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Sample records for low-ion qso absorption-line

  1. A catalogue of absorption-line systems in QSO spectra

    NASA Astrophysics Data System (ADS)

    Ryabinkov, A. I.; Kaminker, A. D.; Varshalovich, D. A.

    2003-12-01

    We present a new catalog of absorption-line systems identified in the quasar spectra. It contains data on 821 QSOs and 8558 absorption systems comprising 16 139 absorption lines with measured redshifts in the QSO spectra. The catalog includes absorption-line systems consisting of lines of heavy elements, lines of neutral hydrogen, Lyman limit systems, damped Lyα absorption systems, and broad absorption-line systems. Using the data of the present catalog we also discuss redshift distributions of absorption-line systems. Tables 1 and 2 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/707

  2. The Early Universe Probed by QSO Absorption Lines

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Iye, Masanori

    2000-12-01

    High-z QSOs are valuable probes of the early universe and provide us information on the era of galaxy formation. QSOs can also be used as background sources against intervening objects such as proto-galactic clouds and faint foreground galaxies. These intervening objects produce absorption lines in the spectra of background QSOs. Gas clouds producing metal absorption lines are thought to exist in the halos of intervening galaxies and are used to evaluate the metal abundances of galaxies at high redshifts. In the course of studying the evolution of metal absorption lines, it was found that the number of absorbers per unit redshift interval increases in the vicinity of QSOs, especially of radio-loud QSOs. The reason of such an excess of metal absorption lines remains still unclear. In this paper, the authors review the absorption properties and enigmas of quasar absorption lines.

  3. Active Galactic Nuclei Probed by QSO Absorption Lines

    NASA Astrophysics Data System (ADS)

    Misawa, Toru

    2007-07-01

    Quasars are the extremely bright nuclei found in about 10% of galaxies. A variety of absorption features (known collectively as quasar absorption lines) are detected in the rest-frame UV spectra of these objects. While absorption lines that have very broad widths originate in gas that is probably physocally related to the quasars, narrow absorption lines (NALs) were thought to arise in galaxies and/or in the intter-alacttic medium between the quasars and us. Using high-resolution spectra of quasars, it is found that a substantial fraction of NALs arise in gas in the immediate vicinity of the quasars. A dramatically variable, moderately-broad absorption line in the spectrum of the quasar HS 1603+3820l is also found. The variability of this line is monitored in a campaign with Subaru telescope. These observational results are compared to models for outflows from the quasars, specifically, models for accretion disk winds and evaporating obscuring tori. It is quite important to determine the mechanism of outflow because of its cosmological implications. The outflow could expel angular momentum from the accretion disk and enable quasars to accrete and shine. In addition, the outflow may also regulate star formation in the early stages of the assembly of the host galaxy and enrich the interstellar and intergalactic medium with metals.

  4. Terminal Velocity Infall in QSO Absorption Line Halos

    NASA Astrophysics Data System (ADS)

    Benjamin, Robert A.

    We explore the hypothesis that clouds detected in quasar absorption line systems are falling at a terminal velocity toward the center of high redshift gaseous galactic halos. Since both the ionization level and terminal velocity of halo clouds increase with increasing distance from the central galaxy, velocity resolved profiles of highly ionized gas are predicted to have a greater width than low ionization gas. A line of sight passing through the center of gaseous halo (an idealized damped Ly alpha system), yields low ionization absorption at the velocity of the galaxy, flanked by high ionization on either side. Reasonable halo parameters yield total velocity extents for C IV of Delta v_{C IV}=100-200 km s^{-1}, in agreement with many systems observed by Lu et al (1997). The remaining systems may better described by the rotating disk model of Prochaska & Wolfe (1998). Finally, observational tests are suggested for verifying or falsifying the terminal velocity hypothesis for these systems.

  5. Variability of the broad absorption lines in the QSO UM 232

    NASA Technical Reports Server (NTRS)

    Barlow, Thomas A.; Junkkarinen, Vesa T.; Burbidge, E. Margaret

    1989-01-01

    Low-resolution spectra of UM 232 taken in 1978, 1979, and 1988 at Lick Observatory are presented. Large changes in the Si IV lambda 1397, CIV lambda 1549, and Al III lambda 1857 broad absorption lines are apparent. The decrease in column density in all three ions and an observed brightening of the QSO suggests that these changes are due to an increase in the ionization level driven by an increase in the central source luminosity. This mechanism has been proposed by Smith and Penston to explain small changes in the absorption spectrum of the QSO 1246-057. The spectra of UM 232 show that the fractional decrease in optical depth is smaller at higher outflow velocies. The structure of the broad absorption-line region (BALR) is investigted by estimating an ionization parameter for each ion species as a function of velocity.

  6. PG 1700 + 518 - a low-redshift, broad absorption line QSO

    SciTech Connect

    Pettini, M.; Boksenberg, A.

    1985-07-01

    The first high-resolution optical spectra and lower resolution UV spectra of PG 1700 + 518, the only known broad-absorption-line (BAL) QSO at low emission redshift (0.288) are presented. The optical data were obtained with the Isaac Newton Telescope on the island of La Palma and the UV data with the International Ultraviolet Explorer satellite. The outstanding feature of the optical spectrum is a strong, broad Mg II absorption trough, detached from the Mg II emission line and indicative of ejection velocities of between 7000 and 18,000 km/s. Also detected were narrow (FWHM = 350 km/s) Mg II absorption lines at absolute z = 0.2698, which are probably related to the mass ejection phenomenon. It is concluded that the emission-line spectrum is similar to that of other low-redshift QSOs although there are some obvious differences from typical BAL QSOs, most notably in the unusually low level of ionization of both emission-line and broad absorption line gas. 21 references.

  7. An X-ray-absorbed radio-quiet QSO with an intervening strong metal absorption-line system

    NASA Astrophysics Data System (ADS)

    Page, M. J.; Mittaz, J. P. D.; Carrera, F. J.

    2000-02-01

    We find evidence for significant X-ray absorption in the QSO RXJ005734.78-272827.4, along with strong absorption lines in its optical spectrum. We propose that the absorption lines are due to an intervening metal-line system at a redshift of z=0.628, and show that this intervening system is also the probable cause of the X-ray absorption. The intervening absorber is inferred to have an X-ray column of ~1022cm-2. This is the first time that an absorption-line system has been identified with an X-ray absorber in a radio-quiet object.

  8. Probing the Circumgalactic Medium of Submillimeter Galaxies with QSO Absorption Line Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fu, Hai; Hennawi, Joseph F.; Prochaska, Jason X.; Stockton, Alan N.; Mutel, Robert Lucien; Casey, Caitlin; Cooray, Asantha R.; Keres, Dusan

    2017-01-01

    We present first results from an ongoing survey to characterize the circumgalactic medium (CGM) of the massive high-redshift galaxieds detected as submillimeter galaxies (SMGs). By cross-matching far-infrared-selected galaxies from Herschel with spectroscopically confirmed quasars, we constructed a sample of 163 SMG-QSO pairs with separations less than 36". We observed 62 SMG-QSO pairs with the Very Large Array (VLA) and the Atacama Large Millimeter Array (ALMA). These observations obtained sub-arcsecond positions of 31 SMGs and identified seven previously-thought SMG-QSO pairs as submillimeter-luminous QSOs. We are currently conducting a redshift survey of the VLA/ALMA-confirmed SMGs and acquiring high S/N UV-optical specrtoscopy of the background QSOs. For the small sample of three VLA-confirmed SMG-QSO pairs that we have the complete data set, absorption line spectra of the background QSOs allow us to analyze the CGM of SMGs for the first time, providing insight into the fuel-supply ultimately powering their tremendous starbursts. Our observations reveal strong HI Ly-alpha absorption (rest-frame equivalent widths about 2-3 A) around all three SMGs; however, none exhibit compelling evidence for strong neutral absorbers (NHI > 1017.2 cm-2) or metal absorption, allowing us to place an 1-sigma upper limit on the covering factor of optically thick HI gas around SMGs of fC < 36.9%. This is significantly lower than the covering factor around the co-eval population of luminous QSOs. Theoretical models predict that the structure of the CGM is entirely determined by dark matter halo mass. Given that that SMGs are believed to inhabit massive dark matter halos comparable to those hosting quasars, this difference in covering factor is unexpected. Therefore, our results tentatively indicate that SMGs may not have substantial cool gas reservoirs in their halos and that they may inhabit much less massive halos than previously thought.

  9. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    NASA Astrophysics Data System (ADS)

    Shi, Xiheng; Zhou, Hongyan; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-03-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of Hβ shows a variation of more than 5σ at a high velocity portion (\\gt 3000 {km} {{{s}}}-1) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He i and optical Fe ii absorptions (λ4233 from b4P5/2 level and λ5169 from a6S5/2) at the same velocity. These Fe ii lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of n({{H}})≈ {10}9.1 {{cm}}-3 and a column density of {N}{col}({{H}})≈ {10}23 {{cm}}-2 for the BOSS data, but the model fails to predict the variations of ionic column densities between the SDSS and BOSS observations if changes in ionizing flux are assumed. We thus propose transverse motion of the absorbing gas being the cause of the observed broad Balmer absorption line variability. In fact, we find that the changes in covering factors of the absorber can well-reproduce all of the observed variations. The absorber is estimated ∼0.94 pc away from the central engine, which is where the outflow likely experiences deceleration due to the collision with the surrounding medium. This scheme is consistent with the argument that LoBAL QSOs may represent the transition from obscured star-forming galaxies to classic QSOs.

  10. Dust depletion of Ca and Ti in QSO absorption-line systems

    NASA Astrophysics Data System (ADS)

    Guber, C. R.; Richter, P.

    2016-06-01

    Aims: To explore the role of titanium- and calcium-dust depletion in gas in and around galaxies, we systematically study Ti/Ca abundance ratios in intervening absorption-line systems at low and high redshift. Methods: We investigate high-resolution optical spectra obtained by the UVES instrument at the Very Large Telescope (VLT) and spectroscopically analyze 34 absorption-line systems at z ≤ 0.5 to measure column densities (or limits) for Ca ii and Ti ii. We complement our UVES data set with previously published absorption-line data on Ti/Ca for redshifts up to z ~ 3.8. Our absorber sample contains 110 absorbers including damped Lyman α systems (DLAs), sub-DLAs, and Lyman-Limit systems (LLS). We compare our Ti/Ca findings with results from the Milky Way and the Magellanic Clouds and discuss the properties of Ti/Ca absorbers in the general context of quasar absorption-line systems. Results: Our analysis indicates that there are two distinct populations of absorbers with either high or low Ti/Ca ratios with a separation at [Ti/Ca] ≈ 1. While the calcium-dust depletion in most of the absorbers appears to be severe, the titanium depletions are mild in systems with high Ti/Ca ratios. The derived trend indicates that absorbers with high Ti/Ca ratios have dust-to-gas ratios that are substantially lower than in the Milky Way. We characterize the overall nature of the absorbers by correlating Ti/Ca with other observables (e.g., metallicity, velocity-component structure) and by modeling the ionization properties of singly-ionized Ca and Ti in different environments. Conclusions: We conclude that Ca ii and Ti ii bearing absorption-line systems trace predominantly neutral gas in the disks and inner halo regions of galaxies, where the abundance of Ca and Ti reflects the local metal and dust content of the gas. Our study suggests that the Ti/Ca ratio represents a useful measure for the gas-to-dust ratio and overall metallicity in intervening absorption-line systems.

  11. Using ISM abundances in the SMC to Correct for Element Depletions by Dust in QSO Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Jenkins, Edward

    2014-10-01

    The availability of 10-m class telescopes with high resolution echelle spectrographs has enabled astronomers to measure accurately the gas-phase abundances of various elements in QSO absorption line systems at high redshifts. These systems offer insights on the chemical evolution of galaxies (and their nearby environments) in their early stages of development. However, in order to obtain total abundances the observations need to be corrected for the depletions caused by the formation of dust, and traditionally people have done so by using the depletion patterns seen in our own Galaxy. There is now evidence that indicates that such patterns in low-metallicity systems differ from those of our Galaxy and thus the corrections may be misleading. The aim of our proposed HST observations is to measure the gas-phase abundances toward stars in the Small Magellanic Cloud, which is a low-metallicity dwarf galaxy where there exist good measurements of stellar comparison abundances. We plan to record ISM absorption features from STIS medium-resolution echelle spectra for 14 stars in the SMC that are known to have varying levels of depletion, so that we can derive the gas-phase abundance patterns of the elements Ni, Fe, Cr, Mn, Si, Mg, Ge, Kr, Zn, and perhaps P.

  12. XMM-Newton Spectroscopy of the X-ray Detected Broad Absorption Line QSO CSO 755

    NASA Technical Reports Server (NTRS)

    Brandt, Niel

    2005-01-01

    We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of approximately 3000 photons we find that this source has an X-ray continuum of "typical" radio-quiet quasars, with a photon index of Gamma=1.83, and a rather flat (X-ray bright) intrinsic optical-to-X-ray spectral slope of alpha_ox=- 1.51. The source shows evidence for intrinsic absorption, and fitting the spectrum with a neutral-absorption model gives a column density of N_H approximately 1.2x10^22 cm^{-2}; this is among the lowest X-ray columns measured for BALQSOs. We do not detect, with high significance, any other absorption features in the X-ray spectrum. Upper limits we place on the rest-frame equivalent width of a neutral (ionized) Fe K-alpha line, less than =180 eV (less than =120 eV), and on the Compton-reflection component parameter, R less than =0.2, suggest that most of the X-rays from the source are directly observed rather than being scattered or reflected; this is also supported by the relatively flat intrinsic alpha ox we measure. The possibility that most of the X-ray flux is scattered due to the high level of UV-optical polarization is ruled out. Considering data for 46 BALQSOs from the literature, including CSO 755, we have found that the UV-optical continuum polarization level of BALQSOs is not correlated with any of their X-ray properties. A lack of significant short-term and long-term X-ray flux variations in the source may be attributed to a large black-hole mass in CSO 755. We note that another luminous BALQSO, PG 2112+059, has both similar shallow C IV BALs and moderate X-ray absorption.

  13. The ultraviolet spectrum of the gravitational lens candidate UM 425 = QSO 1120+019: Evidence for broad absorption line (BAL) structure

    NASA Technical Reports Server (NTRS)

    Michelitsianos, A. G.; Oliversen, R. J.

    1995-01-01

    The UV line profile structure of high-ionization resonance lines found with the International Ultraviolet Explorer (IUE) in the brightest of four multiply imaged sources (images-A) in the candidate gravitational lens UM 425 = QSO 1120+019 indicates broad absorption line (BAL) structure. The deep-broad trough associated with the O IV line extends to velocities approiximately -12,000 km/s, and contains disrete features that suggest multicomponent velocity structure. This structure may include contributions from C IV absorption from the early-type galaxy that is believed to lens UM 425. A strong absorption feature in the blue wing of the Lyman-alpha lambda 1216 emission line may be a Lyman alpha absorption system at a Z(sub Ly alpha) = 1.437 +/- 0.003, or it may be formed by the superposition of the broad N V lambda lambda 1238, 1242 absorption trough on the extended blue emission wing of the QSO Lyman-alpha line. We obtained a redshift of Z(sub QSO) = 1.471 +/- 0.003 from Lyman-alpha lambda 1215, consistent with the redshift found by Meylan and Djorgovski in the optical. The Lyman-alpha line appears unusally weak due to the presence of N V lambda 1240 BAL absorption. A Lyman-limit absorption system at lambda 912 was not observed in the QSO rest frame. The detection of BAL structure in the other weaker ground-state resonance lines of N II (l) and S IV (l) was not found, suggesting these lines are formed in a region that is distinct from the BAL component. Detection of BAL structure in the other fainter images in this system with Hubble Space Telescope (HST) instrumentation, similar to structure observed here in image A, could provide evidence that UM 425 is a gravitational lens.

  14. The dust, nebular emission, and dependence on QSO radio properties of the associated Mg II absorption line systems

    SciTech Connect

    Khare, Pushpa; Daniel, Vanden Berk; Rahmani, Hadi; York, Donald G.

    2014-10-10

    We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, ≤3000 km s{sup –1}; in units of velocity of light, β, ≤0.01) with 0.4 ≤z {sub abs} ≤ 2 in the Sloan Digital Sky Survey DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties, to show that (1) AAS in radio-detected (RD) QSOs cause 2.6 ± 0.2 times higher dust extinction than those in radio-undetected (RUD) ones, which in turn cause 2.9 ± 0.7 times the dust extinction in the intervening systems; (2) AAS in core-dominated QSOs cause 2.0 ± 0.1 times higher dust extinction than those in lobe-dominated QSOs; (3) the occurrence of AAS is 2.1 ± 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 ± 0.1 time more likely in QSOs having black holes with masses larger than 1.23 × 10{sup 9} M {sub ☉} than in those with lower-mass black holes; and (4) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared with those of the control samples, which is at the emission redshift. The presence of AAS enhances the O II emission from the active galactic nucleus and/or the host galaxy. This excess is similar for both RD and RUD samples and is 2.5 ± 0.4 times higher in lobe-dominated samples than in core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z {sub abs} > z {sub em}, which could be infalling galaxies.

  15. Absorption-Line Studies of Seyfert Galaxies

    NASA Astrophysics Data System (ADS)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  16. Continuum Fitting HST QSO Spectra

    NASA Technical Reports Server (NTRS)

    Tytler, David; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The Principal Component Analysis (PCA) method which we are using to fit and describe QSO spectra relies upon the fact that QSO continuum are generally very smooth and simple except for emission and absorption lines. To see this we need high signal-to-noise (S/N) spectra of QSOs at low redshift which have relatively few absorption lines in the Lyman-a forest. We need a large number of such spectra to use as the basis set for the PCA analysis which will find the set of principal component spectra which describe the QSO family as a whole. We have found that too few HST spectra have the required S/N and hence we need to supplement them with ground based spectra of QSOs at higher redshift. We have many such spectra and we have been working to make them suitable for this analysis. We have concentrated on this topic since 12/15/01.

  17. Polarization and Structure of Broad Absorption Line Quasi-Stellar Objects

    NASA Astrophysics Data System (ADS)

    Ogle, Patrick Michael

    This thesis is a spectropolarimetric survey of broad absorption line quasi-stellar objects (BAL QSO). We observed 36 BAL QSO at the Palomar and W. M. Keck Observatories. BAL QSO have higher polarization than other quasars, reinforcing the view that they are normal quasars viewed from an equatorial aspect. However, there is a wide distribution of polarization values, which may be due to intrinsic differences in the geometry or optical depth to scattering. No correlations are found among emission line or broad absorption line properties and continuum polarization, suggesting that these properties are regulated by internal differences unrelated to viewing angle. The continuum polarization of BAL QSO is weakly wavelength-dependent after correction for emission line dilution. In most objects, the polarisation rises to the blue, suggesting that dust scattering or absorption may be important. Broad emission line photons are polarized less than the continuum; and the position angle of the electric vector is rotated with respect to the continuum. The semi-forbidden C III) emission line is polarized differently than the C IV emission line, suggesting resonance scattering in the C III) emission line region. Resonantly scattered photons from the broad absorption line region are detected at high velocities red-ward and blue-ward of the C IV line center in the spectra of some objects. These photons are negatively polarized with respect to the continuum photons, showing that the broad absorption line region and the continuum scattering region are oriented perpendicular to each other. The polarization increases in the BAL troughs, due mainly to partial coverage of the central source by the broad absorption line region. The geometry of the intervening BAL clouds is skewed with respect to the continuum scattering region, which results in position angle rotations in the BAL. The variation of polarization with velocity in the BAL is consistent with a non-radial, accelerating outflow

  18. Quasistellar Objects: Intervening Absorption Lines

    NASA Astrophysics Data System (ADS)

    Charlton, J.; Churchill, C.; Murdin, P.

    2000-11-01

    Every parcel of gas along the line of sight to a distant QUASAR will selectively absorb certain wavelengths of continuum light of the quasar due to the presence of the various chemical elements in the gas. Through the analysis of these quasar absorption lines we can study the spatial distributions, motions, chemical enrichment and ionization histories of gaseous structures from REDSHIFT five unti...

