H > 10(exp 25)/sq cm), so that not even hard X-rays are transmitted. A hidden quasar should be visible in reflected light in X-ray data of higher sensitivity. Observations with NASA's Chandra X-ray Observatory or ESA's XMM are required to settle the matter. No publication resulted from our null result.

  19. Monsters in the dark: predictions for luminous galaxies in the early Universe from the BLUETIDES simulation

    NASA Astrophysics Data System (ADS)

    Waters, Dacen; Wilkins, Stephen M.; Di Matteo, Tiziana; Feng, Yu; Croft, Rupert; Nagai, Daisuke

    2016-09-01

    Using deep Hubble and Spitzer observations Oesch et al. have identified a bright (MUV ≈ -22) star-forming galaxy candidate at z ≈ 11. The presence of GN-z11 implies a number density ˜10-6 Mpc-3, roughly an order of magnitude higher than the expected value based on extrapolations from lower redshift. Using the unprecedented volume and high resolution of the BLUETIDES cosmological hydrodynamical simulation, we study the population of luminous rare objects at z > 10. The luminosity function in BLUETIDES implies an enhanced number of massive galaxies, consistent with the observation of GN-z11. We find about 30 galaxies at MUV ≈ -22 at z = 11 in the BLUETIDES volume, including a few objects about 1.5 mag brighter. The probability of observing GN-z11 in the volume probed by Oesch et al. is ˜13 per cent. The predicted properties of the rare bright galaxies at z = 11 in BLUETIDES closely match those inferred from the observations of GN-z11. BLUETIDES predicts a negligible contribution from faint AGN in the observed SED. The enormous increase in volume surveyed by WFIRST will provide observations of ˜1000 galaxies with MUV < -22 beyond z = 11 out to z = 13.5.

  20. A massive, cooling-flow-induced starburst in the core of a luminous cluster of galaxies.

    PubMed

    McDonald, M; Bayliss, M; Benson, B A; Foley, R J; Ruel, J; Sullivan, P; Veilleux, S; Aird, K A; Ashby, M L N; Bautz, M; Bazin, G; Bleem, L E; Brodwin, M; Carlstrom, J E; Chang, C L; Cho, H M; Clocchiatti, A; Crawford, T M; Crites, A T; de Haan, T; Desai, S; Dobbs, M A; Dudley, J P; Egami, E; Forman, W R; Garmire, G P; George, E M; Gladders, M D; Gonzalez, A H; Halverson, N W; Harrington, N L; High, F W; Holder, G P; Holzapfel, W L; Hoover, S; Hrubes, J D; Jones, C; Joy, M; Keisler, R; Knox, L; Lee, A T; Leitch, E M; Liu, J; Lueker, M; Luong-Van, D; Mantz, A; Marrone, D P; McMahon, J J; Mehl, J; Meyer, S S; Miller, E D; Mocanu, L; Mohr, J J; Montroy, T E; Murray, S S; Natoli, T; Padin, S; Plagge, T; Pryke, C; Rawle, T D; Reichardt, C L; Rest, A; Rex, M; Ruhl, J E; Saliwanchik, B R; Saro, A; Sayre, J T; Schaffer, K K; Shaw, L; Shirokoff, E; Simcoe, R; Song, J; Spieler, H G; Stalder, B; Staniszewski, Z; Stark, A A; Story, K; Stubbs, C W; Suhada, R; van Engelen, A; Vanderlinde, K; Vieira, J D; Vikhlinin, A; Williamson, R; Zahn, O; Zenteno, A

    2012-08-16

    In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous 'cooling flows' of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates and cool gas masses for these 'cool-core' clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical and infrared observations of the galaxy cluster SPT-CLJ2344-4243 (ref. 11) at redshift z = 0.596. These observations reveal an exceptionally luminous (8.2 × 10(45) erg s(-1)) galaxy cluster that hosts an extremely strong cooling flow (around 3,820 solar masses a year). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (formation of around 740 solar masses a year), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool-core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star-formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form through accretion of the intracluster medium, rather than (as is currently thought) assembling entirely via mergers. PMID:22895340

  1. Detection of CO(1 to 0) emission from infrared quasars and luminous Seyfert galaxies

    NASA Technical Reports Server (NTRS)

    Sanders, D. B.; Scoville, N. Z.; Zensus, A.; Soifer, B. T.; Wilson, T. L.

    1989-01-01

    CO(1 to 0) emission has been detected from the infrared quasar IRAS 07598+6508 and the luminous Seyfert galaxies IRAS 08572+3915 and Markarian 463 with the IRAM 30-m telescope. These objects were selected from a complete list of warm ultraluminous IRAS sources. The maximum redshift observed was 0.149 (cz = 44.621 km/s , IRAS 07598+6508). Assuming the same empirical relationship between CO brightness and H2 surface mass density as has been found for giant molecular clouds in the Milky Way, the mass of H2 gas in these objects is in the range 0.7 - 6 x 10 to the 10th solar masses, more than 2 - 20 times the H2 content of the Galaxy. The infrared and molecular gas properties of these galaxies are similar to other 'warm' ultraluminous infrared galaxies such as Mrk 231, and the UV-excess quasar Mrk 1014. It is suggested that objects such as these represent an important link in the evolution of ultraluminous infrared galaxies into UV-excess quasars.

  2. A massive, cooling-flow-induced starburst in the core of a luminous cluster of galaxies

    NASA Astrophysics Data System (ADS)

    McDonald, M.; Bayliss, M.; Benson, B. A.; Foley, R. J.; Ruel, J.; Sullivan, P.; Veilleux, S.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; Bazin, G.; Bleem, L. E.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Cho, H. M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Desai, S.; Dobbs, M. A.; Dudley, J. P.; Egami, E.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Harrington, N. L.; High, F. W.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hrubes, J. D.; Jones, C.; Joy, M.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-van, D.; Mantz, A.; Marrone, D. P.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Miller, E. D.; Mocanu, L.; Mohr, J. J.; Montroy, T. E.; Murray, S. S.; Natoli, T.; Padin, S.; Plagge, T.; Pryke, C.; Rawle, T. D.; Reichardt, C. L.; Rest, A.; Rex, M.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Shaw, L.; Shirokoff, E.; Simcoe, R.; Song, J.; Spieler, H. G.; Stalder, B.; Staniszewski, Z.; Stark, A. A.; Story, K.; Stubbs, C. W.; Šuhada, R.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2012-08-01

    In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous `cooling flows' of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates and cool gas masses for these `cool-core' clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical and infrared observations of the galaxy cluster SPT-CLJ2344-4243 (ref. 11) at redshift z = 0.596. These observations reveal an exceptionally luminous (8.2 × 1045 erg s-1) galaxy cluster that hosts an extremely strong cooling flow (around 3,820 solar masses a year). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (formation of around 740 solar masses a year), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool-core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star-formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form through accretion of the intracluster medium, rather than (as is currently thought) assembling entirely via mergers.

  3. Luminous clusters of Wolf-Rayet stars in the SBmIII galaxy NGC 4214

    NASA Technical Reports Server (NTRS)

    Sargent, Wallace L. W.; Filippenko, Alexei V.

    1991-01-01

    Observations are reported of strong broad emission lines attributed to WR stars in the spectra of several bright knots in the nearby Magellanic irregular galaxy NGC 4214 (classified as type SBmIII), in addition to the emission produced by the more prevalent WN stars). Data are presented on measurements of the line fluxes, the line equivalent widths, and continuum flux densities in the four observed knots, showing that the strongest WR lines generally appear in knots having the most luminous stellar continuum. The significance of this observation is discussed.

  4. Extra-nuclear starbursts: young luminous Hinge clumps in interacting galaxies

    SciTech Connect

    Smith, Beverly J.; Giroux, Mark L.; Soria, Roberto; Struck, Curtis; Swartz, Douglas A.; Yukita, Mihoko E-mail: girouxm@etsu.edu E-mail: curt@iastate.edu

    2014-03-01

    Hinge clumps are luminous knots of star formation near the base of tidal features in some interacting galaxies. We use archival Hubble Space Telescope (HST) UV/optical/IR images and Chandra X-ray maps along with Galaxy Evolution Explorer UV, Spitzer IR, and ground-based optical/near-IR images to investigate the star forming properties in a sample of 12 hinge clumps in five interacting galaxies. The most extreme of these hinge clumps have star formation rates of 1-9 M {sub ☉} yr{sup –1}, comparable to or larger than the 'overlap' region of intense star formation between the two disks of the colliding galaxy system the Antennae. In the HST images, we have found remarkably large and luminous sources at the centers of these hinge clumps. These objects are much larger and more luminous than typical 'super star clusters' in interacting galaxies, and are sometimes embedded in a linear ridge of fainter star clusters, consistent with star formation along a narrow caustic. These central sources have FWHM diameters of ∼70 pc, compared to ∼3 pc in 'ordinary' super star clusters. Their absolute I magnitudes range from M{sub I} ∼ – 12.2 to –16.5; thus, if they are individual star clusters they would lie near the top of the 'super star cluster' luminosity function of star clusters. These sources may not be individual star clusters, but instead may be tightly packed groups of clusters that are blended together in the HST images. Comparison to population synthesis modeling indicates that the hinge clumps contain a range of stellar ages. This is consistent with expectations based on models of galaxy interactions, which suggest that star formation may be prolonged in these regions. In the Chandra images, we have found strong X-ray emission from several of these hinge clumps. In most cases, this emission is well-resolved with Chandra and has a thermal X-ray spectrum, thus it is likely due to hot gas associated with the star formation. The ratio of the extinction

  5. Sloshing Gas in the Core of the Most Luminous Galaxy Cluster RXJ1347.5-1145

    NASA Technical Reports Server (NTRS)

    Markevitch, Maxim; Giacintucci, S.; Dallacasa, D.; Venturi, T.; Brunetti, G.; Cassano, R.; Athreya, R. M.; Johnson, Ryan E.; Zuhone, John; Jones, Christine; Forman, William R.

    2011-01-01

    We present new constraints on the merger history of the most X-ray luminous cluster of galaxies, RXJ1347.5-1145, based its unique multiwavelength morphology. Our X-ray analysis confirms the core gas is undergoing "sloshing" resulting from a prior, large scale, gravitational perturbation. In combination with extensive multiwavelength observations, the sloshing gas points to the primary and secondary clusters having had at least two prior strong gravitational interactions. The evidence supports a model in which the secondary subcluster with mass M=4.8+/-2.4 x 10(exp 14) Stellar Mass has previously (> or approx.=0.6 Gyr ago) passed by the primary cluster, and has now returned for a subsequent crossing where the subcluster's gas has been completely stripped from its dark matter halo. RXJ1347 is a prime example of how core gas sloshing may be used to constrain the merger histories of galaxy clusters through multiwavelength analyses.

  6. Sloshing Gas in the Core of the Most Luminous Galaxy Cluster RXJ1347.5-1145

    NASA Technical Reports Server (NTRS)

    Johnson, Ryan E.; Zuhone, John; Jones, Christine; Forman, William R.; Markevitvh, Maxim

    2011-01-01

    We present new constraints on the merger history of the most X-ray luminous cluster of galaxies, RXJ1347.5-1145, based on its unique multiwavelength morphology. Our X-ray analysis confirms the core gas is undergoing "sloshing" resulting from a prior, large scale, gravitational perturbation. In combination with extensive multiwavelength observations, the sloshing gas points to the primary and secondary clusters having had at least two prior strong gravitational interactions. The evidence supports a model in which the secondary subcluster with mass M=4.8+/-2.4x10(exp 14) solar Mass has previously (> or approx.0.6 Gyr ago) passed by the primary cluster, and has now returned for a subsequent crossing where the subcluster's gas has been completely stripped from its dark matter halo. RXJ1347 is a prime example of how core gas sloshing may be used to constrain the merger histories of galaxy clusters through multiwavelength analyses.

  7. A Study of Four distant, Extremely X-Ray Luminous Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Tucker, Wallace

    1999-01-01

    We identified the extended Einstein IPC X-ray source 1 E 0657-56 with a previously unknown cluster of galaxies at a redshift of z = 0.296. Optical CCD images show the presence of a gravitational arc in this cluster, and galaxy spectra yield a cluster velocity dispersion of 1213(exp +352) - 191 km/s. X-ray data obtained with the ROSAT HRI and ASCA indicate that 1E 0657-56 is a highly luminous cluster in which a merger of subclusters may be occurring. The temperature of the hot gas in 1E 0657-56 is kT = l7.4 +/- 2.5 (keV) , which makes it an unusually hot cluster, with important cosmological implications. Follow-up work with optical, radio and X-ray telescopes is in progress.

  8. A Herschel Spectroscopic Survey of Warm Molecular Gas in Local Infrared Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.; Zhao, Y.; Xu, C. K.; Gao, Y.; GOALS FTS Team

    2013-03-01

    We describe an on-going 194-671 μm spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs) with Herschel SPIRE Fourier Transform Spectrometer (FTS). The survey targets primarily the CO spectral line energy distribution (SLED), from J = 4-3 up to J = 13-12, to probe dense and warm molecular gas that should play an intimate role in star formation and/or active galactic nuclear activities in these galaxies. The program is about 75% finished. At S/N > 5, besides the CO lines, we also detected [N ii] 205 μm and [C i] 370 μm (3 P 2 - 3P1) lines in every target observed. In about half of the observed targets, we also detected [C i] 609 μm (3 P 1 - 3P0).

  9. A Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, Nanyao Y.; Zhao, Y.; Xu, C. K.; Gao, Y.; Armus, L.; Appleton, P. N.; Charmandaris, V.; Diaz Santos, T.; Evans, A. S.; Howell, J.; Issak, K.; Iwasawa, K.; Leech, J.; Lord, S. D.; Mazzarella, J. M.; Petric, A.; Sanders, D. B.; Schulz, B.; Surace, J. A.; Van der Werf, P.

    2013-01-01

    We describe an on-going Herschel 194-671 micron spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs), targeting primarily at the spectral line energy distribution (SLED) of the CO rotational line emission (from J=4-3 up to J=13-12) from warm and dense molecular gas, the [NII] 205 micron line from ionized gas, and the [CI] 370 and 609 micron lines arising mainly from less dense and colder molecular gas where the CO (J=1-0) line is also strong. We present observational results for the first set of 65 sample galaxies that are more or less point sources with respect to the Herschel beams, and show statistical correlations among the shape of the CO SLED, CO line luminosities, IR dust luminosity, and whether a target is known to harbor AGN or not.

  10. SLOSHING GAS IN THE CORE OF THE MOST LUMINOUS GALAXY CLUSTER RXJ1347.5-1145

    SciTech Connect

    Johnson, Ryan E.; Zuhone, John; Jones, Christine; Forman, William R.; Markevitch, Maxim E-mail: cjf@cfa.harvard.edu E-mail: jzuhone@cfa.harvard.edu

    2012-06-01

    We present new constraints on the merger history of the most X-ray luminous cluster of galaxies, RXJ1347.5-1145, based on its unique multiwavelength morphology. Our X-ray analysis confirms that the core gas is undergoing 'sloshing' resulting from a prior, large-scale, gravitational perturbation. In combination with multiwavelength observations, the sloshing gas points to the primary and secondary clusters having had at least two prior strong gravitational interactions. The evidence supports a model in which the secondary subcluster with mass M = 4.8 {+-} 2.4 Multiplication-Sign 10{sup 14} M{sub Sun} has previously ({approx}>0.6 Gyr ago) passed by the primary cluster, and has now returned for a subsequent crossing where the subcluster's gas has been completely stripped from its dark matter halo. RXJ1347 is a prime example of how core gas sloshing may be used to constrain the merger histories of galaxy clusters through multiwavelength analyses.

  11. HERSCHEL OBSERVATIONS OF FAR-INFRARED COOLING LINES IN INTERMEDIATE REDSHIFT (ULTRA)-LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Rigopoulou, D.; Magdis, G. E.; Thatte, N.; Hopwood, R.; Clements, D.; Swinyard, B. M.; Pearson, C.; Farrah, D.; Huang, J.-S.; Alonso-Herrero, A.; Bock, J. J.; Cooray, A.; Griffin, M. J.; Oliver, S.; Smith, A.; Wang, L.; Riechers, D.; Scott, D.; Vaccari, M.; Valtchanov, I.

    2014-01-20

    We report the first results from a spectroscopic survey of the [C II] 158 μm line from a sample of intermediate redshift (0.2 luminous infrared galaxies, (U)LIRGs (L {sub IR} > 10{sup 11.5} L {sub ☉}), using the Spectral and Photometric Imaging REceiver-Fourier Transform Spectrometer on board the Herschel Space Observatory. This is the first survey of [C II] emission, an important tracer of star formation, at a redshift range where the star formation rate density of the universe increases rapidly. We detect strong [C II] 158 μm line emission from over 80% of the sample. We find that the [C II] line is luminous, in the range (0.8-4) × 10{sup –3} of the far-infrared continuum luminosity of our sources, and appears to arise from photodissociation regions on the surface of molecular clouds. The L{sub [C} {sub II]}/L {sub IR} ratio in our intermediate redshift (U)LIRGs is on average ∼10 times larger than that of local ULIRGs. Furthermore, we find that the L{sub [C} {sub II]}/L {sub IR} and L{sub [CII]}/L{sub CO(1-0)} ratios in our sample are similar to those of local normal galaxies and high-z star-forming galaxies. ULIRGs at z ∼ 0.5 show many similarities to the properties of local normal and high-z star-forming galaxies. Our findings strongly suggest that rapid evolution in the properties of the star-forming regions of (U)LIRGs is likely to have occurred in the last 5 billion years.

  12. The Cambridge-Cambridge X-ray Serendipity Survey: I X-ray luminous galaxies

    NASA Technical Reports Server (NTRS)

    Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, M.

    1994-01-01

    We report on the first results obtained from a new optical identification program of 123 faint X-ray sources with S(0.5-2 keV) greater than 2 x 10(exp -14) erg/s/sq cm serendipitously detected in ROSAT PSPC pointed observations. We have spectroscopically identified the optical counterparts to more than 100 sources in this survey. Although the majority of the sample (68 objects) are QSO's, we have also identified 12 narrow emission line galaxies which have extreme X-ray luminosities (10(exp 42) less than L(sub X) less than 10(exp 43.5) erg/s). Subsequent spectroscopy reveals them to be a mixture of star-burst galaxies and Seyfert 2 galaxies in approximately equal numbers. Combined with potentially similar objects identified in the Einstein Extended Medium Sensitivity Survey, these X-ray luminous galaxies exhibit a rate of cosmological evolution, L(sub X) varies as (1 + z)(exp 2.5 +/- 1.0), consistent with that derived for X-ray QSO's. This evolution, coupled with the steep slope determined for the faint end of the X-ray luminosity function (Phi(L(sub X)) varies as L(sub X)(exp -1.9)), implies that such objects could comprise 15-35% of the soft (1-2 keV) X-ray background.

  13. AN INTEGRAL FIELD STUDY OF ABUNDANCE GRADIENTS IN NEARBY LUMINOUS INFRARED GALAXIES

    SciTech Connect

    Rich, J. A.; Kewley, L. J.; Dopita, M. A.; Torrey, P.; Rupke, D. S. N.

    2012-07-01

    We present for the first time metallicity maps generated using data from the Wide Field Spectrograph on the ANU 2.3 m of 10 luminous infrared galaxies (LIRGs) and discuss the abundance gradients and distribution of metals in these systems. We have carried out optical integral field spectroscopy (IFS) of several LIRGs in various merger phases to investigate the merger process. In a major merger of two spiral galaxies with preexisting disk abundance gradients, the changing distribution of metals can be used as a tracer of gas flows in the merging system as low-metallicity gas is transported from the outskirts of each galaxy to their nuclei. We employ this fact to probe merger properties by using the emission lines in our IFS data to calculate the gas-phase metallicity in each system. We create abundance maps and subsequently derive a metallicity gradient from each map. We compare our measured gradients to merger stage as well as several possible tracers of merger progress and observed nuclear abundances. We discuss our work in the context of previous abundance gradient observations and compare our results to new galaxy merger models that trace metallicity gradient. Our results agree with the observed flattening of metallicity gradients as a merger progresses. We compare our results with new theoretical predictions that include chemical enrichment. Our data show remarkable agreement with these simulations.

  14. OT2_peisenha_2: The Most Luminous Obscured Galaxies and Quasars Revealed by WISE and Herschel

    NASA Astrophysics Data System (ADS)

    Eisenhardt, P.

    2011-09-01

    NASA's Wide-field Infrared Survey Explorer (WISE) has surveyed the entire sky at 3.4, 4.6, 12 and 22 microns (W1, W2, W3, and W4), reaching sensitivities hundreds of times deeper than IRAS. We have used WISE photometry to select an all-sky sample of objects which are extremely luminous. The objects are prominent in W4, but faint or undetected in W1 and W2 (W12drops). Followup spectroscopy of ~ 100 sources shows over 70% of W12drops have redshifts > 1.6, which with OT1 PACS and SPIRE photometry of 27 sources leads to over 1E13 solar luminosities, with ~ 10% exceeding 1E14 solar luminosities. High resolution adaptive optics imaging shows these objects are unlensed. We request 47.3 hours of Herschel time to complete the all-sky sample of the brightest 185 W12 drops, fulfilling the primary WISE objective of finding the most extreme luminous IR galaxies in the Universe. These superlative objects will be the most fruitful for detailed studies of the physics of star formation, AGN fueling, and feedback in the most active galaxies.

  15. Spectroscopy of Luminous Compact Blue Galaxies in Distant Clusters. I. Spectroscopic Data

    NASA Astrophysics Data System (ADS)

    Crawford, Steven M.; Wirth, Gregory D.; Bershady, Matthew A.; Hon, Kimo

    2011-11-01

    We used the DEIMOS spectrograph on the Keck II Telescope to obtain spectra of galaxies in the fields of five distant, rich galaxy clusters over the redshift range 0.5 < z < 0.9 in a search for luminous compact blue galaxies (LCBGs). Unlike traditional studies of galaxy clusters, we preferentially targeted blue cluster members identified via multi-band photometric pre-selection based on imaging data from the WIYN telescope. Of the 1288 sources that we targeted, we determined secure spectroscopic redshifts for 848 sources, yielding a total success rate of 66%. Our redshift measurements are in good agreement with those previously reported in the literature, except for 11 targets which we believe were previously in error. Within our sample, we confirm the presence of 53 LCBGs in the five galaxy clusters. The clusters all stand out as distinct peaks in the redshift distribution of LCBGs with the average number density of LCBGs ranging from 1.65 ± 0.25 Mpc-3 at z = 0.55 to 3.13 ± 0.65 Mpc-3 at z = 0.8. The number density of LCBGs in clusters exceeds the field density by a factor of 749 ± 116 at z = 0.55; at z = 0.8, the corresponding ratio is E = 416 ± 95. At z = 0.55, this enhancement is well above that seen for blue galaxies or the overall cluster population, indicating that LCBGs are preferentially triggered in high-density environments at intermediate redshifts. Based in part 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.

  16. Are Luminous cD Halos Formed by the Disruption of Dwarf Galaxies?

    NASA Astrophysics Data System (ADS)

    López-Cruz, Omar; Yee, H. K. C.; Brown, James P.; Jones, Christine; Forman, William

    1997-02-01

    From a total sample of 45 Abell clusters observed by the Einstein X-ray observatory, we present the results on the galaxy luminosity function (LF) for a group of seven clusters that were identified by the morphology of their LFs. The LFs were derived using photometric data to a completeness limit ~5.5 mag below M*. We found that a single Schechter function with an average α ~ -1.0 gives a good fit to these individual LFs within the magnitude range. These seven clusters have common properties, which indicate they form a homogeneous class of dynamically evolved clusters that can be characterized by the presence of a dominant cD galaxy, high richness, symmetrical single-peaked X-ray emission, and high gas mass. On the other hand, steep faint-end slopes (-2.0 <= α <= -1.4) are usually detected in poorer clusters. Our result gives a direct indication that the faint-end slope of the galaxy LF is subject to environmental effects. We propose that the flatness of the faint-end slope in these clusters results from the disruption of a large fraction of dwarf galaxies during the early stages of cluster evolution. The stars and gas from the disrupted galaxies are redistributed throughout the cluster potential during violent relaxation. This heuristic scenario can explain the origin of the luminous halos of cD galaxies and a large fraction of the gas content in the intracluster medium as a by-product. The correlation between the cluster gas mass determined from the modeling of the X-ray emission and the cD halo optical luminosity is presented to support the proposed model.

  17. Morphologies and Color Gradients of Luminous Evolved Galaxies at z ~ 1.5

    NASA Astrophysics Data System (ADS)

    McGrath, Elizabeth J.; Stockton, Alan; Canalizo, Gabriela; Iye, Masanori; Maihara, Toshinori

    2008-07-01

    We have examined in detail the morphologies of seven z ~ 1.5 passively evolving luminous red galaxies using high-resolution HST NICMOS and ACS imaging data. Almost all of these galaxies appear to be relaxed systems, with smooth morphologies at both rest-frame UV and visible wavelengths. Previous results from spectral synthesis modeling favor a single burst of star formation more than 1 Gyr before the observed epoch. The prevalence of old stellar populations, however, does not correlate exclusively with early-type morphologies as it does in the local universe; the light profiles for some of these galaxies appear to be dominated by massive exponential disks. This evidence for massive old disks, along with the apparent uniformity of stellar age across the disk, suggests formation by a mechanism better described as a form of monolithic collapse than as a hierarchical merger. These galaxies could not have undergone a single major merging event since the bulk of their stars were formed, more than 1 Gyr earlier. There is at least one case, however, that appears to be undergoing a "dry merger," which may be an example of the process that converts these unusual galaxies into the familiar spheroids that dominate galaxies comprising old stellar populations at the present epoch. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-10418.

  18. Mapping luminous blue compact galaxies with VIRUS-P. Morphology, line ratios, and kinematics

    NASA Astrophysics Data System (ADS)

    Cairós, L. M.; Caon, N.; García Lorenzo, B.; Kelz, A.; Roth, M.; Papaderos, P.; Streicher, O.

    2012-11-01

    Context. Blue compact galaxies (BCG) are narrow emission-line systems that undergo a violent burst of star formation. They are compact, low-luminosity galaxies, with blue colors and low chemical abundances, which offer us a unique opportunity to investigate collective star formation and its effects on galaxy evolution in a relatively simple, dynamically unperturbed environment. Spatially resolved spectrophotometric studies of BCGs are essential for a better understanding of the role of starburst-driven feedback processes on the kinematical and chemical evolution of low-mass galaxies near and far. Aims: We carry out an integral field spectroscopy (IFS) study of a sample of luminous BCGs, with the aim to probe the morphology, kinematics, dust extinction, and excitation mechanisms of their warm interstellar medium (ISM). Methods: We obtained IFS data for five luminous BCGs with VIRUS-P, the prototype instrument for the Visible Integral Field Replicable Unit Spectrograph, attached to the 2.7 m Harlan J. Smith Telescope at the McDonald Observatory. VIRUS-P consists of a square array of 247 optical fibers, which covers a 109″ × 109″ field of view, with a spatial sampling of 4farcs2 and a 0.3 filling factor. We observed in the 3550-5850 Å spectral range, with a resolution of 5 Å FWHM. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines ([O ii] λ3727, Hγ, Hβ and [O iii] λ5007), and investigated the morphology of diagnostic emission-line ratios and the extinction patterns in the ISM as well as stellar and gas kinematics. Additionally, from integrated spectra we inferred total line fluxes and luminosity-weighted extinction coefficients and gas-phase metallicities. Results: All galaxies exhibit an overall regular morphology in the stellar continuum, while their warm ISM morphology is more complex: in II Zw 33 and Mrk 314, the star-forming regions are aligned along a chain-structure; Haro 1, NGC 4670 and III Zw 102

  19. OT1_nlu_1: Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.

    2010-07-01

    We propose to survey CO spectral line energy distribution (SLED), from J=4-3 up to J=13-12, on 93 local luminous infrared galaxies (LIRGs; L_{IR} > 1.0E11 L_{sun}) with Herschel SPIRE FTS spectrometer. These galaxies, plus 32 additional LIRGs that will have similar data from existing Herschel programs (mainly the HerCULES project), form a flux-limited subset of the Great Observatories All-Sky LIRGs Survey (GOALS) sample. Our proposal is built on the legacy of GOALS and extends beyond the existing Herschel HerCULES program, which emphasizes more on ULIRGs, to a much needed sample coverage of the more numerous and diverse population of less luminous LIRGs. The data from the proposed observations will not only provide much needed local LIRG templates for future ALMA studies of high-redshift counterparts, but also lend us a powerful diagnostic tool to probe the warm and dense molecular gas that are more closely related to the starburst or AGN activity in the nuclei of LIRGs. The data from this proposal will provide important statistical clues to the interplay between the cold and warm molecular gas, IR luminosity, star formation rate and efficiency, and the diverse properties of LIRGs. Specifically, using the homogeneous CO SLED data from this proposal, together with ground-base, low-order CO line data (mainly J=1-0) and other data that have been compiled for the GOALS sample, we will address the following questions: (1) What is the dominant nuclear power source in individual sample galaxy: starburst or AGN? (2) What are the typical physical properties of warm molecular gas in the nuclei of LIRGs? (3) How do the nuclear warm gas components correlate to the cold gas component, star formation rate and efficiency, dust temperature, etc? and (4) How does molecular gas excitation change along a merger sequence?

  20. Mapping the Spatial Distribution of Molecular Hydrogen and PAH emission in Nearby Galaxies with the Spitzer Infrared Spectrograph

    NASA Astrophysics Data System (ADS)

    Brunner, Gregory; Dufour, R. J.; Sheth, K.; Armus, L.; Schinnerer, E.; Vogel, S.; Wolfire, M.

    2007-12-01

    We have embarked on an archival program to map the spatial distribution of pure rotational molecular hydrogen (H2) line emission and polycyclic aromatic hydrogen (PAH) emission (from the 6.2, 7.7, 8.6, 11.3, 12.7, and 17.1 micron PAH features) in nearby galaxies using spatially resolved Spitzer IRS spectra acquired as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) and other Spitzer programs. We present maps of the H2 and PAH emission for several galaxies (M51, M95, and NGC 3521). We compare the emission distributions in order to understand how H2, PAHs, and ionized gas are spatially correlated across dynamically distinct regions in nearby galaxies. This work is based on observations and archival data obtained with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by both AURA grant GO10822.1 and an award issued by JPL/Caltech to Rice University.