  19. Do Atoms Really "Emit" Absorption Lines?

    ERIC Educational Resources Information Center

    Brecher, Kenneth

    1991-01-01

    Presents three absorption line sources that enhance student understanding of the phenomena associated with the interaction of light with matter and help dispel the misconception that atoms "emit" absorption lines. Sources include neodymium, food coloring and other common household liquids, and fluorescent materials. (MDH)

  20. Low-redshift Lyman-alpha absorption lines and the dark matter halos of disk galaxies

    NASA Technical Reports Server (NTRS)

    Maloney, Philip

    1992-01-01

    Ultraviolet observations of the low-redshift quasar 3C 273 using the Hubble Space Telescope have revealed many more Lyman-alpha absorption lines than would be expected from extrapolation of the absorption systems seen toward QSOs at z about 2. It is shown here that these absorption lines can plausibly be produced by gas at large radii in the disks of spiral and irregular galaxies; the gas is confined by the dark matter halos and ionized and heated by the extragalactic radiation field. This scenario does not require the extragalactic ionizing radiation field to decline as rapidly with decreasing z as the QSO emissivity. Observations of Ly-alpha absorption through the halos of known galaxies at low redshift will constrain both the extragalactic background and the properties of galactic halos.

  1. Low redshift Lyman alpha absorption lines and the dark matter halos of disk galaxies

    NASA Technical Reports Server (NTRS)

    Maloney, Philip

    1993-01-01

    Recent observations using the Hubble Space Telescope of the z = 0.156 QSO 3C 273 have discovered a surprisingly large number of Ly-alpha absorption lines. In particular, Morris et al. found 9 certain and 7 possible Ly-alpha lines with equivalent widths above 25 mA. This is much larger (by a factor of 5-10) than the number expected from extrapolation of the high-redshift behavior of the Ly-alpha forest. Within the context of pressure-confined models for the Ly-alpha clouds, this behavior can be understood if the ionizing background declines sharply between z is approximately 2 and z is approximately 0. However, this requires that the ionizing photon flux drop as rapidly as the QSO volume emissivity; moreover, the absorbers must have a space density n(sub O) is approximately 2.6(N/10)h/((D/100 kpc)(sup 2)) Mpc(sup -3) where D is the present-day diameter of the absorbers. It is somewhat surprising that such necessarily fragile objects could have survived in such numbers to the present day. It is shown that it is plausible that the atomic hydrogen extents of spiral and irregular galaxies are large enough to produce the observed number of Ly-alpha absorption lines toward 3C 273, and that the neutral column densities and doppler b-values expected under these conditions fall in the range found by Morris et al. (1991).

  2. VizieR Online Data Catalog: QSO B0218+357 molecular absorption lines (Wallstroem+, 2016)

    NASA Astrophysics Data System (ADS)

    Wallstroem, S. H. J.; Muller, S.; Guelin, M.

    2016-08-01

    ASCII files of the absorption spectra presented in Figure 2. The files are named after the molecule or isotopologue. Column 1 is velocity, column 2 is intensity (normalized to 1), Velocities are in a heliocentric frame, with zabs=0.68466 (11 data files).

  3. A survey of ultraviolet interstellar absorption lines

    NASA Technical Reports Server (NTRS)

    Bohlin, R. C.; Jenkins, E. B.; Spitzer, L., Jr.; York, D. G.; Hill, J. K.; Savage, B. D.; Snow, T. P., Jr.

    1983-01-01

    A telescope-spectrometer on the Copernicus spacecraft made possible the measurement of many ultraviolet absorption lines produced by the interstellar gas. The present survey provides data on ultraviolet absorption lines in the spectra of 88 early-type stars. The stars observed are divided into four classes, including reddened stars, unreddened bright stars, moderately reddened bright stars, and unreddened and moderately reddened faint stars. Data are presented for equivalent width, W, radial velocity V, and rms line width, D, taking into account some 10 to 20 lines of N I, O I, Si II, P II, S II, Cl I, Cl II, Mn II, Fe II, Ni II, Cu II, and H2. The data are based on multiple scans for each line. Attention is given to details of observations, the data reduction procedure, and the computation of equivalent width, mean velocity, and velocity dispersion.

  4. On the identification of deuterium lines in QSO absorption systems

    NASA Astrophysics Data System (ADS)

    Levshakov, S. A.; Takahara, F.

    1996-07-01

    The ambiguity of identification of deuterium lines in QSO absorption systems is considered, under the assumption that the D I and H I absorption lines are formed in turbulent media with a finite correlation length of the stochastic velocity field. The relative shift of the D I and H I lines is shown to vary over the range +/-(4-8) km s^- 1^ for a cloud model with hydrogen column density N_HI_ = 10^17^ cm^-2^, the ratio D/H = 10^-4^, and kinetic temperature T_kin_ = 10^4^ K. The variations in the relative shift of the deuterium lines are fundamental in character and result from the stochastic nature of the formation of absorption lines in turbulent media

  5. Interstellar Mg II and C IV absorption toward Markarian 205 by NGC 4319 - An 'optically thick' QSO absorption system

    NASA Technical Reports Server (NTRS)

    Bowen, David V.; Blades, J. C.

    1993-01-01

    We have used the Goddard High-Resolution Spectrograph aboard HST to detect interstellar Mg II and C IV absorption lines toward Mrk 205, a QSO whose sightline passes within 3/h kpc of the foreground galaxy NGC 4319. Absorption is detected from both local Milky Way gas and from NGC 4319, making this the first observation of an isolated, low-redshift galaxy causing an 'optically thick' QSO absorption system. We also observed for the first time Mg II absorption from two local High Velocity Clouds along this same sightline. The data support the premise that metal absorption lines seen at higher redshift in QSO spectra originate in gas associated with intervening galaxies. However, neither the strong absorption by (half) of our own Galaxy, nor the weak absorption by NGC 4319, may be typical of absorbers in general.

  6. Broad Absorption Line Quasars and Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Wills, B. J.

    2009-12-01

    Luminous QSOs are signposts to galaxy evolution. Local supermassive black holes are the faded relics of quasars in their heyday at redshifts ˜2. Relationships between the masses of these local supermassive black holes and their host galaxy bulges reveal an intimate link, fundamental to galaxy evolution: the newly evolving galaxy fuels the seed black hole through its accretion disk and by loss of angular momentum and energy in the form of outflowing winds. As the central engine approaches Eddington luminosities, winds drive away dusty gas, revealing a luminous QSO and halting star formation in the galaxy bulge. Relativistic winds are manifested in powerful radio jets in ˜10% of quasars, and sub-relativistic winds are revealed by broad blueshifted absorption troughs in the “broad absorption line” (BAL) quasars. Historically, BALs avoid powerful radio quasars. Here we examine the BALs to investigate this inverse connection.

  7. Polarization and Broad Absorption Lines in Quasars

    NASA Astrophysics Data System (ADS)

    Antonucci, Robert

    1990-12-01

    OI 287 is a unique extragalactic source. It appears to take one property from each class of object. It is either some kind of missing link, or a new type of activity. Because of the high optical polarization, OI 287 has been classified with the blazars. However, every other blazar is variable in optical flux, polarization, and polarization angle., while OI 287 is constant at V=17, P=8%, and theta=145 degrees. Also, every other blazar has a radio source dominated by an intense flat-spectrum core, while OI 287 has an upper limit of 2% of the total 20cm flux in the core. The only group of quasars which ever shows even moderate (2-5%) constant optical polarization is the broad absorption line (BAL) objects, e.g. PHL 5200 and H1413+113. Among the BAL quasars, PHL 5200 and H1413+113 have exceptionally smooth deep, attached absorption lines, and also the highest polarization. We want to know whether OI 287 is a BAL quasar. It would be the first definite radio loud example. If it is a BAL quasar then the high polarization is really related to (and perhaps the key to) the BAL phenomenon, and we can use the techniques of spectropolarimetry to help unlock the BAL geometry. The UV spectral shape would also provide help determining the cause of polarization.

  8. Spectrophotometry of six broad absorption line QSOs

    NASA Technical Reports Server (NTRS)

    Junkkarinen, Vesa T.; Burbidge, E. Margaret; Smith, Harding E.

    1987-01-01

    Spectrophotometric observations of six broad absorption-line QSOs (BALQSOs) are presented. The continua and emission lines are compared with those in the spectra of QSOs without BALs. A statistically significant difference is found in the emission-line intensity ratio for (N V 1240-A)/(C IV 1549-A). The median value of (N V)/(C IV) for the BALQSOs is two to three times the median for QSOs without BALs. The absorption features of the BALQSOs are described, and the column densities and limits on the ionization structure of the BAL region are discussed. If the dominant ionization mechanism is photoionization, then it is likely that either the ionizing spectrum is steep or the abundances are considerably different from solar. Collisional ionization may be a significant factor, but it cannot totally dominate the ionization rate.

  9. Narrow UV Absorption Line Outflows from Quasars

    NASA Astrophysics Data System (ADS)

    Hamann, F.; Simon, L.; Rodriguez Hidalgo, P.; Capellupo, D.

    2012-08-01

    Narrow absorption line (NAL) outflows are an important yet poorly understood part of the quasar outflow phenomenon. We discuss one particular NAL outflow that has high speeds, time variability, and moderate ionizations like typical BAL flows, at an estimated location just ˜5 pc from the quasar. It also has a total column density and line widths (internal velocity dispersions) ˜100 times smaller than BALs, with no substantial X-ray absorption. We argue that radiative shielding (in the form of an X-ray/warm absorber) is not critical for the outflow acceleration and that the moderate ionizations occur in dense substructures that have an overall small volume filling factor in the flow. We also present new estimates of the overall incidence of quasar outflow lines; e.g., ˜43% of bright quasars have a C IV NAL outflow while ˜68% have a C IV outflow line of any variety (NAL, BAL, or mini-BAL).

  10. Radiation Pressure-Driven Magnetic Disk Winds in Broad Absorption Line Quasi-Stellar Objects

    NASA Technical Reports Server (NTRS)

    DeKool, Martin; Begelman, Mitchell C.

    1995-01-01

    We explore a model in which QSO broad absorption lines (BALS) are formed in a radiation pressure-driven wind emerging from a magnetized accretion disk. The magnetic field threading the disk material is dragged by the flow and is compressed by the radiation pressure until it is dynamically important and strong enough to contribute to the confinement of the BAL clouds. We construct a simple self-similar model for such radiatively driven magnetized disk winds, in order to explore their properties. It is found that solutions exist for which the entire magnetized flow is confined to a thin wedge over the surface of the disk. For reasonable values of the mass-loss rate, a typical magnetic field strength such that the magnetic pressure is comparable to the inferred gas pressure in BAL clouds, and a moderate amount of internal soft X-ray absorption, we find that the opening angle of the flow is approximately 0.1 rad, in good agreement with the observed covering factor of the broad absorption line region.

  11. Radiation Pressure--driven Magnetic Disk Winds in Broad Absorption Line Quasi-stellar Objects

    NASA Astrophysics Data System (ADS)

    de Kool, Martijn; Begelman, Mitchell C.

    1995-12-01

    We explore a model in which QSO broad absorption lines (BALs) are formed in a radiation pressure- driven wind emerging from a magnetized accretion disk. The magnetic field threading the disk material is dragged by the flow and is compressed by the radiation pressure until it is dynamically important and strong enough to contribute to the confinement of the BAL clouds. We construct a simple self-similar model for such radiatively driven magnetized disk winds, in order to explore their properties. It is found that solutions exist for which the entire magnetized flow is confined to a thin wedge over the surface of the disk. For reasonable values of the mass-loss rate, a typical magnetic field strength such that the magnetic pressure is comparable to the inferred gas pressure in BAL clouds, and a moderate amount of internal soft X-ray absorption, we find that the opening angle of the flow is approximately 0.1 rad, in good agreement with the observed covering factor of the broad absorption line region.

  12. Quasar Absorption Line Survey - Cycle 4 High

    NASA Astrophysics Data System (ADS)

    Bahcall, John

    1994-01-01

    The Absorption Line Survey of bright quasars provides a homogeneous data base for studying fundamental questions about the origin and evolution of gaseous systems in the universe. The initial results determine at small redshifts the number densities of Ly-ALPHA systems, of metal-lines and extragalactic halos, of Lyman-limit systems, of associated absorption systems, and the shapes and intensities of quasar emission lines and spectral energy distributions. The survey reveals that much of the sky is covered by high or very high velocity metal-line clouds present in the Galactic halo. A larger sample, which includes the requested Cycle 3 observations, is required to answer many important questions. For example, what is the correlation function of Ly-ALPHA systems at small redshifts? What fraction of the metal, the Ly-ALPHA, and the Ly-limit systems are associated with galaxies and what are the characteristic sizes of the outer gaseous regions of different types of galaxies? Do absorbing systems show evidence of the large-scale structure seen with galaxies and clusters of galaxies? The observations requested in Cycle 3 will extend the region of coverage of the Key Project sample from the redshift range of z = 0.0 to 1.0 (Cycles 1& 2) to z = 0.0 to 1.6 (Cycles 1-3). THIS FILE CONTAINS THE HIGH PRIORITY OBSERVATIONS FROM CYCLES 2 and 3 WHICH WERE NOT COMPLETED IN THOSE CYCLES.

  13. Time Variable Associated Absorption in the QSO UM 675

    NASA Astrophysics Data System (ADS)

    Hamann, F. W.; Barlow, T. A.; Beaver, E. A.; Burbidge, E. M.; Cohen, R. D.; Junkkarinen, V. T.; Lyons, R. W.

    1994-05-01

    We discuss dramatic changes in the z_a ~ z_e absorption system of the z_e = 2.15 QSO UM 675 (Q0150-203). The C IV lambda 1550 and N V lambda 1240 doublets at z_a = 2.1344 strengthened by a factor of ~ 3 between the observations of Sargent, Boksenberg and Steidel (1988, ApJS, 68, 539; measured November 1981) and our earliest measurements (November and December 1990). During this time, C IV in the z_a = 2.0083 system may also have strengthened. The variability of other lines in these systems is unknown. Continued monitoring is in progress. We consider several models of the z_a ~ z_e absorption environment, and conclude that the absorbing clouds are close to the QSO and photoionized by the QSO continuum. The variability timescale (<~2.9 yrs rest) requires gas densities gap 4000 cm(-3) to allow changes in the ionization balance. This minimum density, and the high ionization needed to produce the Ne VIII lambda 774 and O VI lambda 1035 absorptions reported previously (E. M. Burbidge et al., 1993, BAAS, 24, 1135), requires clouds <~200 pc from the QSO. The full range of absorption line ionizations (including C III lambda 977 and N III lambda 989) implies that the clouds are segregated, spanning a factor of gap 10 in distance or gap 100 in density. Across these regions the H I fraction varies from ~ 10(-3) to ~ 10(-6) . The total hydrogen column ranges from a few times 10(18) cm(-2) in the low ionization gas to ~ 10(20) cm(-2) where the Ne VIII lines form. The Lyman continuum is expected to be optically thin throughout, consistent with the measured absence of a Lyman edge. The metal abundances are roughly solar or above. Implications of these results are discussed. This work is supported by NASA grant NAG 5-1630.

  14. Photoionization-driven Absorption-line Variability in Balmer Absorption Line Quasar LBQS 1206+1052

    NASA Astrophysics Data System (ADS)

    Sun, Luming; Zhou, Hongyan; Ji, Tuo; Jiang, Peng; Liu, Bo; Liu, Wenjuan; Pan, Xiang; Shi, Xiheng; Wang, Jianguo; Wang, Tinggui; Yang, Chenwei; Zhang, Shaohua; Miller, Lauren P.

    2017-04-01

    In this paper we present an analysis of absorption-line variability in mini-BAL quasar LBQS 1206+1052. The Sloan Digital Sky Survey spectrum demonstrates that the absorption troughs can be divided into two components of blueshift velocities of ∼700 and ∼1400 km s‑1 relative to the quasar rest frame. The former component shows rare Balmer absorption, which is an indicator of high-density absorbing gas; thus, the quasar is worth follow-up spectroscopic observations. Our follow-up optical and near-infrared spectra using MMT, YFOSC, TSpec, and DBSP reveal that the strengths of the absorption lines vary for both components, while the velocities do not change. We reproduce all of the spectral data by assuming that only the ionization state of the absorbing gas is variable and that all other physical properties are invariable. The variation of ionization is consistent with the variation of optical continuum from the V-band light curve. Additionally, we cannot interpret the data by assuming that the variability is due to a movement of the absorbing gas. Therefore, our analysis strongly indicates that the absorption-line variability in LBQS 1206+1052 is photoionization driven. As shown from photoionization simulations, the absorbing gas with blueshift velocity of ∼700 km s‑1 has a density in the range of 109 to 1010 cm‑3 and a distance of ∼1 pc, and the gas with blueshift velocity of ∼1400 km s‑1 has a density of 103 cm‑3 and a distance of ∼1 kpc.

  15. Balmer Absorption Lines in FeLoBALs

    NASA Astrophysics Data System (ADS)

    Aoki, K.; Iwata, I.; Ohta, K.; Tamura, N.; Ando, M.; Akiyama, M.; Kiuchi, G.; Nakanishi, K.

    2007-10-01

    We discovered non-stellar Balmer absorption lines in two many-narrow-trough FeLoBALs (mntBALs) by the near-infrared spectroscopy with Subaru/CISCO. Presence of the non-stellar Balmer absorption lines is known to date only in the Seyfert galaxy NGC 4151; thus our discovery is the first cases for quasars. Since all known active galactic nuclei with Balmer absorption lines share similar characteristics, it is suggested that there is a population of BAL quasars which have unique structures at their nuclei or unique evolutionary phase.

  16. Ultraviolet interstellar absorption lines from low-z galaxies

    NASA Astrophysics Data System (ADS)

    Sahu, M. S.

    1997-05-01

    The importance of studying absorption lines from z<<0.1 galaxies are discussed. The Mg II λλ2796 and 2803 Å doublet absorption is sensitive to low column density gas and has been used to search for absorption lines from low-z galaxies. Recent studies of abundances and depletion patterns toward the Small Magellanic Cloud (Welty et al. 1997) and the NGC 1705 sightline (Sahu & Blades, 1997) are reviewed.

  17. EVIDENCE FOR PHOTOIONIZATION-DRIVEN BROAD ABSORPTION LINE VARIABILITY

    SciTech Connect

    Wang, Tinggui; Yang, Chenwei; Wang, Huiyuan; Ferland, Gary

    2015-12-01

    We present a qualitative analysis of the variability of quasar broad absorption lines using the large multi-epoch spectroscopic data set of the Sloan Digital Sky Survey Data Release 10. We confirm that variations of absorption lines are highly coordinated among different components of the same ion or the same absorption component of different ions for C iv, Si iv, and N v. Furthermore, we show that the equivalent widths (EWs) of the lines decrease or increase statistically when the continuum brightens or dims. This is further supported by the synchronized variations of emission and absorption-line EWs when the well-established intrinsic Baldwin effect for emission lines is taken into account. We find that the emergence of an absorption component is usually accompanied by the dimming of the continuum while the disappearance of an absorption-line component is accompanied by the brightening of the continuum. This suggests that the emergence or disappearance of a C iv absorption component is only the extreme case, when the ionic column density is very sensitive to continuum variations or the continuum variability the amplitude is larger. These results support the idea that absorption-line variability is driven mainly by changes in the gas ionization in response to continuum variations, that the line-absorbing gas is highly ionized, and in some extreme cases, too highly ionized to be detected in UV absorption lines. Due to uncertainties in the spectroscopic flux calibration, we cannot quantify the fraction of quasars with asynchronized continuum and absorption-line variations.

  18. Searching for Variability of NV Intrinsic Narrow Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Rodruck, Michael; Charlton, Jane C.; Ganguly, Rajib

    2017-01-01

    The majority of quasar absorption line systems with NV detected are found within the associated region (within 5000km/s of the quasar redshift) and many/most are believed to be related to the quasar accretion disk wind or outflows. The most definite evidence that these NV absorbers are "intrinsic" is partial covering of the quasar continuum source and/or broad line region. Over 50 quasars containing NV narrow absorption lines have observations obtained at different times with the Keck/HIRES and the VLT/UVES spectrographs at high resolution. The interval between these observations range from months to a decade in the quasar rest frame. While variability is common for intrinsic broad and mini-broad absorption lines, intrinsic narrow absorption lines have been found to be less likely to vary, though systematic studies with large, high quality datasets have been limited. The variability timescales are useful for deriving gas densities and thus the distances from the central engines. This is important in mapping the quasar surroundings, understanding the accretion disk wind mechanism, and assessing the effect the wind has on the galaxy surroundings. We report on the results of a systematic study of variability of NV NALs, exploiting the overlap of targets for observations in the archives of Keck and VLT, and discuss the consequences for interpretation of the origin of intrinsic narrow absorption lines.