  1. UNUSUAL PAH EMISSION IN NEARBY EARLY-TYPE GALAXIES: A SIGNATURE OF AN INTERMEDIATE-AGE STELLAR POPULATION?

    SciTech Connect

    Vega, O.; Bressan, A.; Panuzzo, P.; Granato, G. L.; Silva, L.; Zeilinger, W. W.

    2010-10-01

    We present the analysis of Spitzer-IRS spectra of four early-type galaxies (ETGs), NGC 1297, NGC 5044, NGC 6868, and NGC 7079, all classified as LINERs in the optical bands. Their IRS spectra present the full series of H{sub 2} rotational emission lines in the range 5-38 {mu}m, atomic lines, and prominent polycyclic aromatic hydrocarbon (PAH) features. We investigate the nature and origin of the PAH emission, characterized by unusually low 6-9/11.3 {mu}m interband ratios. After the subtraction of a passive ETG template, we find that the 7-9 {mu}m spectral region requires dust features not normally present in star-forming galaxies. Each spectrum is then analyzed with the aim of identifying their components and origin. In contrast to normal star-forming galaxies, where cationic PAH emission prevails, our 6-14 {mu}m spectra seem to be dominated by large and neutral PAH emission, responsible for the low 6-9/11.3 {mu}m ratios, plus two broad dust emission features peaking at 8.2 {mu}m and 12 {mu}m. These broad components, observed until now mainly in evolved carbon stars and usually attributed to pristine material, contribute approximately 30%-50% of the total PAH flux in the 6-14 {mu}m region. We propose that the PAH molecules in our ETGs arise from fresh carbonaceous material that is continuously released by a population of carbon stars, formed in a rejuvenation episode that occurred within the last few Gyr. The analysis of the MIR spectra allows us to infer that, in order to maintain the peculiar size and charge distributions biased to large and neutral PAHs, this material must be shocked and excited by the weak UV interstellar radiation field of our ETGs.

  2. A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy

    NASA Astrophysics Data System (ADS)

    Oesch, P. A.; Brammer, G.; van Dokkum, P. G.; Illingworth, G. D.; Bouwens, R. J.; Labbé, I.; Franx, M.; Momcheva, I.; Ashby, M. L. N.; Fazio, G. G.; Gonzalez, V.; Holden, B.; Magee, D.; Skelton, R. E.; Smit, R.; Spitler, L. R.; Trenti, M.; Willner, S. P.

    2016-03-01

    We present Hubble WFC3/IR slitless grism spectra of a remarkably bright z ≳ 10 galaxy candidate, GN-z11, identified initially from CANDELS/GOODS-N imaging data. A significant spectroscopic continuum break is detected at λ =1.47+/- 0.01 μ {{m}}. The new grism data, combined with the photometric data, rule out all plausible lower redshift solutions for this source. The only viable solution is that this continuum break is the Lyα break redshifted to {z}{grism}={11.09}-0.12+0.08, just ˜400 Myr after the Big Bang. This observation extends the current spectroscopic frontier by 150 Myr to well before the Planck (instantaneous) cosmic reionization peak at z ˜ 8.8, demonstrating that galaxy build-up was well underway early in the reionization epoch at z > 10. GN-z11 is remarkably, and unexpectedly, luminous for a galaxy at such an early time: its UV luminosity is 3× larger than {L}* measured at z ˜ 6-8. The Spitzer IRAC detections up to 4.5 μm of this galaxy are consistent with a stellar mass of ˜109 M⊙. This spectroscopic redshift measurement suggests that James Webb Space Telescope (JWST) will be able to similarly and easily confirm such sources at z > 10 and characterize their physical properties through detailed spectroscopy. Furthermore, WFIRST, with its wide-field near-IR imaging, would find large numbers of similar galaxies and contribute greatly to JWST's spectroscopy, if it is launched early enough to overlap with JWST.

  3. Intrinsic Ellipticity Correlation of SDSS Luminous Red Galaxies and Misalignment with Their Host Dark Matter Halos

    NASA Astrophysics Data System (ADS)

    Okumura, Teppei; Jing, Y. P.; Li, Cheng

    2009-03-01

    We investigate the orientation correlation of giant elliptical galaxies by measuring the intrinsic ellipticity correlation function of 83,773 luminous red galaxies (LRGs) at redshifts 0.16-0.47 from the Sloan Digital Sky Survey. We have accurately determined the correlation up to 30 h-1 Mpc. Luminosity dependence of the ellipticity correlation is also detected although the error bars are large, while no evidence is found for its redshift evolution between z = 0.2 and z = 0.4. Then we use a cosmological N-body simulation to examine misalignment between the central LRGs and their parent dark matter halos. Central and satellite galaxies are assigned to simulated halos by employing a halo occupation distribution model for the LRGs. The ellipticity correlation is predicted to have the same shape as, but an amplitude about four times higher than, our observation if the central LRGs are perfectly aligned with their host halos. This indicates that the central LRG galaxies are preferentially but not perfectly aligned with their host halos. With the assumption that there is a misalignment angle between a central LRG and its host halo which follows a Gaussian distribution with a zero mean and a width σθ, we obtain a tight constraint on the misalignment parameter, σθ = 35.4+4.0 -3.3 deg. This type of intrinsic ellipticity correlation, if not corrected, can lead to contamination at 5% level to the shear power spectrum in weak lensing surveys of limiting magnitude RAB = 24.5 if the source central galaxies follow the same misalignment distribution as the LRGs.

  4. Luminous red galaxies in clusters: central occupation, spatial distributions and miscentring

    NASA Astrophysics Data System (ADS)

    Hoshino, Hanako; Leauthaud, Alexie; Lackner, Claire; Hikage, Chiaki; Rozo, Eduardo; Rykoff, Eli; Mandelbaum, Rachel; More, Surhud; More, Anupreeta; Saito, Shun; Vulcani, Benedetta

    2015-09-01

    Luminous red galaxies (LRG) from the Sloan Digital Sky Survey are among the best understood samples of galaxies and are employed in a broad range of cosmological studies. In this paper, we study how LRGs occupy massive haloes via counts in clusters and reveal several unexpected trends. Using the red-sequence Matched-filter Probabilistic Percolation (redMaPPer) cluster catalogue, we derive the central occupation of LRGs as a function richness. We show that clusters contain a significantly lower fraction of central LRGs than predicted from the two-point correlation function. At halo masses of 1014.5 M⊙, we find Ncen = 0.73 compared to Ncen = 0.89 from correlation studies. Our central occupation function for LRGs converges to 0.95 at large halo masses. A strong anticorrelation between central luminosity and cluster mass at fixed richness is required to reconcile our results with those based on clustering studies. We derive the probability that the brightest cluster member is not the central galaxy. We find PBNC ≈ 20-30 per cent which is a factor of ˜2 lower than the value found by Skibba et al. Finally, we study the radial offsets of bright non-central LRGs from cluster centres and show that bright non-central LRGs follow a different radial distribution compared to red cluster members. This work demonstrates that even the most massive clusters do not always have an LRG at the centre, and that the brightest galaxy in a cluster is not always the central galaxy.

  5. A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies

    SciTech Connect

    Magdis, Georgios E.; Rigopoulou, D.; Hopwood, R.; Clements, D.; Huang, J.-S.; Farrah, D.; Pearson, C.; Alonso-Herrero, Almudena; Bock, J. J.; Cooray, A.; Griffin, M. J.; Oliver, S.; Perez Fournon, I.; Riechers, D.; Swinyard, B. M.; Thatte, N.; Scott, D.; Valtchanov, I.; Vaccari, M.

    2014-11-20

    We present Herschel far-IR photometry and spectroscopy as well as ground-based CO observations of an intermediate redshift (0.21 ≤ z ≤ 0.88) sample of Herschel-selected (ultra)-luminous infrared galaxies (L {sub IR} > 10{sup 11.5} L {sub ☉}). With these measurements, we trace the dust continuum, far-IR atomic line emission, in particular [C II] 157.7 μm, as well as the molecular gas of z ∼ 0.3 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and perform a detailed investigation of the interstellar medium of the population. We find that the majority of Herschel-selected intermediate redshift (U)LIRGs have L {sub C} {sub II}/L {sub FIR} ratios that are a factor of about 10 higher than that of local ULIRGs and comparable to that of local normal and high-z star-forming galaxies. Using our sample to bridge local and high-z [C II] observations, we find that the majority of galaxies at all redshifts and all luminosities follow an L {sub C} {sub II}–L {sub FIR} relation with a slope of unity, from which local ULIRGs and high- z active-galactic-nucleus-dominated sources are clear outliers. We also confirm that the strong anti-correlation between the L {sub C} {sub II}/L {sub FIR} ratio and the far-IR color L {sub 60}/L {sub 100} observed in the local universe holds over a broad range of redshifts and luminosities, in the sense that warmer sources exhibit lower L {sub C} {sub II}/L {sub FIR} at any epoch. Intermediate redshift ULIRGs are also characterized by large molecular gas reservoirs and by lower star formation efficiencies compared to that of local ULIRGs. The high L {sub C} {sub II}/L {sub FIR} ratios, the moderate star formation efficiencies (L {sub IR}/L{sub CO}{sup ′} or L {sub IR}/M{sub H{sub 2}}), and the relatively low dust temperatures of our sample (which are also common characteristics of high-z star-forming galaxies with ULIRG-like luminosities) indicate that the evolution of the physical properties of (U)LIRGs between the

  6. Lensing measurements of the ellipticity of luminous red galaxies dark matter haloes

    NASA Astrophysics Data System (ADS)

    Clampitt, Joseph; Jain, Bhuvnesh

    2016-04-01

    Lensing measurements of the shapes of dark matter haloes can provide tests of gravity theories and possible dark matter interactions. We measure the quadrupole weak lensing signal from the elliptical haloes of 70 000 Sloan Digital Sky Survey luminous red galaxies. We use a new estimator that nulls the spherical halo lensing signal, isolating the shear due to anisotropy in the dark matter distribution. One of the two Cartesian components of our estimator is insensitive to the primary systematic, a spurious alignment of lens and source ellipticities, allowing us to make robust measurements of halo ellipticity. Our best-fitting value for the ellipticity of the surface mass density is 0.24 ± 0.06, which translates to an axis ratio of 0.78. We rule out the hypothesis of no ellipticity at the 4σ confidence level, and ellipticity <0.12 (axis ratio >0.89) at the 2σ level. We discuss how our measurements of halo ellipticity are revised to higher values using estimates of the misalignment of mass and light from simulations. Finally, we apply the same techniques to a smaller sample of redMaPPer galaxy clusters and obtain a 3σ measurement of cluster ellipticity. We discuss how the improved signal-to-noise ratio properties of our estimator can enable studies of halo shapes for different galaxy populations with upcoming surveys.

  7. Hydrogen fluoride toward luminous nearby galaxies: NGC 253 and NGC 4945

    SciTech Connect

    Monje, R. R.; Lis, D. C.; Phillips, T. G.; Lord, S.; Falgarone, E.; Güsten, R.

    2014-04-10

    We present the detection of hydrogen fluoride (HF) in two luminous nearby galaxies, NGC 253 and NGC 4945 using the Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory. The HF line toward NGC 253 has a P-Cygni profile, while an asymmetric absorption profile is seen toward NGC 4945. The P-Cygni profile in NGC 253 suggests an outflow of molecular gas with a mass of M(H{sub 2}){sub out} ∼ 1 × 10{sup 7} M {sub ☉} and an outflow rate as large as M-dot ∼6.4 M {sub ☉} yr{sup –1}. In the case of NGC 4945, the axisymmetric velocity components in the HF line profile are compatible with the interpretation of a fast-rotating nuclear ring surrounding the nucleus and the presence of inflowing gas. The gas falls into the nucleus with an inflow rate of ≤1.2 M {sub ☉} yr{sup –1}, inside an inner radius of ≤200 pc. The gas accretion rate to the central active galactic nucleus is much smaller, suggesting that the inflow may be triggering a nuclear starburst. From these results, the HF J = 1-0 line is seen to provide an important probe of the kinematics of absorbing material along the sight-line to nearby galaxies with bright dust continuum and a promising new tracer of molecular gas in high-redshift galaxies.

  8. Hydrogen Fluoride toward Luminous Nearby Galaxies: NGC 253 and NGC 4945

    NASA Astrophysics Data System (ADS)

    Monje, R. R.; Lord, S.; Falgarone, E.; Lis, D. C.; Neufeld, D. A.; Phillips, T. G.; Güsten, R.

    2014-04-01

    We present the detection of hydrogen fluoride (HF) in two luminous nearby galaxies, NGC 253 and NGC 4945 using the Heterodyne Instrument for the Far-Infrared on board the Herschel Space Observatory. The HF line toward NGC 253 has a P-Cygni profile, while an asymmetric absorption profile is seen toward NGC 4945. The P-Cygni profile in NGC 253 suggests an outflow of molecular gas with a mass of M(H2)out ~ 1 × 107 M ⊙ and an outflow rate as large as dot M ~6.4 M ⊙ yr-1. In the case of NGC 4945, the axisymmetric velocity components in the HF line profile are compatible with the interpretation of a fast-rotating nuclear ring surrounding the nucleus and the presence of inflowing gas. The gas falls into the nucleus with an inflow rate of <=1.2 M ⊙ yr-1, inside an inner radius of <=200 pc. The gas accretion rate to the central active galactic nucleus is much smaller, suggesting that the inflow may be triggering a nuclear starburst. From these results, the HF J = 1-0 line is seen to provide an important probe of the kinematics of absorbing material along the sight-line to nearby galaxies with bright dust continuum and a promising new tracer of molecular gas in high-redshift galaxies.

  9. Lymanα Emission from a Luminous z = 8.68 Galaxy: Implications for Galaxies as Tracers of Cosmic Reionization

    NASA Astrophysics Data System (ADS)

    Zitrin, Adi; Labbé, Ivo; Belli, Sirio; Bouwens, Rychard; Ellis, Richard S.; Roberts-Borsani, Guido; Stark, Daniel P.; Oesch, Pascal A.; Smit, Renske

    2015-09-01

    We report the discovery of Lyman-alpha emission (Lyα) in the bright galaxy EGSY-2008532660 (hereafter EGSY8p7) using the Multi-Object Spectrometer For Infra-Red Exploration spectrograph at the Keck Observatory. First reported by Roberts-Borsani et al., this galaxy was selected for spectroscopic observations because of its photometric redshift ({z}{phot}={8.57}-0.43+0.22), apparent brightness (H{}160=25.26+/- 0.09), and red Spitzer/IRAC [3.6]-[4.5] color indicative of contamination by strong oxygen emission in the [4.5] band. With a total integration of ˜4.3 hr, our data reveal an emission line at ≃11776 Å that we argue is likely Lyα at a redshift of {z}{spec}={8.683}-0.004+0.001, in good agreement with the photometric estimate. The line was detected independently on two nights using different slit orientations and its detection significance is ˜ 7.5σ . An overlapping skyline contributes significantly to the uncertainty on the total line flux, although the significance of the detected line is robust to a variety of skyline-masking procedures. By direct addition and a Gaussian fit, we estimate a 95% confidence range of 1.0-2.5 × 10-17 erg s-1 cm-2, corresponding to a rest-frame equivalent width of 17-42 Å. EGSY8p7 is the most distant spectroscopically confirmed galaxy to date, and the third luminous source in the EGS field beyond {z}{phot}≳ 7.5 with detectable Lyα emission, viewed at a time when the intergalactic medium is believed to be fairly neutral. Although the reionization process was probably patchy, we discuss whether luminous sources with prominent IRAC color excesses may harbor harder ionizing spectra than the dominant fainter population, thereby creating earlier ionized bubbles. Further spectroscopic follow-up of such bright sources promises important insights into the early formation of galaxies.

  10. CO SPECTRAL LINE ENERGY DISTRIBUTIONS OF INFRARED-LUMINOUS GALAXIES AND ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Papadopoulos, Padeli P.; Van der Werf, Paul; Isaak, Kate; Xilouris, Emmanuel M. E-mail: pvdwerf@strw.leidenuniv.n E-mail: xilouris@astro.noa.g

    2010-06-01

    We report on new sensitive CO J = 6-5 line observations of several luminous infrared galaxies (LIRGs; L {sub IR}(8-1000 {mu}m) {approx}> 10{sup 11} L {sub sun}), 36% (8/22) of them ultraluminous infrared galaxies (ULIRGs) (L {sub IR}>10{sup 12} L {sub sun}), and two powerful local active galactic nuclei (AGNs)-the optically luminous QSO PG 1119+120 and the powerful radio galaxy 3C 293-using the James Clerk Maxwell Telescope on Mauna Kea in Hawaii. We combine these observations with existing low-J CO data and dust emission spectral energy distributions in the far-infrared-submillimeter from the literature to constrain the properties of the star-forming interstellar medium (ISM) in these systems. We then build the first local CO spectral line energy distributions (SLEDs) for the global molecular gas reservoirs that reach up to high J-levels. These CO SLEDs are neither biased by strong lensing (which affects many of those constructed for high-redshift galaxies), nor suffer from undersampling of CO-bright regions (as most current high-J CO observations of nearby extended systems do). We find: (1) a significant influence of dust optical depths on the high-J CO lines, suppressing the J = 6-5 line emission in some of the most IR-luminous LIRGs, (2) low global CO line excitation possible even in vigorously star-forming systems, (3) the first case of a shock-powered high-excitation CO SLED in the radio galaxy 3C 293 where a powerful jet-ISM interaction occurs, and (4) unusually highly excitated gas in the optically powerful QSO PG 1119+120. In Arp 220 and possibly other (U)LIRGs very faint CO J = 6-5 lines can be attributed to significant dust optical depths at short submillimeter wavelengths immersing those lines in a strong dust continuum, and also causing the C{sup +} line luminosity deficit often observed in such extreme starbursts. Re-analysis of the CO line ratios available for submillimeter galaxies suggests that similar dust opacities also may be present in these

  11. A MAP OF THE INTEGRATED SACHS-WOLFE SIGNAL FROM LUMINOUS RED GALAXIES

    SciTech Connect

    Granett, Benjamin R.; Neyrinck, Mark C.; Szapudi, Istvan

    2009-08-10

    We construct a map of the time derivative of the gravitational potential traced by Sloan Digital Sky Survey luminous red galaxies (LRGs). The potential decays on large scales due to cosmic acceleration, leaving an imprint on cosmic microwave background (CMB) radiation through the integrated Sachs-Wolfe (ISW) effect. With a template fit, we directly measure this signature on the CMB at a 2{sigma} confidence level. The measurement is consistent with the cross-correlation statistic, strengthening the claim that dark energy is indeed the cause of the correlation. This new approach potentially simplifies the cosmological interpretation. Our constructed linear ISW map shows no evidence for degree-scale cold and hot spots associated with supervoid and supercluster structures. This suggests that the linear ISW effect in a concordance {lambda}CDM cosmology is insufficient to explain the strong CMB imprints from these structures that we previously reported.

  12. HOST GALAXIES OF LUMINOUS TYPE 2 QUASARS AT z {approx} 0.5

    SciTech Connect

    Liu Xin; Greene, Jenny E.; Strauss, Michael A.; Zakamska, Nadia L.; Krolik, Julian H.; Heckman, Timothy M.

    2009-09-10

    We present deep Gemini GMOS optical spectroscopy of nine luminous quasars at redshifts z {approx} 0.5, drawn from the Sloan Digital Sky Survey type 2 quasar sample. Our targets were selected to have high intrinsic luminosities (M{sub V} < -26 mag) as indicated by the [O III] {lambda}5007 A emission-line luminosity (L[{sub OIII}]). Our sample has a median black hole mass of {approx}10{sup 8.8} M{sub sun} inferred assuming the local M {sub BH}-{sigma}{sub *} relation and a median Eddington ratio of {approx}0.7, using stellar velocity dispersions {sigma}{sub *} measured from the G band. We estimate the contamination of the stellar continuum from scattered quasar light based on the strength of broad H{beta}, and provide an empirical calibration of the contamination as a function of L {sub [OIII]}; the scattered-light fraction is {approx}30% of L{sub 5100} for objects with L {sub [OIII]} = 10{sup 9.5} L{sub sun}. Population synthesis indicates that young poststarburst populations (<0.1 Gyr) are prevalent in luminous type 2 quasars, in addition to a relatively old population (>1 Gyr) which dominates the stellar mass. Broad emission complexes around He II {lambda}4686 A with luminosities up to 10{sup 8.3} L{sub sun} are unambiguously detected in three out of the nine targets, indicative of Wolf-Rayet (WR) populations. Population synthesis shows that {approx}5 Myr poststarburst populations contribute substantially to the luminosities (>50% of L{sub 5100}) of all three objects with WR detections. We find two objects with double cores and four with close companions. Our results may suggest that luminous type 2 quasars trace an early stage of galaxy interaction, perhaps responsible for both the quasar and the starburst activity.

  13. THE LUMINOUS INFRARED HOST GALAXY OF SHORT-DURATION GRB 100206A

    SciTech Connect

    Perley, D. A.; Modjaz, M.; Morgan, A. N.; Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Miller, A. A.; Butler, N. R.

    2012-10-20

    The known host galaxies of short-hard gamma-ray bursts (GRBs) to date are characterized by low to moderate star formation rates (SFRs) and a broad range of stellar masses, in general agreement with models associating the phenomenon with an old progenitor, such as merging neutron stars. In this paper, we positionally associate the recent unambiguously short-hard Swift GRB 100206A with a disk galaxy at redshift z = 0.4068 that is rapidly forming stars at a rate of {approx}30 M {sub Sun} yr{sup -1}, almost an order of magnitude higher than any previously identified short-GRB host. The galaxy is very red (g - K = 4.3 AB mag), heavily obscured (A{sub V} Almost-Equal-To 2 mag), and has the highest metallicity of any GRB host to date (12 + log[O/H]{sub KD02} = 9.2): it is a classical luminous infrared galaxy (LIRG), with L {sub IR} Almost-Equal-To 4 Multiplication-Sign 10{sup 11} L {sub Sun }. While these properties could be interpreted to support an association of this GRB with recent star formation, modeling of the broadband spectral energy distribution also indicates that a substantial stellar mass of mostly older stars is also present. The specific SFR is modest (sSFR Almost-Equal-To 0.5 Gyr{sup -1}), the current SFR is not substantially elevated above its long-term average, and the host morphology shows no sign of recent merger activity. Our observations are therefore equally consistent with an older progenitor. Given the precedent established by previous short-GRB hosts and the significant fraction of the universe's stellar mass in LIRG-like systems at z {approx}> 0.3, an older progenitor represents the most likely origin of this event.

  14. The angular power spectra of photometric Sloan Digital Sky Survey luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Thomas, Shaun A.; Abdalla, Filipe B.; Lahav, Ofer

    2011-04-01

    We construct new galaxy angular power spectra Cℓ based on the extended, updated and final Sloan Digital Sky Survey (SDSS) II luminous red galaxy (LRG) photometric redshift survey - MegaZ (DR7). Encapsulating 7746 deg2 we utilize 723 556 photometrically determined LRGs between 0.45 < z < 0.65 in a 3.3 (Gpc h-1)3 spherical harmonic analysis of the galaxy distribution. By combining four photometric redshift bins, we find preliminary parameter constraints of fb≡Ωb/Ωm= 0.173 ± 0.046 and Ωm= 0.260 ± 0.035 assuming H0= 75 km s-1 Mpc-1, ns= 1 and Ωk= 0. These limits are consistent with the cosmic microwave background and the previous data release (DR4). The Cℓ are sensitive to redshift space distortions and therefore we also recast our constraints into a measurement of β≈Ω0.55m/b in different redshift shells. The robustness of these power spectra with respect to a number of potential systematics such as extinction, photometric redshift and ANNz training set extrapolation are examined. The latter includes a cosmological comparison of available photometric redshift estimation codes where we find excellent agreement between template and empirical estimation methods. MegaZ DR7 represents a methodological prototype to next generation surveys such as the Dark Energy Survey and, furthermore, is a photometric precursor to the spectroscopic BOSS survey. Our galaxy catalogue and all power spectra data can be found at .

  15. The Luminous Infrared Host Galaxy of Short-duration GRB 100206A

    NASA Astrophysics Data System (ADS)

    Perley, D. A.; Modjaz, M.; Morgan, A. N.; Cenko, S. B.; Bloom, J. S.; Butler, N. R.; Filippenko, A. V.; Miller, A. A.

    2012-10-01

    The known host galaxies of short-hard gamma-ray bursts (GRBs) to date are characterized by low to moderate star formation rates (SFRs) and a broad range of stellar masses, in general agreement with models associating the phenomenon with an old progenitor, such as merging neutron stars. In this paper, we positionally associate the recent unambiguously short-hard Swift GRB 100206A with a disk galaxy at redshift z = 0.4068 that is rapidly forming stars at a rate of ~30 M ⊙ yr-1, almost an order of magnitude higher than any previously identified short-GRB host. The galaxy is very red (g - K = 4.3 AB mag), heavily obscured (AV ≈ 2 mag), and has the highest metallicity of any GRB host to date (12 + log[O/H]KD02 = 9.2): it is a classical luminous infrared galaxy (LIRG), with L IR ≈ 4 × 1011 L ⊙. While these properties could be interpreted to support an association of this GRB with recent star formation, modeling of the broadband spectral energy distribution also indicates that a substantial stellar mass of mostly older stars is also present. The specific SFR is modest (sSFR ≈ 0.5 Gyr-1), the current SFR is not substantially elevated above its long-term average, and the host morphology shows no sign of recent merger activity. Our observations are therefore equally consistent with an older progenitor. Given the precedent established by previous short-GRB hosts and the significant fraction of the universe's stellar mass in LIRG-like systems at z >~ 0.3, an older progenitor represents the most likely origin of this event.

  16. The Strikingly Uniform, Highly Turbulent Interstellar Medium of the Most Luminous Galaxy in the Universe

    NASA Astrophysics Data System (ADS)

    Díaz-Santos, T.; Assef, R. J.; Blain, A. W.; Tsai, C.-W.; Aravena, M.; Eisenhardt, P.; Wu, J.; Stern, D.; Bridge, C.

    2016-01-01

    Observed at z = 4.601 and with {L}{{bol}} = 3.5 × {10}14 {L}⊙ , W2246-0526 is the most luminous galaxy known in the universe and hosts a deeply buried active galactic nucleus (AGN)/supermassive black hole (SMBH). Discovered using the Wide-field Infrared Survey Explorer, W2246-0526 is classified as a hot dust-obscured galaxy, based on its luminosity and dust temperature. Here, we present spatially resolved ALMA [C ii]157.7 μm observations of W2246-0526, providing unique insight into the kinematics of its interstellar medium (ISM). The measured [C ii] -to-far-infrared ratio is ˜ 2 × {10}-4, implying ISM conditions that compare only with the most obscured, compact starbursts and AGNs in the local universe today. The spatially resolved [C ii] line is strikingly uniform and very broad, 500-600 km s-1 wide, extending throughout the entire galaxy over about 2.5 kpc, with modest shear. Such a large, homogeneous velocity dispersion indicates a highly turbulent medium. W2246-0526 is unstable in terms of the energy and momentum that are being injected into the ISM, strongly suggesting that the gas is being blown away from the system isotropically, likely reflecting a cathartic state on its road to becoming an unobscured quasar. W2246-0526 provides an extraordinary laboratory to study and model the properties and kinematics of gas in an extreme environment under strong feedback, at a time when the universe was 1/10 of its current age: a system pushing the limits that can be reached during galaxy formation.

  17. LUMINOUS X-RAY ACTIVE GALACTIC NUCLEI IN CLUSTERS OF GALAXIES

    SciTech Connect

    Koulouridis, E.; Plionis, M.

    2010-05-10

    We present a study of X-ray active galactic nucleus (AGN) overdensities in 16 Abell clusters, within the redshift range 0.073 < z < 0.279, in order to investigate the effect of the hot inter-cluster environment on the triggering of the AGN phenomenon. The X-ray AGN overdensities, with respect to the field expectations, were estimated for sources with L{sub x} {>=} 10{sup 42} erg s{sup -1} (at the redshift of the clusters) and within an area of 1 h {sup -1} {sub 72} Mpc radius (excluding the core). To investigate the presence or absence of a true enhancement of luminous X-ray AGNs in the cluster area, we also derived the corresponding optical galaxy overdensities, using a suitable range of r-band magnitudes. We always find the latter to be significantly higher (and only in two cases roughly equal) with respect to the corresponding X-ray overdensities. Over the whole cluster sample, the mean X-ray point-source overdensity is a factor of {approx}4 less than that corresponding to bright optical galaxies, a difference which is significant at a >0.995 level, as indicated by an appropriate student's t-test. We conclude that the triggering of luminous X-ray AGNs in rich clusters is strongly suppressed. Furthermore, searching for optical Sloan Digital Sky Survey counterparts of all the X-ray sources, associated with our clusters, we found that about half appear to be background QSOs, while others are background and foreground AGNs or stars. The true overdensity of X-ray point sources, associated with the clusters, is therefore even smaller than what our statistical approach revealed.

  18. EXPLAINING THE [C II]157.7 {mu}m DEFICIT IN LUMINOUS INFRARED GALAXIES-FIRST RESULTS FROM A HERSCHEL/PACS STUDY OF THE GOALS SAMPLE

    SciTech Connect

    Diaz-Santos, T.; Armus, L.; Howell, J. H.; Surace, J. A.; Charmandaris, V.; Murphy, E. J.; Haan, S.; Inami, H.; Malhotra, S.; Meijerink, R.; Stacey, G.; Petric, A. O.; Lu, N.; Veilleux, S.; Van der Werf, P. P.; Lord, S.; Appleton, P.; and others

    2013-09-01

    We present the first results of a survey of the [C II]157.7 {mu}m emission line in 241 luminous infrared galaxies (LIRGs) comprising the Great Observatories All-sky LIRG Survey (GOALS) sample, obtained with the PACS instrument on board the Herschel Space Observatory. The [C II] luminosities, L{sub [C{sub II]}}, of the LIRGs in GOALS range from {approx}10{sup 7} to 2 Multiplication-Sign 10{sup 9} L{sub Sun }. We find that LIRGs show a tight correlation of [C II]/FIR with far-IR (FIR) flux density ratios, with a strong negative trend spanning from {approx}10{sup -2} to 10{sup -4}, as the average temperature of dust increases. We find correlations between the [C II]/FIR ratio and the strength of the 9.7 {mu}m silicate absorption feature as well as with the luminosity surface density of the mid-IR emitting region ({Sigma}{sub MIR}), suggesting that warmer, more compact starbursts have substantially smaller [C II]/FIR ratios. Pure star-forming LIRGs have a mean [C II]/FIR {approx} 4 Multiplication-Sign 10{sup -3}, while galaxies with low polycyclic aromatic hydrocarbon (PAH) equivalent widths (EWs), indicative of the presence of active galactic nuclei (AGNs), span the full range in [C II]/FIR. However, we show that even when only pure star-forming galaxies are considered, the [C II]/FIR ratio still drops by an order of magnitude, from 10{sup -2} to 10{sup -3}, with {Sigma}{sub MIR} and {Sigma}{sub IR}, implying that the [C II]157.7 {mu}m luminosity is not a good indicator of the star formation rate (SFR) for most local LIRGs, for it does not scale linearly with the warm dust emission most likely associated to the youngest stars. Moreover, even in LIRGs in which we detect an AGN in the mid-IR, the majority (2/3) of galaxies show [C II]/FIR {>=} 10{sup -3} typical of high 6.2 {mu}m PAH EW sources, suggesting that most AGNs do not contribute significantly to the FIR emission. We provide an empirical relation between the [C II]/FIR and the specific SFR for star

  19. Kinematics of the ionized gas around ultra-luminous X-ray sources in nearby spiral galaxies.

    NASA Astrophysics Data System (ADS)

    Fuentes-Carrera, Isaura L.; Sánchez Cruces, Mónica; Rosado, Margarita; Benitez-Benitez, Claudia; Salinas-Martínez, Alfredo; Aguilera, Verónica; Cruz-Reyes, Mariana

    2016-07-01

    We present scanning Fabry-Perot observations of the ionized gas surrounding ultra-luminous X-ray sources in four nearby spiral galaxies. We identify non-circular motions that may be associated with either isotropically or beamed expanding gas. Most of the sources observed show asymmetrical distribution of the ionized emission as well as asymmetrical distribution of gas motions. We also study the location of these sources in the context of the whole galaxy in different wavelengths. This work is part of an analysis to determine the nature of these sources and their correlation (if any) with the kinematics of host galaxy.

  20. VizieR Online Data Catalog: Luminous X-ray candidates within D25 of galaxies (Gong+, 2016)

    NASA Astrophysics Data System (ADS)

    Gong, H.; Liu, J.; Maccarone, T.

    2016-02-01

    Using Chandra archive data we conduct a thorough survey of luminous X-ray sources. We directly analyze about 9400 ACIS Observations and cross-correlate the X-ray sources with 77000 galaxies within 250Mpc. The final catalog includes 119 unique luminous X-ray source candidates with LX>3x1040erg/s from 93 galaxies or 41 HLX candidates with LX>1x1041erg/s from 35 galaxies. We derive a moderate contamination rate due to foreground or background sources. We also cross-correlate the catalog with FIRST, perform variability and periodicity tests, and analyze one HLX candidate in particular. Our catalog could be a starting point to perform follow-up observations. (2 data files).

  1. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Luminous Red Galaxy Target Selection

    NASA Astrophysics Data System (ADS)

    Prakash, Abhishek; Licquia, Timothy C.; Newman, Jeffrey A.; Ross, Ashley J.; Myers, Adam D.; Dawson, Kyle S.; Kneib, Jean-Paul; Percival, Will J.; Bautista, Julian E.; Comparat, Johan; Tinker, Jeremy L.; Schlegel, David J.; Tojeiro, Rita; Ho, Shirley; Lang, Dustin; Rao, Sandhya M.; McBride, Cameron K.; Ben Zhu, Guangtun; Brownstein, Joel R.; Bailey, Stephen; Bolton, Adam S.; Delubac, Timothée; Mariappan, Vivek; Blanton, Michael R.; Reid, Beth; Schneider, Donald P.; Seo, Hee-Jong; Carnero Rosell, Aurelio; Prada, Francisco

    2016-06-01

    We describe the algorithm used to select the luminous red galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-field Infrared Survey Explorer. LRG targets are required to meet a set of color selection criteria and have z-band and i-band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS ancillary programs to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least ∼89% of the target sample yields secure redshift measurements. We also present tests of the uniformity and homogeneity of the sample, demonstrating that it should be clean enough for studies of the large-scale structure of the universe at higher redshifts than SDSS-III/BOSS LRGs reached.

  2. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: Luminous Red Galaxy Target Selection

    NASA Astrophysics Data System (ADS)

    Prakash, Abhishek; Licquia, Timothy C.; Newman, Jeffrey A.; Ross, Ashley J.; Myers, Adam D.; Dawson, Kyle S.; Kneib, Jean-Paul; Percival, Will J.; Bautista, Julian E.; Comparat, Johan; Tinker, Jeremy L.; Schlegel, David J.; Tojeiro, Rita; Ho, Shirley; Lang, Dustin; Rao, Sandhya M.; McBride, Cameron K.; Ben Zhu, Guangtun; Brownstein, Joel R.; Bailey, Stephen; Bolton, Adam S.; Delubac, Timothée; Mariappan, Vivek; Blanton, Michael R.; Reid, Beth; Schneider, Donald P.; Seo, Hee-Jong; Carnero Rosell, Aurelio; Prada, Francisco

    2016-06-01

    We describe the algorithm used to select the luminous red galaxy (LRG) sample for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV) using photometric data from both the SDSS and the Wide-field Infrared Survey Explorer. LRG targets are required to meet a set of color selection criteria and have z-band and i-band MODEL magnitudes z < 19.95 and 19.9 < i < 21.8, respectively. Our algorithm selects roughly 50 LRG targets per square degree, the great majority of which lie in the redshift range 0.6 < z < 1.0 (median redshift 0.71). We demonstrate that our methods are highly effective at eliminating stellar contamination and lower-redshift galaxies. We perform a number of tests using spectroscopic data from SDSS-III/BOSS ancillary programs to determine the redshift reliability of our target selection and its ability to meet the science requirements of eBOSS. The SDSS spectra are of high enough signal-to-noise ratio that at least ˜89% of the target sample yields secure redshift measurements. We also present tests of the uniformity and homogeneity of the sample, demonstrating that it should be clean enough for studies of the large-scale structure of the universe at higher redshifts than SDSS-III/BOSS LRGs reached.

  3. The molecular gas in Luminous Infrared Galaxies: a new emergent picture

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Padelis P.; Zhang, Zhi-Yu; Weiss, Axel; van der Werf, Paul; Isaak, Kate; Gao, Yu; Xilouris, Manolis; Greve, Thomas R.

    2013-03-01

    Results from a large, multi-J CO, 13CO, and HCN line survey of Luminous Infrared Galaxies (LIRGs: LIR≥ 1010 L⊙) in the local Universe (z≤0.1), complemented by CO J=4-3 up to J=13-12 observations from the Herschel Space Observatory (HSO), paints a new picture for the average conditions of the molecular gas of the most luminous of these galaxies with turbulence and/or large cosmic ray (CR) energy densities UCR rather than far-UV/optical photons from star-forming sites as the dominant heating sources. Especially in ULIRGs (LIR>1012 L⊙) the Photon Dominated Regions (PDRs) can encompass at most a few % of their molecular gas mass while the large UCR˜ 103 UCR, Galaxy, and the strong turbulence in these merger/starbursts, can volumetrically heat much of their molecular gas to Tkin˜ (100-200) K, unhindered by the high dust extinctions. Moreover the strong supersonic turbulence in ULIRGs relocates much of their molecular gas at much higher average densities (≥104 cm-3) than in isolated spirals (˜ 102-103 cm-3). This renders low-J CO lines incapable of constraining the properties of the bulk of the molecular gas in ULIRGs, with substantial and systematic underestimates of its mass possible when only such lines are used. Finally a comparative study of multi-J HCN lines and CO SLEDs from J=1-0 up to J=13-12 of NGC 6240 and Arp 193 offers a clear example of two merger/starbursts whose similar low-J CO SLEDs, and LIR/LCO,1-0 and LHCN, 1-0/LCO,1-0 ratios (proxies of the so-called SF efficiency and dense gas mass fraction), yield no indications about their strongly diverging CO SLEDs beyond J=4-3, and ultimately the different physical conditions in their molecular ISM. The much larger sensitivity of ALMA and its excellent site in the Atacama desert now allows the observations necessary to assess the dominant energy sources of the molecular gas and its mass in LIRGs without depending on the low-J CO lines.

  4. Evolutionary Paths along the BPT Diagram for Luminous and Ultraluminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Fiorenza, Stephanie L.; Takeuchi, Tsutomu T.; Małek, Katarzyna E.; Liu, Charles T.

    2014-04-01

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGNs) in luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs), which result from galaxy interactions and mergers and produce the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, we present and examine new spectrophotometric data for five U/LIRGs (1011 < L IR < 1013 L ⊙) within the IRAS 2 Jy Redshift Survey with 0.05 <~ z <~ 0.07. We show that our sample consists almost entirely of composite objects—thus hosting both a nuclear starburst and an AGN—using the BPT diagrams. We then show that for our sample of U/LIRGs the properties that describe their nuclear starbursts and AGNs (e.g., star formation rate, L[O III], optical D parameter, D4000, and EW(Hδ)) are independent of one another, ensuring that no biases affect correlations between these parameters and the object locations on the BPT diagrams. Finally, we derive evolutionary paths on the BPT diagram involving {[N\\,{\\scriptsize{II}}]/H\\alpha } that are based on how these parameters vary between two U/LIRGs positioned at the end-points of these paths. The U/LIRGs at the end-points of a given path represent the beginning and end states of a U/LIRG evolving along that path. These paths may be able to specifically explain how all local U/LIRGs evolve along the BPT diagram, and serve as a starting point for future quantitative analysis on the evolution of U/LIRGs.

  5. Cross-correlation of the extragalactic gamma-ray background with luminous red galaxies

    NASA Astrophysics Data System (ADS)

    Shirasaki, Masato; Horiuchi, Shunsaku; Yoshida, Naoki

    2015-12-01

    Measurements of the cross-correlation between the extragalactic gamma-ray background (EGB) and large-scale structure provide a novel probe of dark matter on extragalactic scales. We focus on luminous red galaxies (LRGs) as optimal targets to search for the signal of dark matter annihilation. We measure the cross-correlation function of the EGB taken from the Fermi Large Area Telescope with the LRGs from the Sloan Digital Sky Survey. Statistical errors are calculated using a large set of realistic mock LRG catalogs. The amplitude of the measured cross-correlation is consistent with null detection. Based on an accurate theoretical model of the distribution of dark matter associated with LRGs, we exclude dark matter annihilation cross-sections over ⟨σ v ⟩=3 ×10-25- 1 0-26 cm3 s-1 for a 10 GeV dark matter. We further investigate systematic effects due to uncertainties in the Galactic gamma-ray foreground emission, which we find to be an order of magnitude smaller than the current statistical uncertainty. We also estimate the contamination from astrophysical sources in the LRGs by using known scaling relations between gamma-ray luminosity and star-formation rate, finding them to be negligibly small. Based on these results, we suggest that LRGs remain ideal targets for probing dark matter annihilation with future EGB measurement and galaxy surveys. Increasing the number of LRGs in upcoming galaxy surveys such as LSST would lead to big improvements of factors of several in sensitivity.

  6. Modelling the colour evolution of luminous red galaxies - improvements with empirical stellar spectra

    NASA Astrophysics Data System (ADS)

    Maraston, Claudia; Strömbäck, G.; Thomas, D.; Wake, D. A.; Nichol, R. C.

    2009-03-01

    Predicting the colours of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey has been a long-standing problem. The g, r, i colours of LRGs are inconsistent with stellar population models over the redshift range 0.1 < z < 0.7. We provide a solution to this problem, through a combination of new astrophysics and a fundamental change to the stellar population modelling. We find that the use of the empirical library of Pickles, in place of theoretical libraries based on model atmosphere calculations, modifies the evolutionary population synthesis predicted colours exactly in the way suggested by the data. The reason is a lower (normalized) flux in the empirical libraries, with respect to the theoretical ones, in the wavelength range 5500-6500 Å. The effect increases with decreasing effective temperature roughly independently of gravity. We also find that other recent libraries such as MILES and STELIB behave the same way. We further verified that [α/Fe] effects on stellar spectra cannot substitute the effect of the empirical library because they make both colours bluer. The astrophysical part of our solution regards the composition of the stellar populations of these massive LRGs. We find that on top of the previous effect one needs to consider a model in which ~3 per cent of the stellar mass is in old metal-poor stars. Other solutions such as an overall slightly subsolar metallicity or young stellar populations can be ruled out by the data. The percentage of the metal-poor subpopulation may be affected by the consideration of abundance-ratio effects though in the framework of present calculations the metal-poor option is favoured. Our new model provides a better fit to the colours of LRGs and gives new insight into the formation histories of these most massive galaxies. The new model will also improve the k- and evolutionary corrections for LRGs which are critical for fully exploiting present and future galaxy surveys.

  7. Evolutionary paths along the BPT diagram for luminous and ultraluminous infrared galaxies

    SciTech Connect

    Fiorenza, Stephanie L.; Takeuchi, Tsutomu T.; Małek, Katarzyna E.; Liu, Charles T.

    2014-04-01

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGNs) in luminous infrared galaxies (LIRGs) and ultraluminous infrared galaxies (ULIRGs), which result from galaxy interactions and mergers and produce the bulk of their radiation as infrared (IR) emission, is not well understood. To this effort, we present and examine new spectrophotometric data for five U/LIRGs (10{sup 11} < L {sub IR} < 10{sup 13} L {sub ☉}) within the IRAS 2 Jy Redshift Survey with 0.05 ≲ z ≲ 0.07. We show that our sample consists almost entirely of composite objects—thus hosting both a nuclear starburst and an AGN—using the BPT diagrams. We then show that for our sample of U/LIRGs the properties that describe their nuclear starbursts and AGNs (e.g., star formation rate, L[O III], optical D parameter, D4000, and EW(Hδ)) are independent of one another, ensuring that no biases affect correlations between these parameters and the object locations on the BPT diagrams. Finally, we derive evolutionary paths on the BPT diagram involving [N II]/Hα that are based on how these parameters vary between two U/LIRGs positioned at the end-points of these paths. The U/LIRGs at the end-points of a given path represent the beginning and end states of a U/LIRG evolving along that path. These paths may be able to specifically explain how all local U/LIRGs evolve along the BPT diagram, and serve as a starting point for future quantitative analysis on the evolution of U/LIRGs.

  8. Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes

    NASA Astrophysics Data System (ADS)

    Masaki, Shogo; Hikage, Chiaki; Takada, Masahiro; Spergel, David N.; Sugiyama, Naoshi

    2013-08-01

    We develop a novel abundance matching method to construct a mock catalogue of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogues of haloes and subhaloes in N-body simulations for a Λ-dominated cold dark matter model. Motivated by observations suggesting that LRGs are passively evolving, massive early-type galaxies with a typical age ≳5 Gyr, we assume that simulated haloes at z = 2 (z2-halo) are progenitors for LRG-host subhaloes observed today, and we label the most tightly bound particles in each progenitor z2-halo as LRG `stars'. We then identify the subhaloes containing these stars to z = 0.3 (SDSS redshift) in descending order of the masses of z2-haloes until the comoving number density of the matched subhaloes becomes comparable to the measured number density of SDSS LRGs, bar{n}_LRG=10^{-4} h^3 Mpc^{-3}. Once the above prescription is determined, our only free parameter is the number density of haloes identified at z = 2 and this parameter is fixed to match the observed number density at z = 0.3. By tracing subsequent merging and assembly histories of each progenitor z2-halo, we can directly compute, from the mock catalogue, the distributions of central and satellite LRGs and their internal motions in each host halo at z = 0.3. While the SDSS LRGs are galaxies selected by the magnitude and colour cuts from the SDSS images and are not necessarily a stellar-mass-selected sample, our mock catalogue reproduces a host of SDSS measurements: the halo occupation distribution for central and satellite LRGs, the projected autocorrelation function of LRGs, the cross-correlation of LRGs with shapes of background galaxies (LRG-galaxy weak lensing) and the non-linear redshift-space distortion effect, the Finger-of-God effect, in the angle-averaged redshift-space power spectrum. The mock catalogue generated based on our method can be used for removing or calibrating systematic errors in the cosmological interpretation of LRG clustering

  9. THE HOST GALAXY OF THE SUPER-LUMINOUS SN 2010gx AND LIMITS ON EXPLOSIVE {sup 56}Ni PRODUCTION

    SciTech Connect

    Chen, Ting-Wan; Smartt, Stephen J.; Kotak, Rubina; McCrum, Matt; Fraser, Morgan; Bresolin, Fabio; Kudritzki, Rolf-Peter; Pastorello, Andrea; Valenti, Stefano

    2013-02-01

    Super-luminous supernovae have a tendency to occur in faint host galaxies which are likely to have low mass and low metallicity. While these extremely luminous explosions have been observed from z = 0.1 to 1.55, the closest explosions allow more detailed investigations of their host galaxies. We present a detailed analysis of the host galaxy of SN 2010gx (z = 0.23), one of the best studied super-luminous type Ic supernovae. The host is a dwarf galaxy (M{sub g} = -17.42 {+-} 0.17) with a high specific star formation rate. It has a remarkably low metallicity of 12 + log (O/H) = 7.5 {+-} 0.1 dex as determined from the detection of the [O III] {lambda}4363 line. This is the first reliable metallicity determination of a super-luminous stripped-envelope supernova host. We collected deep multi-epoch imaging with Gemini + GMOS between 240 and 560 days after explosion to search for any sign of radioactive {sup 56}Ni, which might provide further insights on the explosion mechanism and the progenitor's nature. We reach griz magnitudes of m{sub AB} {approx} 26, but do not detect SN 2010gx at these epochs. The limit implies that any {sup 56}Ni production was similar to or below that of SN 1998bw (a luminous type Ic SN that produced around 0.4 M{sub Sun} of {sup 56}Ni). The low volumetric rates of these supernovae ({approx}10{sup -4} of the core-collapse population) could be qualitatively matched if the explosion mechanism requires a combination of low-metallicity (below 0.2 Z{sub Sun }), high progenitor mass (>60 M{sub Sun }) and high rotation rate (fastest 10% of rotators).

  10. MOLECULAR GAS IN LENSED z >2 QUASAR HOST GALAXIES AND THE STAR FORMATION LAW FOR GALAXIES WITH LUMINOUS ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Riechers, Dominik A.

    2011-04-01

    We report the detection of luminous CO(J = 2{yields}1), CO(J = 3{yields}2), and CO(J = 4{yields}3) emission in the strongly lensed high-redshift quasars B1938+666 (z = 2.059), HE 0230-2130 (z = 2.166), HE 1104-1805 (z = 2.322), and B1359+154 (z = 3.240), using the Combined Array for Research in Millimeter-wave Astronomy. B1938+666 was identified in a 'blind' CO redshift search, demonstrating the feasibility of such investigations with millimeter interferometers. These galaxies are lensing-amplified by factors of {mu}{sub L} {approx_equal} 11-170, and thus allow us to probe the molecular gas in intrinsically fainter galaxies than currently possible without the aid of gravitational lensing. We report lensing-corrected intrinsic CO line luminosities of L'{sub CO} = 0.65-21x10{sup 9} K km s{sup -1} pc{sup 2}, translating to H{sub 2} masses of M(H{sub 2}) = 0.52-17 x 10{sup 9} ({alpha}{sub CO}/0.8) M{sub sun}. To investigate whether or not the active galactic nucleus (AGN) in luminous quasars substantially contributes to L{sub FIR}, we study the L'{sub CO}-L{sub FIR} relation for quasars relative to galaxies without a luminous AGN as a function of redshift. We find no substantial differences between submillimeter galaxies and high-z quasars, but marginal evidence for an excess in L{sub FIR} in nearby low-L{sub FIR} AGN galaxies. This may suggest that an AGN contribution to L{sub FIR} is significant in systems with relatively low gas and dust content, but only minor in the most far-infrared-luminous galaxies (in which L{sub FIR} is dominated by star formation).

  11. SPECTROSCOPY OF LUMINOUS z > 7 GALAXY CANDIDATES AND SOURCES OF CONTAMINATION IN z > 7 GALAXY SEARCHES

    SciTech Connect

    Capak, P.; Jullo, E.; Mobasher, B.; Scoville, N. Z.; Salvato, M.; McCracken, H.; Ilbert, O.; Menendez-Delmestre, K.; Aussel, H.; LeFloch, E.; Carilli, C.; Civano, F.; Elvis, M.; Giavalisco, M.; Kartaltepe, J.; Sanders, D. B.; Leauthaud, A.; Koekemoer, A. M.; Kneib, J.-P.; Schinnerer, E.

    2011-04-01

    We present three bright z{sup +}-dropout candidates selected from deep near-infrared (NIR) imaging of the COSMOS 2 deg{sup 2} field. All three objects match the 0.8-8 {mu}m colors of other published z > 7 candidates but are 3 mag brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02 {mu}m with Keck-DEIMOS and all three covering 0.94-1.10 {mu}m and 1.52-1.80 {mu}m with Keck-NIRSPEC detects weak spectral features tentatively identified as Ly{alpha} at z = 6.95 and z = 7.69 in two of the objects. The third object is placed at z {approx} 1.6 based on a 24 {mu}m and weak optical detection. A comparison with the spectral energy distributions of known z < 7 galaxies, including objects with strong spectral lines, large extinction, and large systematic uncertainties in the photometry, yields no objects with similar colors. However, the {lambda} > 1 {mu}m properties of all three objects can be matched to optically detected sources with photometric redshifts at z {approx} 1.8, so the non-detection in the i {sup +} and z {sup +} bands is the primary factor which favors a z > 7 solution. If any of these objects are at z {approx} 7, the bright end of the luminosity function is significantly higher at z > 7 than suggested by previous studies, but consistent within the statistical uncertainty and the dark matter halo distribution. If these objects are at low redshift, the Lyman break selection must be contaminated by a previously unknown population of low-redshift objects with very strong breaks in their broadband spectral energy distributions and blue NIR colors. The implications of this result on luminosity function evolution at high redshift are discussed. We show that the primary limitation of z > 7 galaxy searches with broad filters is the depth of the available optical data.

  12. The molecular gas in luminous infrared galaxies - I. CO lines, extreme physical conditions and their drivers

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Padelis P.; van der Werf, Paul P.; Xilouris, E. M.; Isaak, K. G.; Gao, Yu; Mühle, S.

    2012-11-01

    We report results from a large molecular line survey of luminous infrared galaxies (LIRGs; L IR ≳1011 L) in the local Universe (z ≤ 0.1), conducted during the last decade with the James Clerk Maxwell Telescope and the IRAM 30-m telescope. This work presents the CO and 13CO line data for 36 galaxies, further augmented by multi-J total CO line luminosities available for other infrared (IR) bright galaxies from the literature. This yields a combined sample of N = 70 galaxies with the star formation (SF) powered fraction of their IR luminosities spanning L IR (*)˜(1010-2×1012) L and a wide range of morphologies. Simple comparisons of their available CO spectral line energy distributions (SLEDs) with local ones, as well as radiative transfer models, discern a surprisingly wide range of average interstellar medium (ISM) conditions, with most of the surprises found in the high-excitation regime. These take the form of global CO SLEDs dominated by a very warm (Tkin ≳100 K) and dense (n ≥ 104 cm-3) gas phase, involving galaxy-sized (˜(few) × 109 M⊙) gas mass reservoirs under conditions that are typically found only for ˜(1-3) per cent of mass per typical SF molecular cloud in the Galaxy. Furthermore, some of the highest excitation CO SLEDs are found in ultraluminous infrared galaxies (ULIRGs; LIR ≥ 1012 L⊙) and surpass even those found solely in compact SF-powered hot spots in Galactic molecular clouds. Strong supersonic turbulence and high cosmic ray energy densities rather than far-ultraviolet/optical photons or supernova remnant induced shocks from individual SF sites can globally warm the large amounts of dense gas found in these merger-driven starbursts and easily power their extraordinary CO line excitation. This exciting possibility can now be systematically investigated with Herschel and the Atacama Large Milimeter Array (ALMA). As expected for an IR-selected (and thus SF rate selected) galaxy sample, only few 'cold' CO SLEDs are found, and for

  13. Host Galaxies of Luminous Type 2 Quasars at z ~ 0.5

    NASA Astrophysics Data System (ADS)

    Liu, Xin; Zakamska, Nadia L.; Greene, Jenny E.; Strauss, Michael A.; Krolik, Julian H.; Heckman, Timothy M.

    2009-09-01

    We present deep Gemini GMOS optical spectroscopy of nine luminous quasars at redshifts z ~ 0.5, drawn from the Sloan Digital Sky Survey type 2 quasar sample. Our targets were selected to have high intrinsic luminosities (MV < -26 mag) as indicated by the [O III] λ5007 Å emission-line luminosity (L [O III]). Our sample has a median black hole mass of ~108.8 M sun inferred assuming the local M BH-σ* relation and a median Eddington ratio of ~0.7, using stellar velocity dispersions σ* measured from the G band. We estimate the contamination of the stellar continuum from scattered quasar light based on the strength of broad Hβ, and provide an empirical calibration of the contamination as a function of L [O III]; the scattered-light fraction is ~30% of L 5100 for objects with L [O III] = 109.5 L sun. Population synthesis indicates that young poststarburst populations (<0.1 Gyr) are prevalent in luminous type 2 quasars, in addition to a relatively old population (>1 Gyr) which dominates the stellar mass. Broad emission complexes around He II λ4686 Å with luminosities up to 108.3 L sun are unambiguously detected in three out of the nine targets, indicative of Wolf-Rayet (WR) populations. Population synthesis shows that ~5 Myr poststarburst populations contribute substantially to the luminosities (>50% of L 5100) of all three objects with WR detections. We find two objects with double cores and four with close companions. Our results may suggest that luminous type 2 quasars trace an early stage of galaxy interaction, perhaps responsible for both the quasar and the starburst activity. Based, in part, on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada

  14. HIGHLY IONIZED PLASMA IN THE HALO OF A LUMINOUS SPIRAL GALAXY NEAR z = 0.225

    SciTech Connect

    Narayanan, Anand; Savage, Blair D.; Wakker, Bart P. E-mail: savage@astro.wisc.ed

    2010-04-01

    We present analyses of the physical conditions in the z(O{sub VI})=0.22496 and z(O{sub VI})=0.22638 multiphase absorption systems detected in the ultraviolet Hubble Space Telescope/STIS and FUSE spectra of the quasar H 1821+643 (m{sub V} = 14.2, z{sub em} = 0.297). Both absorbers are likely associated with the extended halo of a {approx}2L*{sub B} Sbc-Sc galaxy situated at a projected distance of {approx}116 h {sup -1}{sub 71} kpc from the sight line. The z = 0.22496 absorber is detected in C II, C III, C IV, O III, O VI, Si II, Si III, and H I (Ly alpha-Lytheta) at >3sigma significance. The components of Si III and Si II are narrow with implied temperatures of T {approx}< 3 x 10{sup 4} K. The low and intermediate ions in this absorber are consistent with an origin in a T {approx} 10{sup 4} K photoionized gas with [Si/H] and [C/H] of {approx}-0.6 dex. In contrast, the broader O VI absorption is likely produced in collisionally ionized plasma under nonequilibrium conditions. The z(O{sub VI})=0.22638 system has broad Ly alpha (BLA) and C III absorption offset by v = -53 km s{sup -1} from O VI. The H I and C III line widths for the BLA imply T = 1.1 x 10{sup 5} K. For non-equilibrium cooling we obtain [C/H] {approx}-1.5 dex and N(H) = 3.2 x 10{sup 18} cm{sup -2} in the BLA. The O VI, offset from the BLA with no detected H I or C III, is likely collisionally ionized at T {approx} 3 x 10{sup 5} K. From the observed multiphase properties and the proximity to a luminous galaxy, we propose that the z = 0.22496 absorber is an extragalactic analog of a highly ionized Galactic HVC, in which the O VI is produced in transition temperature plasma (T {approx} 10{sup 5} K) at the interface layers between the warm (T < 5 x 10{sup 4} K) HVC gas phase and the hot (T {approx}> 10{sup 6} K) coronal halo of the galaxy. The z = 0.22638 O VI-BLA absorber could be tracing a cooling condensing fragment in the nearby galaxy's hot gaseous halo.

  15. Constraining the Luminous Red Galaxy Halo Occupation Distribution Using Counts-In-Cylinders

    NASA Astrophysics Data System (ADS)

    Reid, Beth A.; Spergel, David N.

    2009-06-01

    The low number density of the Sloan Digital Sky Survey (SDSS) luminous red galaxies (LRGs) suggests that LRGs occupying the same dark matter halo can be separated from pairs occupying distinct dark matter halos with high fidelity. We present a new technique, Counts-in-Cylinders (CiC), to constrain the parameters of the satellite contribution to the LRG halo occupation distribution once the parameters of the central galaxy contribution have been fixed. For a fiber-collision-corrected SDSS spectroscopic LRG subsample at 0.16 < z < 0.36, we find that the CiC multiplicity function is fitted by a halo model where the average number of satellites in a halo of mass M is = ((M - M cut)/M 1)α with M cut = 5.0+1.5 -1.3(+2.9 -2.6) × 1013 M sun, M 1 = 4.95+0.37 -0.26(+0.79 -0.53) × 1014 M sun, and α = 1.035+0.10 -0.17(+0.24 -0.31) at the 68% and 95% confidence levels using a WMAP3 cosmology and z = 0.2 halo catalog. Our method tightly constrains the fraction of LRGs that are satellite galaxies, 6.36+0.38 -0.39%, and the combination M cut/1014 M sun + α = 1.53+0.08 -0.09 at the 95% confidence level, though these constraints may be relaxed when cosmological parameters and the central galaxy parameters are allowed to vary simultaneously. We also find that mocks based on a halo catalog produced by a spherical overdensity finder reproduce both the measured CiC multiplicity function and the projected correlation function, while mocks based on a Friends-of-Friends halo catalog has a deficit of close pairs at ~1 h -1 Mpc separations. Because the CiC method relies on higher order statistics of close pairs, it is robust to the choice of halo finder, and yields mock catalogs reproducing Finger-of-God (FOG) features in the observations probed by the CiC group multiplicity function. In a companion paper, we will apply this technique to optimize FOG compression to eliminate the one-halo contribution to the LRG power spectrum.

  16. The Relation Between Accretion Rate And Jet Power in X-Ray Luminous Elliptical Galaxies

    SciTech Connect

    Allen, Steven W.; Dunn, R.J.H.; Fabian, A.C.; Taylor, G.B.; Reynolds, C.S.; /Maryland U.