  19. VizieR Online Data Catalog: Narrow absorption lines of lensed QSO J1029+2623 (Misawa+, 2016)

    NASA Astrophysics Data System (ADS)

    Misawa, T.; Saez, C.; Charlton, J. C.; Eracleous, M.; Chartas, G.; Bauer, F. E.; Inada, N.; Uchiyama, H.

    2016-08-01

    We acquired high-resolution spectra of the brightest two of the three lensed images of the quasar SDSS J1029+2623, A and B with V=18.72 and 18.67mags, with the VLT using the Ultraviolet and Visual Echelle Spectrograph (UVES) in queue mode (ESO program 092.B-0512(A)). The observations were performed from 2014 January 28 to February 26, which is ~4yrs after the first observation on 2010 February 10 (Misawa+ 2013AJ....145...48M), and ~2 months before the third observation on 2014 April 4 (Misawa+ 2014ApJ...794L..20M) with Subaru using the High Dispersion Spectrograph (HDS). The wavelength coverage is 3300-6600Å with R~33000. Log of observations: -------------------------------------------------------------- Target Obs. date Instrument R Ref -------------------------------------------------------------- SDSS J1029+2623 A 2010 Feb 10 Subaru/HDS 30000 1 SDSS J1029+2623 A 2014 Jan 28-Feb 3 VLT/UVES 33000 2 SDSS J1029+2623 A 2014 Apr 4 Subaru/HDS 36000 3 SDSS J1029+2623 B 2010 Feb 10 Subaru/HDS 30000 1 SDSS J1029+2623 B 2014 Feb 4-26 VLT/UVES 33000 2 SDSS J1029+2623 B 2014 Apr 4 Subaru/HDS 36000 3 -------------------------------------------------------------- Ref: 1 = Misawa et al. 2013AJ....145...48M, 2 = This paper, 3 = Misawa et al. 2014ApJ...794L..20M -------------------------------------------------------------- (1 data file).

  20. The MG II absorption system in the QSO PKS 2128-12 - A galaxy disc/halo with a radius of 65 KPC

    NASA Astrophysics Data System (ADS)

    Bergeron, J.

    1986-01-01

    An imaging survey of the field around QSO PKS 2128-12, a QSO with low redshift narrow Mg II absorption line systems, is performed to verify the assumption that sharp metal-rich absorption systems found in the spectra of QSO's arise in intervening materials. The absorber has a redshift, z = 0.4299, that is smaller than that of the QSO emission redshift. The closest galaxy to the QSO, lies 64 kpc north-east of it, and has a redshift equal to that of the absorber. It is gas-rich, and its V and red magnitudes are about those expected for a spiral galaxy. Since the absorbing gas is found to have a small velocity dispersion, fairly high abundances and column densities, and a moderate degree of ionization, it is more likely associated with material in the disc of this galaxy than with a large surrounding halo. This QSO-galaxy pair increases by a factor of four the projected distance from a galaxy center at which absorbing ionized gas has been detected, strongly favoring the assumption of intervening galaxies at least for moderately ionized absorbers.

  1. The Nature of Low-ionization Broad Absorption Line Quasi-stellar Objects

    NASA Astrophysics Data System (ADS)

    Lazarova, Mariana Spasova

    The tight correlations between properties of galaxy bulges and their central supermassive black holes have been reproduced successfully in simulations of galaxy collisions if feedback processes are invoked. Mergers of gas-rich galaxies of comparable size have been shown to trigger starbursts, fuel the central black holes, and transform disks into ellipticals. Feedback from the black hole accretion in the form of extreme outflows has need suggested as the mechanism by which the black hole stop its own growth and quenches the star formation in the galaxy by expelling the gas supply. Such winds have been detected in Broad Absorption Line (BAL) QSOs. However, observational evidence that BAL QSOs may be an evolutionary link between mergers and QSO is missing. In this thesis, we provide the first detailed study of the spectral energy distributions and host galaxy morphologies of a statistically significant volume-limited sample of 22 optically-selected low-ionization Broad Absorption Line QSOs (LoBALs) at 0.5 < z < 0.6. By comparing their mid-IR spectral properties and far-IR SEDs with those of a control sample of 35 non-LoBALs (non-LoBALs) matched in Mi, we investigate the differences between the two populations in terms of their infrared emission and star formation activity. We model the SEDs and decouple the AGN and starburst contributions to the far-infrared luminosity in LoBALs and in non-LoBALs. We estimate star formation rates (SFRs) corrected for the AGN contribution to the FIR flux and find that LoBALs have comparable levels of star formation activity to non-LoBALs when considering the entire samples. Overall, our results show that there is no strong evidence from the mid- and far-IR properties that LoBALs are drawn from a different parent population than non-LoBALs. We conducted the first high-resolution morphological analysis of LoBALs using observations obtained with the Hubble Space Telescope Wide Field Camera 3 in two channels. Signs of recent or ongoing

  2. Mapping of the Local Interstellar Medium using Absorption Line Spectroscopy

    NASA Astrophysics Data System (ADS)

    Penprase, Bryan Edward

    2017-01-01

    Using the Yale SMARTS 1.5-meter telescope at CTIO and the CHIRON spectrograph, we have developed a program for mapping the local interstellar medium using a sample of over 200 newly observed B stars previously unobserved using Na I absorption lines. This sample includes stars that extend out to map beyond the local bubble to 500 pc. The sample has been observed using high resolution absorption lines, and when combined with previously observed stars with Na I and Ca II data provides a more complete picture of the local ISM than previous surveys. The distances to the stars using the new GAIA database also allows for more accurate determination of distances to features in the lcoal ISM, and new maps of the structure of the ISM hav been prepared with the data.

  3. Broad Absorption Line Quasar catalogues with Supervised Neural Networks

    SciTech Connect

    Scaringi, Simone; Knigge, Christian; Cottis, Christopher E.; Goad, Michael R.

    2008-12-05

    We have applied a Learning Vector Quantization (LVQ) algorithm to SDSS DR5 quasar spectra in order to create a large catalogue of broad absorption line quasars (BALQSOs). We first discuss the problems with BALQSO catalogues constructed using the conventional balnicity and/or absorption indices (BI and AI), and then describe the supervised LVQ network we have trained to recognise BALQSOs. The resulting BALQSO catalogue should be substantially more robust and complete than BI-or AI-based ones.

  4. The intervening and associated O VI absorption-line systems in the ultraviolet spectrum of H1821+643

    NASA Astrophysics Data System (ADS)

    Savage, Blair D.; Tripp, Todd M.; Lu, Limin

    1998-02-01

    GHRS and FOS ultraviolet spectra of the bright QSO H1821+643 reveal the presence of strong O VI 1031.93, 1037.62 A absorption systems at z(abs) = 0.225 and 0.297, the latter being at the redshift of the QSO itself. Ground-based galaxy redshift measurements by us and others reveal two emission-line galaxies near the redshift of the intervening system at z(abs) = 0.225, suggesting the existence of a galaxy group at this redshift. The intervening O VI absorption system is also detected in H I but is not detected in the lines of Si II, Si IV, C IV, or N V. These ionization characteristics can be explained by a low-density, extended diffuse gas distribution that is photoionized by the metagalactic UV background if the gas has a metallicity of 0.1 times solar. Such a photoionized gas may be associated with the extended halo of the luminous intervening spiral galaxy at a projected distance of 100 h kpc, or with an intragroup medium. Alternatively, the absorption may be produced in hot collisionally ionized halo gas or in a hot intragroup medium. The associated system with z(abs) = 0.297 contains narrow and broad O VI absorption. The narrow absorption, which is also detected in H I, C III, C IV, and Si IV, can be modeled as gas photoionized by H1821+643 with roughly solar abundances. This gas is probably situated close to H1821+643. The broad O VI absorption that is centered at the emission redshift of H1821+643 may represent a weak and narrow example of the broad absorption line phenomena.

  5. AFGL atmospheric absorption line parameters compilation - 1982 edition

    NASA Astrophysics Data System (ADS)

    Rothman, L. S.; Gamache, R. R.; Barbe, A.; Goldman, A.; Gillis, J. R.; Brown, L. R.; Toth, R. A.; Flaud, J.-M.; Camy-Peyret, C.

    1983-08-01

    The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 per cm, improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-micron bands of methane. The atlas now contains about 181,000 rotation and vibration-rotation transitions between 0 and 17,900 per cm. The sources of the absorption parameters are summarized.

  6. AFGL atmospheric absorption line parameters compilation - 1980 version

    NASA Astrophysics Data System (ADS)

    Rothman, L. S.

    1981-03-01

    A new version of the AFGL atmospheric absorption line parameters compilation is now available. Major modifications since the last edition of 1978 include the strongest bands of water vapor, updated line positions for carbon dioxide, improved ozone parameters in the 5- and 10 micron regions, and updated and additional data for methane in the 3.5- and 7.7 micron regions. The atlas now contains over 159,000 rotational and vibration-rotation transitions from 0.3 to 17,880 per cm.

  7. Observational Cosmology Using Absorption Lines in Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Aghaee, A.

    2016-09-01

    Distant, highly luminous quasars are important cosmological probes for a variety of astrophysical questions: the first generation of galaxies, the star formation history and metal enrichment in the early Universe, the growth of the first super massive black holes (SMBHs), the role of feedback from quasars and SMBHs in galaxy evolution, the epoch of reionization, etc. In addition, they are used as background illuminating source that reveal any object located by chance on the line of sight. I will present our group works in these issues that can be done using absorption lines in the quasar spectra.

  8. Monitoring the variability of intrinsic absorption lines in quasar spectra , ,

    SciTech Connect

    Misawa, Toru; Charlton, Jane C.; Eracleous, Michael

    2014-09-01

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 yr (1-3.5 yr in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems or in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable BALs. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density ∼10{sup 3}-10{sup 5} cm{sup –3} and upper limits on the distance of the absorbers from the central engine of the order of a few kiloparsecs. Motivated by the observed variability properties, we suggest that mini-BALs can vary because of fluctuations of the ionizing continuum or changes in partial coverage while NALs can vary primarily because of changes in partial coverage.

  9. Oscillator strength measurements of atomic absorption lines from stellar spectra

    NASA Astrophysics Data System (ADS)

    Lobel, Alex

    2011-05-01

    Herein we develop a new method to determine oscillator strength values of atomic absorption lines with state-of-the-art detailed spectral synthesis calculations of the optical spectrum of the Sun and of standard spectral reference stars. We update the log(gf) values of 911 neutral lines observed in the KPNO-FTS flux spectrum of the Sun and high-resolution echelle spectra (R = 80 000) of Procyon (F5 IV-V) and Eps Eri (K2 V) observed with large signal-to-noise (S/N) ratios of 2000 using the new Mercator-Hermes spectrograph at La Palma Observatory (Spain). We find for 483 Fe I, 85 Ni I, and 51 Si I absorption lines in the sample a systematic overestimation of the literature log(gf) values with central line depths below 15%. We employ a curve-of-growth analysis technique to test the accuracy of the new oscillator strength values and compare calculated equivalent line widths to the Moore, Minnaert, and Houtgast atlas of the Sun. The online SpectroWeb database at http://spectra.freeshell.org interactively displays the observed and synthetic spectra and provides the new log(gf) values together with important atomic line data. The graphical database is under development for stellar reference spectra of every spectral sub-class observed with large spectral resolution and S/N ratios.

  10. Radiation pressure confinement - IV. Application to broad absorption line outflows

    NASA Astrophysics Data System (ADS)

    Baskin, Alexei; Laor, Ari; Stern, Jonathan

    2014-12-01

    A fraction of quasars present broad absorption lines, produced by outflowing gas with typical velocities of 3000-10 000 km s-1. If the outflowing gas fills a significant fraction of the volume where it resides, then it will be highly ionized by the quasar due to its low density, and will not produce the observed UV absorption. The suggestion that the outflow is shielded from the ionizing radiation was excluded by recent observations. The remaining solution is a dense outflow with a filling factor f < 10-3. What produces such a small f? Here, we point out that radiation pressure confinement (RPC) inevitably leads to gas compression and the formation of dense thin gas sheets/filaments, with a large gradient in density and ionization along the line of sight. The total column of ionized dustless gas is a few times 1022 cm-2, consistent with the observed X-ray absorption and detectable P V absorption. The predicted maximal columns of various ions show a small dependence on the system parameters, and can be used to test the validity of RPC as a solution for the overionization problem. The ionization structure of the outflow implies that if the outflow is radiatively driven, then broad absorption line quasars should have L/L_Eddgtrsim 0.1.

  11. Polarization and Broad Absorption Lines in Quasars-Repeat

    NASA Astrophysics Data System (ADS)

    Antonucci, Robert

    1990-12-01

    OI 287 is a unique extragalactic source. It appears to take one property from each class of object. It is either some kind of missing link, or a new type of activity. Because of the high optical polarization, OI 287 has been classified with the blazars. However, every other blazar is variable in optical flux, polarization, and polarization angle., while OI 287 is constant at V=17, P=8%, and theta=145 degrees. Also, every other blazar has a radio source dominated by an intense flat-spectrum core, while OI 287 has an upper limit of 2% of the total 20cm flux in the core. The only group of quasars which ever shows even moderate (2-5%) constant optical polarization is the broad absorption line (BAL) objects, e.g. PHL 5200 and H1413+113. Among the BAL quasars, PHL 5200 and H1413+113 have exceptionally smooth deep, attached absorption lines, and also the highest polarization. We want to know whether OI 287 is a BAL quasar. It would be the first definite radio loud example. If it is a BAL quasar then the high polarization is really related to (and perhaps the key to) the BAL phenomenon, and we can use the techniques of spectropolarimetry to help unlock the BAL geometry. The UV spectral shape would also provide help determining the cause of polarization.

  12. FUSE and STIS Observations of Intervening O VI Absorption Line Systems in the Spectrum of PG 0953+415

    NASA Astrophysics Data System (ADS)

    Savage, B. D.; Sembach, K. R.; Tripp, T. M.; Richter, P.; Jenkins, E. B.

    2000-12-01

    We analyze Far Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS) observations of the intergalactic O VI absorption line systems in the direction of the bright QSO PG 0953+415 (z = 0.239). The FUSE observations cover the wavelength range from 905 to 1187 Å with a velocity resolution of 20 km/s. The STIS observations obtained with the E140M echelle spectrograph extend from 1150 to 1730 Å with a resolution of 8 km/s. These are supplemented with STIS G140M and G230M observations from 1145-1201 Å and from 1724-1814 A with a resolution of 30 km/s. We detect a strong O VI system at z = 0.06807 in the lines of H I Ly alpha, beta, and gamma, O VI 1031.93, 1037.62, N V 1238.80, 1242.80, C IV 1548.20, 1550.77, and C III 977.02 Å. We confirm the detection of the z = 0.14232 O VI system studied previously by Tripp and Savage (2000). The new FUSE observations of this system record Ly beta , O VI 1031.93, 1037.62, and C III 977.02 Å. We derive column densities for the absorption lines detected in both O VI systems using curve of growth and profile fitting techniques. We study the physical conditions in each system and attempt to determine the origin(s) of the ionization. Both detected O VI systems occur at redshifts where there are peaks in the number density of intervening galaxies along the line of sight based on a WIYN redshift survey of galaxies in the one degree field centered on PG 0953+415. We discuss the implications of these observations for the baryonic content of O VI absorption line systems. Financial support has been provided by NASA contract NAS-532985 and STSCI Grants GO 06499.02 and GO 08165.02.

  13. PG 1411 + 442 - The nearest broad absorption line quasar

    NASA Technical Reports Server (NTRS)

    Malkan, Matthew A.; Green, Richard F.; Hutchings, John B.

    1987-01-01

    IUE observations reveal strong, moderately broad absorption troughs in the blue wings of the C IV and N V emission lines of the quasar PG 1411 + 442. No absorption from weakly ionized gas is detected. The emission-line strengths and overall shape of the ultraviolet/optical/near-infrared/far-infrared continuum of the new broad absorption line quasar are within the range normally measured in quasars. Its redshift is low enough to allow the morphology of the host galaxy to be studied in deep broad-band and intermediate-band CCD images. The galaxy appears to be a large spiral with a very long arm or tail. The inclination angle is 57 deg, which rules out the possibility that the line of sight to the nucleus intersects a large path length in a galactic disk.

  14. A Refined QSO Selection Method Using Diagnostics

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Won; Protopapas, Pavlos; Trichas, Markos; Rowan-Robinson, Michael; Khardon, Roni; Alcock, Charles; Byun, Yong-Ik

    2012-04-01

    We present 663 QSO candidates in the Large Magellanic Cloud (LMC) that were selected using multiple diagnostics. We started with a set of 2,566 QSO candidates selected using the methodology presented in our previous work based on time variability of the MACHO LMC light curves. We then obtained additional information for the candidates by cross-matching them with the Spitzer SAGE, the 2MASS, the Chandra, the XMM, and an LMC UBVI catalogues. Using that information, we specified diagnostic features based on mid-IR colours, photometric redshifts using SED template fitting, and X-ray luminosities, in order to discriminate more high-confidence QSO candidates in the absence of spectral information. We then trained a one-class Support Vector Machine model using those diagnostics features. We applied the trained model to the original candidates, and finally selected 663 high-confidence QSO candidates. We cross-matched those 663 QSO candidates with 152 newly-confirmed QSOs and 275 non-QSOs in the LMC fields, and found that the false positive rate was less than 1%.

  15. Monitoring the Variability of Intrinsic Absorption Lines in Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Charlton, Jane C.; Eracleous, Michael

    2014-09-01

    We have monitored 12 intrinsic narrow absorption lines (NALs) in five quasars and seven mini-broad absorption lines (mini-BALs) in six quasars for a period of 4-12 yr (1-3.5 yr in the quasar rest-frame). We present the observational data and the conclusions that follow immediately from them, as a prelude to a more detailed analysis. We found clear variability in the equivalent widths (EWs) of the mini-BAL systems but no easily discernible changes in their profiles. We did not detect any variability in the NAL systems or in narrow components that are often located at the center of mini-BAL profiles. Variations in mini-BAL EWs are larger at longer time intervals, reminiscent of the trend seen in variable BALs. If we assume that the observed variations result from changes in the ionization state of the mini-BAL gas, we infer lower limits to the gas density ~103-105 cm-3 and upper limits on the distance of the absorbers from the central engine of the order of a few kiloparsecs. Motivated by the observed variability properties, we suggest that mini-BALs can vary because of fluctuations of the ionizing continuum or changes in partial coverage while NALs can vary primarily because of changes in partial coverage. Based on data collected at Subaru telescope, which is operated by the National Astronomical Observatory of Japan. Based on observations obtained at the European Southern Observatory at La Silla, Chile in programs 65.O-0063(B), 65.O-0474(A), 67.A-0078(A), 68.A-0461(A), 69.A-0204(A), 70.B-0522(A), 072.A-0346(A), 076.A-0860(A), 079.B-0469(A), and 166.A-0106(A).

  16. Frequency of Oxygen VI in Intervening QSO Absorption Systems

    NASA Astrophysics Data System (ADS)

    Burles, Scott; Tytler, David

    1994-12-01

    We have conducted the first survey for QSO with O VI lambda lambda 1032,1038 absorption lines. We obtained medium resolution (R ~ 1300), high signal-to-noise (~ 20) spectra of 11 QSOs (0.53<= zem <=2.08) taken with the Faint Object Spectrograph from the Hubble Space Telescope Archive. The O VI doublet is found exclusively in the Lyman-alpha forest. All previous surveys of metal lines in QSO absorption systems were done redward of Lyalpha emission, avoiding blending due to Lyman-alpha forest clouds. The higher density of lines in the Lyman-alpha forest demands new stringent criteria to ensure the identification of the O VI doublet. We used simulated spectra to determine the statistical significance of lines indentified in the Lyman-alpha forest. We found 12 O VI doublets and 9 are expected to be real. Six constitute a uniform sample with both lines exceeding a rest equivalent width of W_r =0.21 Angstroms. The number of O VI doublets per unit redshift is = 1.0 +/-0.6 at a mean absorption redshift of zave = 0.9. For comparable W_r the density of O VI absorbers is similar to Mg II (Tytler et al 1986; Steidel & Sargent 1992) and C IV absorbers (Sargent et al 1988; Bahcall et al 1993). We searched for other common ions in the O VI absorption systems. Out of 8 O VI absorption systems in which C IV is also found, C IV is stronger in all except zabs=1.0828 towards PG1206+459 which we believe is collisionally ionized. A rough estimate of the cosmological mass density of O VI is carried out. If we assume that O VI lines are linear, we get a lower limit of Omega (OVI) >= 3 times 10(-9) h(-1}_{100) . Since O > O VI, if the mean metal abundance were below 0.002 solar, then the accompanying Hydrogen and Helium would account for all baryons in the universe. We conclude that mean abundances are above 0.002 solar, and much greater if the gas is not highly ionized (O >> O VI).