    2006-03-10

    Using Chandra X-ray observations of nine nearby, X-ray luminous elliptical galaxies with good optical velocity dispersion measurements, we show that a tight correlation exists between the Bondi accretion rates calculated from the observed gas temperature and density profiles and estimated black hole masses, and the power emerging from these systems in relativistic jets. The jet powers, which are inferred from the energies and timescales required to inflate cavities observed in the surrounding X-ray emitting gas, can be related to the accretion rates using a power law model of the form log (P{sub Bondi}/10{sup 43} erg s{sup -1}) = A + B log (P{sub jet}/10{sup 43} erg s{sup -1}), with A = 0.62 {+-} 0.15 and B = 0.77 {+-} 0.18. Our results show that a significant fraction of the energy associated with the rest mass of material entering the Bondi accretion radius (2.4{sub -0.7}{sup +1.0} per cent, for P{sub jet} = 10{sup 43} erg s{sup -1}) eventually emerges in the relativistic jets. Our results have significant implications for studies of accretion, jet formation and galaxy formation. The observed tight correlation suggests that the Bondi formulae provide a reasonable description of the accretion process in these systems, despite the likely presence of magnetic pressure and angular momentum in the accreting gas. The similarity of the P{sub Bondi} and P{sub jet} values argues that a significant fraction of the matter entering the accretion radius flows down to regions close to the black holes, where the jets are presumably formed. The tight correlation between P{sub Bondi} and P{sub jet} also suggests that the accretion flows are approximately stable over timescales of a few million years. Our results show that the black hole ''engines'' at the hearts of large elliptical galaxies and groups feed back sufficient energy to stem cooling and star formation, leading naturally to the observed exponential cut off at the bright end of the galaxy luminosity function.

  17. Interferometric follow-up of WISE hyper-luminous hot, dust-obscured galaxies

    SciTech Connect

    Wu, Jingwen; Wright, Edward L.; Bussmann, R. Shane; Tsai, Chao-Wei; Eisenhardt, Peter R. M.; Stern, Daniel; Moustakas, Leonidas; Petric, Andreea; Blain, Andrew; Bridge, Carrie R.; Benford, Dominic J.; Assef, Roberto J.; Gelino, Christopher R.

    2014-09-20

    The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 μm and 4.6 μm) but are bright in the two redder passbands of WISE (12 μm and 22 μm). We report on initial follow-up observations of three of these hot, dust-obscured galaxies, or Hot DOGs, using the Combined Array for Research in Millimeter-wave Astronomy and the Submillimeter Array interferometer arrays at submillimeter/millimeter wavelengths. We report continuum detections at ∼1.3 mm of two sources (WISE J014946.17+235014.5 and WISE J223810.20+265319.7, hereafter W0149+2350 and W2238+2653, respectively), and upper limits to CO line emission at 3 mm in the observed frame for two sources (W0149+2350 and WISE J181417.29+341224.8, hereafter W1814+3412). The 1.3 mm continuum images have a resolution of 1''-2'' and are consistent with single point sources. We estimate the masses of cold dust are 2.0 × 10{sup 8} M {sub ☉} for W0149+2350 and 3.9 × 10{sup 8} M {sub ☉} for W2238+2653, comparable to cold dust masses of luminous quasars. We obtain 2σ upper limits to the molecular gas masses traced by CO, which are 3.3 × 10{sup 10} M {sub ☉} and 2.3 × 10{sup 10} M {sub ☉} for W0149+2350 and W1814+3412, respectively. We also present high-resolution, near-IR imaging with the WFC3 on the Hubble Space Telescope for W0149+2653 and with NIRC2 on Keck for W2238+2653. The near-IR images show morphological structure dominated by a single, centrally condensed source with effective radius less than 4 kpc. No signs of gravitational lensing are evident.

  18. Unravelling the morphologies of luminous compact galaxies using the HST/ACS GOODS survey

    NASA Astrophysics Data System (ADS)

    Rawat, A.; Kembhavi, A. K.; Hammer, F.; Flores, H.; Barway, S.

    2007-07-01

    Context: Luminous Compact Galaxies (LCGs) (MB ≤ -20, R1/2 ≤ 4.5 kpc and EW0(OII) ≥ 15 Å) constitute one of the most rapidly evolving galaxy populations over the last ~8 Gyr history of the universe. Due to their inherently compact sizes, any detailed quantitative analysis of their morphologies has proved to be difficult in the past. Hence, the morphologies and thereby the local counterparts of these enigmatic sources have been hotly debated. Aims: Our aim is to use the high angular resolution, deep, multiband HST/ACS imaging data, from the HST/ACS GOODS survey, to study the quantitative morphology of a complete sample of LCGs in the redshift range 0.5≤ z ≤1.2. Methods: We have derived structural parameters for a representative sample of 39 LCGs selected from the GOODS-S HST/ACS field, using full 2-dimensional surface brightness profile fitting of the galaxy images in each of the four filters available. B435W-z850LP color maps are constructed for the sample to aid in the morphological classification. We then use the rest frame B band bulge flux fraction (B/T) to determine the morphological class of galaxies which are well fit by a bulge+disk two dimensional structure. Mergers were essentially identified visually by the presence of multiple maxima of comparable intensity in the rest frame B band images, aided by the color maps to distinguish them from HII regions. We also make use of the Spitzer 24 μ m source catalog of sources in the CDFS to derive the dust enshrouded star formation rates (SFR) for some of the sample LCGs Results: We derive the following morphological mix for our sample of intermediate redshift LCGs: Mergers: ~36%, Disk dominated: ~22%, S0: ~20%, Early types: ~7%, Irr/tadpole: ~15%. We establish that our sample LCGs are intermediate mass objects with stellar mass ranging from 9.44 ≤ Log10(M/M⊙) ≤ 10.96, with a median mass of Log10(M/M⊙)=10.32. We also derive SFR values ranging from a few to ~65 M⊙/year as expected for this class

  19. The Discovery and Characterization of Surprisingly Luminous Galaxy Candidates at 9-10: The Power of Combining HST and Spitzer

    NASA Astrophysics Data System (ADS)

    Illingworth, Garth D.; Oesch, P.; Bouwens, R.; Labbe, I.; XDF/HUDF09 Team

    2014-01-01

    Deep observations with the WFC3/IR camera on HST have pushed the frontier for galaxies in the young universe to 9-11, just ~450 Myr from the Big Bang at the heart of the reionization epoch. However, until recently only a small number of intrinsically very faint galaxies had been identified at these redshifts from extremely deep WFC3/IR data in the XDF/HUDF and the GOODS-South field and from the CLASH cluster survey. This changed with our recent analysis of the completed CANDELS survey data over the GOODS-North/HDF-N field. We discovered four surprisingly bright Lyman-break galaxy candidates at 9-10, the brightest of which has a most probable redshift of 10.2. These sources are a factor ~10-20x more luminous than any previous candidate at redshifts 9-10. The high number of such luminous sources suggests that star-formation was highly stochastic in the very early universe resulting in large field-to-field variance. Furthermore, three of these bright candidates show significant detections in Spitzer/IRAC, substantially enhancing the probability that these galaxies are at 9-10. The IRAC data probes the rest-frame optical light and indicates that these sources already had a stellar mass of 10^9 Msol at a cosmic time of only 450-500 Myr. While the overall star formation rate density of galaxies with SFR>0.7 Msol/yr has been shown to increase rapidly in just 200 Myr from 10 to 8, the discovery of these luminous sources has very promising implications for the detection of galaxies at times significantly earlier than 450 Myr with JWST.

  20. Spectroscopy of Luminous z > 7 Galaxy Candidates and Sources of Contamination in z > 7 Galaxy Searches

    NASA Astrophysics Data System (ADS)

    Capak, P.; Mobasher, B.; Scoville, N. Z.; McCracken, H.; Ilbert, O.; Salvato, M.; Menéndez-Delmestre, K.; Aussel, H.; Carilli, C.; Civano, F.; Elvis, M.; Giavalisco, M.; Jullo, E.; Kartaltepe, J.; Leauthaud, A.; Koekemoer, A. M.; Kneib, J.-P.; LeFloch, E.; Sanders, D. B.; Schinnerer, E.; Shioya, Y.; Shopbell, P.; Tanaguchi, Y.; Thompson, D.; Willott, C. J.

    2011-04-01

    We present three bright z +-dropout candidates selected from deep near-infrared (NIR) imaging of the COSMOS 2 deg2 field. All three objects match the 0.8-8 μm colors of other published z > 7 candidates but are 3 mag brighter, facilitating further study. Deep spectroscopy of two of the candidates covering 0.64-1.02 μm with Keck-DEIMOS and all three covering 0.94-1.10 μm and 1.52-1.80 μm with Keck-NIRSPEC detects weak spectral features tentatively identified as Lyα at z = 6.95 and z = 7.69 in two of the objects. The third object is placed at z ~ 1.6 based on a 24 μm and weak optical detection. A comparison with the spectral energy distributions of known z < 7 galaxies, including objects with strong spectral lines, large extinction, and large systematic uncertainties in the photometry, yields no objects with similar colors. However, the λ > 1 μm properties of all three objects can be matched to optically detected sources with photometric redshifts at z ~ 1.8, so the non-detection in the i + and z + bands is the primary factor which favors a z > 7 solution. If any of these objects are at z ~ 7, the bright end of the luminosity function is significantly higher at z > 7 than suggested by previous studies, but consistent within the statistical uncertainty and the dark matter halo distribution. If these objects are at low redshift, the Lyman break selection must be contaminated by a previously unknown population of low-redshift objects with very strong breaks in their broadband spectral energy distributions and blue NIR colors. The implications of this result on luminosity function evolution at high redshift are discussed. We show that the primary limitation of z > 7 galaxy searches with broad filters is the depth of the available optical data. Based on observations with 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

  1. Applications of the Halo Model to Large Scale Structure Measurements of the Luminous Red Galaxies

    NASA Astrophysics Data System (ADS)

    Reid, Beth A.; Spergel, D. N.; Bode, P.

    2009-01-01

    The power spectrum of density fluctuations in the evolved universe provides constraints on cosmological parameters that are complementary to the CMB and other astronomical probes. The Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy (LRG) sample probes a volume of 3 Gpc3, and systematic errors in modeling the nonlinearities limit our ability to extract information on the shape of the linear power spectrum. In Chapter 2 of this dissertation we present the technique `Counts-in-Cylinders' (CiC) and use it to measure the multiplicity function of groups of LRGs in SDSS. We use the Halo Occupation Distribution description of the galaxy-matter mapping and N-body simulations to connect this observation with constraints on the distribution of LRGs in dark matter halos. In Chapter 3 we study the effects of resolution on statistics relating to both the large and small scale distributions and motions of matter and dark matter halos. We combine these results to produce a large set of high quality mock LRG catalogs that reproduce the higher order statistics in the density field probed by the CiC technique. Using these catalogs we present a detailed analysis of the method used in Tegmark et al. 2006 to estimate the LRG power spectrum, and find that the large nonlinear correction necessary for their analysis is degenerate with changes in the linear spectrum we wish to constrain. We show that the CiC group-finding method in Chapter 2 can be used to reconstruct the underlying halo density field. The power spectrum of this field has only percent-level deviations from the underlying matter power spectrum, and will therefore provided tighter constraints on cosmological parameters. Techniques presented in this dissertation will be useful for final analysis of the SDSS LRGs and upcoming surveys probing much larger volumes. B.A.R. gratefully acknowledges support from the NSF Graduate Research Fellowship.

  2. VizieR Online Data Catalog: [NII]205um emission in local luminous IR galaxies (Zhao+, 2016)

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Lu, N.; Xu, C. K.; Gao, Y.; Lord, S. D.; Charmandaris, V.; Diaz-Santos, T.; Evans, A.; Howell, J.; Petric, A. O.; van der Werf, P. P.; Sanders, D. B.

    2016-05-01

    The primary sample studied in this paper is from the Herschel open time project Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies (OT1nlu1; PI: N. Lu). The observations were conducted with the Herschel SPIRE/FTS in its point source spectroscopy mode and high spectral resolution configuration, yielding a spectral resolution of 0.04/cm (or 1.2GHz) over the spectral coverage of 194-672um. (1 data file).

  3. redMaGiC. Selecting Luminous Red Galaxies from the DES Science Verification Data

    SciTech Connect

    Rozo, E.

    2015-07-20

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sam- ple of constant comoving density. Additionally, we demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range z ϵ [0.2,0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1Mpc)-3, and a median photo-z bias (zspec zphoto) and scatter (σz=(1 + z)) of 0.005 and 0.017 respectively.The corresponding 5σ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1% level.

  4. redMaGiC: selecting luminous red galaxies from the DES Science Verification data

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Rykoff, E. S.; Abate, A.; Bonnett, C.; Crocce, M.; Davis, C.; Hoyle, B.; Leistedt, B.; Peiris, H. V.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carollo, D.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Childress, M. J.; Cunha, C. E.; D'Andrea, C. B.; Davis, T.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Glazebrook, K.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lidman, C.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; O'Neill, C. R.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thaler, J.; Thomas, D.; Uddin, S.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.; da Costa, L. N.

    2016-09-01

    We introduce redMaGiC, an automated algorithm for selecting luminous red galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the colour cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine learning-based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalogue sampling the redshift range z ∈ [0.2, 0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1 Mpc)-3, and a median photo-z bias (zspec - zphoto) and scatter (σz/(1 + z)) of 0.005 and 0.017, respectively. The corresponding 5σ outlier fraction is 1.4 per cent. We also test our algorithm with Sloan Digital Sky Survey Data Release 8 and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1 per cent level.

  5. Faint CO Line Wings in Four Star-forming (Ultra)luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Leroy, Adam K.; Walter, Fabian; Decarli, Roberto; Bolatto, Alberto; Zschaechner, Laura; Weiss, Axel

    2015-09-01

    We report the results of a search for large velocity width, low-intensity line wings—a commonly used signature of molecular outflows—in four low redshift (ultra)luminous infrared galaxies that appear to be dominated by star formation. The targets were drawn from a sample of fourteen targets presented in Chung et al., who showed the stacked CO spectrum of the sample to exhibit 1000 km s-1-wide line wings. We obtained sensitive, wide bandwidth imaging of our targets using the IRAM Plateau de Bure Interferometer. We detect each target at very high significance but do not find the claimed line wings in these four targets. Instead, we constrain the flux in the line wings to be only a few percent. Casting our results as mass outflow rates following Cicone et al. we show them to be consistent with a picture in which very high mass loading factors preferentially occur in systems with high active galactic nucleus contributions to their bolometric luminosity. We identify one of our targets, IRAS 05083 (VII Zw 31), as a candidate molecular outflow.

  6. redMaGiC: selecting luminous red galaxies from the DES Science Verification data

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Rykoff, E. S.; Abate, A.; Bonnett, C.; Crocce, M.; Davis, C.; Hoyle, B.; Leistedt, B.; Peiris, H. V.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carollo, D.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Childress, M. J.; Cunha, C. E.; D'Andrea, C. B.; Davis, T.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Glazebrook, K.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lidman, C.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; O'Neill, C. R.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thaler, J.; Thomas, D.; Uddin, S.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.; da Costa, L. N.

    2016-09-01

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photozs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range $z\\in[0.2,0.8]$. Our fiducial sample has a comoving space density of $10^{-3}\\ (h^{-1} Mpc)^{-3}$, and a median photoz bias ($z_{spec}-z_{photo}$) and scatter $(\\sigma_z/(1+z))$ of 0.005 and 0.017 respectively. The corresponding $5\\sigma$ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photoz biases at the 0.1% level.

  7. redMaGiC: Selecting Luminous Red Galaxies from the DES Science Verification Data

    NASA Astrophysics Data System (ADS)

    Rozo, E.; Rykoff, E. S.; Abate, A.; Bonnett, C.; Crocce, M.; Davis, C.; Hoyle, B.; Leistedt, B.; Peiris, H. V.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Carollo, D.; Kind, M. Carrasco; Carretero, J.; Castander, F. J.; Childress, M. J.; Cunha, C. E.; D'Andrea, C. B.; Davis, T.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Glazebrook, K.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kim, A. G.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lidman, C.; Lima, M.; Maia, M. A. G.; March, M.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; O'Neill, C. R.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Thaler, J.; Thomas, D.; Uddin, S.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.; da Costa, L. N.

    2016-05-01

    We introduce redMaGiC, an automated algorithm for selecting Luminous Red Galaxies (LRGs). The algorithm was specifically developed to minimize photometric redshift uncertainties in photometric large-scale structure studies. redMaGiC achieves this by self-training the color-cuts necessary to produce a luminosity-thresholded LRG sample of constant comoving density. We demonstrate that redMaGiC photo-zs are very nearly as accurate as the best machine-learning based methods, yet they require minimal spectroscopic training, do not suffer from extrapolation biases, and are very nearly Gaussian. We apply our algorithm to Dark Energy Survey (DES) Science Verification (SV) data to produce a redMaGiC catalog sampling the redshift range z ∈ [0.2, 0.8]. Our fiducial sample has a comoving space density of 10-3 (h-1Mpc)-3, and a median photo-z bias (zspec - zphoto) and scatter (σz/(1 + z)) of 0.005 and 0.017 respectively. The corresponding 5σ outlier fraction is 1.4%. We also test our algorithm with Sloan Digital Sky Survey (SDSS) Data Release 8 (DR8) and Stripe 82 data, and discuss how spectroscopic training can be used to control photo-z biases at the 0.1% level.

  8. Applications of the halo model to large scale structure measurements of the Luminous Red Galaxies

    NASA Astrophysics Data System (ADS)

    Reid, Beth Ann

    The power spectrum of density fluctuations in the evolved universe provides constraints on cosmological parameters that are complementary to cosmic microwave background and other astronomical probes. The Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy (LRG) sample probes a volume of ~ 3 (Gpc) 3 , and systematic errors in modeling the nonlinearities limit our ability to extract information on the shape of the linear power spectrum. There are three main effects that distort the observed power spectrum from the linear power spectrum: nonlinear gravitational evolution, redshift space distortions, and a nonlinear relation between the galaxy density field and the underlying matter density field. In this thesis we introduce a new method to mitigate the latter two distortions and rely on carefully tuned N-body simulations to model the first. In Chapter 2 we present the technique 'Counts-in-Cylinders' (CiC) and use it to measure the multiplicity function of groups of LRGs in SDSS. We use the Halo Occupation Distribution description of the galaxy-matter mapping and N -body simulations to connect this observation with constraints on the distribution of LRGs in dark matter halos. In Chapter 3 we study the effects of resolution on statistics relating to both the large and small scale distributions and motions of matter and dark matter halos. We combine these results to produce a large set of high quality mock LRG catalogs that reproduce the higher order statistics in the density field probed by the CiC technique. Using these catalogs we present a detailed analysis of the method used in Tegmark et al. (2006) to estimate the LRG power spectrum, and find that the large nonlinear correction necessary for their analysis is degenerate with changes in the linear spectrum we wish to constrain. We show that the CiC group-finding method in Chapter 2 can be used to reconstruct the underlying halo density field. The power spectrum of this field has only percent-level deviations from

  9. Cosmological baryonic and matter densities from 600000 SDSS luminous red galaxies with photometric redshifts

    NASA Astrophysics Data System (ADS)

    Blake, Chris; Collister, Adrian; Bridle, Sarah; Lahav, Ofer

    2007-02-01

    We analyse MegaZ-LRG, a photometric-redshift catalogue of luminous red galaxies (LRGs) based on the imaging data of the Sloan Digital Sky Survey (SDSS) 4th Data Release. MegaZ-LRG, presented in a companion paper, contains >106 photometric redshifts derived with ANNZ, an artificial neural network method, constrained by a spectroscopic subsample of ~13000 galaxies obtained by the 2dF-SDSS LRG and Quasar (2SLAQ) survey. The catalogue spans the redshift range 0.4 < z < 0.7 with an rms redshift error σz ~ 0.03(1 + z), covering 5914 deg2 to map out a total cosmic volume 2.5h-3Gpc3. In this study we use the most reliable 600000 photometric redshifts to measure the large-scale structure using two methods: (1) a spherical harmonic analysis in redshift slices, and (2) a direct re-construction of the spatial clustering pattern using Fourier techniques. We present the first cosmological parameter fits to galaxy angular power spectra from a photometric-redshift survey. Combining the redshift slices with appropriate covariances, we determine best-fitting values for the matter density Ωm and baryon density Ωb of Ωmh = 0.195 +/- 0.023 and Ωb/Ωm = 0.16 +/- 0.036 (with the Hubble parameter h = 0.75 and scalar index of primordial fluctuations nscalar = 1 held fixed). These results are in agreement with and independent of the latest studies of the cosmic microwave background radiation, and their precision is comparable to analyses of contemporary spectroscopic-redshift surveys. We perform an extensive series of tests which conclude that our power spectrum measurements are robust against potential systematic photometric errors in the catalogue. We conclude that photometric-redshift surveys are competitive with spectroscopic surveys for measuring cosmological parameters in the simplest `vanilla' models. Future deep imaging surveys have great potential for further improvement, provided that systematic errors can be controlled.

  10. LUMINOUS INFRARED GALAXIES WITH THE SUBMILLIMETER ARRAY. III. THE DENSE KILOPARSEC MOLECULAR CONCENTRATIONS OF Arp 299

    SciTech Connect

    Sliwa, Kazimierz; Wilson, Christine D.; Petitpas, Glen R.; Armus, Lee; Juvela, Mika; Matsushita, Satoki; Peck, Alison B.; Yun, Min S. E-mail: wilson@physics.mcmaster.ca E-mail: lee@ipac.caltech.edu E-mail: satoki@asiaa.sinica.edu.tw E-mail: myun@astro.umass.edu

    2012-07-01

    We have used high-resolution ({approx}2.''3) observations of the local (D{sub L} = 46 Mpc) luminous infrared galaxy Arp 299 to map out the physical properties of the molecular gas that provides the fuel for its extreme star formation activity. The {sup 12}CO J = 3-2, {sup 12}CO J = 2-1, and {sup 13}CO J = 2-1 lines were observed with the Submillimeter Array, and the short spacings of the {sup 12}CO J = 2-1 and J = 3-2 observations have been recovered using the James Clerk Maxwell Telescope single dish observations. We use the radiative transfer code RADEX to estimate the physical properties (density, column density, and temperature) of the different regions in this system. The RADEX solutions of the two galaxy nuclei, IC 694 and NGC 3690, are consistent with a wide range of gas components, from warm moderately dense gas with T{sub kin} > 30 K and n(H{sub 2}) {approx} 0.3-3 Multiplication-Sign 10{sup 3} cm{sup -3} to cold dense gas with T{sub kin} {approx} 10-30 K and n(H{sub 2}) > 3 Multiplication-Sign 10{sup 3} cm{sup -3}. The overlap region is shown to have a better constrained solution with T{sub kin} {approx} 10-50 K and n(H{sub 2}) {approx} 1-30 Multiplication-Sign 10{sup 3} cm{sup -3}. We estimate the gas masses and star formation rates of each region in order to derive molecular gas depletion times. The depletion times of all regions (20-50 Myr) are found to be about two orders of magnitude lower than those of normal spiral galaxies. This rapid depletion time can probably be explained by a high fraction of dense gas on kiloparsec scales in Arp 299. We estimate the CO-to-H{sub 2} factor, {alpha}{sub co} to be 0.4 {+-} 0.3(3 Multiplication-Sign 10{sup -4}/x{sub CO}) M{sub Sun} (K km s{sup -1} pc{sup 2}){sup -1} for the overlap region. This value agrees well with values determined previously for more advanced merger systems.

  11. The [NII] 205 μm Emission in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Zhao, Yinghe; Lu, Nanyao; Xu, C. Kevin; Gao, Yu; Lord, Steven D.; Charmandaris, Vassilis; Diaz-Santos, Tanio; Evans, Aaron; Howell, Justin; Petric, Andreea O.; van der Werf, Paul P.; Sanders, David B.

    2016-03-01

    In this paper, we present the measurements of the [N ii] 205 μm line for a flux-limited sample of 122 (ultra-)luminous infrared galaxies [(U)LIRGs] and 20 additional normal galaxies, obtained with the Herschel Space Observatory (Herschel). We explore the far-infrared (FIR) color dependence of the [N ii] 205 μm (L[N ii]205 μm) to the total infrared (LIR) luminosity ratio, and find that L[N ii]205 μm/LIR only depends modestly on the 70-160 μm flux density ratio ({f}70/{f}160) when {f}70/{f}160≲ 0.6, whereas such dependence becomes much steeper for {f}70/{f}160\\gt 0.6. We also investigate the relation between L[N ii]205 μm and star formation rate (SFR), and show that L[N ii]205 μm has a nearly linear correlation with SFR, albeit the intercept of such a relation varies somewhat with {f}60/{f}100, consistent with our previous conclusion that [N ii] 205 μm emission can serve as an SFR indicator with an accuracy of ˜0.4 dex, or ˜0.2 dex if {f}60/{f}100 is known independently. Furthermore, together with the Infrared Space Observatory measurements of [N ii], we use a total of ˜200 galaxies to derive the local [N ii] 205 μm luminosity function (LF) by tying it to the known IR LF with a bivariate method. As a practical application, we also compute the local SFR volume density ({\\dot{ρ }}{{SFR}}) using the newly derived SFR calibrator and LF. The resulting {log} {\\dot{ρ }}{{SFR}}=-1.96+/- 0.11 {M}⊙ yr-1 Mpc-3 agrees well with previous studies. Finally, we determine the electron densities (ne) of the ionized medium for a subsample of 12 (U)LIRGs with both [N ii] 205 μm and [N ii] 122 μm data, and find that ne is in the range of ˜1-100 cm-3, with a median value of 22 cm-3. Based on Herschel observations. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  12. VLT adaptive optics search for luminous substructures in the lens galaxy towards SDSS J0924+0219

    NASA Astrophysics Data System (ADS)

    Faure, C.; Sluse, D.; Cantale, N.; Tewes, M.; Courbin, F.; Durrer, P.; Meylan, G.

    2011-12-01

    The anomalous flux ratios between quasar images are suspected of being caused by substructures in lens galaxies. We present new deep and high-resolution H and Ks imaging of the strongly lensed quasar SDSS J0924+0219 obtained using the ESO VLT with adaptive optics and the laser guide star system. SDSS J0924+0219 is particularly interesting because the observed flux ratio between the quasar images vastly disagree with the predictions from smooth mass models. With our adaptive optics observations we find a luminous object, Object L, located ~0.3'' to the north of the lens galaxy, but we show that it cannot be responsible for the anomalous flux ratios. Object L as well as a luminous extension of the lens galaxy to the south are seen in the archival HST/ACS image in the F814W filter. This suggests that Object L is part of a bar in the lens galaxy, as also supported by the presence of a significant disk component in the light profile of the lens galaxy. Finally, we find no evidence of any other luminous substructure that may explain the quasar images flux ratios. However, owing to the persistence of the flux ratio anomaly over time (~7 years), a combination of microlensing and millilensing is the favorite explanation for the observations. Based on observations obtained with the ESO VLT at Paranal observatory (Prog ID 084.A-0762(A); PI: Meylan). Also based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with the CASTLES (Cfa-Arizona Space Telescope LEns Survey) survey (ID: 9744, PI: C. S. Kochanek).

  13. Morphology and Molecular Gas Fractions of Local Luminous Infrared Galaxies as a Function of Infrared Luminosity and Merger Stage

    NASA Astrophysics Data System (ADS)

    Larson, K. L.; Sanders, D. B.; Barnes, J. E.; Ishida, C. M.; Evans, A. S.; U, V.; Mazzarella, J. M.; Kim, D.-C.; Privon, G. C.; Mirabel, I. F.; Flewelling, H. A.

    2016-07-01

    We present a new, detailed analysis of the morphologies and molecular gas fractions (MGFs) for a complete sample of 65 local luminous infrared galaxies from Great Observatories All-Sky Luminous Infrared Galaxies (LIRG) Survey using high resolution I-band images from The Hubble Space Telescope, the University of Hawaii 2.2 m Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single undisturbed galaxies, minor mergers, and major mergers, with the latter divided into five distinct stages from pre-first pericenter passage to final nuclear coalescence. We find that major mergers of molecular gas-rich spirals clearly play a major role for all sources with {L}{IR}\\gt {10}11.5{L}ȯ ; however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach {L}{IR}\\gt {10}12.0{L}ȯ until late in the merger process when both disks are near final coalescence. The mean MGF ({MGF} = {M}{{{H}}2}/({M}* +{M}{{{H}}2})) for non-interacting and early-stage major merger LIRGs is 18 ± 2%, which increases to 33 ± 3%, for intermediate stage major merger LIRGs, consistent with the hypothesis that, during the early-mid stages of major mergers, most of the initial large reservoir of atomic gas (HI) at large galactocentric radii is swept inward where it is converted into molecular gas (H2).

  14. THE ATACAMA COSMOLOGY TELESCOPE: DETECTION OF SUNYAEV-ZEL'DOVICH DECREMENT IN GROUPS AND CLUSTERS ASSOCIATED WITH LUMINOUS RED GALAXIES

    SciTech Connect

    Hand, Nick; Das, Sudeep; Dunkley, Joanna; Hajian, Amir; Appel, John W.; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hincks, Adam D.; Battaglia, Nick; Richard Bond, J.; Devlin, Mark J.; Klein, Jeff; Duenner, Rolando; Halpern, Mark; Hasselfield, Matthew; Hilton, Matt; Hlozek, Renee; Hughes, John P.; Irwin, Kent D.; Kosowsky, Arthur

    2011-07-20

    We present a detection of the Sunyaev-Zel'dovich (SZ) decrement associated with the luminous red galaxy (LRG) sample of the Sloan Digital Sky Survey. The SZ data come from 148 GHz maps of the equatorial region made by the Atacama Cosmology Telescope. The LRG sample is divided by luminosity into four bins, and estimates for the central SZ temperature decrement are calculated through a stacking process. We detect and account for a bias of the SZ signal due to weak radio sources. We use numerical simulations to relate the observed decrement to Y{sub 200} and clustering properties to relate the galaxy luminosity to halo mass. We also use a relation between brightest cluster galaxy luminosity and cluster mass based on stacked gravitational lensing measurements to estimate the characteristic halo masses. The masses are found to be around 10{sup 14} M{sub sun}.