  17. The Level of Ionization and Chemical Composition of QSO BAL Regions

    NASA Astrophysics Data System (ADS)

    Kopko, M., Jr.; Turnshek, D. A.; Espey, B. R.

    1992-05-01

    We present results from our attempts to understand the level of ionization and chemical composition of the Broad Absorption Line (BAL) regions of QSOs. We discuss three aspects of the work: 1) We consider methods used to derive BAL region column densities as a function of outflow velocity from BAL profiles, discussing the problems associated with making assumptions about BAL region cloud sizes, covering factors, and internal kinematics (thermal versus turbulent velocities). 2) We apply these methods to a study of the ionization and chemical composition of QSO BAL regions using Ferland's photoionization code CLOUDY. 3) We present results for several BAL QSOs in our study, taking advantage of the presence of absorption from different ions of the same element to derive photoionization parameters. This allows us to derive more stringent constraints than has been possible in the past.

  18. NE VIII lambda 774 and time variable associated absorption in the QSO UM 675

    NASA Technical Reports Server (NTRS)

    Hamann, Fred; Barlow, Thomas A.; Beaver, E. A.; Burbidge, E. M.; Cohen, Ross D.; Junkkarinen, Vesa; Lyons, R.

    1995-01-01

    We discuss measurements of Ne VIII lambda 774 absorption and the time variability of other lines in the z(sub a) approximately equal z(sub e) absorption system of the z(sub e) = 2.15 QSO UM 675 (0150-203). The C IV lambda 1549 and N V 1240 doublets at z(sub a) = 2.1340 (shifted approximately 1500 km/s from z(sub e) strengthened by a factor of approximately 3 between observations by Sargent, Boksenberg and Steidel (1981 November) and our earliest measurements (1990 November and December). We have no information on changes in other z(sub a) approximately equal z(sub e) absorption lines. Continued monitoring since 1990 November shows no clear changes in any of the absorptions between approximately 1100 and 1640 A rest. The short timescale of the variability (less than or approximately equal to 2.9 yr rest) strongly suggests that the clouds are dense, compact, close to the QSO, and photoionized by the QSO continuum. If the line variability is caused by changes in the ionization, the timescale requires densities greater than approximately 4000/cu cm. Photoionization calculations place the absorbing clouds within approximately 200 pc of the continuum source. The full range of line ionizations (from Ne VIII lambda 774 to C III lambda 977) in optically thin gas (no Lyman limit) implies that the absorbing regions span a factor of more than approximately 10 in distance or approximately 100 in density. Across these regions, the total hydrogen (H I + H II) column ranges from a few times 10(exp 18)/sq cm in the low-ionization gas to approximately 10(exp 20)/sq cm where the Ne VIII doublet forms. The metallicity is roughly solar or higher, with nitrogen possibly more enhanced by factors of a few. The clouds might contribute significant line emission if they nearly envelop the QSO. The presence of highly ionized Ne VIII lambda 774 absorption near the QSO supports recent studies that link z(sub a) approximately equal to z(sub e) systems with X-ray 'wamr absorbers. We show that the

  19. NE VIII lambda 774 and time variable associated absorption in the QSO UM 675

    NASA Astrophysics Data System (ADS)

    Hamann, Fred; Barlow, Thomas A.; Beaver, E. A.; Burbidge, E. M.; Cohen, Ross D.; Junkkarinen, Vesa; Lyons, R.

    1995-04-01

    We discuss measurements of Ne VIII lambda 774 absorption and the time variability of other lines in the za approximately equal ze absorption system of the ze = 2.15 QSO UM 675 (0150-203). The C IV lambda 1549 and N V 1240 doublets at za = 2.1340 (shifted approximately 1500 km/s from ze strengthened by a factor of approximately 3 between observations by Sargent, Boksenberg and Steidel (1981 November) and our earliest measurements (1990 November and December). We have no information on changes in other za approximately equal ze absorption lines. Continued monitoring since 1990 November shows no clear changes in any of the absorptions between approximately 1100 and 1640 A rest. The short timescale of the variability (less than or approximately equal to 2.9 yr rest) strongly suggests that the clouds are dense, compact, close to the QSO, and photoionized by the QSO continuum. If the line variability is caused by changes in the ionization, the timescale requires densities greater than approximately 4000/cu cm. Photoionization calculations place the absorbing clouds within approximately 200 pc of the continuum source. The full range of line ionizations (from Ne VIII lambda 774 to C III lambda 977) in optically thin gas (no Lyman limit) implies that the absorbing regions span a factor of more than approximately 10 in distance or approximately 100 in density. Across these regions, the total hydrogen (H I + H II) column ranges from a few times 1018/sq cm in the low-ionization gas to approximately 1020/sq cm where the Ne VIII doublet forms. The metallicity is roughly solar or higher, with nitrogen possibly more enhanced by factors of a few. The clouds might contribute significant line emission if they nearly envelop the QSO. The presence of highly ionized Ne VIII lambda 774 absorption near the QSO supports recent studies that link za approximately equal to ze systems with X-ray 'wamr absorbers. We show that the Ne VIII absorbing gas would itself produce measurable warm

  20. Anomalous absorption line in the magneto-optical response of graphene.

    PubMed

    Gusynin, V P; Sharapov, S G; Carbotte, J P

    2007-04-13

    The intensity as well as position in energy of the absorption lines in the infrared conductivity of graphene, both exhibit features that are directly related to the Dirac nature of its quasiparticles. We show that the evolution of the pattern of absorption lines as the chemical potential is varied encodes the information about the presence of the anomalous lowest Landau level. The first absorption line related to this level always appears with full intensity or is entirely missing, while all other lines disappear in two steps. We demonstrate that if a gap develops, the main absorption line splits into two provided that the chemical potential is greater than or equal to the gap.

  1. Interstellar absorption lines in the spectrum of Gamma Velorum

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Bhavsar, S. P.

    1979-01-01

    Copernicus scans of selected interstellar absorption lines in the UV spectrum of Gamma Vel are analyzed, together with ground-based data, to obtain column densities for various ion states of C, N, O, Na, Mg, Al, Si, P, S, Cl, Ar, Ca, Mn, Fe, and CO. N I and O I are fitted to a single empirical curve of growth with a velocity parameter (b) of 8 km/s; Mg II, Si II, P II, S II, Mn II, and Fe II are fitted to another curve with b between 3 and 9 km/s. Abundance determinations relative to H I show that: (1) C, N, P, S, and Ar are probably close to their solar values; (2) O may be depleted by about a factor of 2; (3) Mg, Al, Si, Cl, Mn, and Fe are depleted by a factor of 4 or more: (4) Al is depleted by at least a factor of 10 in the H II region; and (5) both N V and O VI are present, but not C IV. The N V/O VI ratio implies that the electron temperature in the H II region is about 275,000 K.

  2. Probing Quasar Winds Using Intrinsic Narrow Absorption Lines

    NASA Astrophysics Data System (ADS)

    Culliton, Christopher S.; Charlton, Jane C.; Eracleous, Michael; Roberts, Amber; Ganguly, Rajib; Misawa, Toru; Muzahid, Sowgat

    2017-01-01

    Quasar outflows are important for understanding the accretion and growth processes of the central black hole. Furthermore, outflows potentially have a role in providing feedback to the galaxy, and halting star formation and infall of gas. The geometry and density of these outflows remain unknown, especially as a function of ionization and velocity. Having searched ultraviolet spectra at both high redshift (VLT/UVES; 1.4absorption lines (NALs) that are intrinsic to (physically associated with) the quasar. We identify intrinsic NALs with a wide range of properties, including ejection velocity, coverage fraction, and ionization level. We also consider the incidence of intrinsic absorbers as a function of quasar properties (optical, radio and X-ray fluxes), and find that radio properties and quasar orientation are influential in determining if a quasar is likely to host an intrinsic system. We find that there is a continuum of properties within the intrinsic NAL sample, rather than discrete families, ranging from partially covered CIV systems with black Lya and with a separate low ionization gas phase to partially covered NV systems with partially covered Lya and without detected low ionization gas. Additionally, we construct a model describing the spatial distributions, geometries, and varied ionization structures of intrinsic NALs.

  3. The Physical Nature of Polar Broad Absorption Line Quasars

    NASA Technical Reports Server (NTRS)

    Ghost, Kajal; Punsly, Brian

    2007-01-01

    It has been shown based on radio variability arguments that some BALQSOs (broad absorption line quasars) are viewed along the polar axis (o rthogonal to accretion disk) in the recent article of Zhou et a. Thes e arguments are based on the brightness temperature, T(sub b) exceedi ng 10(exp 12) K which leads to the well-known inverse Compton catastr ophe unless the radio jet is relativistic and is viewed along its axi s. In this letter, we expand the Zhou et al sample of polar BALQSOs u sing their techniques applied to SDSS DR5. In the process, we clarify a mistake in their calculation of brightness temperature. The expanded sample of high T(sub b) BALQSOS, has an inordinately large fraction of LoBALQSOs (low ionization BALQSOs). We consider this an important clue to understanding the nature of the polar BALQSOs. This is expec ted in the polar BALQSO analytical/numerical models of Punsly that pr edicted that LoBALQSOs occur when the line of sight is very close to the polar axis, where the outflow density is the highest.

  4. VERY LARGE TELESCOPE SPECTROPOLARIMETRY OF BROAD ABSORPTION LINE QSOs

    SciTech Connect

    DiPompeo, M. A.; Brotherton, M. S.; De Breuck, C.

    2011-03-15

    We present spectropolarimetry of 19 confirmed and four possible bright, southern broad absorption line (BAL) quasars from the European Southern Observatory Very Large Telescope. A wide range of redshifts is covered in the sample (from 0.9 to 3.4), and both low- and high-ionization quasars are represented, as well as radio-loud and radio-quiet BALQSOs. We continue to confirm previously established spectropolarimetric properties of BALQSOs, including the generally rising continuum polarization with shorter wavelengths and comparatively large fraction with high broadband polarization (6 of 19 with polarizations >2%). Emission lines are polarized less than or similar to the continuum, except in a few unusual cases, and absorption troughs tend to have higher polarizations. A search for correlations between polarization properties has been done, identifying two significant or marginally significant correlations. These are an increase in continuum polarization with decreasing optical luminosity (increasing absolute B magnitude) and decreasing C IV emission-line polarization with increased continuum polarization.

  5. Outflow and hot dust emission in broad absorption line quasars

    SciTech Connect

    Zhang, Shaohua; Zhou, Hongyan; Wang, Huiyuan; Wang, Tinggui; Xing, Feijun; Jiang, Peng; Zhang, Kai E-mail: whywang@mail.ustc.edu.cn

    2014-05-01

    We have investigated a sample of 2099 broad absorption line (BAL) quasars with z = 1.7-2.2 built from the Sloan Digital Sky Survey Data Release Seven and the Wide-field Infrared Survey. This sample is collected from two BAL quasar samples in the literature and is refined by our new algorithm. Correlations of outflow velocity and strength with a hot dust indicator (β{sub NIR}) and other quasar physical parameters—such as an Eddington ratio, luminosity, and a UV continuum slope—are explored in order to figure out which parameters drive outflows. Here β{sub NIR} is the near-infrared continuum slope, which is a good indicator of the amount of hot dust emission relative to the accretion disk emission. We confirm previous findings that outflow properties moderately or weakly depend on the Eddington ratio, UV slope, and luminosity. For the first time, we report moderate and significant correlations of outflow strength and velocity with β{sub NIR} in BAL quasars. It is consistent with the behavior of blueshifted broad emission lines in non-BAL quasars. The statistical analysis and composite spectra study both reveal that outflow strength and velocity are more strongly correlated with β{sub NIR} than the Eddington ratio, luminosity, and UV slope. In particular, the composites show that the entire C IV absorption profile shifts blueward and broadens as β{sub NIR} increases, while the Eddington ratio and UV slope only affect the high and low velocity part of outflows, respectively. We discuss several potential processes and suggest that the dusty outflow scenario, i.e., that dust is intrinsic to outflows and may contribute to the outflow acceleration, is most likely.

  6. The Luminosity Function of QSO Host Galaxies

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  7. A Kennicutt-Schmidt Law for Intervening Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Chelouche, Doron; Bowen, David V.

    2010-10-01

    We argue that most strong intervening metal absorption line systems, where the rest equivalent width of the Mg II λ2796 line is >0.5 Å, are interstellar material in, and outflowing from, star-forming disks. We show that a version of the Kennicutt-Schmidt law is readily obtained if the Mg II equivalent widths are interpreted as kinematic broadening from absorbing gas in outflowing winds originating from star-forming galaxies. Taking a phenomenological approach and using a set of observational constraints available for star-forming galaxies, we are able to account for the density distribution of strong Mg II absorbers over cosmic time. The association of intervening material with star-forming disks naturally explains the metallicity and dust content of strong Mg II systems, as well as their high H I column densities, and does not require the advection of metals from compact star-forming regions into the galaxy halos to account for the observations. We find that galaxies with a broad range of luminosities can give rise to absorption of a given rest equivalent width and discuss possible observational strategies to better quantify true galaxy-absorber associations and further test our model. We show that the redshift evolution in the density of absorbers closely tracks the star formation history of the universe and that strong intervening systems can be used to directly probe the physics of both bright and faint galaxies over a broad redshift range. In particular, in its simplest form, our model suggests that many of the statistical properties of star-forming galaxies and their associated outflows have not evolved significantly since z ~ 2. By identifying strong intervening systems with galaxy disks and quantifying a version of the Kennicutt-Schmidt law that applies to them, a new probe of the interstellar medium is found which provides complementary information to that obtained through emission studies of galaxies. Implications of our results for galaxy feedback and

  8. A REFINED QSO SELECTION METHOD USING DIAGNOSTICS TESTS: 663 QSO CANDIDATES IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Kim, Dae-Won; Protopapas, Pavlos; Trichas, Markos; Alcock, Charles; Rowan-Robinson, Michael; Khardon, Roni; Byun, Yong-Ik

    2012-03-10

    We present 663 QSO candidates in the Large Magellanic Cloud (LMC) selected using multiple diagnostics. We started with a set of 2566 QSO candidates selected using the methodology presented in our previous work based on time variability of the MACHO LMC light curves. We then obtained additional information for the candidates by crossmatching them with the Spitzer SAGE, the Two Micron All Sky Survey, the Chandra, the XMM, and an LMC UBVI catalog. Using this information, we specified six diagnostic features based on mid-IR colors, photometric redshifts using spectral energy distribution template fitting, and X-ray luminosities in order to further discriminate high-confidence QSO candidates in the absence of spectra information. We then trained a one-class Support Vector Machine model using the diagnostics features of the confirmed 58 MACHO QSOs. We applied the trained model to the original candidates and finally selected 663 high-confidence QSO candidates. Furthermore, we crossmatched these 663 QSO candidates with the newly confirmed 151 QSOs and 275 non-QSOs in the LMC fields. On the basis of the counterpart analysis, we found that the false positive rate is less than 1%.

  9. Survey incompleteness and the evolution of the QSO luminosity function

    NASA Technical Reports Server (NTRS)

    Majewski, Steven R.; Munn, Jeffrey A.; Kron, Richard G.; Bershady, Matthew A.; Smetanka, John J.; Koo, David C.

    1993-01-01

    We concentrate on a type of QSO survey which depends on selecting QSO candidates based on combinations of colors. Since QSO's have emission lines and power-law continua, they are expected to yield broadband colors unlike those of stellar photospheres. Previously, the fraction of QSO's expected to be hiding (unselected) within the locus of stellar (U-J, J-F) colors was estimated at about 15 percent. We have now verified that the KK88 survey is at least 11 percent incomplete, but have determined that it may be as much as 34 percent incomplete. The 'missing' QSO's are expected to be predominantly at z less than or = 2.2. We have studied the proper motion and variability properties of all stellar objects with J less than or = 22.5 or F less than or = 21.5 in the SA 57 field which has previously been surveyed with a multicolor QSO search by KK88.

  10. Detection of emission lines from z ˜ 3 DLAs towards the QSO J2358+0149

    NASA Astrophysics Data System (ADS)

    Srianand, Raghunathan; Hussain, Tanvir; Noterdaeme, Pasquier; Petitjean, Patrick; Krühler, Thomas; Japelj, Jure; Pâris, Isabelle; Kashikawa, Nobunari

    2016-07-01

    Using VLT/X-shooter, we searched for emission line galaxies associated with four damped Lyman α systems (DLAs) and one sub-DLA at 2.73 ≤z ≤3.25 towards QSO J2358+0149. We detect [O III] emission from a `low-cool' DLA at zabs = 2.9791 (having log N(H I) = 21.69 ± 0.10, [Zn/H] = -1.83 ± 0.18) at an impact parameter of, ρ ˜ 12 kpc. The associated galaxy is compact with a dynamical mass of (1-6) × 109 M⊙, very high excitation ([O III]/[O II] and [O III]/[Hβ] both greater than 10), 12+[O/H]≤8.5 and moderate star formation rate (SFR ≤2 M⊙ yr-1). Such properties are typically seen in the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is inconsistent with that of an extended disc and the gas is part of either a large scale wind or cold accretion. We detect Lyα emission from the zabs = 3.2477 DLA [having log N(H I) = 21.12 ± 0.10 and [Zn/H] = -0.97 ± 0.13]. The Lyα emission is redshifted with respect to the metal absorption lines by 320 km s-1, consistent with the location of the red hump expected in radiative transport models. We derive SFR ˜0.2-1.7 M⊙ yr-1 and Lyα escape fraction of ≥10 per cent. No other emission line is detected from this system. Because the DLA has a small velocity separation from the quasar (˜500 km s-1) and the DLA emission is located within a small projected distance (ρ < 5 kpc), we also explore the possibility that the Lyα emission is being induced by the QSO itself. QSO-induced Lyα fluorescence is possible if the DLA is within a physical separation of 340 kpc to the QSO. Detection of stellar continuum light and/or the oxygen emission lines would disfavour this possibility. We do not detect any emission line from the remaining three systems.

  11. DISCOVERY OF THE TRANSITION OF A MINI-BROAD ABSORPTION LINE INTO A BROAD ABSORPTION LINE IN THE SDSS QUASAR J115122.14+020426.3

    SciTech Connect

    Hidalgo, Paola Rodriguez; Eracleous, Michael; Charlton, Jane; Hamann, Fred; Murphy, Michael T.; Nestor, Daniel

    2013-09-20

    We present the detection of a rare case of dramatic strengthening in the UV absorption profiles in the spectrum of the quasar J115122.14+020426.3 between observations {approx}2.86 yr apart in the quasar rest frame. A spectrum obtained in 2001 by the Sloan Digital Sky Survey shows a C IV ''mini-broad'' absorption line (FWHM = 1220 km s{sup -1}) with a maximum blueshift velocity of {approx}9520 km s{sup -1}, while a later spectrum from the Very Large Telescope shows a significantly broader and stronger absorption line, with a maximum blueshift velocity of {approx}12, 240 km s{sup -1} that qualifies as a broad absorption line. A similar variability pattern is observed in two additional systems at lower blueshifted velocities and in the Ly{alpha} and N V transitions as well. One of the absorption systems appears to be resolved and shows evidence for partial covering of the quasar continuum source (C{sub f} {approx} 0.65), indicating a transverse absorber size of, at least, {approx}6 Multiplication-Sign 10{sup 16} cm. In contrast, a cluster of narrower C IV lines appears to originate in gas that fully covers the continuum and broad emission line sources. There is no evidence for changes in the centroid velocity of the absorption troughs. This case suggests that at least some of the absorbers that produce ''mini-broad'' and broad absorption lines in quasar spectra do not belong to intrinsically separate classes. Here, the ''mini-broad'' absorption line is most likely interpreted as an intermediate phase before the appearance of a broad absorption line due to their similar velocities. While the current observations do not provide enough constraints to discern among the possible causes for this variability, future monitoring of multiple transitions at high resolution will help achieve this goal.

  12. Study of a homogeneous QSO sample: relations between the QSO and its host galaxy

    NASA Astrophysics Data System (ADS)

    Letawe, Y.; Letawe, G.; Magain, P.