  15. Rest-Frame Mid-Infrared Detection of an Extremely Luminous Lyman Break Galaxy with the Spitzer Infrared Spectrograph (IRS)

    NASA Technical Reports Server (NTRS)

    Teplitz, H. I.; Charmandaris, V.; Armus, L.; Appleton, P. N.; Houck, J. R.; Soifer, B. T.; Weedman, D.; Brandl, B. R.; vanCleve, J.; Grillmair, C.; Uchid, K. I.

    2004-01-01

    We present the first rest-frame of approximately 4 microns detection of a Lyman break galaxy. The data were obtained using the 16 microns imaging capability of the Spitzer Infrared Spectrograph. The target object, J134026.44+634433.2, is an extremely luminous Lyman break galaxy at z=2.79, first identified in Sloan Digital Sky Survey (SDSS) spectra (as reported by Bentz et al.). The source is strongly detected with a flux of 0.94 +/- 0.02 mJy. Combining Spitzer and SDSS photometry with supporting ground-based J- and K-band data, we show that the spectral energy distribution is consistent with an actively star-forming galaxy. We also detect other objects in the Spitzer field of view, including a very red mid-infrared source. We find no evidence of a strong lens among the mid-infrared sources.

  16. CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

    SciTech Connect

    Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth; Cuesta, Antonio; Padmanabhan, Nikhil; Seo, Hee-Jong; De Putter, Roland; Ross, Ashley J.; Percival, Will J.; Saito, Shun; Schlafly, Eddie; Hernandez-Monteagudo, Carlos; Sanchez, Ariel G.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Mena, Olga; Viel, Matteo; and others

    2012-12-10

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg{sup 2}, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg{sup 2} and probes a volume of 3 h {sup -3} Gpc{sup 3}, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of {approx}15%, with a bin size of {delta}{sub l} = 10 on scales of the baryon acoustic oscillations (BAOs; at l {approx} 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat {Lambda}CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H{sub 0} constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find {Omega}{sub {Lambda}} = 0.73 {+-} 0.019 and H{sub 0} to be 70.5 {+-} 1.6 s{sup -1} Mpc{sup -1} km. For an open {Lambda}CDM model, when combined with WMAP7 + HST, we find {Omega}{sub K} = 0.0035 {+-} 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 {+-} 0.078, and H{sub 0} to be 71.3 {+-} 1.7 s{sup -1} Mpc{sup -1} km, which is competitive with the latest large-scale structure constraints from large spectroscopic

  17. Clustering of Sloan Digital Sky Survey III Photometric Luminous Galaxies: The Measurement, Systematics, and Cosmological Implications

    NASA Astrophysics Data System (ADS)

    Ho, Shirley; Cuesta, Antonio; Seo, Hee-Jong; de Putter, Roland; Ross, Ashley J.; White, Martin; Padmanabhan, Nikhil; Saito, Shun; Schlegel, David J.; Schlafly, Eddie; Seljak, Uros; Hernández-Monteagudo, Carlos; Sánchez, Ariel G.; Percival, Will J.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Reid, Beth; Mena, Olga; Viel, Matteo; Eisenstein, Daniel J.; Prada, Francisco; Weaver, Benjamin A.; Bahcall, Neta; Bizyaev, Dimitry; Brewinton, Howard; Brinkman, Jon; Nicolaci da Costa, Luiz; Gott, John R.; Malanushenko, Elena; Malanushenko, Viktor; Nichol, Bob; Oravetz, Daniel; Pan, Kaike; Palanque-Delabrouille, Nathalie; Ross, Nicholas P.; Simmons, Audrey; de Simoni, Fernando; Snedden, Stephanie; Yeche, Christophe

    2012-12-01

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg2, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg2 and probes a volume of 3 h -3 Gpc3, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of ~15%, with a bin size of δ l = 10 on scales of the baryon acoustic oscillations (BAOs; at l ~ 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat ΛCDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H 0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find ΩΛ = 0.73 ± 0.019 and H 0 to be 70.5 ± 1.6 s-1 Mpc-1 km. For an open ΛCDM model, when combined with WMAP7 + HST, we find Ω K = 0.0035 ± 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 ± 0.078, and H 0 to be 71.3 ± 1.7 s-1 Mpc-1 km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power spectra give consistent

  18. Quiescent luminous red galaxies as cosmic chronometers: on the significance of mass and environmental dependence

    NASA Astrophysics Data System (ADS)

    Liu, G. C.; Lu, Y. J.; Xie, L. Z.; Chen, X. L.; Zhao, Y. H.

    2016-01-01

    Context. Massive luminous red galaxies (LRGs) are believed to be evolving passively and can be used as cosmic chronometers to estimate the Hubble constant (the differential age method). However, different LRGs may be located in different environments. The environmental effects, if any, on the mean ages of LRGs, and the ages of the oldest LRGs at different redshift, may limit the use of the LRGs as cosmic chronometers. Aims: We aim to investigate the environmental and mass dependence of the formation of "quiescent" LRGs, selected from the Sloan Digital Sky Survey (SDSS) data release 8, and to pave the way for using LRGs as cosmic chronometers. Methods: Using the population synthesis software STARLIGHT, we derive the stellar populations in each LRG through the full spectrum fitting and obtain the mean age distribution and the mean star formation history (SFH) of those LRGs. Results: We find that there is no apparent dependence of the mean age and the SFH of quiescent LRGs on their environment, while the ages of those quiescent LRGs depend weakly on their mass. We compare the SFHs of the SDSS LRGs with those obtained from a semi-analytical galaxy formation model and find that they are roughly consistent with each other if we consider the errors in the STARLIGHT-derived ages. We find that a small fraction of later star formation in LRGs leads to a systematical overestimation (~28%) of the Hubble constant by the differential age method, and the systematical errors in the STARLIGHT-derived ages may lead to an underestimation (~ 16%) of the Hubble constant. However, these errors can be corrected by a detailed study of the mean SFH of those LRGs and by calibrating the STARLIGHT-derived ages with those obtained independently by other methods. Conclusions: The environmental effects do not play a significant role in the age estimates of quiescent LRGs; and the quiescent LRGs as a population can be used securely as cosmic chronometers, and the Hubble constant can be measured

  19. The FUR to near-IR morphologies of luminous infrared galaxies in the goals sample

    SciTech Connect

    Petty, S. M.; Armus, L.; Díaz-Santos, T.; Howell, J. H.; Surace, J. A.; Charmandaris, V.; Psychogyios, A.; Evans, A. S.; Stierwalt, S.; Floc’h, E. Le; Bridge, C.; Inami, H.

    2014-12-01

    We compare the morphologies of a sample of 20 luminous infrared galaxies (LIRGs) from the Great Observatories All-sky LIRG Survey (GOALS) in the FUV, B, I, and H bands, using the Gini (G) and M{sub 20} parameters to quantitatively estimate the distribution and concentration of flux as a function of wavelength. Hubble Space Telescope (HST) images provide an average spatial resolution of ∼80 pc. While our LIRGs can be reliably classified as mergers across the entire range of wavelengths studied here, there is a clear shift toward more negative M{sub 20} (more bulge-dominated) and a less significant decrease in G values at longer wavelengths. We find no correlation between the derived FUV G-M{sub 20} parameters and the global measures of the IR to FUV flux ratio (IRX). Given the fine resolution in our HST data, this suggests either that the UV morphology and IRX are correlated on very small scales, or that the regions emitting the bulk of the IR emission emit almost no FUV light. We use our multi-wavelength data to simulate how merging LIRGs would appear from z∼0.5–3 in deep optical and near-infrared images such as the Hubble Ultra-Deep Field, and use these simulations to measure the G-M{sub 20} at these redshifts. Our simulations indicate a noticeable decrease in G, which flattens at z⩾2 by as much as 40%, resulting in mis-classifying our LIRGs as disk-like, even in the rest-frame FUV. The higher redshift values of M{sub 20} for the GOALS sources do not appear to change more than about 10% from the values at z∼0. The change in G-M{sub 20} is caused by the surface brightness dimming of extended tidal features and asymmetries, and also the decreased spatial resolution which reduced the number of individual clumps identified. This effect, seen as early as z∼0.5, could easily lead to an underestimate of the number of merging galaxies at high-redshift in the rest-frame FUV.

  20. A New Measurement of the Bulk Flow of X-Ray Luminous Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Kashlinsky, A.; Atrio-Barandela, F.; Ebeling, H.; Edge, A.; Kocevski, D.

    2010-01-01

    We present new measurements of the large-scale bulk flows of galaxy clusters based on five-year WMAP data and a significantly expanded X-ray cluster catalog. Our method probes the flow via measurements of the kinematic Sunyaev-Zel'dovich (SZ) effect produced by the hot gas in moving clusters. It computes the dipole in the cosmic microwave background data at cluster pixels, which preserves the SZ component while integrating down other contributions. Our improved catalog of over 1000 clusters enables us to further investigate possible systematic effects and, thanks to a higher median cluster redshift, allows us to measure the bulk flow to larger scales. We present a corrected error treatment and demonstrate that the more X-ray luminous clusters, while fewer in number, have much larger optical depth, resulting in a higher dipole and thus a more accurate flow measurement. This results in the observed correlation of the dipole derived at the aperture of zero monopole with the monopole measured over the cluster central regions. This correlation is expected if the dipole is produced by the SZ effect and cannot be caused by unidentified systematics (or primary cosmic microwave background anisotropies). We measure that the flow is consistent with approximately constant velocity out to at least [similar, equals]800 Mpc. The significance of the measured signal peaks around 500 h -1 70 Mpc, most likely because the contribution from more distant clusters becomes progressively more diluted by the WMAP beam. However, at present, we cannot rule out that these more distant clusters simply contribute less to the overall motion.

  1. Interpreting the IR SED of z~0.3-2.8 IR-Luminous Galaxies and AGN Using Hydrodynamic Simulations

    NASA Astrophysics Data System (ADS)

    Roebuck, Eric John; Sajina, Anna; Hayward, Christopher C.; Pope, Alexandra; Kirkpatrick, Allison; Hernquist, Lars E.; Yan, Lin

    2016-01-01

    We use three-dimensional hydrodynamical galaxy merger simulations to further investigate the nature of a sample of 342 24 μm-selected (ultra) luminous infrared galaxies at z~0.3-2.8. All of our sources have low-resolution Spitzer/IRS spectra -- the largest such sample outside the local universe. These spectra allow us to determine that our sample consists of a mixture of star forming galaxies (SFGs), AGN, and composites. We address the question of how well do empirical IR AGN fraction estimates trace the intrinsic AGN fraction (i.e. the AGN-to-total power in the galaxy prior to dust re-processing), including how they relate to galaxy properties such as merger stage, dust/gas content, and star formation rates. We do this by fitting the observed SEDs of our sample with theoretical SEDs based on GADGET hydrodynamic merger simulations additionally processed through the SUNRISE radiative transfer code. We additionally investigate systematic uncertainties associated with these quantities using the goodness of fits to our model library. The key findings are: 1) our simulation-based fits are in broad agreement with the empirical model-based fits, 2) much of the AGN fraction of LIR is missed if the AGN's contribution to heating the host galaxy dust is not accounted for, and 3) the IR AGN fraction traces the intrinsic AGN fraction up to the coalescence stage, however may underestimate the intrinsic AGN fraction post coalescence.

  2. A Search for Moderate-redshift Survivors from the Population of Luminous Compact Passive Galaxies at High Redshift

    NASA Astrophysics Data System (ADS)

    Stockton, Alan; Shih, Hsin-Yi; Larson, Kirsten; Mann, Andrew W.

    2014-01-01

    From a search of a ~2400 deg2 region covered by both the Sloan Digital Sky Survey and UKIRT Infrared Deep Sky Survey databases, we have attempted to identify galaxies at z ~ 0.5 that are consistent with their being essentially unmodified examples of the luminous passive compact galaxies found at z ~ 2.5. After isolating good candidates via deeper imaging, we further refine the sample with Keck moderate-resolution spectroscopy and laser guide star adaptive-optics imaging. For four of the five galaxies that so far remain after passing through this sieve, we analyze plausible star-formation histories based on our spectra in order to identify galaxies that may have survived with little modification from the population formed at high redshift. We find two galaxies that are consistent with having formed >~ 95% of their mass at z > 5. We attempt to estimate masses both from our stellar population determinations and from velocity dispersions. Given the high frequency of small axial ratios, both in our small sample and among samples found at high redshifts, we tentatively suggest that some of the more extreme examples of passive compact galaxies may have prolate morphologies. Some of 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.

  3. A search for moderate-redshift survivors from the population of luminous compact passive galaxies at high redshift

    SciTech Connect

    Stockton, Alan; Shih, Hsin-Yi; Larson, Kirsten; Mann, Andrew W. E-mail: hsshih@ifa.hawaii.edu E-mail: amann@ifa.hawaii.edu

    2014-01-10

    From a search of a ∼2400 deg{sup 2} region covered by both the Sloan Digital Sky Survey and UKIRT Infrared Deep Sky Survey databases, we have attempted to identify galaxies at z ∼ 0.5 that are consistent with their being essentially unmodified examples of the luminous passive compact galaxies found at z ∼ 2.5. After isolating good candidates via deeper imaging, we further refine the sample with Keck moderate-resolution spectroscopy and laser guide star adaptive-optics imaging. For four of the five galaxies that so far remain after passing through this sieve, we analyze plausible star-formation histories based on our spectra in order to identify galaxies that may have survived with little modification from the population formed at high redshift. We find two galaxies that are consistent with having formed ≳ 95% of their mass at z > 5. We attempt to estimate masses both from our stellar population determinations and from velocity dispersions. Given the high frequency of small axial ratios, both in our small sample and among samples found at high redshifts, we tentatively suggest that some of the more extreme examples of passive compact galaxies may have prolate morphologies.

  4. A multiwavelength and multiscale study of Luminous and Ultraluminous Infrared Galaxies in the local Universe

    NASA Astrophysics Data System (ADS)

    Herrero-Illana, Rubén

    2014-10-01

    This dissertation deals with the multiwavelength study of luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs, respectively) in the local Universe under different spatial scales. The work is focused on the properties of massive starbursts, the contribution of active galactic nuclei (AGN) and the interplay between both phenomena. The study of local (U)LIRGs is the best scenario where to understand the properties of these objects at cosmological distances, where their luminosity contribution dominates the cosmic infrared background. Our first approach to the study of (U)LIRGs consisted of a spectral line study in the millimeter range, obtained with the IRAM 30m radio-telescope in Pico Veleta, Granada of a subsample of 56 (U)LIRGs from the GOALS project sample. We observed and analyzed spectra of several molecular features, focusing in the study of carbon monoxide (CO), a well-known tracer of cold molecular gas. We explored the relation between them as well as the properties of molecular gas. Besides of the sample characterization, we confirmed the increase of the isotopic ratio 12CO/13CO with the dust temperature, explained by the 12CO optical depth decreasing with temperature. We have also studied the kinematics and gas distribution using the spectral profiles of several molecular transitions. In a second part of this thesis, we analyzed the central kiloparsec region of a sample of 12 LIRGs, stressing the importance of the multiwavelength approach, aimed at deriving the star formation processes of these galaxies, as well as to study the contribution of the putative AGN to the bolometric luminosity in our sample. For one of these LIRGs, NGC1614, we performed a deep multiwavelength study, including data from radio, infrared, optical and X-rays. These data allowed us to establish that the the IR emission in the circumnuclear region is completely dominated by a powerful starburst and, in case it hosts an AGN, its contribution is irrelevant. We also performed

  5. NUSTAR Unveils a Heavily Obscured Low-luminosity Active Galactic Nucleus in the Luminous Infrared Galaxy NGC 6286

    NASA Astrophysics Data System (ADS)

    Ricci, C.; Bauer, F. E.; Treister, E.; Romero-Cañizales, C.; Arevalo, P.; Iwasawa, K.; Privon, G. C.; Sanders, D. B.; Schawinski, K.; Stern, D.; Imanishi, M.

    2016-03-01

    We report the detection of a heavily obscured active galactic nucleus (AGN) in the luminous infrared galaxy (LIRG) NGC 6286 identified in a 17.5 ks Nuclear Spectroscopic Telescope Array observation. The source is in an early merging stage and was targeted as part of our ongoing NuSTAR campaign observing local luminous and ultra-luminous infrared galaxies in different merger stages. NGC 6286 is clearly detected above 10 keV and by including the quasi-simultaneous Swift/XRT and archival XMM-Newton and Chandra data, we find that the source is heavily obscured (NH ≃(0.95-1.32) × 1024 cm-2) with a column density consistent with being Compton-thick (CT, {log}({N}{{H}}/{{cm}}-2)≥slant 24). The AGN in NGC 6286 has a low absorption-corrected luminosity (L2-10 keV ˜ 3-20 × 1041 erg s-1) and contributes ≲1% to the energetics of the system. Because of its low luminosity, previous observations carried out in the soft X-ray band (<10 keV) and in the infrared did not notice the presence of a buried AGN. NGC 6286 has multiwavelength characteristics typical of objects with the same infrared luminosity and in the same merger stage, which might imply that there is a significant population of obscured low-luminosity AGNs in LIRGs that can only be detected by sensitive hard X-ray observations.

  6. Modelling the spectral energy distribution of galaxies. V. The dust and PAH emission SEDs of disk galaxies

    NASA Astrophysics Data System (ADS)

    Popescu, C. C.; Tuffs, R. J.; Dopita, M. A.; Fischera, J.; Kylafis, N. D.; Madore, B. F.

    2011-03-01

    We present a self-consistent model of the spectral energy distributions (SEDs) of spiral galaxies from the ultraviolet (UV) to the mid-infrared (MIR)/far-infrared (FIR)/submillimeter (submm) based on a full radiative transfer calculation of the propagation of starlight in galaxy disks. This model predicts not only the total integrated energy absorbed in the UV/optical and re-emitted in the infrared/submm, but also the colours of the dust emission based on an explicit calculation of the strength and colour of the UV/optical radiation fields heating the dust, and incorporating a full calculation of the stochastic heating of small dust grains and PAH molecules. The geometry of the translucent components of the model is empirically constrained using the results from the radiation transfer analysis of Xilouris et al. on spirals in the middle range of the Hubble sequence, while the geometry of the optically thick components is constrained from physical considerations with a posteriori checks of the model predictions with observational data. Following the observational constraints, the model has both a distribution of diffuse dust associated with the old and young disk stellar populations as well as a clumpy component arising from dust in the parent molecular clouds in star forming regions. In accordance with the fragmented nature of dense molecular gas in typical star-forming regions, UV light from massive stars is allowed to either freely stream away into the diffuse medium in some fraction of directions or be geometrically blocked and locally absorbed in clumps. These geometrical constraints enable the dust emission to be predicted in terms of a minimum set of free parameters: the central face-on dust opacity in the B-band τ^f_B, a clumpiness factor F for the star-forming regions, the star-formation rate SFR, the normalised luminosity of the old stellar population old and the bulge-to-disk ratio B/D. We show that these parameters are almost orthogonal in their

  7. Colors of Luminous Bulges in Cluster MS 1054-03 and Field Galaxies at Redshifts z~0.83

    NASA Astrophysics Data System (ADS)

    Koo, David C.; Datta, Susmita; Willmer, Christopher N. A.; Simard, Luc; Tran, Kim-Vy; Im, Myungshin

    2005-11-01

    Using Hubble Space Telescope images, we separate the bulgelike (dubbed ``pbulge'') and disklike (``pdisk'') components of 71 galaxies in the rich cluster MS 1054-03 and of 21 in the field. Our key finding is that luminous pbulges are very red, with rest-frame U-B~0.45, while predicted colors are bluer by 0.20 mag. Moreover, these very red colors appear to be independent of environment, pbulge luminosity, pdisk color, and pbulge fraction. These results challenge any model of hierarchical galaxy formation that predicts the colors of distant (z~0.8) luminous field and cluster bulges will differ. Our findings also disagree with other claims that 30% to 50% of bright bulges and elliptical galaxies at z~1 are very blue (U-B<=0). Based on observations 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; made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 and associated with proposals GO-7372, GTO-5090, and GTO-5109.

  8. The Cambridge-Cambridge x-ray serendipity survey. 2: Classification of x-ray luminous galaxies

    NASA Technical Reports Server (NTRS)

    Boyle, B. J.; Mcmahon, R. G.; Wilkes, B. J.; Elvis, Martin

    1994-01-01

    We present the results of an intermediate-resolution (1.5 A) spectroscopic study of 17 x-ray luminous narrow emission-line galaxies previously identified in the Cambridge-Cambridge ROSAT Serendipity Survey and the Einstein Extended Medium Sensitivity Survey. Emission-line ratios reveal that the sample is composed of ten Seyfert and seven starburst galaxies. Measured linewidths for the narrow H alpha emission lines lie in the range 170 - 460 km s(exp -1). Five of the objects show clear evidence for asymmetry in the (OIII) lambda 5007 emission-line profile. Broad H alpha emission is detected in six of the Seyfert galaxies, which range in type from Seyfert 1.5 to 2. Broad H beta emission is only detected in one Seyfert galaxy. The mean full width at half maximum for the broad lines in the Seyfert galaxies is FWHM = 3900 +/- 1750 km s(exp -1). Broad (FWHM = 2200 +/- 600 km s(exp -1) H alpha emission is also detected in three of the starburst galaxies, which could originate from stellar winds or supernovae remnants. The mean Balmer decrement for the sample is H alpha / H beta = 3, consistent with little or no reddening for the bulk of the sample. There is no evidence for any trend with x-ray luminosity in the ratio of starburst galaxies to Seyfert galaxies. Based on our previous observations, it is therefore likely that both classes of object comprise approximately 10 percent of the 2 keV x-ray background.

  9. 2D kinematical study in local luminous compact blue galaxies. Starburst origin in UCM2325+2318

    NASA Astrophysics Data System (ADS)

    Castillo-Morales, A.; Pérez-Gallego, J.; Gallego, J.; Guzmán, R.; Castander, F.; Garland, C.; Gruel, N.; Pisano, D. J.; Muñoz-Mateos, J. C.; Ocaña, F.; Zamorano, J.

    2013-05-01

    Luminous Compact Blue Galaxies (LCBGs) are small, but vigorously star forming galaxies. Their presence at different redshifts denotes their cosmological relevance and implies that local starburst galaxies, when properly selected, are unique laboratories for studying the complex ecosystem of the star formation process over time. We have selected a representative sample of 22 LCBGs from the SDSS and UCM databases which, although small, provides an excellent reference for comparison with current and future surveys of similar starbursts at high-z. We are carrying out a 2D optical spectroscopic study of this LCBG sample, including spatially resolved maps of kinematics, extinction, SFR and metallicity. This will help us to answer questions regarding the nature of these objects. In this poster we show our results on the kinematical study (Pérez-Gallego et al. 2011) which allows us to classify these galaxies into three different classes: rotating disk (RD) 48%, perturbed rotation (PR) 28% and complex kinematics (CK) 24%. We find 5% of objects show evidence of a recent major merger, 10% of a minor merger, and 45% of a companion. This argues in favor of ongoing interactions with close companions as a mechanism for the enhanced star formation activity in these galaxies. We find only 5% of objects with clear evidence of AGN activity, and 27% with kinematics consistent with SN-driven galactic winds. Therefore, a different mechanism may be responsible for quenching the star formation in LCBGs. The detailed analysis of the physical properties for each galaxy in the sample is on progress and we show in this poster the results on UCM2325+2318 as a prototype LCBG. Between the possible mechanisms to explain the starburst activity in this galaxy, our 2D spectroscopic data support the scenario of an on-going interaction with the possibility for clump B to be the dwarf satellite galaxy (Castillo-Morales et al. 2011, Pérez-Gallego et al. 2010).

  10. Lyα and CIII] Emission in z = 7 - 9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?

    NASA Astrophysics Data System (ADS)

    Stark, Daniel P.; Ellis, Richard S.; Charlot, Stéphane; Chevallard, Jacopo; Tang, Mengtao; Belli, Sirio; Zitrin, Adi; Mainali, Ramesh; Gutkin, Julia; Vidal-García, Alba; Bouwens, Rychard; Oesch, Pascal

    2016-09-01

    We discuss new Keck/MOSFIRE spectroscopic observations of four luminous galaxies at z ≃ 7 - 9 selected to have intense optical line emission by Roberts-Borsani et al. (2016). Previous follow-up has revealed Lyα in two of the four galaxies. Our new MOSFIRE observations confirm that Lyα is present in the entire sample. We detect Lyα emission in the galaxy COS-zs7-1, confirming its redshift as zLyα = 7.154, and we detect Lyα in EGS-zs8-2 at zLyα = 7.477, verifying an earlier tentative detection. The ubiquity of Lyα in this sample is puzzling given that the IGM is expected to be significantly neutral over 7 < z < 9. To investigate this result in more detail, we have initiated a campaign to target UV metal lines in the four Lyα emitters as a probe of both the ionizing field and the Lyα velocity offset at early times. Here we present the detection of CIII] emission in the z = 7.73 galaxy EGS-zs8-1, requiring an intense radiation field and moderately low metallicity. We argue that the radiation field is likely to affect the local environment, increasing the transmission of Lyα through the galaxy. Moreover, the centroid of CIII] indicates that Lyα is redshifted by 340 km sec-1. This velocity offset is larger than that seen in less luminous systems, providing an explanation for the transmission of Lyα emission through the IGM. Since the transmission is further enhanced by the likelihood that such systems are also situated in large ionized bubbles, the visibility of Lyα at z > 7 is expected to be strongly luminosity-dependent, with transmission accelerated in systems with intense star formation.

  11. A dual velocity in the highly ionized wind of the luminous narrow line Seyfert galaxy PG 1211+143

    NASA Astrophysics Data System (ADS)

    Pounds, K. A.; Lobban, A.; Reeves, J. N.; Vaughan, S.

    2016-05-01

    An extended XMM-Newton observation of the luminous narrow line Seyfert galaxy PG 1211+143 in 2014 has revealed a complex high velocity outflow, with components distinguished in velocity, ionization and short-term variability. We report here the detection of previously unseen spectral structure in Fe K absorption, finding a second velocity component of the highly ionized wind, apparently co-moving with a low ionization flow detected in the soft X-ray spectrum. Comparison with the first observation in 2001 finds a similar outflow energy rate.

  12. CaII in Luminous Narrow-line Seyfert 1 Galaxies

    NASA Astrophysics Data System (ADS)

    Leighly, Karen; Dietrich, M.

    2009-01-01

    FeII emission is an important component of the low-ionization broad-line emission in quasars, comprising up to 1/3 of the total line emission, and performing as a primary coolant. In addition, FeII potentially can be used as a probe of gas metallicity (i.e., preceding stellar evolution). However, FeII is difficult to study because the Fe+ ion yields a complex spectrum of several hundred-thousand emission lines. CaII has been shown to be a valuable surrogate for FeII, with the H&K lines analogous to the UV FeII, and the IR triplet analogous to optical FeII. The advantage of studying CaII compared with FeII is that while the gross atomic structure is similar, the number of lines is dramatically reduced (five versus thousands). CaII H&K (3934, 3968Å) has rarely been identified in emission in quasars and AGN, possibly because the gas is very optically thick and the emission has been converted to the CaII IR triplet (8498, 85442, 8662Å), or because of absorption in the host galaxy. An exception is the luminous narrow-line quasar PHL 1811, and examination of quasars in the SDSS reveals a number of others that show CaII H&K as well, along with other objects that appear otherwise similar but do not have CaII H&K in their spectra. We present preliminary results from observations using SpeX on the IRTF, NASA's 3m telescope on Mauna Kea, to study CaII IR triplet emission in a sample of quasars both with and without CaII H&K. The sample has a range of optical FeII/Hα914 ratios, and the IR CaII triplet/OI (8446Å) ratio follows roughly the same pattern. This behavior is expected if the IR CaII triplet is analogous to optical FeII, and the OI is produced by Bowen fluorescence. A range of CaII H&K/CaII IR triplet ratios is found. Additional results will be presented.

  13. Where are the Luminous Red Galaxies (LRGs)? Using correlation measurements and lensing to relate LRGs to dark matter haloes

    NASA Astrophysics Data System (ADS)

    Hikage, Chiaki; Mandelbaum, Rachel; Takada, Masahiro; Spergel, David N.

    2013-11-01

    Non-linear redshift-space distortions, the Finger-of-God (FoG) effect, can complicate the interpretation of the galaxy power spectrum. Here, we demonstrate the method proposed by Hikage, Takada & Spergel to use complimentary observations to directly constrain this effect on the data. We use catalogues of Luminous Red Galaxies (LRGs) and photometric galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) to measure the redshift-space power spectrum of LRGs, the cross-correlation of LRGs with the shapes of background photometric galaxies (galaxy-galaxy weak lensing) and the projected cross-correlation of LRGs with photometric galaxies having similar photometric redshifts to the LRG spectroscopic redshift. All of these measurements use a reconstructed halo field. While we use the position of each LRG for single LRG systems, we compare the measurements using different halo-centre proxies for multiple-LRG systems (4.5 per cent of all the haloes): the brightest LRG position (BLRG), the faintest LRG position (FLRG) and their arithmetical mean position (Mean), respectively, in each system. We find significant differences in the measured correlations of different centres, showing consistent off-centring effects in the three observables. By comparing the measurements with a halo model that treats the satellite photometric galaxies as being distributed according to a generalized Navarro, Frenk and White profile, we find that ˜40 (70) per cent of BLRGs (FLRGs) are off-centred satellite galaxies in the multiple-LRG systems. The satellite LRGs have typical off-centring radius of ˜400 kpc h-1, and velocity dispersion of about 500 km s-1 in host haloes with a mean mass of 1.6 × 1014 M⊙ h-1. We show that, if LRGs in the single LRG systems have similar offsets, the residual FoG contamination in the LRG power spectrum can be significant at k ≳ 0.1 h Mpc-1, which may cause a bias in cosmological parameters determined by the shape of the power spectrum, such as

  14. The Atacama Cosmology Telescope: Detection or Sunyaev-Zel'Dovich Decrement in Groups and Clusters Associated with Luminous Red Galaxies

    NASA Technical Reports Server (NTRS)

    Hand, Nick; Appel, John William; Battaglia, Nick; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Dunkley, Joanna; Dunner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hajian, Amir; Halpern, Mark; Hasselfield, Matthew; Hilton, Matt; Hincks, Adam D.; Hlozek, Renee; Hughes, John P.; Irwin, Kent D.; Klein, Jeff; Kosowsky, Arthur; Lin, Yen-Ting; Marriage, Tobias A.; Marsden, Danica; McLaren, Mike; Wollack, Ed

    2010-01-01

    We present a detection of the Sunyaev-Zel'dovich (SZ) decrement associated with the Luminous Red Galaxy (LRG) sample of the Sloan Digital Sky Survey. The SZ data come from 148 GHz maps of the equatorial region made by the Atacama Cosmology Telescope (ACT). The LRG sample is divided by luminosity into four bins, and estimates for the central Sunyaev-Zel'dovich temperature decrement are calculated through a stacking process. We detect and account for a bias of the SZ signal due to weak radio sources. We use numerical simulations to relate the observed decrement to Y(sub 200) and clustering properties to relate the galaxy luminosity bins to mass. We also use a relation between BCG luminosity and cluster mass based on stacked gravitational lensing measurements to estimate the characteristic halo masses. The masses are found to be in the range approx.10(exp 13) - 10(exp 14)/h Stellar Mass, a lower range than has been previously probed.