    2010-04-01

    We analyse a sample of 69 quasi-stellar objects (QSOs) which have been randomly selected in a complete sample of 104 QSOs (R <= 18,0.142 < z < 0.198,δ < 10°). 60 have been observed with the NTT/SUSI2 at La Silla, through two filters in the optical band (WB 655 and V 812), and the remaining nine are taken from archive data bases. The filter V 812 contains the redshifted Hβ and forbidden [OIII] emission lines, while WB 655 covers a spectral region devoid of emission lines, thus measuring the QSO and stellar continua. The contributions of the QSO and the host are separated thanks to the MCS deconvolution algorithm, allowing a morphological classification of the host, and the computation of several parameters such as the host and nucleus absolute V magnitude, distance between the luminosity centre of the host and the QSO and colour of the host and nucleus. We define a new asymmetry coefficient, independent of any galaxy models and well suited for QSO host studies. The main results from this study are (i) 25 per cent of the total number of QSO hosts are spirals, 51 per cent are ellipticals and 60 per cent show signs of interaction, (ii) highly asymmetric systems tend to have a higher gas ionization level and (iii) elliptical hosts contain a substantial amount of ionized gas and some show off-nuclear activity. These results agree with hierarchical models merger driven evolution. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under programme IDs 77.B-0229 and 78.B-0081. E-mail: gletawe@ulg.ac.be

  13. The Intrinsic Absorber in QSO 2359-1241: Keck and HUBBLE SPACE TELESCOPE Observations

    NASA Astrophysics Data System (ADS)

    Arav, Nahum; Brotherton, Michael S.; Becker, Robert H.; Gregg, Michael D.; White, Richard L.; Price, Trevor; Hack, Warren

    2001-01-01

    We present detailed analyses of the absorption spectrum seen in QSO 2359-1241 (NVSS J235953-124148). Keck HIRES data reveal absorption from 20 transitions arising from He I, Mg I, Mg II, Ca II, and Fe II. Hubble Space Telescope data show broad absorption lines (BALs) from Al III λ1857, C IV λ1549, Si IV λ1397, and N V λ1240. Absorption from excited Fe II states constrains the temperature of the absorber to 2000<~T<~10,000 K and puts a lower limit of 105 cm-3 on the electron number density. Saturation diagnostics show that the real column densities of He I and Fe II can be determined, allowing us to derive meaningful constraints on the ionization equilibrium and abundances in the flow. The ionization parameter is constrained by the iron, helium, and magnesium data to -3.0<~log(U)<~-2.5, and the observed column densities can be reproduced without assuming departure from solar abundances. From comparison of the He I and Fe II absorption features, we infer that the outflow seen in QSO 2359-1241 is not shielded by a hydrogen ionization front and therefore that the existence of low-ionization species in the outflow (e.g., Mg II, Al III, Fe II) does not necessitate the existence of such a front. We find that the velocity width of the absorption systematically increases as a function of ionization and to a lesser extent with abundance. Complementary analyses of the radio and polarization properties of the object are discussed in a companion paper (Brotherton et al.).

  14. Interstellar Gas-phase Element Depletions in the Small Magellanic Cloud: A Guide to Correcting for Dust in QSO Absorption Line Systems

    NASA Astrophysics Data System (ADS)

    Jenkins, Edward B.; Wallerstein, George

    2017-04-01

    We present data on the gas-phase abundances for 9 different elements in the interstellar medium of the Small Magellanic Cloud (SMC), based on the strengths of ultraviolet absorption features over relevant velocities in the spectra of 18 stars within the SMC. From this information and the total abundances defined by the element fractions in young stars in the SMC, we construct a general interpretation on how these elements condense into solid form onto dust grains. As a group, the elements Si, S, Cr, Fe, Ni, and Zn exhibit depletion sequences similar to those in the local part of our Galaxy defined by Jenkins. The elements Mg and Ti deplete less rapidly in the SMC than in the Milky Way, and Mn depletes more rapidly. We speculate that these differences might be explained by the different chemical affinities to different existing grain substrates. For instance, there is evidence that the mass fractions of polycyclic aromatic hydrocarbons in the SMC are significantly lower than those in the Milky Way. We propose that the depletion sequences that we observed for the SMC may provide a better model for interpreting the element abundances in low-metallicity Damped Lyman Alpha (DLA) and sub-DLA absorption systems that are recorded in the spectra of distant quasars and gamma-ray burst afterglows. Based on observations with the NASA/ESA Hubble Space Telescope and additional data obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Associations of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. These observations are associated with program nr. 13778.

  15. QSO selection in the ALHAMBRA survey

    NASA Astrophysics Data System (ADS)

    Matute, I.; Márquez, I.; Masegosa, J.; Perea, J.; Del Olmo, A.; Husillos, C.

    2011-11-01

    During the past decade photometric redshift (photo-z) determination for the extragalactic population has been drastically improved. This improvement has allow to close the gap between the several hundred thousand of objects per deg^2 detected in modern cosmological surveys and their identification through spectroscopic follow-ups. Only recently, a similar level of precision has been achieved for AGN as for normal galaxies. We characterize the efficiency of the ALHAMBRA survey to derive highly accurate photometric redshifts (photo-z) for the brightest of the AGN sample, the QSOs. This characterization is required before any further analysis whether it implies individual objects or statistical properties of the QSO population as a whole (e.g. luminosity functions). We present the results for the QSO photo-z calibration making use of the published spectroscopic information from other major cosmological surveys overlapping with ALHAMBRA (e.g. COSMOS, GOODS, SDSS, DEEP, SWIRE & AEGIS). With the appropriate selection of templates and priors, the analysis of the ALHAMBRA fields shows an excellent agreement between the spectro-z and photo-z, obtaining σ[Δ z/(1+z)] < 0.02 with a low fraction (<7%) of catastrophic failures.

  16. A Comprehensive Study of Broad Absorption Line Quasars. I. Prevalence of HeI* Absorption Line Multiplets in Low-ionization Objects

    NASA Astrophysics Data System (ADS)

    Liu, Wen-Juan; Zhou, Hongyan; Ji, Tuo; Yuan, Weimin; Wang, Ting-Gui; Jian, Ge; Shi, Xiheng; Zhang, Shaohua; Jiang, Peng; Shu, Xinwen; Wang, Huiyuan; Wang, Shu-Fen; Sun, Luming; Yang, Chenwei; Liu, Bo; Zhao, Wen

    2015-03-01

    Neutral helium multiplets, He i* λ λ 3189,3889,10830, are very useful diagnostics for the geometry and physical conditions of the absorbing gas in quasars. So far only a handful of He i* detections have been reported. Using a newly developed method, we detected the He i*λ 3889 absorption line in 101 sources of a well-defined sample of 285 Mg ii broad absorption line (BAL) quasars selected from SDSS DR5. This has increased the number of He i* BAL quasars by more than one order of magnitude. We further detected He i*λ 3189 in 50% (52/101) of the quasars in the sample. The detection fraction of He i* BALs in Mg ii BAL quasars is ∼35% as a whole, and it increases dramatically with increasing spectral signal-to-noise ratio (S/N), from ∼18% at S/N ≤slant 10 to ∼93% at S/N ≥slant 35. This suggests that He i* BALs could be detected in most Mg ii LoBAL quasars, provided the spectra S/N is high enough. Such a surprisingly high He i* BAL fraction is actually predicted from photoionization calculations based on a simple BAL model. The result indicates that He i* absorption lines can be used to search for BAL quasars at low z, which cannot be identified by ground-based optical spectroscopic surveys with commonly seen UV absorption lines. Using He i* λ3889, we discovered 19 BAL quasars at z\\lt 0.3 from the available SDSS spectral database. The fraction of He i* BAL quasars is similar to that of LoBAL objects.

  17. Current QSO statistics - Implications for the intergalactic medium

    NASA Technical Reports Server (NTRS)

    Sherman, R. D.

    1981-01-01

    The results of numerous QSO surveys have been compiled and analyzed to form a single spatially averaged QSO ionizing function that is independent of evolution mode (number density or luminosity). An intergalactic medium (IGM) that satisfies the observational constraints may now have a density with respect to closure of approximately 0.1, which is substantially less than hitherto modeled. The aggregate of QSO data also indicate that if evolution is due to number density, then, when split into luminosity classes, an exponential in look-back time fits the data better than a power law, and the evolution rates increase roughly with absolute luminosity if analyzed by the exponential.

  18. The Physical Constraints on a New LoBAL QSO at z = 4.82

    NASA Astrophysics Data System (ADS)

    Yi, Weimin; Green, Richard; Bai, Jin-Ming; Wang, Tinggui; Grier, Catherine J.; Trump, Jonathan R.; Brandt, William N.; Zuo, Wenwen; Yang, Jinyi; Wang, Feige; Yang, Chenwei; Wu, Xue-Bing; Zhou, Hongyan; Fan, Xiaohui; Jiang, Linhua; Yang, Qian; Varricatt, Watson; Kerr, Tom; Milne, Peter; Benigni, Sam; Wang, Jian-Guo; Zhang, Jujia; Wang, Fang; Wang, Chuan-Jun; Xin, Yu-Xin; Fan, Yu-Feng; Chang, Liang; Zhang, Xiliang; Lun, Bao-Li

    2017-04-01

    Very few low-ionization broad absorption line (LoBAL) QSOs have been found at high redshifts, to date. One high-redshift LoBAL QSO, J0122+1216, was recently discovered by the Lijiang 2.4 m Telescope, with an initial redshift determination of 4.76. Aiming to investigate its physical properties, we carried out follow-up observations in the optical and near-IR spectroscopy. Near-IR spectra from UKIRT and P200 confirm that it is a LoBAL, with a new redshift determination of 4.82 ± 0.01 based on the Mg ii emission-line. The new Mg ii redshift determination reveals strong blueshifts and asymmetry of the high-ionization emission lines. We estimate a black hole mass of ∼2.3 × 109 M ⊙ and Eddington ratio of ∼1.0 according to the empirical Mg ii-based single-epoch relation and bolometric correction factor. It is possible that strong outflows are the result of an extreme quasar environment driven by the high Eddington ratio. A lower limit on the outflowing kinetic power (>0.9% L Edd) is derived from both emission and absorption lines, indicating that these outflows play a significant role in the feedback process that regulates the growth of its black hole, as well as host galaxy evolution.

  19. Cosmological test with the QSO Hubble diagram

    NASA Astrophysics Data System (ADS)

    López-Corredoira, M.; Melia, F.; Lusso, E.; Risaliti, G.

    2016-03-01

    A Hubble diagram (HD) has recently been constructed in the redshift range 0 ≲ z ≲ 6.5 using a nonlinear relation between the ultraviolet (UV) and X-ray luminosities of quasi stellar objects (QSOs). The Type Ia Supernovae (SN) HD has already provided a high-precision test of cosmological models, but the fact that the QSO distribution extends well beyond the supernova range (z ≲ 1.8), in principle provides us with an important complementary diagnostic whose significantly greater leverage in z can impose tighter constraints on the distance versus redshift relationship. In this paper, we therefore perform an independent test of nine different cosmological models, among which six are expanding, while three are static. Many of these are disfavored by other kinds of observations (including the aforementioned Type Ia SNe). We wish to examine whether the QSO HD confirms or rejects these earlier conclusions. We find that four of these models (Einstein-de Sitter, the Milne universe, the static universe with simple tired light and the static universe with plasma tired light) are excluded at the > 99% C.L. The quasi-steady state model is excluded at > 95% C.L. The remaining four models (ΛCDM/wCDM, the Rh = ct universe, the Friedmann open universe and a static universe with a linear Hubble law) all pass the test. However, only ΛCDM/wCDM and Rh = ct also pass the Alcock-Paczyński (AP) test. The optimized parameters in ΛCDM/wCDM are Ωm = 0.20-0.20+0.24 and wde = -1.2-∞+1.6 (the dark energy equation-of-state). Combined with the AP test, these values become Ωm = 0.38-0.19+0.20 and wde = -0.28-0.40+0.52. But whereas this optimization of parameters in ΛCDM/wCDM creates some tension with their concordance values, the Rh = ct universe has the advantage of fitting the QSO and AP data without any free parameters.

  20. Statistical and physical evolution of QSO's

    NASA Technical Reports Server (NTRS)

    Caditz, David; Petrosian, Vahe

    1989-01-01

    The relationship between the physical evolution of discrete extragalactic sources, the statistical evolution of the observed population of sources, and the cosmological model is discussed. Three simple forms of statistical evolution: pure luminosity evolution (PLE), pure density evolution (PDE), and generalized luminosity evolution (GLE), are considered in detail together with what these forms imply about the physical evolution of individual sources. Two methods are used to analyze the statistical evolution of the observed distribution of QSO's (quasars) from combined flux limited samples. It is shown that both PLE and PDE are inconsistent with the data over the redshift range 0 less than z less than 2.2, and that a more complicated form of evolution such as GLE is required, independent of the cosmological model. This result is important for physical models of AGN, and in particular, for the accretion disk model which recent results show may be inconsistent with PLE.

  1. Archival research on absorption lines in violently star-forming galaxies

    NASA Technical Reports Server (NTRS)

    Gallagher, J. S.

    1989-01-01

    A computerized analysis of a starburst model is discussed. The model proposes that the absorption line equivalent width should scale with the level of star forming activity. Archival International Ultraviolet Explorer (IUE) data on IUE spectra of luminous blue galaxies were compared with previous IUE observations of extragalactic HII regions and low luminosity galaxies. The comparisons are summarized and causes for offsets are discussed.

  2. Resolution Effects on Quasar Absorption Line Studies of ΛCDM Simulations

    NASA Astrophysics Data System (ADS)

    Kacprzak, Glenn; Ceverino, D.; Churchill, C. W.; Murphy, M. T.; Evans, J. L.

    2009-01-01

    The technique of using background quasars to study absorption lines produced by gaseous halos of foreground galaxies provides a uniquely powerful tool to probe the gas-galaxy and IGM interface. With absorption lines, we are capable of studying the kinematic, chemical, and ionization conditions of galactic halos over all redshifts out to projected galactocentric radii of several 100 kpc. However, interpreting these data can be difficult. We have recently begun to produce similar absorption line observations of galaxies and their gaseous halos in LCDM cosmological simulations in order to constrain the dynamic interaction of the galaxy/halo/cosmic web environment and the distribution of gas within halos. The simulations are performed using the Eulerian Gasdynamics plus N-body Adaptive Refinement Tree (ART) code, were the highest resolution gas cells are 20-100 pc. However, absorption lines are primarily produced/observed in the halos of galaxies where the resolution is lower. Here, we quantify how varying the resolution affects the measured absorption velocity spreads, number of clouds, and covering fractions of halo gas within the simulated galaxies. This is an important step toward understanding the interplay between halo gas kinematics and small scale structure. It is crucial that we understand these effects in order to correctly interpret our observations.

  3. Absorption-line spectrum of GC 1556 + 335 - ejected or intervening material

    SciTech Connect

    Morris, S.L.; Weymann, R.J.; Foltz, C.B.; Turnshek, D.A.; Shectman, S.

    1986-11-01

    Two rich C IV absorption complexes in the radio-loud QSO GC 1556 + 335 are described. Column densities for seven of the redshift systems in these complexes are measured, and limits on the distances between the QSO and absorbing clouds are derived using ionization parameters estimated from matching photoionization models to the observations and a density estimated from an upper limit to the C II(asterisk) column density in the z = 1.65367 redshift system. These limits show that GC 1556 + 335 is not a typical member of the BALQSO class. Two alternative models are discussed in which the absorption complexes are caused by material either entrained into a radio jet from the QSO or contained in two clusters of galaxies along the line of sight. It is suggested that the emission associated with the complexes may be detectable, and that a study of the velocity field and geometry of such emission might be decisive in determining the mechanism responsible for the absorption. 40 references.

  4. High-resolution optical and ultraviolet absorption-line studies of interstellar gas

    NASA Technical Reports Server (NTRS)

    Cowie, Lennox L.; Songaila, Antoinette

    1986-01-01

    Recent progress in the characterization of the interstellar medium (ISM) by means of optical and UV spectral data is summarized. The gas is studied by focusing on background stars whose spectra can be accurately modeled to provide the light source for the absorption-line scans. The capabilities of earth- and space-based instruments which have been and are used for the surveys are delineated. The distributions of diffuse gas densities and characteristics of the cold, warm and hot gas in the Galaxy are described in terms of the elemental abundances, kinetics and distributions of the gas. Particular note is taken of gas in the solar neighborhood and around SNR, and of absorption-line data of cosmological significance.

  5. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  6. Discovery of an X-ray Violently Variable Broad Absorption Line Quasar

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Gutierrez, Carlos M.; Punsly, Brian; Chevallier, Loic; Goncalves, Anabela C.

    2006-01-01

    In this letter, we report on a quasar that is violently variable in the X-rays, XVV. It is also a broad absorption line quasar (BALQSO) that exhibits both high ionization and low ionization UV absorption lines (LoBALQSO). It is very luminous in the X-rays (approximately 10(exp 46) ergs s(sup -l) over the entire X-ray band). Surprisingly, this does not over ionize the LoBAL outflow. The X-rays vary by a factor of two within minutes in the quasar rest frame, which is shorter than 1/30 of the light travel time across a scale length equal to the black hole radius. We concluded that the X-rays are produced in a relativistic jet beamed toward earth in which variations in the Doppler enhancement produce the XVV behavior.

  7. Radiatively driven winds for different power law spectra. [for explaining narrow and broad quasar absorption lines

    NASA Technical Reports Server (NTRS)

    Beltrametti, M.

    1980-01-01

    The analytic solutions for radiatively driven winds are given for the case in which the winds are driven by absorption of line and continuum radiation. The wind solutions are analytically estimated for different parameters of the central source and for different power law spectra. For flat spectra, three sonic points can exist; it is shown, however, that only one of these sonic points is physically realistic. Parameters of the central source are given which generate winds of further interest for explaining the narrow and broad absorption lines in quasars. For the quasar model presented here, winds which could give rise to the narrow absorption lines are generated by central sources with parameters which are not realistic for quasars.

  8. A method for measuring magnetic fields in sunspots using Zeeman-broadened absorption lines

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2017-04-01

    We present measurements of magnetic fields in several sunspots using high-resolution spectra obtained with the ESPARTACO spectrograph at the Universidad de los Andes, with the aim to explore experimental possibilities for students. Because the Zeeman line splitting is smaller than the line width, our work only observes broadened absorption lines. This broadening, however, can be measured and suitably modeled, giving realistic quantitative results.

  9. Synthetic absorption lines for a clumpy medium: a spectral signature for cloud acceleration in AGN?

    NASA Astrophysics Data System (ADS)

    Waters, Tim; Proga, Daniel; Dannen, Randall; Kallman, Timothy R.

    2017-01-01

    There is increasing evidence that the highly ionised multiphase components of AGN disc winds may be due to thermal instability. The ions responsible for forming the observed X-ray absorption lines may only exist in relatively cool clumps that can be identified with the so-called `warm absorbers'. Here we calculate synthetic absorption lines for such warm absorbers from first principles by combining 2D hydrodynamic solutions of a two-phase medium with a dense grid of photoionization models to determine the detailed ionization structure of the gas. Our calculations reveal that cloud disruption, which leads to a highly complicated velocity field (i.e. a clumpy flow), will only mildly affect line shapes and strengths when the warm gas becomes highly mixed but not depleted. Prior to complete disruption, clouds which are optically thin to the driving UV resonance lines will cause absorption at an increasingly blueshifted line of sight velocity as they are accelerated. This behavior will imprint an identifiable signature on the line profile if warm absorbers are enshrouded in an even broader absorption line produced by a high column of intercloud gas. Interestingly, we show that it is possible to develop a spectral diagnostic for cloud acceleration by differencing the absorption components of a doublet line, a result which can be qualitatively understood using a simple partial covering model. Our calculations also permit us to comment on the spectral differences between cloud disruption and ionization changes driven by flux variability. Notably, cloud disruption offers another possibility for explaining absorption line variability.

  10. Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456

    NASA Astrophysics Data System (ADS)

    Reeves, J. N.; Braito, V.; Nardini, E.; Behar, E.; O'Brien, P. T.; Tombesi, F.; Turner, T. J.; Costa, M. T.

    2016-06-01

    High-resolution soft X-ray spectroscopy of the prototype accretion disk wind quasar, PDS 456, is presented. Here, the XMM-Newton reflection grating spectrometer spectra are analyzed from the large 2013-2014 XMM-Newton campaign, consisting of five observations of approximately 100 ks in length. During the last observation (OBS. E), the quasar is at a minimum flux level, and broad absorption line (BAL) profiles are revealed in the soft X-ray band, with typical velocity widths of {σ }{{v}}˜ {{10,000}} km s-1. During a period of higher flux in the third and fourth observations (OBS. C and D, respectively), a very broad absorption trough is also present above 1 keV. From fitting the absorption lines with models of photoionized absorption spectra, the inferred outflow velocities lie in the range ˜ 0.1{--}0.2c. The absorption lines likely originate from He and H-like neon and L-shell iron at these energies. A comparison with earlier archival data of PDS 456 also reveals a similar absorption structure near 1 keV in a 40 ks observation in 2001, and generally the absorption lines appear most apparent when the spectrum is more absorbed overall. The presence of the soft X-ray BALs is also independently confirmed by an analysis of the XMM-Newton EPIC spectra below 2 keV. We suggest that the soft X-ray absorption profiles could be associated with a lower ionization and possibly clumpy phase of the accretion disk wind, where the latter is known to be present in this quasar from its well-studied iron K absorption profile and where the wind velocity reaches a typical value of 0.3c.

  11. VizieR Online Data Catalog: HeI* in broad absorption line QSOs (Liu+, 2015)

    NASA Astrophysics Data System (ADS)

    Liu, W.-J.; Zhou, H.; Ji, T.; Yuan, W.; Wang, T.-G.; Jian, G.; Shi, X.; Zhang, S.; Jiang, P.; Shu, X.; Wang, H.; Wang, S.-F.; Sun, L.; Yang, C.; Liu, B.; Zhao, W.

    2015-04-01

    Neutral helium multiplets, HeI*λλ3189, 3889, 10830, are very useful diagnostics for the geometry and physical conditions of the absorbing gas in quasars. So far only a handful of HeI* detections have been reported. Using a newly developed method, we detected the HeI*λ3889 absorption line in 101 sources of a well-defined sample of 285 MgII broad absorption line (BAL) quasars selected from SDSS DR5. This has increased the number of HeI* BAL quasars by more than one order of magnitude. We further detected HeI*λ3189 in 50% (52/101) of the quasars in the sample. The detection fraction of HeI* BALs in MgII BAL quasars is ~35% as a whole, and it increases dramatically with increasing spectral signal-to-noise ratio (S/N), from ~18% at S/N<=10 to ~93% at S/N>=35. This suggests that HeI* BALs could be detected in most MgII LoBAL quasars, provided the spectra S/N is high enough. Such a surprisingly high HeI* BAL fraction is actually predicted from photoionization calculations based on a simple BAL model. The result indicates that HeI* absorption lines can be used to search for BAL quasars at low z, which cannot be identified by ground-based optical spectroscopic surveys with commonly seen UV absorption lines. Using HeI*λ3889, we discovered 19 BAL quasars at z<0.3 from the available SDSS spectral database. The fraction of HeI* BAL quasars is similar to that of LoBAL objects. (7 data files).

  12. Candidate Hα emission and absorption line sources in the Galactic Bulge Survey

    NASA Astrophysics Data System (ADS)

    Wevers, T.; Jonker, P. G.; Nelemans, G.; Torres, M. A. P.; Groot, P. J.; Steeghs, D.; Maccarone, T. J.; Hynes, R. I.; Heinke, C.; Britt, C.

    2017-04-01

    We present a catalogue of candidate Hα emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (l × b) = (6° × 1°) centred at b = 1.5° above and below the Galactic Centre), covering the magnitude range 16 ≤ r΄ ≤ 22.5. We utilize (r΄ - i΄, r΄ - Hα) colour-colour diagrams to select Hα emission and absorption line candidates, and also identify blue objects (compared to field stars) using the r΄ - i΄ colour index. We identify 1337 Hα emission line candidates and 336 Hα absorption line candidates. These catalogues likely contain a plethora of sources, ranging from active (binary) stars, early-type emission line objects, cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) to background active galactic nuclei (AGN). The 389 blue objects we identify are likely systems containing a compact object, such as CVs, planetary nebulae and LMXBs. Hot subluminous dwarfs (sdO/B stars) are also expected to be found as blue outliers. Cross-matching our outliers with the GBS X-ray catalogue yields 16 sources, including 7 (magnetic) CVs and 1 qLMXB candidate among the emission line candidates and 1 background AGN for the absorption line candidates. One of the blue outliers is a high-state AM CVn system. Spectroscopic observations combined with the multiwavelength coverage of this area, including X-ray, ultraviolet and (time-resolved) optical and infrared observations, can be used to further constrain the nature of individual sources.

  13. Improved And Quality Assessed Emission And Absorption Line Measurements In Sloan Digital Sky Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Oh, Kyuseok; Sarzi, M.; Schawinski, K.; Yi, S. K.

    2011-01-01

    We have established a new database of absorption and emission line measurements from the Sloan Digital Sky Survey 7th data release for the galaxies within a redshift of 0.2. This work used publicly available codes, pPXF(penalized pixel-fitting) and GANDALF(gas and absorption line fitting), to achieve robust spectral fits and reliable measurements. The absorption line strengths measured by SDSS pipeline are seriously contaminated by emission fill-in. We effectively separate emission lines from absorption lines. For instance, this work successfully extract [NI] doublet from Mgb and it leads to more realistic result of alpha enhancement on late-type galaxies compared to the previous database. Besides accurately measuring line strengths, the database will be provided with new parameters that are indicative of line strength measurement quality. Users can build a subset of database optimal for their studies using specific cuts in the fitting quality parameters as well as empirical signal-to-noise. Applying these parameters, we found galaxies with dramatically broad line regions among the galaxies with poor fitting quality parameters. We applied a new continuum finding prescriptions to newly identified BLRs and they turned out to be Seyfert I nuclei.

  14. New aspects of absorption line formation in intervening turbulent clouds - I. General principles

    NASA Astrophysics Data System (ADS)

    Levshakov, Sergei A.; Kegel, Wilhelm H.

    1997-07-01

    We study the formation of absorption lines in intervening clouds with stochastic velocity fields, accounting for the fact that actually only one line of sight is observed. Our results show that the introduction of the finite velocity correlation length leads to a new type of absorption line profiles which are asymmetric in general, may have different shifts of the centres of gravity, and look like barely resolved blends, i.e. could be interpreted in a standard Voigt fitting analysis as being caused by several independent clouds with different physical parameters. Numerical results are presented for the HI Lyalpha line with N_Hi=10^12,10^14,10^15 and 10^16cm^-2, T_kin=10^4 K, and different sets of turbulent parameters. The intensity fluctuations within the line profile caused by `turbulent noise' are investigated and the confidence belts for the absorption lines are calculated. We conclude that an exact measurement of the column densities of the absorbing atoms N_a from the observed values of the optical depths tau lambda is actually impossible for the case of the correlated velocity field. One can only determine a range of values within which N_a is to be found with a certain probability.

  15. SimBAL: A Spectral Synthesis Approach to Analyzing Broad Absorption Line Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Terndrup, Donald M.; Leighly, Karen; Gallagher, Sarah; Richards, Gordon T.

    2017-01-01

    Broad Absorption Line quasars (BALQSOs) show blueshifted absorption lines in their rest-UV spectra, indicating powerful winds emerging from the central engine. These winds are essential part of quasars: they can carry away angular momentum and thus facilitate accretion through a disk, they can distribute chemically-enriched gas through the intergalactic medium, and they may inject kinetic energy to the host galaxy, influencing its evolution. The traditional method of analyzing BALQSO spectra involves measuring myriad absorption lines, computing the inferred ionic column densities in each feature, and comparing with the output of photonionization models. This method is inefficient and does not handle line blending well. We introduce SimBAL, a spectral synthesis fitting method for BALQSOs, which compares synthetic spectra created from photoionization model results with continuum-normalized observed spectra using Bayesian model calibration. We find that we can obtain an excellent fit to the UV to near-IR spectrum of the low-redshift BALQSO SDSS J0850+4451, including lines from diverse ionization states such as PV, CIII*, SIII, Lyalpha, NV, SiIV, CIV, MgII, and HeI*.

  16. Absorption Line Analysis to Interprete and Constrain Cosmological Simulations of Galaxy Evolution with Feedback

    NASA Astrophysics Data System (ADS)

    Churchill, Christopher

    2011-10-01

    The mammoth challenge for contemporary studies of galaxy formation and evolution are to establish detailed models in the cosmological context in which both the few parsec scale physics within galaxies are self-consistently unified and made consistent with the observed universe of galaxies. They key diagnostics reside with the gas physics, which dictate virtually every aspect of galaxy formation and evolution. The small scale physics includes stellar feedback, gas cooling, heating, and advection and the multiphase interstellar medium; the large scale physics includes intergalactic accretion, local merging, effects of supernovae driven winds, and the development of extended metal-enriched gas halos.Absorption line data have historically proven to be {and shall in the future} virtually the most powerful tool for understanding gas physics on all spatial scales over the majority of the age of the universe- the key to success. Simply stated, absorption lines are one of astronomy's most powerful observational windows on the universe {galaxy formation, galaxy winds, IGM metal enrichment, etc.}. The high quality and vast numbers of absorption line data {obtained with HST and FUSE} probe a broad range of gas structures {ISM, HVCs, halos, IGM} over the full cosmic span when galaxies are actively evolving.We propose to use LCDM hydrodynamic cosmological simulations employing a Eulerian Gasdynamics plus N-body Adaptive Refinement Tree {ART} code to develop and refine our understanding of stellar feedback physics and its role in governing the gas physics that regulates the evolution of galaxies and the IGM. We aim to substantially progress our understanding of all possible gas phases embedded within and extending far from galaxies. Our methodology is to apply a series of quantitative observational constraints from absorption line systems to better understand extended galaxy halos and the influence of the cosmological environment of the simulated galaxies: {1} galaxy halos

  17. Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+641. 2.5

    NASA Technical Reports Server (NTRS)

    Zheng, W.; Kriss, G. A.; Wang, J. X.; Brotherton, M.; Oegerle, W. R.; Blair, W. P.; Davidsen, A. F.; Green, R. F.; Hutchings, J. B.; Kaiser, M. E.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present a moderate-resolution (approximately 20 km/s) spectrum of the broad-absorption line QSO PG 1351+64 between 915-1180 angstroms, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional low-resolution spectra at longer wavelengths were also obtained with the Hubble Space Telescope (HST) and ground-based telescopes. Broad absorption is present on the blue wings of C III lambda977, Ly-beta, O VI lambda-lambda-1032,1038, Ly-alpha, N V lambda-lambda-1238,1242, Si IV lambda-lambda-1393,1402, and C IV lambda-lambda-1548,1450. The absorption profile can be fitted with five components at velocities of approximately -780, -1049, -1629, -1833, and -3054 km/s with respect to the emission-line redshift of z = 0.088. All the absorption components cover a large fraction of the continuum source as well as the broad-line region. The O VI emission feature is very weak, and the O VI/Ly-alpha flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The ultraviolet continuum shows a significant change in slope near 1050 angstroms in the restframe. The steeper continuum shortward of the Lyman limit extrapolates well to the observed weak X-ray flux level. The absorbers' properties are similar to those of high-redshift broad absorption-line QSOs. The derived total column density of the UV absorbers is on the order of 10(exp 21)/s, unlikely to produce significant opacity above 1 keV in the X-ray. Unless there is a separate, high-ionization X-ray absorber, the QSO's weak X-ray flux may be intrinsic. The ionization level of the absorbing components is comparable to that anticipated in the broad-line region, therefore the absorbers may be related to broad-line clouds along the line of sight.

  18. Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+64. 3.1

    NASA Technical Reports Server (NTRS)

    Zheng, W.; Kriss, G. A.; Wang, J. X.; Brotherton, M.; Oegerle, W. R.; Blair, W. P.; Davidsen, A. F.; Green, R. F.; Hutchings, J. B.; Kaiser, M. E.; Fisher, R. (Technical Monitor)

    2001-01-01

    We present a moderate-resolution (approximately 20 km s(exp -1) spectrum of the mini broad absorption line QSO PG 1351+64 between 915-1180 A, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional low-resolution spectra at longer wavelengths were also obtained with the Hubble Space Telescope (HST) and ground-based telescopes. Broad absorption is present on the blue wings of C III (lambda)977, Ly(beta), O VI (lambda)(lambda)1032,1038, Ly(alpha), N V (lambda)(lambda)1238,1242, Si IV (lambda)(lambda)1393,1402, and C IV (lambda)(lambda)1548,1450. The absorption profile can be fitted with five components at velocities of approximately -780, -1049, -1629, -1833, and -3054 km s(exp -1) with respect to the emission-line redshift of z = 0.088. All the absorption components cover a large fraction of the continuum source as well as the broad-line region. The O VI emission feature is very weak, and the O VI/Ly(alpha) flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The UV (ultraviolet) continuum shows a significant change in slope near 1050 A in the restframe. The steeper continuum shortward of the Lyman limit extrapolates well to the observed weak X-ray flux level. The absorbers' properties are similar to those of high-redshift broad absorption-line QSOs. The derived total column density of the UV absorbers is on the order of 10(exp 21) cm(exp -2), unlikely to produce significant opacity above 1 keV in the X-ray. Unless there is a separate, high-ionization X-ray absorber, the QSO's weak X-ray flux may be intrinsic. The ionization level of the absorbing components is comparable to that anticipated in the broad-line region, therefore the absorbers may be related to broad-line clouds along the line of sight.

  19. The transmission correlation in the QSO Ly(alpha) forest produced by finite width lines

    NASA Astrophysics Data System (ADS)

    Zuo, Lin; Bond, J. Richard

    1994-03-01

    The transmission of a quasar spectrum (flux divided by the continuum) is correlated because of the finite width of absorption lines. We describe a technique for calculating the transmission correlation function produced by randomly distributed lines. We also introduce straightforward procedure for measuring the pixel-pixel transmission correlation function xipp directly from observed quasar spectra. We apply the method to 12 Sargent, Boksenberg, & Steidel Quasi-Stellar Objects (QSO) spectra and compare these with theoretical transmission correlation functions and with xipp measured from computer-simulated quasar spectra of Ly(alpha) forest models with Poisson-distributed lines. The simulations are designed to mimic the observed spectrum as closely as possible, with the same wavelength sampling, instrumental resolution, continuum and noise properties. The comparisons with line distributions that are power laws in column density and redshift, and Gaussians in line width b reveal an excess in the observed xipp at Delta(v) is approximately or equal to 150 km/s, if we adopt the Carswell et al. (1991) parameters for the Gaussian (mean b0 = 30 km/s, dispersion sigmab = 10 km/s). One possibility is that the Ly(alpha) forest lines are actually clustered at velocity separation scales Delta(v) is approximately or equal to 150 km/s. Another possibility we explore is that the b-distribution has more large b clouds and a larger dispersion. We find the observed xipp is barely consistent with b0 = 40 km/s and sigmab = 25 km/s. We show that the measured xipp is relatively insensitive to the noise level and to errors in the continuum determination, unlike the traditional line counting methods, where the outcome is quite vulnerable to both. It also requires no line deblending and thus offers a powerful tool for extracting information from the crowded Ly(alpha) forest.

  20. A New NIR Flareof the QSO PMNJ2301-0157

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Miramon, J.; Recillas, E.; Porras, A.; Chavushyan, V.; Mayya, D. Y.

    2016-12-01

    We report on the new NIR flare of the high redshift QSO PMNJ2301-0157 (z=0.778), cross identified with the source BZQJ 2301-1058. On November 13th,2016 (MJD 2457705.722), we found the source with the following flux in the NIR band: H = 14.287 +/- 0.03.

  1. NIR flare of the QSO PMNJ2301-0157

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Miramon, J.; Porras, A.; Recillas, E.; Chavushyan, V.; Carraminana, A.

    2015-10-01

    We report on the recent NIR flare of the high redshift QSO PMNJ2301-0157 (z=0.778), cross identified with the source BZQJ 2301-1058. On September 25th,2015 (MJD 2457290.775), we found the source with the following flux in the NIR band: H = 14.954 +/- 0.07.

  2. THE SLOAN DIGITAL SKY SURVEY REVERBERATION MAPPING PROJECT: RAPID C iv BROAD ABSORPTION LINE VARIABILITY

    SciTech Connect

    Grier, C. J.; Brandt, W. N.; Trump, J. R.; Schneider, D. P.; Hall, P. B.; Shen, Yue; Vivek, M.; Dawson, K. S.; Ak, N. Filiz; Chen, Yuguang; Denney, K. D.; Kochanek, C. S.; Peterson, B. M.; Green, Paul J.; Jiang, Linhua; McGreer, Ian D.; Pâris, I.; Tao, Charling; Bizyaev, Dmitry; and others

    2015-06-10

    We report the discovery of rapid variations of a high-velocity C iv broad absorption line trough in the quasar SDSS J141007.74+541203.3. This object was intensively observed in 2014 as a part of the Sloan Digital Sky Survey Reverberation Mapping Project, during which 32 epochs of spectroscopy were obtained with the Baryon Oscillation Spectroscopic Survey spectrograph. We observe significant (>4σ) variability in the equivalent width (EW) of the broad (∼4000 km s{sup −1} wide) C iv trough on rest-frame timescales as short as 1.20 days (∼29 hr), the shortest broad absorption line variability timescale yet reported. The EW varied by ∼10% on these short timescales, and by about a factor of two over the duration of the campaign. We evaluate several potential causes of the variability, concluding that the most likely cause is a rapid response to changes in the incident ionizing continuum. If the outflow is at a radius where the recombination rate is higher than the ionization rate, the timescale of variability places a lower limit on the density of the absorbing gas of n{sub e} ≳ 3.9 × 10{sup 5} cm{sup −3}. The broad absorption line variability characteristics of this quasar are consistent with those observed in previous studies of quasars, indicating that such short-term variability may in fact be common and thus can be used to learn about outflow characteristics and contributions to quasar/host-galaxy feedback scenarios.

  3. DISENTANGLING THE CIRCUMNUCLEAR ENVIRONS OF CENTAURUS A. II. ON THE NATURE OF THE BROAD ABSORPTION LINE

    SciTech Connect

    Espada, D.; Matsushita, S.; Sakamoto, K.; Peck, A. B.; Henkel, C.; Iono, D.; Israel, F. P.; Muller, S.; Petitpas, G.; Pihlstroem, Y.; Taylor, G. B.; Trung, D. V.

    2010-09-01

    We report on atomic gas (H I) and molecular gas (as traced by CO(2-1)) redshifted absorption features toward the nuclear regions of the closest powerful radio galaxy, Centaurus A (NGC 5128). Our H I observations using the Very Long Baseline Array allow us to discern with unprecedented sub-parsec resolution H I absorption profiles toward different positions along the 21 cm continuum jet in the inner 0.''3 (or 5.4 pc). In addition, our CO(2-1) data obtained with the Submillimeter Array probe the bulk of the absorbing molecular gas with little contamination by emission, which was not possible with previous CO single-dish observations. We shed light on the physical properties of the gas in the line of sight with these data, emphasizing the still open debate about the nature of the gas that produces the broad absorption line ({approx}55 km s{sup -1}). First, the broad H I line is more prominent toward the central and brightest 21 cm continuum component than toward a region along the jet at a distance {approx}20 mas (or 0.4 pc) further from the nucleus. This indicates that the broad absorption line arises from gas located close to the nucleus, rather than from diffuse and more distant gas. Second, the different velocity components detected in the CO(2-1) absorption spectrum match well with other molecular lines, such as those of HCO{sup +}(1-0), except the broad absorption line that is detected in HCO{sup +}(1-0) (and most likely related to that of the H I). Dissociation of molecular hydrogen due to the active galactic nucleus seems to be efficient at distances r {approx}< 10 pc, which might contribute to the depth of the broad H I and molecular lines.

  4. A Survey for Intervening CIV Absorption-Line Systems Using SDSS Quasar Spectra

    NASA Astrophysics Data System (ADS)

    Monier, Eric M.; Nestor, D. B.; Daino, M. M.; Quider, A. M.; Rao, S. M.; Turnshek, D. A.

    2006-06-01

    Intervening CIV absorption-line systems are readily found in Sloan Digital Sky Survey (SDSS) quasar spectra at redshifts z > 1.5. Given the large number of absorbers, high statistical accuracy is possible in comparison to what was possible in the past. Here we present preliminary results on the incidence and evolution of the CIV systems as a function of CIV rest equivalent width. The absorber incidence is proportional to the product of gas cross-section and co-moving number density of absorbers, while the rest equivalent width is related to their kinematic spread. We discuss the interpretation of our results.

  5. The VLBI structure of radio-loud Broad Absorption Line quasars

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jiang, D. R.; Gu, M.