  15. PHOTOMETRIC REDSHIFTS AND SYSTEMATIC VARIATIONS IN THE SPECTRAL ENERGY DISTRIBUTIONS OF LUMINOUS RED GALAXIES FROM SDSS DR7

    SciTech Connect

    Greisel, N.; Seitz, S.; Bender, R.; Saglia, R. P.; Snigula, J.; Drory, N.

    2013-05-10

    We describe the construction of a template set of spectral energy distributions (SEDs) for the estimation of photometric redshifts of luminous red galaxies (LRGs) with a Bayesian template fitting method. By examining the color properties of several publicly available SED sets within a redshift range of 0 < z {approx}< 0.5 and comparing them to Sloan Digital Sky Survey (SDSS) Data Release 7 data, we show that only some of the investigated SEDs approximately match the colors of the LRG data throughout the redshift range, however not at the quantitative level required for precise photometric redshifts. This is because the SEDs of galaxies evolve with time (and redshift) and because at fixed redshift the LRG colors have an intrinsic spread such that they cannot be matched by one SED only. We generate new SEDs by superposing model SEDs of composite stellar populations with a burst model, allowing both components to be reddened by dust, in order to match the data in five different redshift bins. We select a set of SEDs which represents the LRG data in color space within five redshift bins, thus defining our new SED template set for photometric redshift estimates. The results we obtain with the new template set and our Bayesian template fitting photometric redshift code (PhotoZ) are nearly unbiased, with a scatter of {sigma}{sub {Delta}z} = 0.027 (including outliers), a fraction of catastrophic outliers (|z{sub phot} - z{sub spec}|/(1 + z{sub spec}) > 0.15) of {eta} = 0.12%, and a normalized median absolute rest frame deviation (NMAD) of {sigma}{sub NMAD} = 1.48 Multiplication-Sign MAD = 0.017 for non-outliers. We show that templates that optimally describe the brightest galaxies (-24.5 {<=} M{sub R} {<=} -22.7) indeed vary from z = 0.1 to z = 0.5, consistent with aging of the stellar population. Furthermore, we find that templates that optimally describe galaxies at z < 0.1 strongly differ as a function of the absolute magnitude of the galaxies, indicating an increase in

  16. Neutral carbon and CO in 76 (U)LIRGs and starburst galaxy centers. A method to determine molecular gas properties in luminous galaxies

    NASA Astrophysics Data System (ADS)

    Israel, F. P.; Rosenberg, M. J. F.; van der Werf, P.

    2015-06-01

    In this paper we present fluxes in the [ CI ] lines of neutral carbon at the centers of some 76 galaxies with far-infrared luminosities ranging from 109 to 1012L⊙, as obtained with the Herschel Space Observatory and ground-based facilities, along with the line fluxes of the J = 7-6, J = 4-3, J = 2-112CO, and J = 2-113CO transitions. With this dataset, we determine the behavior of the observed lines with respect to each other and then investigate whether they can be used to characterize the molecular interstellar medium (ISM) of the parent galaxies in simple ways and how the molecular gas properties define the model results. In most starburst galaxies, the [ CI ] to 13CO line flux ratio is much higher than in Galactic star-forming regions, and it is correlated to the total far-infrared luminosity. The [ CI ] (1-0)/12CO (4-3), the [ CI ] (2-1)/12CO (7-6), and the [ CI ] (2-1)/(1-0) flux ratios are correlated, and they trace the excitation of the molecular gas. In the most luminous infrared galaxies (LIRGs), the ISM is fully dominated by dense (n( H2) = 104-105 cm-3) and moderately warm (Tkin ≈ 30 K) gas clouds that appear to have low [C°]/[CO] and [13CO]/[12CO] abundances. In less luminous galaxies, emission from gas clouds at lower densities becomes progressively more important, and a multiple-phase analysis is required to determine consistent physical characteristics. Neither the 12CO nor the [ CI ] velocity-integrated line fluxes are good predictors of molecular hydrogen column densities in individual galaxies. In particular, so-called X( [ CI ]) conversion factors are not superior to X( 12CO) factors. The methods and diagnostic diagrams outlined in this paper also provide a new and relatively straightforward means of deriving the physical characteristics of molecular gas in high-redshift galaxies up to z = 5, which are otherwise hard to determine.

  17. THE ROLE OF STARBURST-ACTIVE GALACTIC NUCLEUS COMPOSITES IN LUMINOUS INFRARED GALAXY MERGERS: INSIGHTS FROM THE NEW OPTICAL CLASSIFICATION SCHEME

    SciTech Connect

    Yuan, T.-T.; Kewley, L. J.; Sanders, D. B. E-mail: kewley@ifa.hawaii.ed

    2010-02-01

    We investigate the fraction of starbursts, starburst-active galactic nucleus (AGN) composites, Seyferts, and low-ionization narrow emission-line region galaxies (LINERs) as a function of infrared luminosity (L{sub IR}) and merger progress for approx500 infrared (IR)-selected galaxies. Using the new optical classifications afforded by the extremely large data set of the Sloan Digital Sky Survey, we find that the fraction of LINERs in IR-selected samples is rare (<5%) compared with other spectral types. The lack of strong IR emission in LINERs is consistent with recent optical studies suggesting that LINERs contain AGN with lower accretion rates than in Seyfert galaxies. Most previously classified IR-luminous LINERs are classified as starburst-AGN composite galaxies in the new scheme. Starburst-AGN composites appear to 'bridge' the spectral evolution from starburst to AGN in ULIRGs. The relative strength of the AGN versus starburst activity shows a significant increase at high IR luminosity. In ULIRGs (L{sub IR} > 10{sup 12} L{sub sun}), starburst-AGN composite galaxies dominate at early-intermediate stages of the merger, and AGN galaxies dominate during the final merger stages. Our results are consistent with models for IR-luminous galaxies where mergers of gas-rich spirals fuel both starburst and AGN, and where the AGN becomes increasingly dominant during the final merger stages of the most luminous IR objects.

  18. Stellar mass - Metallicity Relation for AKARI-FMOS Infrared Luminous Galaxies at z~0.9

    NASA Astrophysics Data System (ADS)

    Oi, Nagisa; Matsuhara, Hideo; Goto, Tomo; Pearson, Chris; Buat, Véronique; Malkan, Matthew A.

    2015-08-01

    Heavy elements are synthesized in stars and returned into the interstellar medium reflecting the result of the past star formation activity in a galaxy. Thus, the gas phase metallicity is a key parameter in understanding the processes of the formation and the evolution of a galaxy. Many investigations of stellar mass (M*) and gas phase metallicity (Z) relation (MZ relation), which is more massive galaxies tend to be more metal-rich, and a fundamental relation (FMR), whereby galaxies define a tight surface in the three-dimensional space of M*, Z, and Star Formation Rate (SFR) have done up to z~3.3. However, this relation only holds to ultraviolet, optical, or near-infrared selected star forming galaxies. Since most of star formation activities in galaxies at high-z universe are hidden by dust, to fully understand the MZ relation and its evolution, it is critical to study dusty galaxies.Here, we investigate the MZ relation and FMR for infrared bright galaxies at z~0.9 discovered by AKARI NEP-Deep survey.We estimated the M* and Z from SED fitting using the AKARI NEP-Deep data with its follow-up multi-wavelength photometric data (from X-ray to FIR) and from Halpha-[NII] emission line ratio taken by Subaru/FMOS, respectively. We found that (1) the infrared bright galaxies at z~0.9 is already chemically evolved to the level of star-forming galaxies in the local universe, and (2) the metallicity of our sample is systematically larger than that of the FMR. The results suggest a possibility that metal was actively created in dusty galaxies up to z~1, then outflow blows out dust and gas, suddenly stopping the chemical evolution and star formation activity, and the galaxies end up being what they are today.

  19. The Modes of Star Formation in Luminous and Ultraluminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Kartaltepe, Jeyhan S.; Candels Team

    2015-01-01

    In the local universe, Ultraluminous Infrared Galaxies (ULIRGs, LIR>1012 Lsun) are all interacting and merging systems. To date, studies of ULIRGs at high redshift have found a variety of results due to their varying selection effects and small sample sizes. Some studies have found that mergers still dominate the galaxy morphology while others have found a high fraction of morphologically normal or clumpy star forming disks. Near-infrared imaging is crucial for interpreting galaxy structure at high redshift since it probes the rest frame optical light of a galaxy and thus we can compare directly to studies in the local universe. We explore the evolution of the morphological properties of (U)LIRGs over cosmic time using a large sample of galaxies from Herschel observations of the CANDELS fields (including GOODS, COSMOS, and UDS). In particular, we investigate whether the role of galaxy mergers has changed between z~2 and now using the extensive visual classification catalogs produced by the CANDELS team. The combination of a selection from Herschel, near the peak of IR emission, and rest-frame optical morphologies from CANDELS, provides the ideal comparison to nearby (U)LIRGs. We then study the how role of galaxy mergers and the presence of AGN activity correspond to the galaxy's position in the star formation rate - stellar mass plane. Are galaxies that have specific star formation rates elevated above the main sequence more likely to be mergers?

  20. Probing dark matter in the luminous radio galaxy 3C220.3 and the structure of the z=2.22 SMG/AGN it is lensing.

    NASA Astrophysics Data System (ADS)

    Wilkes, Belinda

    2013-09-01

    The radio galaxy 3C 220.3 (z=0.685) is lensing a submm galaxy (SMG) at z=2.221 housing an AGN. This unique system allows accurate estimates of both stellar and dark mass in the luminous radio galaxy. In addition, the lensing magnification of 7 offers an unprecedented view of the interaction between star formation and AGN feedback in a luminous, dusty galaxy at the peak epoch of cosmic star formation. Our previous 10ks Chandra observation shows X-ray emission throughout the system, including the SMG, but with too few counts to identify the origin(s). We propose deeper Chandra and HST observations to (1) locate the X-ray sources, measure the X-ray properties and independently estimate the bolometric luminosities of both AGN (2) better map the offset between the SMG's UV and dust emission.

  1. Probing dark matter in the luminous radio galaxy 3C220.3 and the structure of the z=2.22 SMG/AGN it is lensing.

    NASA Astrophysics Data System (ADS)

    Wilkes, Belinda

    2013-10-01

    The radio galaxy 3C 220.3 {z=0.685} is lensing a submm galaxy {SMG} at z=2.221 housing an AGN. This unique system allows accurate estimates of both stellar and dark mass in the luminous radio galaxy. In addition, the lensing magnification of 7 offers an unprecedented view of the interaction between star formation and AGN feedback in a luminous, dusty galaxy at the peak epoch of cosmic star formation. Our previous 10ks Chandra observation shows X-ray emission throughout the system, including the SMG, but with too few counts to identify the origin{s}. We propose deeper Chandra and HST observations to {1} locate the X-ray sources, measure the X-ray properties and independently estimate the bolometric luminosities of both AGN {2} better map the offset between the SMG's UV and dust emission.

  2. The Origin and Evolution of (Ultra)Luminous Infrared Galaxies Over Cosmic Time

    NASA Astrophysics Data System (ADS)

    Kartaltepe, Jeyhan S.; CANDELS Collaboration

    2014-01-01

    In the local universe, Ultraluminous Infrared Galaxies (ULIRGs, L_IR>10^12 L_sun) are all interacting and merging systems. To date, studies of ULIRGs at high redshift have found a variety of results due to their varying selection effects and small sample sizes. Some studies have found that mergers still dominate the galaxy morphology while others have found a high fraction of morphologically normal or clumpy star forming disks. Near-infrared imaging is crucial for interpreting galaxy structure at high redshift since it probes the rest frame optical light of a galaxy and thus we can compare directly to studies in the local universe. We explore the evolution of the morphological properties of (U)LIRGs over cosmic time using a large sample of galaxies from Herschel observations of the CANDELS fields (including GOODS, COSMOS, and UDS). In particular, we investigate whether the role of galaxy mergers has changed between 2 and now using the extensive visual classification catalogs produced by the CANDELS team. The combination of a selection from Herschel, near the peak of IR emission, and rest-frame optical morphologies from CANDELS, provides the ideal comparison to nearby (U)LIRGs. We then study the how role of galaxy mergers and the presence of AGN activity correspond to the galaxy's position in the star formation rate - stellar mass plane.

  3. Are luminous radio-loud active galactic nuclei triggered by galaxy interactions?

    NASA Astrophysics Data System (ADS)

    Ramos Almeida, C.; Bessiere, P. S.; Tadhunter, C. N.; Pérez-González, P. G.; Barro, G.; Inskip, K. J.; Morganti, R.; Holt, J.; Dicken, D.

    2012-01-01

    We present the results of a comparison between the optical morphologies of a complete sample of 46 southern 2 Jy radio galaxies at intermediate redshifts (0.05 < z < 0.7) and those of two control samples of quiescent early-type galaxies: 55 ellipticals at redshifts z ≤ 0.01 from the Observations of Bright Ellipticals at Yale (OBEY) survey, and 107 early-type galaxies at redshifts 0.2 < z < 0.7 in the Extended Groth Strip (EGS). Based on these comparisons, we discuss the role of galaxy interactions in the triggering of powerful radio galaxies (PRGs). We find that a significant fraction of quiescent ellipticals at low and intermediate redshifts show evidence for disturbed morphologies at relatively high surface brightness levels, which are likely the result of past or on-going galaxy interactions. However, the morphological features detected in the galaxy hosts of the PRGs (e.g. tidal tails, shells, bridges, etc.) are up to 2 mag brighter than those present in their quiescent counterparts. Indeed, if we consider the same surface brightness limits, the fraction of disturbed morphologies is considerably smaller in the quiescent population (53 per cent at z < 0.2 and 48 per cent at 0.2 ≤ z < 0.7) than in the PRGs (93 per cent at z < 0.2 and 95 per cent at 0.2 ≤ z < 0.7 considering strong-line radio galaxies only). This supports a scenario in which PRGs represent a fleeting active phase of a subset of the elliptical galaxies that have recently undergone mergers/interactions. However, we demonstrate that only a small proportion (≲20 per cent) of disturbed early-type galaxies are capable of hosting powerful radio sources.

  4. XMM-NEWTON OBSERVATIONS OF LUMINOUS SOURCES IN NEARBY GALAXIES NGC 4395, NGC 4736, AND NGC 4258

    SciTech Connect

    Akyuz, A.; Avdan, H.; Kayaci, S.; Ozel, M. E.; Sonbas, E.; Balman, S.

    2013-03-15

    We present the results of a study of non-nuclear discrete sources in a sample of three nearby spiral galaxies (NGC 4395, NGC 4736, and NGC 4258) based on XMM-Newton archival data supplemented with Chandra data for spectral and timing analyses. A total of 75 X-ray sources have been detected within the D{sub 25} regions of the target galaxies. The large collecting area of XMM-Newton makes the statistics sufficient to obtain spectral fitting for 16 (about 20%) of these sources. Compiling the extensive archival exposures available, we were able to obtain the detailed spectral shapes of diverse classes of point sources. We have also studied temporal properties of these luminous sources. Eleven of them are found to show short-term (less than 80 ks) variation while eight of them show long-term variation within factors of {approx}2-5 during a time interval of {approx}2-12 years. Timing analysis provides strong evidence that most of these sources are accreting X-ray binary systems. One source that has properties different from others was suspected to be a supernova remnant, and our follow-up optical observation confirmed this. Our results indicate that sources within the three nearby galaxies are showing a variety of source populations, including several ultraluminous X-ray sources, X-ray binaries, transients together with a super soft source, and a background active galactic nucleus candidate.

  5. XMM-Newton analysis of a newly discovered, extremely X-ray luminous galaxy cluster at high redshift

    NASA Astrophysics Data System (ADS)

    Thoelken, S.; Schrabback, T.

    2016-06-01

    Galaxy clusters, the largest virialized structures in the universe, provide an excellent method to test cosmology on large scales. The galaxy cluster mass function as a function of redshift is a key tool to determine the fundamental cosmological parameters and especially measurements at high redshifts can e.g. provide constraints on dark energy. The fgas test as a direct cosmological probe is of special importance. Therefore, relaxed galaxy clusters at high redshifts are needed but these objects are considered to be extremely rare in current structure formation models. Here we present first results from an XMM-Newton analysis of an extremely X-ray luminous, newly discovered and potentially cool core cluster at a redshift of z=0.9. We carefully account for background emission and PSF effects and model the cluster emission in three radial bins. Our preliminary results suggest that this cluster is indeed a good candidate for a cool core cluster and thus potentially of extreme value for cosmology.

  6. Triggered or Self-Regulated Star Formation within Intermediate Redshift Luminous Infrared Galaxies. I. Morphologies and Spectral Energy Distributions

    NASA Astrophysics Data System (ADS)

    Melbourne, J.; Ammons, M.; Wright, S. A.; Metevier, A.; Steinbring, E.; Max, C.; Koo, D. C.; Larkin, J. E.; Barczys, M.

    2008-04-01

    As part of the Center for Adaptive Optics (AO) Treasury Survey (CATS) we imaged a set of 15 intermediate redshift (z ~ 0.8) luminous infrared (IR) galaxies (LIRGs) with the Keck Laser Guide Star (LGS) AO facility. These galaxies were selected from the Great Observatories Origins Deep Survey (GOODS) southern field, allowing us to combine the high spatial resolution Hubble Space Telescope optical (B, V, i, and z-bands) images with our near-infrared (K'-band) images to study the LIRG morphologies and spatially resolved spectral energy distributions (SEDs). Two thirds of the LIRGs are disk galaxies, with only one third showing some evidence for interactions, minor, or major mergers. In contrast with local LIRG disks (which are primarily barred systems), only 10% of the LIRG disks in our sample contain a prominent bar. While the optical bands tend to show a significant point-like substructure, indicating distributed star formation, the AO K-band images tend to be smooth. They lack point-like structures to a K ~ 23.5 limit. This places an upper bound on the number of red super giants per blue knot at less than 4000. The SEDs of the LIRGs are consistent with distributed dusty star formation, as exhibited by optical to IR colors redder than allowed by old stellar populations alone. This effect is most pronounced in the galaxy cores, possibly indicating central star formation. We also observed a set of 11 intermediate redshift comparison galaxies, selected to be non-ellipticals with apparent K-band magnitudes comparable to the LIRGs. The "normal" (non-LIRG) systems tended to have lower optical luminosity, lower stellar mass, and more irregular morphology than the LIRGs. Half of the "normal" galaxies have SEDs consistent with intermediate aged stellar populations and minimal dust. The other half show evidence for some dusty star formation, usually concentrated in their cores. Our work suggests that the LIRG disk galaxies are similar to large disk systems today, undergoing

  7. Declining rotation curves - The end of a conspiracy. [HI rotation velocity decrease of two galaxies as indication of large luminous to dark mass ratio

    SciTech Connect

    Casertano, S.; Van gorkom, J.H. Pittsburgh Univ., PA Columbia Univ., New York National Radio Astronomy Observatory, Socorro, NM )

    1991-04-01

    Two new H I rotation curves, observed at the Very Large Array as part of a search for galaxies with extended H I envelopes, are presented. The two curves are characterized by a large decrease in rotation velocity (more than 50 km/s, or about 25 percent of the maximum rotation velocity) between 1 and 3 optical radii. The velocity decrease is present on both sides of each galaxy and is not due to projection effects. The decrease in rotation velocity is interpreted as an indication of a large ratio of luminous to dark mass in the luminous regions of these systems. While confirming the idea that dark matter is ubiquitous, the discovery indicates that the match between the properties of luminous and dark matter required by the well-known 'conspiracy' is not perfect. 69 refs.

  8. Studying Cosmic Evolution with the XMM-Newton Distant Cluster Project: X-ray Luminous Galaxy Clusters at z>~1 and their Galaxy Populations

    NASA Astrophysics Data System (ADS)

    Fassbender, Rene

    2008-06-01

    Investigating X-ray luminous galaxy clusters at z>~1 provides a fundamental constraint on evolutionary studies of the largest virialized structures in the Universe, the baryonic matter in form of the hot ICM, their galaxy populations, and the effects of Dark Energy. The main aim of this work is to establish the observational foundation for the XMM-Newton Distant Cluster Project (XDCP). This new serendipitous survey is focused on the most distant systems at z>1, based on the selection of extended X-ray sources, their identification as clusters via two-band imaging, and their final spectroscopic confirmation. Almost 1000 extended sources were selected as cluster candidates from the analysis of 80 deg^2 of deep XMM-Newton archival data, of which 75% could be readily identified as systems at z<~0.6. For the remaining 250 distant cluster candidates a new strategy for their confirmation and redshift estimates was adopted, based on Z- and H-band photometry and the observed Z-H red-sequence color of early-type cluster galaxies. From observations of 25% of the sample, more than 20 X-ray clusters were discovered at a photometric redshift of z>~0.9. The new Z-H method has allowed a cluster sample study over an unprecedented redshift baseline of 0.2<~z<~1.5. From a comparison of the observed color evolution of the red-sequence with model predictions, the formation epoch of early-type galaxies could be constrained as z_f=4.2+-1.1, confirming their well-established old age. The preliminary investigation of the H-band luminosity evolution of 63 BCGs provides for the first time direct observational indications that the most massive cluster galaxies have doubled their stellar mass since z~1.5. The finding that BCGs were assembled in the last 9Gyr is now in qualitative agreement with the latest simulations.

  9. Star Formation and AGN Activity in Luminous and Ultraluminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Kartaltepe, Jeyhan

    2015-08-01

    In the local universe, Ultraluminous Infrared Galaxies (ULIRGs, L_IR > 10^12 L⊙) are all interacting and merging systems. We explore the evolution of the morphological and nuclear properties of (U)LIRGs over cosmic time using a large sample of galaxies from Her- schel observations of the CANDELS fields (including GOODS, COSMOS, and UDS). In particular, we investigate whether the role of galaxy mergers has changed between z ˜ 2 and now using the extensive visual classification catalogs produced by the CANDELS team. The combination of a selection from Herschel, near the peak of IR emission, and rest-frame optical morphologies from CANDELS, provides the ideal comparison to nearby (U)LIRGs. We also use rest-frame optical emission line diagnostics, X-ray luminosity, and MIR colors to separate AGN from star-formation dominated galaxies. We then study the how role of galaxy mergers and the presence of AGN activity correspond to the galaxy’s position in the star formation rate - stellar mass plane. Are galaxies that have specific star formation rates elevated above the main sequence more likely to be mergers? We investigate how AGN identified with different methods correspond to different morphologies and merger stages as well as position on the star formation rate - stellar mass plane.

  10. Constraining Gamma-Ray Emission from Luminous Infrared Galaxies with Fermi-LAT; Tentative Detection of Arp 220

    NASA Astrophysics Data System (ADS)

    Griffin, Rhiannon D.; Dai, Xinyu; Thompson, Todd A.

    2016-05-01

    Star-forming galaxies produce gamma-rays primarily via pion production, resulting from inelastic collisions between cosmic-ray protons and the interstellar medium (ISM). The dense ISM and high star formation rates of luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) imply that they should be strong gamma-ray emitters, but so far only two LIRGs have been detected. Theoretical models for their emission depend on the unknown fraction of cosmic-ray protons that escape these galaxies before interacting. We analyze Fermi-LAT data for 82 of the brightest Infrared Astronomical Satellite LIRGs and ULIRGs. We examine each system individually and carry out a stacking analysis to constrain their gamma-ray fluxes. We report the detection of the nearest ULIRG Arp 220 (˜4.6σ). We observe a gamma-ray flux (0.8–100 GeV) of 2.4 × 10‑10 phot cm‑2 s‑1 with a photon index of 2.23 (8.2 × 1041 erg s‑1 at 77 Mpc). We also derive upper limits (ULs) for the stacked LIRGs and ULIRGs. The gamma-ray luminosity of Arp 220 and the stacked ULs agree with calorimetric predictions for dense star-forming galaxies. With the detection of Arp 220, we extend the gamma-ray–IR luminosity correlation to the high-luminosity regime with {log}{L}0.1-100{GeV}=1.25× {log}{L}8-1000μ {{m}}+26.7 as well as the gamma-ray–radio continuum luminosity correlation with {log}{L}0.1-100{GeV}=1.22× {log}{L}1.4{GHz}+13.3. The current survey of Fermi-LAT is on the verge of detecting more LIRGs/ULIRGs in the local universe, and we expect even more detections with deeper Fermi-LAT observations or the next generation of gamma-ray detectors.

  11. Constraining Gamma-Ray Emission from Luminous Infrared Galaxies with Fermi-LAT; Tentative Detection of Arp 220

    NASA Astrophysics Data System (ADS)

    Griffin, Rhiannon D.; Dai, Xinyu; Thompson, Todd A.

    2016-05-01

    Star-forming galaxies produce gamma-rays primarily via pion production, resulting from inelastic collisions between cosmic-ray protons and the interstellar medium (ISM). The dense ISM and high star formation rates of luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs) imply that they should be strong gamma-ray emitters, but so far only two LIRGs have been detected. Theoretical models for their emission depend on the unknown fraction of cosmic-ray protons that escape these galaxies before interacting. We analyze Fermi-LAT data for 82 of the brightest Infrared Astronomical Satellite LIRGs and ULIRGs. We examine each system individually and carry out a stacking analysis to constrain their gamma-ray fluxes. We report the detection of the nearest ULIRG Arp 220 (∼4.6σ). We observe a gamma-ray flux (0.8–100 GeV) of 2.4 × 10‑10 phot cm‑2 s‑1 with a photon index of 2.23 (8.2 × 1041 erg s‑1 at 77 Mpc). We also derive upper limits (ULs) for the stacked LIRGs and ULIRGs. The gamma-ray luminosity of Arp 220 and the stacked ULs agree with calorimetric predictions for dense star-forming galaxies. With the detection of Arp 220, we extend the gamma-ray–IR luminosity correlation to the high-luminosity regime with {log}{L}0.1-100{GeV}=1.25× {log}{L}8-1000μ {{m}}+26.7 as well as the gamma-ray–radio continuum luminosity correlation with {log}{L}0.1-100{GeV}=1.22× {log}{L}1.4{GHz}+13.3. The current survey of Fermi-LAT is on the verge of detecting more LIRGs/ULIRGs in the local universe, and we expect even more detections with deeper Fermi-LAT observations or the next generation of gamma-ray detectors.

  12. Constraints on cold dark matter theories from observations of massive x-ray-luminous clusters of galaxies at high redshift

    NASA Technical Reports Server (NTRS)

    Luppino, G. A.; Gioia, I. M.

    1995-01-01

    During the course of a gravitational lensing survey of distant, X-ray selected Einstein Observatory Extended Medium Sensitivity Survey (EMSS) clusters of galaxies, we have studied six X-ray-luminous (L(sub x) greater than 5 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) clusters at redshifts exceeding z = 0.5. All of these clusters are apparently massive. In addition to their high X-ray luminosity, two of the clusters at z approximately 0.6 exhibit gravitationally lensed arcs. Furthermore, the highest redshift cluster in our sample, MS 1054-0321 at z = 0.826, is both extremely X-ray luminous (L(sub 0.3-3.5keV)=9.3 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) and exceedingly rich with an optical richness comparable to an Abell Richness Class 4 cluster. In this Letter, we discuss the cosmological implications of the very existence of these clusters for hierarchical structure formation theories such as standard Omega = 1 CDM (cold dark matter), hybrid Omega = 1 C + HDM (hot dark matter), and flat, low-density Lambda + CDM models.

  13. Three-dimensional spectroscopy of local luminous compact blue galaxies: kinematic maps of a sample of 22 objects

    NASA Astrophysics Data System (ADS)

    Pérez-Gallego, J.; Guzmán, R.; Castillo-Morales, A.; Gallego, J.; Castander, F. J.; Garland, C. A.; Gruel, N.; Pisano, D. J.; Zamorano, J.

    2011-12-01

    We use three-dimensional optical spectroscopy observations of a sample of 22 local luminous compact blue galaxies (LCBGs) to create kinematic maps. By means of these, we classify the kinematics of these galaxies into three different classes: rotating disc (RD), perturbed rotation (PR) and complex kinematics (CK). We find 48 per cent are RDs, 28 per cent are PRs and 24 per cent are CKs. RDs show rotational velocities that range between ˜50 and ˜200 km s-1, and dynamical masses that range between ˜1 × 109 and ˜3 × 1010 M⊙. We also address the following two fundamental questions through the study of the kinematic maps: (i) What processes are triggering the current starburst in LCBGs? We search our maps of the galaxy velocity fields for signatures of recent interactions and close companions that may be responsible for the enhanced star formation in our sample. We find that 5 per cent of objects show evidence of a recent major merger, 10 per cent of a minor merger and 45 per cent of a companion. This argues in favour of ongoing interactions with close companions as a mechanism for the enhanced star formation activity in these galaxies. (ii) What processes may eventually quench the current starbust in LCBGs? Velocity and velocity width maps, together with emission line ratio maps, can reveal signatures of active galactic nuclei (AGNs) activity or supernova (SN)-driven galactic winds that could halt the current burst. We find only 5 per cent of objects with clear evidence of AGN activity and 27 per cent with kinematics consistent with SN-driven galactic winds. Therefore, a different mechanism may be responsible for quenching the star formation in LCBGs. Finally, from our analysis, we find that the velocity widths of RDs, rather than accounting exclusively for the rotational nature of these objects, may account as well for other kinematic components and may not be good tracers of their dynamical masses.