    2016-02-01

    The nature and origin of Broad Absorption Line (BAL) quasars and their relationship to non-BAL quasars are an open question. The BAL quasars are probably normal quasars seen along a particular line of sight. Alternatively, they are young or recently refueled. The high resolution radio morphology of BAL quasars is very important to understand the radio properties of BAL quasars. We present VLBA observations at L and C bands for a sample of BAL quasars. The observations will help us to explore the VLBI radio properties, and distinguish the present models of explaining BAL phenomena.

  6. Atlas of absorption lines from 0 to 17 900 cm(-1)

    NASA Technical Reports Server (NTRS)

    Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Smith, M. A. H.; Richardson, D. J.; Larsen, J. C.

    1981-01-01

    Plots of absorption line strength versus line position for wavenumbers from 0 to 17,900 cm(-1) are shown for 20 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO). Also shown are similar plots of lower-state energy values for adsorption lines for the strongly adsorbing atmospheric gases (H2O, CO2, O3, and CH4) for wavenumbers from 0 to 5000 cm(-1).

  7. Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

    NASA Technical Reports Server (NTRS)

    Welty, Daniel E.

    1990-01-01

    Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties.

  8. Neutral atomic absorption lines and far-UV extinction: Possible implications for depletions and grain parameters

    NASA Astrophysics Data System (ADS)

    Welty, Daniel E.

    1990-07-01

    Researchers examine nine lines of sight within the Galaxy and one in the Large Magellanic Cloud (LMC) for which data on both neutral atomic absorption lines (Snow 1984; White 1986; Welty, Hobbs, and York 1989) and far UV extinction (Bless and Savage 1972; Jenkins, Savage, and Spitzer 1986) are available, in order to test the assumption that variations in gamma/alpha will cancel in taking ratios of the ionization balance equation, and to try to determine to what extent that assumption has affected the aforementioned studies of depletions and grain properties.

  9. VizieR Online Data Catalog: QSOs narrow absorption line variability (Hacker+, 2013)

    NASA Astrophysics Data System (ADS)

    Hacker, T. L.; Brunner, R. J.; Lundgren, B. F.; York, D. G.

    2013-06-01

    Catalogues of 2,522 QAL systems and 33 variable NAL systems detected in SDSS DR7 quasars with repeat observations. The object identifiers, position coordinates, and plate-MJD-fibre designations are taken from the SpecObjAll table in the SDSS Catalogue Archive Server (CAS) while the quasar redshifts (zqso) are from Hewett & Wild (2010, Cat. J/MNRAS/405/2302). The absorption system redshift (zabs), system grade, and detected lines are outputs of the York et al. (2013, in. prep.) QAL detection pipeline. Some absorption lines are flagged based on alternate identifications (a), proximity of masked pixels (b), or questionable continuum fits (c). (3 data files).

  10. The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029---Ejected or Intervening?

    NASA Astrophysics Data System (ADS)

    Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.

    1996-10-01

    We report the discovery of a high-ionization broad absorption line system at a redshift of zabs = 0.695 in the spectrum of the zem = 1.052 radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000 to 5000 km s-1 is detected from C IV, N V, and O VI in Hubble Space Telescope (HST) Faint Object Spectrograph spectra of the quasar. A narrow-line system (FWHM ~ 250 km s-1) at zabs = 0.7016 is resolved from the broad blend and includes absorption by Ly alpha and the C IV, N V, and O VI doublets. No absorption by low-ionization metal species (e.g., Si II and Mg II) is detected in the HST or ground-based spectra for either the broad or the narrow system. The centroids of the broad system lines are displaced by ~56,000 km s-1 to the blue of the quasar's broad emission lines. The reddest extent of the broad-line absorption is more than 50,000 km s-1 from the quasar. The properties of this system are unprecedented, whether it is an intervening or an ejected system.

  11. The Hubble Space Telescope Quasar Absorption Line Key Project: The Unusual Absorption-Line System in the Spectrum of PG 2302+029--Ejected or Intervening?

    NASA Technical Reports Server (NTRS)

    Jannuzi, B. T.; Hartig, G. F.; Kirhakos, S.; Sargent, W. L. W.; Turnshek, D. A.; Weymann, R. J.; Bahcall, J. N.; Bergeron, J.; Boksenberg, A.; Savage, B. D.; Schneider, D. P.; Wolfe, A. M.

    1996-01-01

    We report the discovery of a high-ionization broad absorption line system at a redshift of z(sub abs) = 0.695 in the spectrum of the z(sub em) = 1.052 radio-quiet quasar PG 2302+029. Broad absorption with FWHM from 3000 to 5000 km/s is detected from C iv, N v, and O vi in Hubble Space Telescope (HST) Faint Object Spectrograph spectra of the quasar. A narrow-line system (FWHM approx. 250 km/s) at z(sub abs) = 0.7016 is resolved from the broad blend and includes absorption by Ly alpha and the C iv, N v, and O vi doublets. No absorption by low-ionization metal species (e.g., Si II and Mg II) is detected in the HST or ground-based spectra for either the broad or the narrow system. The centroids of the broad system lines are displaced by approx. 56,000 km/s to the blue of the quasar's broad emission lines. The reddest extent of the broad-line absorption is more than 50,000 km/s from the quasar. The properties of this system are unprecedented, whether it is an intervening or an ejected system.

  12. Interstellar Abundances in the SMC - Implications for QSO - Line Systems and for Chem EV of Universe-Cyc 4 Med Early Acq for 5608

    NASA Astrophysics Data System (ADS)

    Welty, Daniel

    1994-01-01

    We propose a detailed study of the interstellar (IS) abundances and depletions for one line of sight in the SMC - a nearby low metallicity, low dust-to-gas ratio system where stellar abundance data are also available. We will use the GHRS ECH-B to obtain absorption-line profiles of Zn II, Cr II, Si II, Fe II, Mn II, Mg II, and Al III, to determine both the detailed component structures and the relative abundances of those species in the various components. We will use the derived component structures to obtain similarly detailed abundances for S II, Ni II, and Al II from existing lower resolution short-wavelength IUE spectra (in which severe blending of components has to now prevented accurate abundance determinations). In addition to the intrinsic interest in obtaining detailed IS abundance and depletion data for an external galaxy quite different from our own, such data are needed for interpreting the abundance patterns found in QSO absorption-line systems. A number of the QSOALS examined to date seem to exhibit overall metallicities of about 0.1 x Solar, with some additional depletion of refractory elements. If the pattern of that depletion can be constrained, then the build-up of many elements can be traced, via the QSOALS, from redshifts 3.5 to 0.5 - with significant implications for the formation and evolution of galaxies.

  13. Quasar Absorption Lines from Radiative Shocks: Implications for Multiphase Outflows and Feedback

    NASA Astrophysics Data System (ADS)

    Faucher-Giguère, C.-A.

    2012-08-01

    Photoionization modeling of certain low-ionization broad absorption lines in quasars implies very compact (ΔR ˜0.01 pc), galaxy-scale (R˜ kpc) absorbers blueshifted by several 1000 km s-1. While these are likely signatures of quasar outflows, the lifetimes of such compact absorbers are too short for them to be direct ejecta from a nuclear wind. Instead, I argue that the absorbing clouds must be transient and created in situ. Following arguments detailed by Faucher-Giguère, Quataert, & Murray (2011), I show that a model in which the cool absorbers form in radiative shocks arising when a quasar blast wave impacts an interstellar cloud along the line of sight successfully explains the key observed properties. Using this radiative shock model, the outflow kinetic luminosities for three luminous quasars are estimated to be Ėk ≍ 2-5% LAGN (with corresponding momentum fluxes Ṗ ≍2-15 LAGN/c), consistent with feedback models of the M-σ relation. These energetics are similar to those recently inferred of molecular outflows in local ultra-luminous infrared galaxies and in post-starburt winds, suggesting that active galactic nuclei (AGN) are capable of driving such outflows. Radiative shocks probably affect the multiphase structure of outflows in a range of other systems, potentially including narrower and higher-ionization quasar absorption lines, and compact intergalactic absorbers ejected by star formation and/or AGN activity.

  14. When galaxies collide: understanding the broad absorption-line radio galaxy 4C +72.26

    NASA Astrophysics Data System (ADS)

    Smith, D. J. B.; Simpson, C.; Swinbank, A. M.; Rawlings, S.; Jarvis, M. J.

    2010-05-01

    We present a range of new observations of the `broad absorption-line radio galaxy' 4C +72.26 (z ~ 3.5), including sensitive rest-frame ultraviolet integral field spectroscopy using the Gemini/GMOS-N instrument and Subaru/CISCO K-band imaging and spectroscopy. We show that 4C +72.26 is a system of two vigorously star-forming galaxies superimposed along the line of sight separated by ~1300 +/- 200 km s-1 in velocity, with each demonstrating spectroscopically resolved absorption lines. The most active star-forming galaxy also hosts the accreting supermassive black hole which powers the extended radio source. We conclude that the star formation is unlikely to have been induced by a shock caused by the passage of the radio jet, and instead propose that a collision is a more probable trigger for the star formation. Despite the massive starburst, the ultraviolet-mid-infrared spectral energy distribution suggests that the pre-existing stellar population comprises ~1012Msolar of stellar mass, with the current burst only contributing a further ~2 per cent, suggesting that 4C +72.26 has already assembled most of its final stellar mass.

  15. THE PHYSICAL CONDITIONS OF THE INTRINSIC N V NARROW ABSORPTION LINE SYSTEMS OF THREE QUASARS

    SciTech Connect

    Wu Jian; Charlton, Jane C.; Misawa, Toru; Eracleous, Michael; Ganguly, Rajib E-mail: misawatr@shinshu-u.ac.j

    2010-10-20

    We employ detailed photoionization models to infer the physical conditions of intrinsic narrow absorption line systems found in high-resolution spectra of three quasars at z = 2.6-3.0. We focus on a family of intrinsic absorbers characterized by N V lines that are strong relative to the Ly{alpha} lines. The inferred physical conditions are similar for the three intrinsic N V absorbers, with metallicities greater than 10 times the solar value (assuming a solar abundance pattern), and with high ionization parameters (log U {approx} 0). Thus, we conclude that the unusual strength of the N V lines results from a combination of partial coverage, a high ionization state, and high metallicity. We consider whether dilution of the absorption lines by flux from the broad emission line region can lead us to overestimate the metallicities and we find that this is an unlikely possibility. The high abundances that we infer are not surprising in the context of scenarios in which metal enrichment takes place very early on in massive galaxies. We estimate that the mass outflow rate in the absorbing gas (which is likely to have a filamentary structure) is less than a few M{sub sun} yr{sup -1} under the most optimistic assumptions, although it may be embedded in a much hotter, more massive outflow.

  16. THE JHU-SDSS METAL ABSORPTION LINE CATALOG: REDSHIFT EVOLUTION AND PROPERTIES OF Mg II ABSORBERS

    SciTech Connect

    Zhu Guangtun; Menard, Brice

    2013-06-20

    We present a generic and fully automatic method aimed at detecting absorption lines in the spectra of astronomical objects. The algorithm estimates the source continuum flux using a dimensionality reduction technique and nonnegative matrix factorization, and then detects and identifies metal absorption lines. We apply it to a sample of {approx}10{sup 5} quasar spectra from the Sloan Digital Sky Survey and compile a sample of {approx}40,000 Mg II- and Fe II-absorber systems, spanning the redshift range 0.4 < z < 2.3. The corresponding catalog is publicly available. We study the statistical properties of these absorber systems and find that the rest equivalent width distribution of strong Mg II absorbers follows an exponential distribution at all redshifts, confirming previous studies. Combining our results with recent near-infrared observations of Mg II absorbers, we introduce a new parameterization that fully describes the incidence rate of these systems up to z {approx} 5. We find the redshift evolution of strong Mg II absorbers to be remarkably similar to the cosmic star formation history over 0.4 < z < 5.5 (the entire redshift range covered by observations), suggesting a physical link between these two quantities.

  17. Multiple Velocity Components in the CIV Absorption Line of NGC5548

    NASA Astrophysics Data System (ADS)

    Mathur, S.; Elvis, M.; Wilkes, B. J.

    1998-12-01

    The bright, variable, Seyfert 1 galaxy NGC 5548 has been extensively studied at many wavelengths. It has been a target of reverberation mapping experiments in the optical and UV (Peterson et al. 1992, Clavel et al. 1991, Korista et al. 1995). These have led to the accurate determination of the physical size of the BELR. The UV spectrum also shows absorption lines (Shull & Sachs 1993, Mathur, Elvis & Wilkes 1995 (MEW95)). Recently, based on ASCA and HST FOS data, MEW95 showed that the ionizaed X-ray and UV absorption in NGC5548 is likely to originate in the same material. We have now obtained high resolution GHRS spectrum around the CIV line. We find that the absorption line splits into multiple velocity components. The X-ray absorber would be associated with one of these components. We also have a tentative evidence for inflow based on the redshifted absorption component. This is in accord with the radial infall in NGC 5548 found by Done & Krolik (1996) based on the kinematic model of the BELR.

  18. The Unusual Absorption Line System of PG 2302+029 -- Ejected or Intervening?

    NASA Astrophysics Data System (ADS)

    Jannuzi, Buell

    1997-07-01

    A high-ionization broad absorption line system {C IV, N V, and O VI doublets; FWHM 3, 000 to 5, 000 km s^-1; z_rmabs=0.7} in the HST FOS UV spectrum of PG 2302+029 {z=1.052} has unprecedented properties. A distinct narrow line system {FWHM <250 km s^-1, z_abs=0.702} is also resolved within the broad system. If produced by material intrinsic to the quasar then the absorbing gas has been ejected from the quasar at more than sim56, 000 km s^-1. This extremely large ejection velocity as well as its ``detached'' nature {the reddest extent of the broad line absorption is more than 50, 000 km s^-1 from the quasar rest frame} would be unlike any known intrinsic absorber in QSOs. Alternatively, the broad and narrow systems could be produced by gas in a foreground cluster or super-cluster of galaxies. However, previous examples of such absorption have always included absorption by low-ionization species {e.g. Mg II, Si II}, which are not detected in the PG 2302+029 systems. We will undertake STIS and WFPC2 observations designed to help to identify the cause of this absorption system and allow us to determine whether the system is an extreme example of previously known classes of quasar absorption lines or represents an entirely new phenomenon.

  19. Made-to-measure galaxy modelling utilising absorption line strength data

    NASA Astrophysics Data System (ADS)

    Long, R. J.

    2016-12-01

    We enhance the Syer & Tremaine made-to-measure (M2M) particle method of stellar dynamical modelling to model simultaneously both kinematic data and absorption line strength data, thus creating a ‘chemo-M2M’ modelling scheme. We apply the enhanced method to four galaxies (NGC 1248, NGC 3838, NGC 4452, NGC 4551) observed using the SAURON integral-field spectrograph as part of the ATLAS3D programme. We are able to reproduce successfully the 2D line strength data achieving mean χ2 per bin values of ≈ 1 with > 95% of particles having converged weights. Because M2M uses a 3D particle system, we are also able to examine the underlying 3D line strength distributions. The extent to which these distributions are plausible representations of real galaxies requires further consideration. Overall, we consider the modelling exercise to be a promising first step in developing a ‘chemo-M2M’ modelling system and in understanding some of the issues to be addressed. While the made-to-measure techniques developed have been applied to absorption line strength data, they are in fact general and may be of value in modelling other aspects of galaxies.

  20. Detectability of cold streams into high-redshift galaxies by absorption lines

    NASA Astrophysics Data System (ADS)

    Goerdt, Tobias; Dekel, Avishai; Sternberg, Amiel; Gnat, Orly; Ceverino, Daniel

    2012-08-01

    Cold gas streaming along the dark matter filaments of the cosmic web is predicted to be the major source of fuel for disc buildup, violent disc instability and star formation in massive galaxies at high redshift. We investigate to what extent such cold gas is detectable in the extended circumgalactic environment of galaxies via Lyα absorption and selected low-ionization metal absorption lines. We model the expected absorption signatures using high-resolution zoom-in adaptive mesh refinement cosmological simulations. In the post-processing, we distinguish between self-shielded gas and unshielded gas. In the self-shielded gas, which is optically thick to Lyman continuum radiation, we assume pure collisional ionization for species with an ionization potential greater than 13.6 eV. In the optically-thin, unshielded gas, these species are also photoionized by the metagalactic radiation. In addition to absorption of radiation from background quasars, we compute the absorption line profiles of radiation emitted by the galaxy at the centre of the same halo. We predict the strength of the absorption signal for individual galaxies without stacking. We find that the Lyα absorption profiles produced by the streams are consistent with observations of absorption and emission Lyα profiles in high-redshift galaxies. Due to the low metallicities in the streams, and their low covering factors, the metal absorption features are weak and difficult to detect.

  1. The Dust-to-Gas Ratio in the Damped Ly alpha Clouds Towards the Gravitationally Lensed QSO 0957+561

    NASA Technical Reports Server (NTRS)

    Zuo, Lin; Beaver, E. A.; Burbidge, E. Margaret; Cohen, Ross D.; Junkkarinen, Vesa T.; Lyons, R. W.

    1997-01-01

    We present HST/FOS spectra of the two bright images (A and B) of the gravitationally lensed QSO 0957+561 in the wavelength range 2200-3300 A. We find that the absorption system (Z(sub abs)) = 1.3911) near z(sub em) is a weak, damped Ly alpha system with strong Ly alpha absorption lines seen in both images. However, the H(I) column densities are different, with the line of sight to image A intersecting a larger column density. The continuum shapes of the two spectra differ in the sense that the flux level of image A increases more slowly toward shorter wavelengths than that of image B. We explain this as the result of differential reddening by dust grains in the damped Ly alpha absorber. A direct outcome of this explanation is a determination of the dust-to-gas ratio, k, in the damped Ly alpha system. We derive k = 0.55 + 0.18 for a simple 1/lambda extinction law and k = 0.31 + 0.10 for the Galactic extinction curve. For gravitationally lensed systems with damped Ly alpha absorbers, our method is a powerful tool for determining the values and dispersion of k, and the shapes of extinction curves, especially in the FUV and EUV regions. We compare our results with previous work.

  2. Evidence for active galactic nucleus feedback in the broad absorption lines and reddening of MRK 231 {sup ,}

    SciTech Connect

    Leighly, Karen M.; Baron, Eddie; Lucy, Adrian B.; Terndrup, Donald M.; Dietrich, Matthias; Gallagher, Sarah C.

    2014-06-20

    We present the first J-band spectrum of Mrk 231, which reveals a large He I* λ10830 broad absorption line with a profile similar to that of the well-known Na I broad absorption line. Combining this spectrum with optical and UV spectra from the literature, we show that the unusual reddening noted by Veilleux et al. is explained by a reddening curve like those previously used to explain low values of total-to-selective extinction in Type Ia supernovae. The nuclear starburst may be the origin and location of the dust. Spatially resolved emission in the broad absorption line trough suggests nearly full coverage of the continuum emission region. The broad absorption lines reveal higher velocities in the He I* lines (produced in the quasar-photoionized H II region) compared with the Na I and Ca II lines (produced in the corresponding partially ionized zone). Cloudy simulations show that a density increase is required between the H II and partially ionized zones to produce ionic column densities consistent with the optical and IR absorption line measurements and limits, and that the absorber lies ∼100 pc from the central engine. These results suggest that the He I* lines are produced in an ordinary quasar BAL wind that impacts upon, compresses, and accelerates the nuclear starburst's dusty effluent (feedback in action), and the Ca II and Na I lines are produced in this dusty accelerated gas. This unusual circumstance explains the rarity of Na I absorption lines; without the compression along our line of sight, Mrk 231 would appear as an ordinary iron low-ionization, broad absorption line quasar.

  3. The Connection between Galaxies and Intergalactic Absorption Lines at Redshift 2<~z<~3

    NASA Astrophysics Data System (ADS)

    Adelberger, Kurt L.; Shapley, Alice E.; Steidel, Charles C.; Pettini, Max; Erb, Dawn K.; Reddy, Naveen A.