  14. Searching for the Most UV-Luminous Galaxies in the Distant Universe

    NASA Astrophysics Data System (ADS)

    Stevans, Matthew L.; Finkelstein, Steven L.; Wold, Isak; Gebhardt, Karl; Jogee, Shardha; Papovich, Casey J.; Ciardullo, Robin; Gronwall, Caryl; Acquaviva, Viviana; Casey, Caitlin; HETDEX Team

    2016-01-01

    How galaxies grow and evolve over cosmic time is one of the largest unanswered questions in astronomy. With 50% of the stellar mass in today's galaxies having formed before z~1 (Dickinson et al. 2003) and the cosmic star formation density peaking between 1 < z < 3 (Madau & Dickinson 2014), the epoch at z>3 is particularly important for understanding the rise of the Hubble sequence at later times. We present multi-wavelength photometry from the the unprecedentedly large 28 deg2 Hobby Eberly Telescope Dark Energy Experiment (HETDEX) / Spitzer-HETDEX Exploratory Large Area (SHELA) survey in a study of 800,000 galaxies at redshifts of 1.9 to 3.5 including significant numbers of the most massive and most rare galaxies, unseen in pencil-beam deep field surveys. We use ugriz photometry from the Dark Energy Camera (DECam) and fit galaxy spectral energy distributions (SEDs) with stellar population spectral templates to select LBGs at z~3-4 and measure the rest-frame ultraviolet (UV) luminosity function. Our survey's large area and moderate depth provide a unique view of the bright-end (MAB<-22). Contamination by stellar sources or active galactic nuclei (AGNs) can be ruled out by the inclusion of multi-wavelength data. Probing a volume of 0.5 Gpc3 at 1.9 < z < 3.5, similar to that of the Sloan Digital Sky Survey (SDSS) at z < 0.5, we provide the most definitive constraints for numerical models of cosmic galaxy evolution, expanding our knowledge of galaxy growth during this critical era in cosmic history.

  15. The X-ray halo of an extremely luminous LSB disk galaxy

    NASA Technical Reports Server (NTRS)

    Weiner, Benjamin J.

    2004-01-01

    We are continuing to refine our upper limit on emission from halo gas in Malin 2. The upper limit is, of course, below the detected flux, but is made more difficult to quantify by the disk and possible AGN sources. We are also exploring spectral and spatial-size constraints to help separate the sources of emission. On the theory side, more recent work on the X-ray halo luminosity from halo gas leftover from galaxy formation has lowered the prediction for disk galaxies (e.g. Toft et al. 2002, MNRAS, 335, 799). While our upper limit is well below the original prediction, refinements in model have moved the theoretical goalposts, so that the observation may be consistent with newer models. A recent theoretical development, which our observations of Malin 2 appear to support, is that a substantial amount of mass can be accreted onto galaxies without being heated at a virial shock. The previous standard theory was that gas accreting into a halo hits a virial shock and is heated to high temperatures, which could produce X-ray halos in massive galaxies. Recent models show that "smooth accretion" of matter bypasses the virial shocking (Murali e t al. 2002, ApJ, 571, 1; Birnboim & Dekel 2003, MNRAS, 345, 349). Additionally, new hydrodynamical simulations of galaxy mergers by UCSC graduate student T. J. Cox show that hot gas halos can be created by gas blown out from the merger, taking up orbital energy of the merging galaxies (Cox et al. 2004, ApJ, 607, L87). If mergers rather than virial shocking are the origin of hot gas halos, the existence of an X-ray halo should depend more on past merger activity than halo mass. Then it makes sense that elliptical galaxies and poor groups with ellipticals, which are probably formed in mergers, have X-ray gas halos; while a giant, quiescent LSB disk galaxy like Malin 2, which has never suffered a major merger, does not have an X-ray halo. While both the observational expectations and theoretical models have changed since we began this

  16. An extremely luminous panchromatic outburst from the nucleus of a distant galaxy.

    PubMed

    Levan, A J; Tanvir, N R; Cenko, S B; Perley, D A; Wiersema, K; Bloom, J S; Fruchter, A S; Postigo, A de Ugarte; O'Brien, P T; Butler, N; van der Horst, A J; Leloudas, G; Morgan, A N; Misra, K; Bower, G C; Farihi, J; Tunnicliffe, R L; Modjaz, M; Silverman, J M; Hjorth, J; Thöne, C; Cucchiara, A; Cerón, J M Castro; Castro-Tirado, A J; Arnold, J A; Bremer, M; Brodie, J P; Carroll, T; Cooper, M C; Curran, P A; Cutri, R M; Ehle, J; Forbes, D; Fynbo, J; Gorosabel, J; Graham, J; Hoffman, D I; Guziy, S; Jakobsson, P; Kamble, A; Kerr, T; Kasliwal, M M; Kouveliotou, C; Kocevski, D; Law, N M; Nugent, P E; Ofek, E O; Poznanski, D; Quimby, R M; Rol, E; Romanowsky, A J; Sánchez-Ramírez, R; Schulze, S; Singh, N; van Spaandonk, L; Starling, R L C; Strom, R G; Tello, J C; Vaduvescu, O; Wheatley, P J; Wijers, R A M J; Winters, J M; Xu, D

    2011-07-01

    Variable x-ray and γ-ray emission is characteristic of the most extreme physical processes in the universe. We present multiwavelength observations of a unique γ-ray-selected transient detected by the Swift satellite, accompanied by bright emission across the electromagnetic spectrum, and whose properties are unlike any previously observed source. We pinpoint the event to the center of a small, star-forming galaxy at redshift z = 0.3534. Its high-energy emission has lasted much longer than any γ-ray burst, whereas its peak luminosity was ∼100 times higher than bright active galactic nuclei. The association of the outburst with the center of its host galaxy suggests that this phenomenon has its origin in a rare mechanism involving the massive black hole in the nucleus of that galaxy. PMID:21680811

  17. An Extremely Luminous Panchromatic Outburst from the Nucleus of a Distant Galaxy

    NASA Astrophysics Data System (ADS)

    Levan, A. J.; Tanvir, N. R.; Cenko, S. B.; Perley, D. A.; Wiersema, K.; Bloom, J. S.; Fruchter, A. S.; Postigo, A. de Ugarte; O'Brien, P. T.; Butler, N.; van der Horst, A. J.; Leloudas, G.; Morgan, A. N.; Misra, K.; Bower, G. C.; Farihi, J.; Tunnicliffe, R. L.; Modjaz, M.; Silverman, J. M.; Hjorth, J.; Thöne, C.; Cucchiara, A.; Cerón, J. M. Castro; Castro-Tirado, A. J.; Arnold, J. A.; Bremer, M.; Brodie, J. P.; Carroll, T.; Cooper, M. C.; Curran, P. A.; Cutri, R. M.; Ehle, J.; Forbes, D.; Fynbo, J.; Gorosabel, J.; Graham, J.; Hoffman, D. I.; Guziy, S.; Jakobsson, P.; Kamble, A.; Kerr, T.; Kasliwal, M. M.; Kouveliotou, C.; Kocevski, D.; Law, N. M.; Nugent, P. E.; Ofek, E. O.; Poznanski, D.; Quimby, R. M.; Rol, E.; Romanowsky, A. J.; Sánchez-Ramírez, R.; Schulze, S.; Singh, N.; van Spaandonk, L.; Starling, R. L. C.; Strom, R. G.; Tello, J. C.; Vaduvescu, O.; Wheatley, P. J.; Wijers, R. A. M. J.; Winters, J. M.; Xu, D.

    2011-07-01

    Variable x-ray and γ-ray emission is characteristic of the most extreme physical processes in the universe. We present multiwavelength observations of a unique γ-ray-selected transient detected by the Swift satellite, accompanied by bright emission across the electromagnetic spectrum, and whose properties are unlike any previously observed source. We pinpoint the event to the center of a small, star-forming galaxy at redshift z = 0.3534. Its high-energy emission has lasted much longer than any γ-ray burst, whereas its peak luminosity was ˜100 times higher than bright active galactic nuclei. The association of the outburst with the center of its host galaxy suggests that this phenomenon has its origin in a rare mechanism involving the massive black hole in the nucleus of that galaxy.

  18. NEAR-INFRARED ADAPTIVE OPTICS IMAGING OF INFRARED LUMINOUS GALAXIES: THE BRIGHTEST CLUSTER MAGNITUDE-STAR FORMATION RATE RELATION

    SciTech Connect

    Randriamanakoto, Z.; Väisänen, P.; Escala, A.; Kankare, E.; Kotilainen, J.; Mattila, S.; Ryder, S.

    2013-10-01

    We have established a relation between the brightest super star cluster (SSC) magnitude in a galaxy and the host star formation rate (SFR) for the first time in the near-infrared (NIR). The data come from a statistical sample of ∼40 luminous IR galaxies (LIRGs) and starbursts utilizing K-band adaptive optics imaging. While expanding the observed relation to longer wavelengths, less affected by extinction effects, it also pushes to higher SFRs. The relation we find, M{sub K} ∼ –2.6log SFR, is similar to that derived previously in the optical and at lower SFRs. It does not, however, fit the optical relation with a single optical to NIR color conversion, suggesting systematic extinction and/or age effects. While the relation is broadly consistent with a size-of-sample explanation, we argue physical reasons for the relation are likely as well. In particular, the scatter in the relation is smaller than expected from pure random sampling strongly suggesting physical constraints. We also derive a quantifiable relation tying together cluster-internal effects and host SFR properties to possibly explain the observed brightest SSC magnitude versus SFR dependency.

  19. Hyper-luminous dust-obscured galaxies discovered by the Hyper Suprime-Cam on Subaru and WISE

    NASA Astrophysics Data System (ADS)

    Toba, Yoshiki; Nagao, Tohru; Strauss, Michael A.; Aoki, Kentaro; Goto, Tomotsugu; Imanishi, Masatoshi; Kawaguchi, Toshihiro; Terashima, Yuichi; Ueda, Yoshihiro; Bosch, James; Bundy, Kevin; Doi, Yoshiyuki; Inami, Hanae; Komiyama, Yutaka; Lupton, Robert H.; Matsuhara, Hideo; Matsuoka, Yoshiki; Miyazaki, Satoshi; Morokuma, Tomoki; Nakata, Fumiaki; Oi, Nagisa; Onoue, Masafusa; Oyabu, Shinki; Price, Paul; Tait, Philip J.; Takata, Tadafumi; Tanaka, Manobu M.; Terai, Tsuyoshi; Turner, Edwin L.; Uchida, Tomohisa; Usuda, Tomonori; Utsumi, Yousuke; Yamada, Yoshihiko; Wang, Shiang-Yu

    2015-10-01

    We present the photometric properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR (MIR) images taken with Wide-Field Infrared Survey Explorer, we discovered 48 DOGs with i - Ks > 1.2 and i - [22] > 7.0, where i, Ks, and [22] represent AB magnitude in the i-band, Ks-band, and 22 μm, respectively, in the GAMA 14 hr field (˜ 9 deg2). Among these objects, 31 (˜ 65%) show power-law spectral energy distributions (SEDs) in the near-IR (NIR) and MIR regime, while the remainder show an NIR bump in their SEDs. Assuming that the redshift distribution for our DOGs sample is Gaussian, with mean and sigma z = 1.99 ± 0.45, we calculated their total IR luminosity using an empirical relation between 22 μm luminosity and total IR luminosity. The average value of the total IR luminosity is (3.5 ± 1.1) × 1013 L⊙, which classifies them as hyper-luminous infrared galaxies. We also derived the total IR luminosity function (LF) and IR luminosity density (LD) for a flux-limited subsample of 18 DOGs with 22 μm flux greater than 3.0 mJy and with i-band magnitude brighter than 24 AB magnitude. The derived space density for this subsample is log φ = -6.59 ± 0.11 [Mpc-3]. The IR LF for DOGs including data obtained from the literature is fitted well by a double-power law. The derived lower limit for the IR LD for our sample is ρIR ˜ 3.8 × 107 [L⊙ Mpc-3] and its contributions to the total IR LD, IR LD of all ultra-luminous infrared galaxies, and that of all DOGs are > 3%, > 9%, and > 15%, respectively.

  20. PTF10iya: a short-lived, luminous flare from the nuclear region of a star-forming galaxy

    NASA Astrophysics Data System (ADS)

    Cenko, S. Bradley; Bloom, Joshua S.; Kulkarni, S. R.; Strubbe, Linda E.; Miller, Adam A.; Butler, Nathaniel R.; Quimby, Robert M.; Gal-Yam, Avishay; Ofek, Eran O.; Quataert, Eliot; Bildsten, Lars; Poznanski, Dovi; Perley, Daniel A.; Morgan, Adam N.; Filippenko, Alexei V.; Frail, Dale A.; Arcavi, Iair; Ben-Ami, Sagi; Cucchiara, Antonio; Fassnacht, Christopher D.; Green, Yoav; Hook, Isobel M.; Howell, D. Andrew; Lagattuta, David J.; Law, Nicholas M.; Kasliwal, Mansi M.; Nugent, Peter E.; Silverman, Jeffrey M.; Sullivan, Mark; Tendulkar, Shriharsh P.; Yaron, Ofer

    2012-03-01

    We present the discovery and characterization of PTF10iya, a short-lived (Δt≈ 10 d, with an optical decay rate of ˜0.3 mag d-1), luminous (? mag) transient source found by the Palomar Transient Factory. The ultraviolet/optical spectral energy distribution is reasonably well fitted by a blackbody with T≈ (1-2) × 104 K and peak bolometric luminosity LBB≈ (1-5) × 1044 erg s-1 (depending on the details of the extinction correction). A comparable amount of energy is radiated in the X-ray band that appears to result from a distinct physical process. The location of PTF10iya is consistent with the nucleus of a star-forming galaxy (z= 0.224 05 ± 0.000 06) to within 350 mas (99.7 per cent confidence radius), or a projected distance of less than 1.2 kpc. At first glance, these properties appear reminiscent of the characteristic 'big blue bump' seen in the near-ultraviolet spectra of many active galactic nuclei (AGNs). However, emission-line diagnostics of the host galaxy, along with a historical light curve extending back to 2007, show no evidence for AGN-like activity. We therefore consider whether the tidal disruption of a star by an otherwise quiescent supermassive black hole may account for our observations. Though with limited temporal information, PTF10iya appears broadly consistent with the predictions for the early 'super-Eddington' phase of a solar-type star being disrupted by a ˜107 M⊙ black hole. Regardless of the precise physical origin of the accreting material, the large luminosity and short duration suggest that otherwise quiescent galaxies can transition extremely rapidly to radiate near the Eddington limit; many such outbursts may have been missed by previous surveys lacking sufficient cadence.

  1. A multi-wavelength view of the central kiloparsec region in the luminous infrared galaxy NGC 1614

    SciTech Connect

    Herrero-Illana, Rubén; Pérez-Torres, Miguel Á.; Alberdi, Antxon; Hernández-García, Lorena; Alonso-Herrero, Almudena; Colina, Luis; Efstathiou, Andreas; Miralles-Caballero, Daniel; Väisänen, Petri; Packham, Christopher C.; Rajpaul, Vinesh; Zijlstra, Albert A.

    2014-05-10

    The Luminous Infrared Galaxy NGC 1614 hosts a prominent circumnuclear ring of star formation. However, the nature of the dominant emitting mechanism in its central ∼100 pc is still under debate. We present sub-arcsecond angular resolution radio, mid-infrared, Paα, optical, and X-ray observations of NGC 1614, aimed at studying in detail both the circumnuclear ring and the nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array and the Gemini/T-ReCS 8.7 μm emission, as well as the Paα line emission, show remarkable morphological similarities within the star-forming ring, suggesting that the underlying emission mechanisms are tightly related. We used a Hubble Space Telescope/NICMOS Paα map of similar resolution to our radio maps to disentangle the thermal free-free and non-thermal synchrotron radio emission, from which we obtained the intrinsic synchrotron power law for each individual region within the central kiloparsec of NGC 1614. The radio ring surrounds a relatively faint, steep-spectrum source at the very center of the galaxy, suggesting that the central source is not powered by an active galactic nucleus (AGN), but rather by a compact (r ≲ 90 pc) starburst (SB). Chandra X-ray data also show that the central kiloparsec region is dominated by SB activity, without requiring the existence of an AGN. We also used publicly available infrared data to model-fit the spectral energy distribution of both the SB ring and a putative AGN in NGC 1614. In summary, we conclude that there is no need to invoke an AGN to explain the observed bolometric properties of the galaxy.

  2. NGC 1614 - An IR-luminous merger but not (yet?) an active galaxy

    NASA Technical Reports Server (NTRS)

    Neff, S. G.; Hutchings, J. B.; Standord, S. A.; Unger, S. W.

    1990-01-01

    New observations of the merging galaxy NGC 1614 are described. The system has a nuclear region of QSO-like luminosity, but shows no direct evidence for an active nucleus. It is heavily and unevenly reddened across its nucleus, while infrared imaging also shows a 'ridge' of dust. The inner spiral structure of the galaxy has normal rotation for an inclined disk, as indicated by the H-alpha emission. A linear 'tail' to the S and extended arms to the E have more positive velocities, and probably are the remains of an interacting companion and the tidal plume(s) caused by the collision. The only H I seen in emission appears to coincide with bright knots of H-alpha and forbidden O III emission of the base of the tail. The lack of direct evidence for an active nucleus indicates that if NGC 1614 is a precursor to a Seyfert-like system the AGN has not yet turned on.

  3. Identification of an Extensive Luminous Halo Around the Ringed Spiral Galaxy NGC 7217

    NASA Astrophysics Data System (ADS)

    Buta, R.; van Driel, W.; Braine, J.; Combes, F.

    1993-12-01

    The isolated spiral galaxy NGC 7217 is characterized by flocculent spiral structure and three optical ring-like zones: a stellar nuclear ring, a weak inner pseudoring, and a bright patchy outer ring. The rings all have nearly the same shape and position angle in projection. To understand this kind of ringed galaxy, we have obtained deep CCD BVRI surface photometry and mapping of the CO and HI gas distributions and kinematics. Our images reveal something that was missed in previous studies: a large, nearly round halo of light extending far beyond the outer ring. We interpret this as bulge light which comes back to dominate the luminosity distribution at large radii. Ellipse fits to isophotes out to 240('') radius reveal a minimum axis ratio of 0.83 just outside the outer ring at 90('') , and then a rise to 0.96 at about 140('') . The luminosity profiles are well-fitted by a combined r({1/) 4} bulge and exponential disk model. In all filters, the bulge dominates at all radii, and the bulge-to-total disk ratio is about 2.3 (B). If the minimum axis ratio of 0.83 approximates the apparent flattening of the disk, then NGC 7217 is remarkably axisymmetric. Nevertheless, the I-band image reveals a tightly-wrapped, two-armed spiral pattern in the outer ring region. The outer ring includes 4.5% of the total B luminosity and is the locus of most of the recent star formation in the galaxy; it is also where the HI gas is concentrated. An additional noteworthy feature is a circumnuclear dust ring 1.2 kpc in diameter. Other dust lanes are seen only on the near side of the galaxy. The rings of NGC 7217 could be resonances with a very weak internal perturbation. We are attempting to simulate the structure using the I-band light distribution to help define the potential. But most interesting is the recent discovery of a substantial population of counter-rotating stars in the galaxy (Kuijken 1993, PASP, 105, 1016). One possible explanation for these stars is that the bulge is more

  4. The Dragonfly Galaxy. II. ALMA unveils a triple merger and gas exchange in a hyper-luminous radio galaxy at z = 2

    NASA Astrophysics Data System (ADS)

    Emonts, B. H. C.; De Breuck, C.; Lehnert, M. D.; Vernet, J.; Gullberg, B.; Villar-Martín, M.; Nesvadba, N.; Drouart, G.; Ivison, R.; Seymour, N.; Wylezalek, D.; Barthel, P.

    2015-12-01

    The Dragonfly Galaxy (MRC 0152-209), at redshift z ~ 2, is one of the most vigorously star-forming radio galaxies in the Universe. What triggered its activity? We present ALMA Cycle 2 observations of cold molecular CO(6-5) gas and dust, which reveal that this is likely a gas-rich triple merger. It consists of a close double nucleus (separation ~4 kpc) and a weak CO-emitter at ~10 kpc distance, all of which have counterparts in HST/NICMOS imagery. The hyper-luminous starburst and powerful radio-AGN were triggered at this precoalescent stage of the merger. The CO(6-5) traces dense molecular gas in the central region, and complements existing CO(1-0) data, which reveal more widespread tidal debris of cold gas. We also find ~1010 M⊙ of molecular gas with enhanced excitation at the highest velocities. At least 20-50% of this high-excitation, high-velocity gas shows kinematics that suggests it is being displaced and redistributed within the merger, although with line-of-sight velocities of |v| < 500 km s-1, this gas will probably not escape the system. The processes that drive the redistribution of cold gas are likely related to either the gravitational interaction between two kpc-scale discs, or starburst/AGN-driven outflows. We estimate that the rate at which the molecular gas is redistributed is at least [Ṁentity!#x2009!]~ 1200 ± 500 M⊙ yr-1, and could perhaps even approach the star formation rate of ~3000 ± 800 M⊙ yr-1. The fact that the gas depletion and gas redistribution timescales are similar implies that dynamical processes can be important in the evolution of massive high-z galaxies.

  5. Role of active galactic nuclei in the luminous infrared galaxy phase at z ≤ 3

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Yi; Hashimoto, Yasuhiro; Foucaud, Sébastien

    2016-03-01

    To understand the interactions between active galactic nuclei (AGNs) and star formation during the evolution of galaxies, we investigate 142 galaxies detected in both X-ray and 70 μm observations in the COSMOS (Cosmic Evolution Survey) field. All of our data are obtained from the archive X-ray point-source catalogues from Chandra and XMM-Newton observations, and the far-infrared 70 μm point-source catalogue from Spitzer-MIPS observations. Although the IRAC [3.6 μm]-[4.5 μm] versus [5.8 μm]-[8.0 μm] colours of our sample indicate that only ˜63 per cent of our sources would be classified as AGNs, the ratio of the rest-frame 2-10 keV luminosity to the total infrared luminosity (8-1000 μm) shows that the entire sample has comparatively higher X-ray luminosity than that expected from pure star-forming galaxies, suggesting the presence of an AGN in all of our sources. From an analysis of the X-ray hardness ratio, we find that sources with both 70 μm and X-ray detection tend to have a higher hardness ratio relative to the whole X-ray-selected source population, suggesting the presence of more X-ray absorption in the 70 μm detected sources. In addition, we find that the observed far-infrared colours of 70 μm detected sources with and without X-ray emission are similar, suggesting the far-infrared emission could be mainly powered by star formation.

  6. The distribution of dark and luminous matter in the unique galaxy cluster merger Abell 2146

    NASA Astrophysics Data System (ADS)

    King, Lindsay J.; Clowe, Douglas I.; Coleman, Joseph E.; Russell, Helen R.; Santana, Rebecca; White, Jacob A.; Canning, Rebecca E. A.; Deering, Nicole J.; Fabian, Andrew C.; Lee, Brandyn E.; Li, Baojiu; McNamara, Brian R.

    2016-06-01

    Abell 2146 (z = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the Chandra X-ray Observatory, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the total gravitating mass in the system, using the distorted shapes of distant galaxies seen with Advanced Camera for Surveys - Wide Field Channel on Hubble Space Telescope, is presented. The highest peak in the reconstruction of the projected mass is centred on the brightest cluster galaxy (BCG) in Abell 2146-A. The mass associated with Abell 2146-B is more extended. Bootstrapped noise mass reconstructions show the mass peak in Abell 2146-A to be consistently centred on the BCG. Previous work showed that BCG-A appears to lag behind an X-ray cool core; although the peak of the mass reconstruction is centred on the BCG, it is also consistent with the X-ray peak given the resolution of the weak lensing mass map. The best-fitting mass model with two components centred on the BCGs yields M200 = 1.1^{+0.3}_{-0.4} × 1015 and 3^{+1}_{-2} × 1014 M⊙ for Abell 2146-A and Abell 2146-B, respectively, assuming a mass concentration parameter of c = 3.5 for each cluster. From the weak lensing analysis, Abell 2146-A is the primary halo component, and the origin of the apparent discrepancy with the X-ray analysis where Abell 2146-B is the primary halo is being assessed using simulations of the merger.

  7. VizieR Online Data Catalog: DYNAMO. Hα luminous galaxies sample (Green+, 2014)

    NASA Astrophysics Data System (ADS)

    Green, A. W.; Glazebrook, K.; McGregor, P. J.; Damjanov, I.; Wisnioski, E.; Abraham, R. G.; Colless, M.; Sharp, R. G.; Crain, R. A.; Poole, G. B.; McCarthy, P. J.

    2014-11-01

    We have selected a representative sample of 67 galaxies classified as star forming in the Max-Planck-Institut fur Astrophysik and Johns Hopkins University (MPA-JHU) value-added catalogue (http://www.mpa-garching.mpg.de/SDSS/DR4/) of the Sloan Digital Sky Survey (SDSS, York et al., 2000AJ....120.1579Y). Integral-field spectroscopic data were obtained using two different telescopes; the 3.9m Anglo-Australian Telescope and the ANU 2.3m Telescope, both situated at Siding Spring Observatory, Australia. (4 data files).

  8. The Molecular Gas in Luminous Infrared Galaxies. II. Extreme Physical Conditions and Their Effects on the X co Factor

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Padelis P.; van der Werf, Paul; Xilouris, E.; Isaak, Kate G.; Gao, Yu

    2012-05-01

    In this work, we conclude the analysis of our CO line survey of luminous infrared galaxies (LIRGs: L IR >~ 1011 L ⊙) in the local universe (Paper I) by focusing on the influence of their average interstellar medium (ISM) properties on the total molecular gas mass estimates via the so-called X co = M(H2)/L co, 1-0 factor. One-phase radiative transfer models of the global CO spectral line energy distributions (SLEDs) yield an X co distribution with langX corang ~ (0.6 ± 0.2) M ⊙ (K km s-1 pc2)-1 over a significant range of average gas densities, temperatures, and dynamic states. The latter emerges as the most important parameter in determining X co, with unbound states yielding low values and self-gravitating states yielding the highest ones. Nevertheless, in many (U)LIRGs where available higher-J CO lines (J = 3-2, 4-3, and/or J = 6-5) or HCN line data from the literature allow a separate assessment of the gas mass at high densities (>=104 cm-3) rather than a simple one-phase analysis, we find that near-Galactic X co ~ (3-6) M ⊙ (K km s-1 pc2)-1 values become possible. We further show that in the highly turbulent molecular gas in ULIRGs, a high-density component will be common and can be massive enough for its high X co to dominate the average value for the entire galaxy. Using solely low-J CO lines to constrain X co in such environments (as has been the practice up until now) may have thus resulted in systematic underestimates of molecular gas mass in ULIRGs, as such lines are dominated by a warm, diffuse, and unbound gas phase with low X co but very little mass. Only well-sampled high-J CO SLEDs (J = 3-2 and higher) and/or multi-J observations of heavy rotor molecules (e.g., HCN) can circumvent such a bias, and the latter type of observations may have actually provided early evidence of it in local ULIRGs. The only way that the global X co of such systems could be significantly lower than Galactic is if the average dynamic state of the dense gas is strongly

  9. Completing the CO spectral line energy distribution for luminous starburst galaxies discovered with the SPT

    NASA Astrophysics Data System (ADS)

    Aravena, Manuel; Weiss, Axel; de Breuck, Carlos; Stark, Antony A.; Marrone, Dan; McIntyre, Vince; Vieira, Joaquin; Greve, Thomas; Chapman, Scott; Murphy, Eric; Aguirre, James; Bothwell, Matt; Gullberg, Bitten

    2013-04-01

    We propose to use ATCA to observe the CO J=3-2 line emission in three gravitationally lensed, highly magnified dusty star-forming galaxies at z~2.5 discovered by the South Pole Telescope (SPT) millimeter survey. The redshifts of all targets were identified by the detection of several J>6 CO emission lines with APEX/Z-Spec and confirmed with VLT optical spectroscopy. Two of the sources have significant detections of the CO 1-0 line with ATCA, while CO 1-0 observations of the other source are being requested in a companion proposal. The proposed observations are critical to complete the CO spectral energy distribution (SLED) of these sources and thus "fill the gap" between the high-J CO observed with APEX/Z-Spec and the CO 1-0 line detected with ATCA. This will allow us to constrain the physical conditions of the interstellar medium by comparing the line strengths with large velocity gradient models. The strong magnification is key, allowing us to characterize the CO emission in galaxies that would be otherwise hard to detect.

  10. Studies of Entropy Distributions in X-ray Luminous Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Cavagnolo, K. W.; Donahue, M. E.; Voit, G. M.; Sun, M.; Evrard, A. E.

    2005-12-01

    We present entropy distributions for a sample of galaxy clusters from the Chandra public archive, which builds on our previous analysis of nine nearby, bright clusters. By studying the entropy distribution within clusters we quantify the effect of radiative cooling, supernovae feedback, and AGN feedback on cluster properties. This expanded sample contains both cooling flow and non-cooling flow clusters while our previous work focused only on classical cooling flow clusters. We also test the predictions of Mathiesen and Evrard (2001) by checking whether the spectral fit temperature is an unbiased estimate of the mass-weighted temperature, and how this estimate effects the calculation of the intracluster medium mass. Temperature and entropy maps for the clusters in our sample using the Voronoi Tesselation method as employed by Statler et al (in preparation) will also be presented. These maps serve as a prelude to future work in which we will investigate how well such maps may represent the "true" projected quantities of a cluster by comparing deprojected real and simulated clusters from our sample and the Virtual Cluster Exploratory, respectively. Our discussion focuses on tying together feedback mechanisms with the breaking of self-similar relations expected in cluster and galaxy formation models.

  11. ROSAT HRI and ASCA Observations of the Spiral Galaxy NGC 6946 and its Northeast Complex of Luminous Supernova Remnants

    NASA Technical Reports Server (NTRS)

    Schlegel, E.; Swank, Jean (Technical Monitor)

    2001-01-01

    Analysis of 80 ks ASCA (Advanced Satellite for Cosmology and Astrophysics) and 60 ks ROSAT HRI (High Resolution Image) observations of the face-on spiral galaxy NGC 6946 are presented. The ASCA image is the first observation of this galaxy above approximately 2 keV. Diffuse emission may be present in the inner approximately 4' extending to energies above approximately 2-3 keV. In the HRI data, 14 pointlike sources are detected, the brightest two being a source very close to the nucleus and a source to the northeast that corresponds to a luminous complex of interacting supernova remnants (SNRs). We detect a point source that lies approximately 30" west of the SNR complex but with a luminosity -1115 of the SNR complex. None of the point sources show evidence of strong variability; weak variability would escape our detection. The ASCA spectrum of the SNR complex shows evidence for an emission line at approximately 0.9 keV that could be either Ne IX at approximately 0.915 keV or a blend of ion stages of Fe L-shell emission if the continuum is fitted with a power law. However, a two-component, Raymond-Smith thermal spectrum with no lines gives an equally valid continuum fit and may be more physically plausible given the observed spectrum below 3 keV. Adopting this latter model, we derive a density for the SNR complex of 10-35 cm(exp -3), consistent with estimates inferred from optical emission-line ratios. The complex's extraordinary X-ray luminosity may be related more to the high density of the surrounding medium than to a small but intense interaction region where two of the complex's SNRs are apparently colliding.

  12. Resolving the Large Scale Spectral Variability of the Luminous Seyfert 1 Galaxy 1H 0419-577

    NASA Technical Reports Server (NTRS)

    Pounds, K. A.; Reeves, J. N.; Page, K. L.; OBrien, P. T.

    2004-01-01

    An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 in September 2002, when the source was in an extreme low-flux state, found a very hard X-ray spectrum at 1-10 keV with a strong soft excess below approximately 1 keV. Comparison with an earlier XMM-Newton observation when 1H 0419-577 was X-ray bright indicated the dominant spectral variability was due to a steep power law or cool Comptonized thermal emission. Four further XMM-Newton observations, with 1H 0419-577 in intermediate flux states, now support that conclusion, while we also find the variable emission component in intermediate state difference spectra to be strongly modified by absorption in low ionisation matter. The variable soft excess is seen to be an artefact of absorption of the underlying continuum while the core soft emission is attributed to recombination in an extended region of more highly ionised gas. This new analysis underlines the importance of fully accounting for absorption in characterizing AGN X-ray spectra.

  13. Discovery of a 3.6-hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Rappaport, Saul; Tennant, Allyn F.; Swartz, Douglas A.; Pooley, David; Madhusudhan, N.

    2006-01-01

    We report the discovery of an eclipsing X-ray binary with a 3.62-hr period within 24 arcsec of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the binary, and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an X-ray luminosity of up to 7e38. In this case the binary may well be comprised of a naked He-burning donor star with a neutron-star accretor, though a stellar-mass black-hole accretor cannot be completely excluded. There is no obvious evidence for a strong stellar wind in the X-ray orbital light curve that would be expected from a massive He star; thus, the mass of the He star should be <3-4 solar masses. If correct, this would represent a new class of very luminous X-ray binary----perhaps related to Cyg X-3. Other less likely possibilities include a conventional low-mass X-ray binary that somehow manages to produce such a high X-ray luminosity and is apparently persistent over an interval of years; or a foreground AM Her binary of much lower luminosity that fortuitously lies in the direction of NGC 4214. Any model for this system must accommodate the lack of an optical counterpart down to a limiting magnitude of 22.6 in the visible.

  14. THE BLACK HOLE SPIN AND SOFT X-RAY EXCESS OF THE LUMINOUS SEYFERT GALAXY FAIRALL 9

    SciTech Connect

    Lohfink, Anne M.; Reynolds, Christopher S.; Mushotzky, Richard F.; Miller, Jon M.; Brenneman, Laura W.; Nowak, Michael A.; Fabian, Andrew C.

    2012-10-10

    We present an analysis of all XMM-Newton and Suzaku X-ray spectra of the nearby luminous Seyfert galaxy Fairall 9. Confirming previous analyses, we find robust evidence for a broad iron line associated with X-ray reflection from the innermost accretion disk. By fitting a spectral model that includes a relativistically ionized reflection component, we examine the constraints on the inclination of the inner accretion disk and the black hole spin, and the complications introduced by the presence of a photoionized emission line system. Employing multi-epoch fitting, we attempt to obtain robust and concordant measures of the accretion disk parameters. We also clearly see a soft X-ray excess in Fairall 9. During certain epochs, the soft excess can be described with the same disk reflection component that produces the iron line. However, there are epochs where an additional soft component is required. This can be attributed to either an additional highly ionized, strongly blurred disk reflection component or a new X-ray continuum component.

  15. A High Resolution, Unobscured View of the Active Regions in (Ultra) Luminous Infrared Galaxies from a VLA 33 GHz Survey

    NASA Astrophysics Data System (ADS)

    Barcos-Muñoz, L.; Leroy, A.; Evans, A.; et al.

    2016-06-01

    I will present a new survey of 33 GHz radio continuum emission from local U/LIRGs carried out using the Karl G. Jansky Very Large Array (VLA). This is the first such survey and it combines high resolution, good sensitivity, and multi-configuration observations that should have sensitivity to emission on all spatial scales. (Ultra) luminous infrared galaxies host some of the most extreme star-forming environments in the local universe, with large reservoirs of molecular gas and dust concentrated in the central few kpc. Our VLA observations allow us to see through the dust in these systems to resolve the sizes of their active regions, which is essential to understand the surface and volume densities of star formation and gas in these extreme systems. I will present the best size measurements to date of the active regions for our 22 targets. I will show what these sizes imply about gas volume and surface density and infrared luminosity surface densities. I will also lay out the physical implications of these values for the strength of star formation and feedback (especially radiative feedback) in extreme environments.

  16. FAST MOLECULAR OUTFLOWS IN LUMINOUS GALAXY MERGERS: EVIDENCE FOR QUASAR FEEDBACK FROM HERSCHEL

    SciTech Connect

    Veilleux, S.; Meléndez, M.; Sturm, E.; Gracia-Carpio, J.; Contursi, A.; Lutz, D.; Poglitsch, A.; Davies, R.; Genzel, R.; Tacconi, L.; De Jong, J. A.; Fischer, J.; González-Alfonso, E.; Sternberg, A.; Netzer, H.; Hailey-Dunsheath, S.; Verma, A.; Rupke, D. S. N.; Maiolino, R.; Teng, S. H. E-mail: marcio@astro.umd.edu; and others

    2013-10-10

    We report the results from a systematic search for molecular (OH 119 μm) outflows with Herschel/PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7 μm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than –50 km s{sup –1}, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (∼145°) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km s{sup –1}, is seen in only four objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of ∼–1000 km s{sup –1} are measured in several objects, but median outflow velocities are typically ∼–200 km s{sup –1}. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large active galactic nucleus (AGN) fractions and luminosities [log (L{sub AGN}/L{sub ☉}) ≥ 11.8 ± 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. However, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.

  17. Fast Molecular Outflows in Luminous Galaxy Mergers: Evidence for Quasar Feedback from Herschel

    NASA Technical Reports Server (NTRS)

    Veilleux, S.; Melendez, M.; Sturm, E.; Garcia-Carpio, J.; Fischer, J.; Gonzalez-Alfonso, E.; Contursi, A.; Lutz, D.; Poglitsch, A.; Davies, R.; Genzel, R.; Tacconi, L.; deJong, J. A.; Sternberg, A.; Netzer, H.; Hailey-Dunsheath, S.; Verma, A.; Rupke, D. S. N.; Maiolino, R.; Teng, S. H.; Polisensky, E.

    2013-01-01

    We report the results from a systematic search for molecular (OH 119 micron) outflows with Herschel/PACS in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7 micron silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than-50 km/s, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (approx. 145 deg.) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km/s is seen in only four objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of approx. -1000 km/s are measured in several objects, but median outflow velocities are typically approx.-200 km/s-1. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large active galactic nucleus (AGN) fractions and luminosities [log (L(sub AGN)/L(sub solar)) => 11.8 +/- 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. However, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.

  18. AGN feedback in X-ray luminous galaxy cluster: PKS 0745-191

    NASA Astrophysics Data System (ADS)

    Sonkamble, Satish Shripati; Vagshette, Nilkanth Dattatray; Patil, Madhav Khushalrao

    2015-08-01

    We present 117 ks Chandra observation of the cooling flow cluster PKS 0745-191 providing evidence of the strong interaction between the radio source associated with the center dominant galaxy PGC 021813 and the intra-cluster gas. This system is one of the strongest cool core cluster, requiring extreme mechanical feedback from its central AGN to offset cooling of the ICM. This analysis has enabled us to detect two pairs of X-ray cavities in the central ˜ 20 kpc region. In addition to the cavities, we have also evidenced relatively cooler X-ray arc and a temperature jump due to the shock front at 92'' (184 kpc) on the western side. 2D temperature maps as well as spectral analysis of X-ray photons extracted from wedge shaped reigns revealed six different cold fronts, 3 along the eastern direction, 2 on the west direction and one in the south direction of the X-ray peak. The apparent positions of cold fronts are found to match with the spiral structure apparent in the X-ray surface brightness distribution of PKS 0745-191 that is probably due to the gas sloshing. The Mach number for this shock is found to be ˜ 1.36. Systematic study of the X-ray cavities revealed a mechanical power of ˜ 2.95 X 1045 erg s-1 and is sufficient to offset the cooling due to radiative loss. We found that the radio source associated with the center dominant galaxy of this cluster is efficient enough to carve the observed cavities. The ratio of radio luminosity to mechanical cavity power is ˜ 10-3 .

  19. Half of the Most Luminous Quasars May Be Obscured: Investigating the Nature of WISE-Selected Hot Dust-Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Assef, R. J.; Eisenhardt, P. R. M.; Stern, D.; Tsai, C.-W.; Wu, J.; Wylezalek, D.; Blain, A. W.; Bridge, C. R.; Donoso, E.; Gonzales, A.; Griffith, R. L.; Jarrett, T. H.

    2015-05-01

    The Wide-field Infrared Survey Explorer mission has unveiled a rare population of high-redshift (z = 1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities {{L}IR}\\gt {{10}13} {{L}⊙ }, and sometimes exceeding {{10}14} {{L}⊙ }. Previous work has shown that their dust temperatures and overall far-infrared spectral energy distributions (SEDs) are significantly hotter than expected to be powered by star formation. We present here an analysis of the rest-frame optical through mid-infrared SEDs for a large sample of these so-called “hot, dust-obscured galaxies” (Hot DOGs). We find that the SEDs of Hot DOGs are generally well modeled by the combination of a luminous, yet obscured active galactic nuclei (AGNs) that dominates the rest-frame emission at λ \\gt 1 μ m and the bolometric luminosity output, and a less luminous host galaxy that is responsible for the bulk of the rest optical/UV emission. Even though the stellar mass of the host galaxies may be as large as 1011-1012 M⊙, the AGN emission, with a range of luminosities comparable to those of the most luminous QSOs known, require that either Hot DOGs have black hole masses significantly in excess of the local relations, or that they radiate significantly above the Eddington limit, at a level at least 10 times more efficiently than z ˜ 2 QSOs. We show that, while rare, the number density of Hot DOGs is comparable to that of equally luminous but unobscured (i.e., Type 1) QSOs. This may be at odds with the trend suggested at lower luminosities for the fraction of obscured AGNs to decrease with increasing luminosity. That trend may, instead, reverse at higher luminosities. Alternatively, Hot DOGs may not be the torus-obscured counterparts of the known optically selected, largely unobscured, hyper-luminous QSOs, and may represent a new component of the galaxy evolution paradigm. Finally, we discuss the environments of Hot DOGs and statistically show that these objects are in regions as dense as

  20. A population of massive, luminous galaxies hosting heavily dust-obscured gamma-ray bursts: Implications for the use of GRBs as tracers of cosmic star formation

    SciTech Connect

    Perley, D. A.; Levan, A. J.; Tanvir, N. R.; Cenko, S. B.; Bloom, J. S.; Filippenko, A. V.; Morgan, A. N.; Hjorth, J.; Krühler, T.; Fynbo, J. P. U.; Milvang-Jensen, B.; Fruchter, A.; Kalirai, J.; Jakobsson, P.; Prochaska, J. X.

    2013-12-01

    We present observations and analysis of the host galaxies of 23 heavily dust-obscured gamma-ray bursts (GRBs) observed by the Swift satellite during the years 2005-2009, representing all GRBs with an unambiguous host-frame extinction of A{sub V} > 1 mag from this period. Deep observations with Keck, Gemini, Very Large Telescope, Hubble Space Telescope, and Spitzer successfully detect the host galaxies and establish spectroscopic or photometric redshifts for all 23 events, enabling us to provide measurements of the intrinsic host star formation rates, stellar masses, and mean extinctions. Compared to the hosts of unobscured GRBs at similar redshifts, we find that the hosts of dust-obscured GRBs are (on average) more massive by about an order of magnitude and also more rapidly star forming and dust obscured. While this demonstrates that GRBs populate all types of star-forming galaxies, including the most massive, luminous systems at z ≈ 2, at redshifts below 1.5 the overall GRB population continues to show a highly significant aversion to massive galaxies and a preference for low-mass systems relative to what would be expected given a purely star-formation-rate-selected galaxy sample. This supports the notion that the GRB rate is strongly dependent on metallicity, and may suggest that the most massive galaxies in the universe underwent a transition in their chemical properties ∼9 Gyr ago. We also conclude that, based on the absence of unobscured GRBs in massive galaxies and the absence of obscured GRBs in low-mass galaxies, the dust distributions of the lowest-mass and the highest-mass galaxies are relatively homogeneous, while intermediate-mass galaxies (∼10{sup 9} M {sub ☉}) have diverse internal properties.

  1. SN 2010ay is a Luminous and Broad-lined Type Ic Supernova within a Low-metallicity Host Galaxy

    NASA Astrophysics Data System (ADS)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.; Hodapp, K. W.; Jedicke, R.; Kaiser, N.; Kirshner, R. P.; Kudritzki, R.-P.; Luppino, G. A.; Lupton, R. H.; Magnier, E. A.; Monet, D. G.; Morgan, J. S.; Onaka, P. M.; Price, P. A.; Stubbs, C. W.; Tonry, J. L.; Wainscoat, R. J.; Waterson, M. F.

    2012-09-01

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3π survey just ~4 days after explosion. The supernova (SN) had a peak luminosity, MR ≈ -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si ≈ 19 × 103 km s-1 at ~40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines ~2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56Ni, M Ni = 0.9 M ⊙. Applying scaling relations to the light curve, we estimate a total ejecta mass, M ej ≈ 4.7 M ⊙, and total kinetic energy, EK ≈ 11 × 1051 erg. The ratio of M Ni to M ej is ~2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H)PP04 + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and ~0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E γ <~ 6 × 1048 erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E >~ 1048 erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF 060218. If this SN did not harbor a GRB, these observations challenge the importance of progenitor metallicity for the production of relativistic ejecta and suggest that other parameters

  2. SN 2010ay Is a Luminous and Broad-Lined Type Ic Supernova Within a Low-Metallicity Host Galaxy

    NASA Technical Reports Server (NTRS)

    Sanders, N. E.; Soderberg, A. M.; Valenti, S.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Smartt, S.; Hurley, K.; Barthelmy, S. D.; Levesque, E. M.; Narayan, G.; Botticella, M. T.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Gehrels, N.; Golenetskii, S.; Mazets, E.; Cline, T.; von Kienlin, A.; Boynton, W.; Chambers, K. C.; Grav, T.; Heasley, J. N.

    2012-01-01

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3pi survey just approximately 4 days after explosion. The supernova (SN) had a peak luminosity, MR approx. -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si (is) approx. 19×10(exp 3) km s-1 at approximately 40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines approximately 2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of 56Ni, MNi = 0.9 solar mass. Applying scaling relations to the light curve, we estimate a total ejecta mass, Mej (is) approx. 4.7 solar mass, and total kinetic energy, EK (is) approx. 11 × 10(exp 51) erg. The ratio of MNi to Mej is approximately 2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log(O/H)PP04 + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and (is) approximately 0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E(gamma) (is) approximately less than 6 × 10(exp 48) erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E (is) approximately greater than 10(exp 48) erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less-stringent constraints on a weak afterglow like that seen from XRF

  3. The most luminous H α emitters at z ˜ 0.8-2.23 from HiZELS: evolution of AGN and star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Sobral, David; Kohn, Saul A.; Best, Philip N.; Smail, Ian; Harrison, Chris M.; Stott, John; Calhau, João; Matthee, Jorryt

    2016-04-01

    We use new near-infrared spectroscopic observations to investigate the nature and evolution of the most luminous Hα emitters at z ˜ 0.8-2.23, which evolve strongly in number density over this period, and compare them to more typical Hα emitters. We study 59 luminous Hα emitters with LHα > L_{Hα }^{ast }, roughly equally split per redshift slice at z ˜ 0.8, 1.47 and 2.23 from the HiZELS and CF-HiZELS surveys. We find that, overall, 30 ± 8 per cent are active galactic nuclei [AGNs; 80 ± 30 per cent of these AGNs are broad-line AGNs, BL-AGNs], and we find little to no evolution in the AGN fraction with redshift, within the errors. However, the AGN fraction increases strongly with Hα luminosity and correlates best with LHα/L_{Hα }^{ast }(z). While LHα ≤ L_{Hα }^{ast }(z) Hα emitters are largely dominated by star-forming galaxies (>80 per cent), the most luminous Hα emitters (L_{Hα }>10L_{Hα }^{ast }(z)) at any cosmic time are essentially all BL-AGN. Using our AGN-decontaminated sample of luminous star-forming galaxies, and integrating down to a fixed Hα luminosity, we find a factor of ˜1300 evolution in the star formation rate density from z = 0 to 2.23. This is much stronger than the evolution from typical Hα star-forming galaxies and in line with the evolution seen for constant luminosity cuts used to select `ultraluminous' infrared galaxies and/or sub-millimetre galaxies. By taking into account the evolution in the typical Hα luminosity, we show that the most strongly star-forming Hα-selected galaxies at any epoch (L_{Hα }>L^{ast }_{Hα }(z)) contribute the same fractional amount of ≈15 per cent to the total star formation rate density, at least up to z = 2.23.

  4. Characterizing the chemically enriched circumgalactic medium of ˜38 000 luminous red galaxies in SDSS DR12

    NASA Astrophysics Data System (ADS)

    Huang, Yun-Hsin; Chen, Hsiao-Wen; Johnson, Sean D.; Weiner, Benjamin J.

    2016-01-01

    We report a definitive detection of chemically enriched cool gas around massive quiescent galaxies at z ≈ 0.4-0.7. The result is based on a survey of 37 621 luminous red galaxy (LRG)-quasi-stellar object pairs in SDSS DR12 with projected distance d < 500 kpc. The LRGs are characterized by a predominantly old stellar population (age ≳ 1 Gyr) with 13 per cent displaying [O II] emission features and LINER-like spectra. Both passive and [O II]-emitting LRGs share the same stellar mass distribution with a mean of ≈ 11.4 and a dispersion of 0.2 dex. Both LRG populations exhibit associated strong Mg II absorbers out to d < 500 kpc. The mean gas covering fraction at d ≲ 120 kpc is < κ rangle _{Mg II} > 15 per cent and declines quickly to < κ rangle _{Mg II} ≈ 5 per cent at d ≲ 500 kpc. No clear dependence on stellar mass is detected for the observed Mg II absorption properties. The observed velocity dispersion of Mg II-absorbing gas relative to either passive or [O II]-emitting LRGs is merely 60 per cent of what is expected from virial motion in these massive haloes. While no apparent azimuthal dependence is seen for < κ rangle _{Mg II} around passive LRGs at all radii, a modest enhancement in < κ rangle _{Mg II} is detected along the major axis of [O II]-emitting LRGs at d < 50 kpc. The suppressed velocity dispersion of Mg II-absorbing gas around both passive and [O II]-emitting LRGs, together with an elevated < κ rangle _{Mg II} along the major axis of [O II]-emitting LRGs at d < 50 kpc, provides important insights into the origin of the observed chemically enriched cool gas in LRG haloes. We consider different scenarios and conclude that the observed Mg II absorbers around LRGs are best explained by a combination of cool clouds formed in thermally unstable LRG haloes and satellite accretion through filaments.

  5. Supernova 2013fc in a circumnuclear ring of a luminous infrared galaxy: the big brother of SN 1998S

    NASA Astrophysics Data System (ADS)

    Kangas, T.; Mattila, S.; Kankare, E.; Lundqvist, P.; Väisänen, P.; Childress, M.; Pignata, G.; McCully, C.; Valenti, S.; Vinkó, J.; Pastorello, A.; Elias-Rosa, N.; Fraser, M.; Gal-Yam, A.; Kotak, R.; Kotilainen, J. K.; Smartt, S. J.; Galbany, L.; Harmanen, J.; Howell, D. A.; Inserra, C.; Marion, G. H.; Quimby, R. M.; Silverman, J. M.; Szalai, T.; Wheeler, J. C.; Ashall, C.; Benetti, S.; Romero-Cañizales, C.; Smith, K. W.; Sullivan, M.; Takáts, K.; Young, D. R.

    2016-02-01

    We present photometric and spectroscopic observations of SN 2013fc, a bright type II supernova (SN) in a circumnuclear star-forming ring in the luminous infrared galaxy ESO 154-G010, observed as part of the Public ESO Spectroscopic Survey of Transient Objects. SN 2013fc is both photometrically and spectroscopically similar to the well-studied type IIn SN 1998S and to the bright type II-L SN 1979C. It exhibits an initial linear decline, followed by a short plateau phase and a tail phase with a decline too fast for 56Co decay with full γ-ray trapping. Initially, the spectrum was blue and featureless. Later on, a strong broad (˜8000 km s-1) H α emission profile became prominent. We apply a STARLIGHT stellar population model fit to the SN location (observed when the SN had faded) to estimate a high extinction of AV = 2.9 ± 0.2 mag and an age of 10_{-2}^{+3} Myr for the underlying cluster. We compare the SN to SNe 1998S and 1979C and discuss its possible progenitor star considering the similarities to these events. With a peak brightness of B = -20.46 ± 0.21 mag, SN 2013fc is 0.9 mag brighter than SN 1998S and of comparable brightness to SN 1979C. We suggest that SN 2013fc was consistent with a massive red supergiant (RSG) progenitor. Recent mass loss probably due to a strong RSG wind created the circumstellar matter illuminated through its interaction with the SN ejecta. We also observe a near-infrared excess, possibly due to newly condensed dust.

  6. Sub-kpc star formation law in the local luminous infrared galaxy IC 4687 as seen by ALMA

    NASA Astrophysics Data System (ADS)

    Pereira-Santaella, M.; Colina, L.; García-Burillo, S.; Planesas, P.; Usero, A.; Alonso-Herrero, A.; Arribas, S.; Cazzoli, S.; Emonts, B.; Piqueras López, J.; Villar-Martín, M.

    2016-03-01

    We analyze the spatially resolved (250 pc scales) and integrated star formation (SF) law in the local luminous infrared galaxy (LIRG) IC 4687. This is one of the first studies of the SF law on a starburst LIRG at these small spatial scales. We combined new interferometric ALMA CO(2-1) data with existing HST/NICMOS Paα narrowband imaging and VLT/SINFONI near-IR integral field spectroscopy to obtain accurate extinction-corrected SF rate (SFR) and cold molecular gas surface densities (Σgas and ΣSFR). We find that IC 4687 forms stars very efficiently with an average depletion time (tdep) of 160 Myr for the individual 250 pc regions. This is approximately one order of magnitude shorter than the tdep of local normal spirals and also shorter than that of main-sequence high-z objects, even when we use a Galactic αCO conversion factor. This result suggests a bimodal SF law in the ΣSFR∝ΣgasN representation. A universal SF law is recovered if we normalize the Σgas by the global dynamical time. However, at the spatial scales studied here, we find that the SF efficiency (or tdep) does not depend on the local dynamical time for this object. Therefore, an alternative normalization (e.g., free-fall time) should be found if a universal SF law exists at these scales. A FITS file for the reduced datacube 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/A44

  7. A comparison of the morphological properties between local and z ∼ 1 infrared luminous galaxies: Are local and high-z (U)LIRGs different?

    SciTech Connect

    Hung, Chao-Ling; Sanders, D. B.; Larson, Kirsten L.; Lee, Nicholas; Li, Yanxia; Lockhart, Kelly; Shih, Hsin-Yi; Barnes, Joshua E.; Casey, Caitlin M.; Koss, Michael; Kartaltepe, Jeyhan S.; Smith, Howard A.

    2014-08-10

    Ultraluminous and luminous infrared galaxies (ULIRGs and LIRGs) are the most extreme star-forming galaxies in the universe and dominate the total star formation rate density at z > 1. In the local universe (z < 0.3), the majority of ULIRGs and a significant portion of LIRGs are triggered by interactions between gas-rich spiral galaxies, yet it is unclear if this is still the case at high z. To investigate the relative importance of galaxy interactions in infrared luminous galaxies, we carry out a comparison of optical morphological properties between local (U)LIRGs and (U)LIRGs at z = 0.5-1.5 based on the same sample selection, morphology classification scheme, and optical morphology at similar rest-frame wavelengths. In addition, we quantify the systematics in comparing local and high-z data sets by constructing a redshifted data set from local (U)LIRGs, in which its data quality mimics the high-z data set. Based on the Gini-M{sub 20} classification scheme, we find that the fraction of interacting systems decreases by ∼8% from local to z ≲ 1, and it is consistent with the reduction between local and redshifted data sets (6{sub −6}{sup +14}%). Based on visual classifications, the merger fraction of local ULIRGs is found to be ∼20% lower compared to published results, and the reduction due to redshifting is 15{sub −8}{sup +10}%. Consequently, the differences of merger fractions between local and z ≲ 1 (U)LIRGs is only ∼17%. These results demonstrate that there is no strong evolution in the fraction of (U)LIRGs classified as mergers at least out to z ∼ 1. At z > 1, the morphology types of ∼30% of (U)LIRGs cannot be determined due to their faintness in the F814W band; thus, the merger fraction measured at z > 1 suffers from large uncertainties.

  8. Comparing FIR, UV and SED star formation rates for IR-luminous galaxies at 1≤z≤2 in CANDELS

    NASA Astrophysics Data System (ADS)

    Pforr, Janine; Dickinson, Mark; Kartaltepe, Jeyhan; Inami, Hanae; Penner, Kyle

    2015-08-01

    Galaxy formation and evolution studies rely on the robust determination of galaxy properties such as stellar masses and star formation rates (SFR). One the one hand these are important to distinguish between star bursting galaxies, normally star forming galaxies and those in the process of quenching and reveal the underlying processes causing these phenomena. On the other hand, they are crucial to derive reliable estimates of global properties like the star formation rate density of the Universe and the stellar mass assembly. We exploit the excellent multi-wavelength data in the GOODS-S, GOODS-N, UDS and COSMOS CANDELS fields ranging from deep ground and space-based optical data, deep-NIR HST data from CANDELS to the deepest FIR PACS data available from CANDELS-Herschel and Pep/GOODS-Herschel to estimate SFRs of IR-luminous galaxies between redshift 1 and 2. We determine SFRs in three different ways:1) from SED-fitting to the optical/IR multi-wavelength data, 2) from far-IR luminosities using 24 micron and Herschel PACS fluxes and 3) from UV slope and UV luminosity measurements. While for the majority of objects the different estimates agree very well, we find a subsample of outliers that are classified as pseudo-quiescent by the SED-fit. We present possible reasons for these misclassifications as well as potential remedies.

  9. ALMA DETECTION OF THE VIBRATIONALLY EXCITED HCN J = 4-3 EMISSION LINE IN THE AGN-HOSTING LUMINOUS INFRARED GALAXY IRAS 20551–4250

    SciTech Connect

    Imanishi, Masatoshi; Nakanishi, Kouichiro

    2013-10-01

    We present results from our ALMA Cycle 0 observations, at the frequencies around the HCN, HCO{sup +}, and HNC J = 4-3 transition lines, of the luminous infrared galaxy IRAS 20551–4250 at z = 0.043, which is known to host an energetically important obscured active galactic nucleus (AGN). In addition to the targeted HCN, HCO{sup +}, and HNC J = 4-3 emission lines, two additional strong emission lines are seen, which we attribute to H{sub 2}S and CH{sub 3}CN(+CCH). The HCN-to-HCO{sup +} J = 4-3 flux ratio (∼0.7) is higher than in the other starburst-dominated galaxy (∼0.2) observed in our ALMA Cycle 0 program. We tentatively (∼5σ) detected the vibrationally excited (v {sub 2} = 1) HCN J = 4-3 (l = 1f) emission line, which is important for testing an infrared radiative pumping scenario for HCN. This is the second detection of this molecular transition in external galaxies. The most likely reason for this detection is not only the high flux of this emission line, but also the small molecular line widths observed in this galaxy, suggesting that vibrational excitation of HCN may be relatively common in AGN-hosting galaxies.

  10. SN 2010ay IS A LUMINOUS AND BROAD-LINED TYPE Ic SUPERNOVA WITHIN A LOW-METALLICITY HOST GALAXY

    SciTech Connect

    Sanders, N. E.; Soderberg, A. M.; Foley, R. J.; Chornock, R.; Chomiuk, L.; Berger, E.; Valenti, S.; Smartt, S.; Botticella, M. T.; Hurley, K.; Barthelmy, S. D.; Gehrels, N.; Cline, T.; Levesque, E. M.; Narayan, G.; Briggs, M. S.; Connaughton, V.; Terada, Y.; Golenetskii, S.; Mazets, E.; and others

    2012-09-10

    We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3{pi} survey just {approx}4 days after explosion. The supernova (SN) had a peak luminosity, M{sub R} Almost-Equal-To -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v{sub Si} Almost-Equal-To 19 Multiplication-Sign 10{sup 3} km s{sup -1} at {approx}40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover, the velocity declines {approx}2 times slower than other SNe Ic-BL and GRB-SNe. Assuming that the optical emission is powered by radioactive decay, the peak magnitude implies the synthesis of an unusually large mass of {sup 56}Ni, M{sub Ni} = 0.9 M{sub Sun }. Applying scaling relations to the light curve, we estimate a total ejecta mass, M{sub ej} Almost-Equal-To 4.7 M{sub Sun }, and total kinetic energy, E{sub K} Almost-Equal-To 11 Multiplication-Sign 10{sup 51} erg. The ratio of M{sub Ni} to M{sub ej} is {approx}2 times as large for SN 2010ay as typical GRB-SNe and may suggest an additional energy reservoir. The metallicity (log (O/H){sub PP04} + 12 = 8.19) of the explosion site within the host galaxy places SN 2010ay in the low-metallicity regime populated by GRB-SNe, and {approx}0.5(0.2) dex lower than that typically measured for the host environments of normal (broad-lined) SNe Ic. We constrain any gamma-ray emission with E{sub {gamma}} {approx}< 6 Multiplication-Sign 10{sup 48} erg (25-150 keV), and our deep radio follow-up observations with the Expanded Very Large Array rule out relativistic ejecta with energy E {approx}> 10{sup 48} erg. We therefore rule out the association of a relativistic outflow like those that accompanied SN 1998bw and traditional long-duration gamma-ray bursts (GRBs), but we place less