    2005-08-01

    Absorption-line spectroscopy of 23 background QSOs and numerous background galaxies has let us measure the spatial distribution of metals and neutral hydrogen around 1044 UV-selected galaxies at redshifts 1.8<~z<~3.3. The typical galaxy is surrounded to radii r~40 proper kpc by gas that has a large velocity spread (Δv>260 km s-1) and produces very strong absorption lines (NCIV>>1014 cm-2) in the spectra of background objects. These absorption lines are almost as strong as those produced by a typical galaxy's own interstellar gas. Absorption with an average column density of NCIV~=1014 cm-2 extends out to ~80 kpc, a radius large enough to imply that most strong intergalactic C IV absorption is associated with star-forming galaxies like those in our sample. Our measurement of the galaxy-C IV spatial correlation function shows that even the weakest detectable C IV systems are found in the same regions as galaxies; we find that the cross-correlation length increases with C IV column density and is similar to the galaxy autocorrelation length (r0~4 h-1 Mpc) for NCIV>~1012.5 cm-2. Distortions in the redshift-space galaxy-C IV correlation function on small scales may imply that some of the C IV systems have large peculiar velocities. Four of the five detected O VI absorption systems in our sample lie within 400 proper kpc of a known galaxy. Strong Lyα absorption is produced by the intergalactic gas within 1 h-1 comoving Mpc of most galaxies, but for a significant minority (~1/3) the absorption is weak or absent. This is not observed in smooth-particle hydrodynamic simulations that omit the effects of ``feedback'' from galaxy formation. We were unable to identify any statistically significant differences in age, dust reddening, environment, or kinematics between galaxies with weak nearby H I absorption and the rest, although galaxies with weak absorption may have higher star formation rates. Galaxies near intergalactic C IV systems appear to reside in relatively dense

  4. Thomson Thick X-Ray Absorption in a Broad Absorption Line Quasar, PG 0946+301.

    PubMed

    Mathur; Green; Arav; Brotherton; Crenshaw; deKool; Elvis; Goodrich; Hamann; Hines; Kashyap; Korista; Peterson; Shields; Shlosman; van Breugel W; Voit

    2000-04-20

    We present a deep ASCA observation of a broad absorption line quasar (BALQSO) PG 0946+301. The source was clearly detected in one of the gas imaging spectrometers, but not in any other detector. If BALQSOs have intrinsic X-ray spectra similar to normal radio-quiet quasars, our observations imply that there is Thomson thick X-ray absorption (NH greater, similar1024 cm-2) toward PG 0946+301. This is the largest column density estimated so far toward a BALQSO. The absorber must be at least partially ionized and may be responsible for attenuation in the optical and UV. If the Thomson optical depth toward BALQSOs is close to 1, as inferred here, then spectroscopy in hard X-rays with large telescopes like XMM would be feasible.

  5. Spectropolarimetry of PKS 0040-005 and the orientation of broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Brotherton, M. S.; De Breuck, C.; Schaefer, J. J.

    2006-10-01

    We have used the Very Large Telescope (VLT) to obtain spectropolarimetry of the radio-loud, double-lobed broad absorption line (BAL) quasar PKS 0040-005. We find that the optical continuum of PKS 0040-005 is intrinsically polarized at 0.7 per cent with an electric vector position angle nearly parallel to that of the large-scale radio axis. This result is naturally explained in terms of an equatorial scattering region seen at a small inclination, building a strong case that the BAL outflow is not equatorial. In conjunction with other recent results concerning BAL quasars, the era of simply characterizing these sources as `edge-on' is over. Based on observations collected at the European Southern Observatory, Paranal, project 71.B-0121(A). E-mail: mbrother@uwyo.edu (MSB); cdbreuc@eso.org (CDB); schaefjj@ufl.edu (JJS) ‡ ESO Visitor.

  6. WAVELENGTH MEASUREMENTS OF K TRANSITIONS OF OXYGEN, NEON, AND MAGNESIUM WITH X-RAY ABSORPTION LINES

    SciTech Connect

    Liao Jinyuan; Zhang Shuangnan; Yao Yangsen

    2013-09-10

    Accurate atomic transition data are important in many astronomical research areas, especially for studies of line spectroscopy. Whereas transition data of He-like and H-like ions (i.e., ions in high-charge states) have been accurately calculated, the corresponding data of K transitions of neutral or low-ionized metal elements are still very uncertain. Spectroscopy of absorption lines produced in the interstellar medium (ISM) has been proven to be an effective way to measure the central wavelengths of these atomic transitions. In this work, we analyze 36 Chandra High Energy Transmission Grating observations to search for and measure the ISM absorption lines along sight lines to 11 low-mass X-ray binaries. We correct the Galactic rotation velocity to the rest frame for every observation and then use two different methods to merge all the corrected spectra to a co-added spectrum. However, the co-added spectra obtained by this method exhibit biases, toward to either observations with high counts or lines with high signal-to-noise ratios. We do a Bayesian analysis of several significantly detected lines to obtain the systematic uncertainty and the bias correction for other lines. Compared to previous studies, our results improve the wavelength accuracy by a factor of two to five and significantly reduce the systematic uncertainties and biases. Several weak transitions (e.g., 1s-2p of Mg IV and Mg V; 1s-3p of Mg III and Mg V) are also detected for the first time, albeit with low significance; future observations with improved accuracy are required to confirm these detections.

  7. THE INTRINSIC FRACTIONS AND RADIO PROPERTIES OF LOW-IONIZATION BROAD ABSORPTION LINE QUASARS

    SciTech Connect

    Dai Xinyu; Shankar, Francesco; Sivakoff, Gregory R.

    2012-10-01

    Low-ionization (Mg II, Fe II, and Fe III) broad absorption line quasars (LoBALs) probe a relatively obscured quasar population and could be at an early evolutionary stage for quasars. We study the intrinsic fractions of LoBALs using the Sloan Digital Sky Survey (SDSS), Two Micron All Sky Survey, and Faint Images of the Radio Sky at Twenty cm survey. We find that the LoBAL fractions of the near-infrared (NIR) and radio samples are approximately 5-7 times higher than those measured in the optical sample. This suggests that the fractions measured in the NIR and radio bands are closer to the intrinsic fractions of the populations, and that the optical fractions are significantly biased due to obscuration effects, similar to high-ionization broad absorption line quasars (HiBALs). Considering a population of obscured quasars that do not enter the SDSS, which could have a much higher LoBAL fraction, we expect that the intrinsic fraction of LoBALs could be even higher. We also find that the LoBAL fractions decrease with increasing radio luminosities, again, similarly to HiBALs. In addition, we find evidence for increasing fractions of LoBALs toward higher NIR luminosities, especially for FeLoBALs with a fraction of {approx}18% at M{sub K{sub s}}< -31 mag. This population of NIR-luminous LoBALs may be at an early evolutionary stage of quasar evolution. To interpret the data, we use a luminosity-dependent model for LoBALs that yields significantly better fits than those from a pure geometric model.

  8. Multi-Sightline Observation of Narrow Absorption Lines in Lensed Quasar SDSS J1029+2623

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Saez, Cristian; Charlton, Jane C.; Eracleous, Michael; Chartas, George; Bauer, Franz E.; Inada, Naohisa; Uchiyama, Hisakazu

    2016-07-01

    We exploit the widely separated images of the lensed quasar SDSS J1029+2623 ({z}{em} = 2.197, θ = 22.″5) to observe its outflowing wind through two different sightlines. We present an analysis of three observations, including two with the Subaru telescope in 2010 February and 2014 April, separated by four years, and one with the Very Large Telescope, separated from the second Subaru observation by ˜2 months. We detect 66 narrow absorption lines (NALs), of which 24 are classified as intrinsic NALs that are physically associated with the quasar based on partial coverage analysis. The velocities of intrinsic NALs appear to cluster around values of {v}{ej} ˜ 59,000, 43,000, and 29,000 km s-1, which is reminiscent of filamentary structures obtained by numerical simulations. There are no common intrinsic NALs at the same redshift along the two sightlines, implying that the transverse size of the NAL absorbers should be smaller than the sightline distance between two lensed images. In addition to the NALs with large ejection velocities of {v}{ej} > 1000 km s-1, we also detect broader proximity absorption lines (PALs) at {z}{abs} ˜ {z}{em}. The PALs are likely to arise in outflowing gas at a distance of r ≤ 620 pc from the central black hole with an electron density of n e ≥8.7 × 103 cm-3. These limits are based on the assumption that the variability of the lines is due to recombination. We discuss the implications of these results on the three-dimensional structure of the outflow.

  9. Composite Spectra of Broad Absorption Line Quasars in SDSS-III BOSS

    NASA Astrophysics Data System (ADS)

    Herbst, Hanna; Hamann, Fred; Paris, Isabelle; Capellupo, Daniel M.

    2017-01-01

    We present preliminary results from a study of broad absorption line (BAL) quasars in the SDSS-III BOSS survey. We’re particularly interested in BALs because they arise from quasar outflows, which may be a source of feedback to the host galaxy. We analyze median composite spectra for BOSS QSOs in the redshift range 2.1 to 3.4 sorted by the strength of the BAL absorption troughs, parameterized by the Balnicity Index (BI), to study trends in the emission and absorption properties of BAL quasars. The wavelength coverage and high number of quasars observed in the BOSS survey allow us to examine BALs in the Lyman forest. Our main preliminary results when sorting the quasars by BI are 1) doublet absorption lines such as P V 1128A show a 1:1 ratio across all BI, indicating large column densities at all BI. This suggests that weaker BAL troughs result from smaller covering fractions rather than lower column densities. 2) The He II emission line, which is a measure of the far-UV/near-UV hardness of the ionizing continuum, is weaker in the larger BI composite spectra, indicating a far-UV spectral softening correlated with BI. This is consistent with the radiatively-driven BAL outflows being helped by intrinsically weaker ionizing continuum shapes (e.g., Baskin, Laor, and Hamann 2013). We also find a trend for slightly redder continuum slopes in the larger BI composite spectra, suggesting that the slope differences in the near-UV are also intrinsic.

  10. QSO clustering - II. The correlation function of IRAS seyfert galaxies.

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Shanks, T.

    1994-12-01

    We investigate the clustering properties of 192 Seyfert galaxies from the IRAS all-sky survey. Using the spatial correlation function, we detect evidence of Seyfert clustering at the 2σ confidence level at < 10 h^-1^ Mpc separations, and at the 3{SIGMA} level at < 20 h^-1^ Mpc separations. Comparison of the QSO correlation function amplitude at high redshifts, z = 1.4, with that of Seyferts below 10 h^-1^ comoving Mpc leads us to reject the stable model of AGN clustering evolution at the 4σ level, whereas a comoving model where QSOs randomly sample the galaxy distribution is more consistent. The main uncertainty here now lies in the statistical error on the amplitude of the clustering in the faint QSO surveys at z = 1.4. The Seyfert-QDOT cross-correlation function is measured to be approximately a factor of 2 higher than the QDOT galaxy autocorrelation function, suggesting an enhanced environment for Seyferts with respect to IRAS galaxies, but it is not clear whether this is also the case with respect to optical galaxies. We conclude that the comoving model is probably favoured overall, at least on the r < 10 h^-1^ Mpc scales investigated here, but it is not yet possible to rule out intermediate models: for example, an enhanced-environment, stable model with ξ(r)=(r/3)^-1.8^ at z = 1.4, which is statistically consistent with the faint QSO data.

  11. A novel control system for automatically locking a diode laser frequency to a selected gas absorption line

    NASA Astrophysics Data System (ADS)

    Dong, Lei; Yin, Wangbao; Ma, Weiguang; Jia, Suotang

    2007-05-01

    A novel control system has been developed for avoiding manual operation during traditional frequency locking. The control system uses a computer with a commercial data acquisition card. This accomplishes the whole operation of frequency locking, including generating ramp, searching locking point, engaging a proportional-integral-differential (PID) regulator at the proper time and outputting PID compensation signal. Moreover, a new method has also been employed to make the novel control system accurately identify the locking points of all absorption lines within the scanning range, so that the laser frequency can be automatically firmly brought onto any selected absorption line centre without any adjusting time. The operation of the system, the ability to identify absorption lines and the performance of the frequency locking were discussed in detail. Successful tests were made with two different lasers: external cavity diode lasers and distributed feedback diode lasers.

  12. The Hubble Space Telescope quasar absorption line key project. III - First observational results on Milky Way gas

    NASA Technical Reports Server (NTRS)

    Savage, Blair D.; Lu, Limin; Bahcall, John N.; Bergeron, Jacqueline; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Lockman, Felix J.; Sargent, W. L. W.

    1993-01-01

    Absorption lines found near zero redshift due to Milky Way disk and halo gas in the spectra of 15 quasars observed with the Faint Object Spectrograph (FOS) of the HST at a resolution of about 230 km/s are reported. Results show that Milky Way absorption lines comprise about 44 percent of all absorption lines seen in the first group of Key Project FOS spectra. Milky Way lines were observed for 3C 273 and H1821 + 643. Limits to the Mg-to-H abundance ratio obtained for very high velocity Mg II absorption detections imply gas-phase Mg abundances for the very high velocity gas ranging from more than 0.059 to more than 0.32 times the solar abundance. In all cases where high-velocity H I emission is seen, corresponding high-velocity metal-line absorption is observed.

  13. Cavity ring-down spectroscopy of Doppler-broadened absorption line with sub-MHz absolute frequency accuracy.

    PubMed

    Cheng, C-F; Sun, Y R; Pan, H; Lu, Y; Li, X-F; Wang, J; Liu, A-W; Hu, S-M

    2012-04-23

    A continuous-wave cavity ring-down spectrometer has been built for precise determination of absolute frequencies of Doppler-broadened absorption lines. Using a thermo-stabilized Fabry-Pérot interferometer and Rb frequency references at the 780 nm and 795 nm, 0.1 - 0.6 MHz absolute frequency accuracy has been achieved in the 775-800 nm region. A water absorption line at 12579 cm(-1) is studied to test the performance of the spectrometer. The line position at zero-pressure limit is determined with an uncertainty of 0.3 MHz (relative accuracy of 0.8 × 10(-9)).

  14. Time-dependent excitation and ionization modelling of absorption-line variability due to GRB 080310

    NASA Astrophysics Data System (ADS)

    Vreeswijk, P. M.; Ledoux, C.; Raassen, A. J. J.; Smette, A.; De Cia, A.; Woźniak, P. R.; Fox, A. J.; Vestrand, W. T.; Jakobsson, P.

    2013-01-01

    We model the time-variable absorption of Fe II, Fe III, Si II, C II and Cr II detected in Ultraviolet and Visual Echelle Spectrograph (UVES) spectra of gamma-ray burst (GRB) 080310, with the afterglow radiation exciting and ionizing the interstellar medium in the host galaxy at a redshift of z = 2.42743. To estimate the rest-frame afterglow brightness as a function of time, we use a combination of the optical VRI photometry obtained by the RAPTOR-T telescope array, which is presented in this paper, and Swift's X-Ray Telescope (XRT) observations. Excitation alone, which has been successfully applied for a handful of other GRBs, fails to describe the observed column density evolution in the case of GRB 080310. Inclusion of ionization is required to explain the column density decrease of all observed Fe II levels (including the ground state 6D9/2) and increase of the Fe III 7S3 level. The large population of ions in this latter level (up to 10% of all Fe III) can only be explained through ionization of Fe II, as a large fraction of the ionized Fe II ions (we calculate 31% using the Flexible Atomic and Cowan codes) initially populate the 7S3 level of Fe III rather than the ground state. This channel for producing a significant Fe III 7S3 level population may be relevant for other objects in which absorption lines from this level, the UV34 triplet, are observed, such as broad absorption line (BAL) quasars and η Carinae. This provides conclusive evidence for time-variable ionization in the circumburst medium, which to date has not been convincingly detected. However, the best-fit distance of the neutral absorbing cloud to the GRB is 200-400 pc, i.e. similar to GRB-absorber distance estimates for GRBs without any evidence for ionization. We find that the presence of time-varying ionization in GRB 080310 is likely due to a combination of the super-solar iron abundance ([Fe/H] = +0.2) and the low H I column density (log N(H i) = 18.7) in the host of GRB 080310. Finally

  15. Constraining the variation of the fine-structure constant with observations of narrow quasar absorption lines

    SciTech Connect

    Songaila, A.; Cowie, L. L.

    2014-10-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10{sup –5}, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (– 0.59 ± 0.55) × 10{sup –5} in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10{sup –5}, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (– 0.47 ± 0.53) × 10{sup –5}. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (– 0.01 ± 0.26) × 10{sup –5}. We conclude that spectroscopic measurements of

  16. Inter-Stellar Medium Absorption Lines As Outflow Tracers - A Comparison Between AGNs And SFGs

    NASA Astrophysics Data System (ADS)

    Talia, Margherita; Cimatti, A.; Brusa, M.

    2016-10-01

    To reproduce the properties of galaxies in the local Universe, as well as the scaling relations between host galaxies and black holes properties, many galaxy formation models invoke the presence of fast and energetic winds extending over galaxy scales. These massive gas outflows can be powered either by star-formation (SF) or AGN activity, though the relative dominance and efficiency of the different mechanisms is not yet fully understoodIn the last decade much effort has been put in the search for observational evidence of such phenomena, especially at the peak of both SF and AGN activity through cosmic time (1absorption lines in the UV regime, as well as broad, blue-shifted profiles in optical emission lines have been observed in galaxies at all redshifts and are usually interpreted as evidence of fast material moving towards our line of sight. More recently, especially thanks to new facilities like ALMA, outflows are being observed also in neutral and molecular gasIn order to study the differences and possible synergy between the two main driving outflow mechanisms (AGN or SF activity) and to understand the role that outflows might play in SF quenching and galaxy evolution, we collected a large sample of AGNs and SFGs at z>1.7 from large optical spectroscopic surveys (zCOSMOS, VUDS, ESO public surveys), complemented with HST imaging, X-ray (Chandra) and IR data. The richness of available data for our sample allowed us to map a large portion of the physical parameters space. We concentrated our analysis on the ISM absorption lines in the rest-frame UV wavelength range. Through stacking tecniques we studied the relation between such lines and AGN and SFG properties. I will present our results (Talia et al

  17. Improved and Quality-assessed Emission and Absorption Line Measurements in Sloan Digital Sky Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Oh, Kyuseok; Sarzi, Marc; Schawinski, Kevin; Yi, Sukyoung K.

    2011-08-01

    We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionized gas emission. In order to check for systematic departures from the rather standard set of assumptions that enters our models, we provide a quality assessment for our fit to the SDSS spectra in our sample, for both the stellar continuum and the nebular emissions and across different wavelength regions. This quality assessment also allows the identification of objects with either problematic data or peculiar features. We hope to foster the discovery potential of our database; therefore, our spectral fit is available to the community. For example, based on the quality assessment around the Hα and [N II] λ6584 lines, approximately 1% of the SDSS spectra classified as "galaxies" by the SDSS pipeline do in fact require additional broad lines to be matched, even though they do not show a strong continuum from an active nucleus, as

  18. Time-Variable Complex Metal Absorption Lines in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Eracleous, Michael; Charlton, Jane C.; Tajitsu, Akito

    2005-08-01

    We present a new spectrum of the quasar HS 1603+3820 taken 1.28 yr (0.36 yr in the quasar rest frame) after a previous observation with Subaru+HDS. The new spectrum enables us to search for time variability as an identifier of intrinsic narrow absorption lines (NALs). This quasar shows a rich complex of C IV NALs within 60,000 km s-1 of the emission redshift. On the basis of covering factor analysis, Misawa et al. found that the C IV NAL system at zabs=2.42-2.45 (system A, at a shift velocity of vsh=8300-10,600 km s-1 relative to the quasar) was intrinsic to the quasar. With our new spectrum, we perform time variability analysis, as well as covering factor analysis, to separate intrinsic NALs from intervening NALs for eight C IV systems. Only system A, which was identified as an intrinsic system in the earlier paper by Misawa et al., shows a strong variation in line strength (Wobs~10.4-->19.1 Å). We speculate that a broad absorption line (BAL) could be forming in this quasar (i.e., many narrower lines will blend together to make a BAL profile). We illustrate the plausibility of this suggestion with the help of a simulation in which we vary the column densities and covering factors of the NAL complex. Under the assumption that a change of ionization state causes the variability, a lower limit can be placed on the electron density (ne>~3×104cm-3) and an upper limit on the distance from the continuum source (r<=6 kpc). On the other hand, if the motion of clumpy gas causes the variability (a more likely scenario), the crossing velocity and the distance from the continuum source are estimated to be vcross>8000 km s-1 and r<3 pc. In this case, the absorber does not intercept any flux from the broad emission line region, but only flux from the UV continuum source. If we adopt the dynamical model of Murray et al., we can obtain a much more strict constraint on the distance of the gas parcel from the continuum source, r<0.2 pc. Based on data collected at the Subaru

  19. Evidence for two spatially separated UV continuum emitting regions in the Cloverleaf broad absorption line quasar

    NASA Astrophysics Data System (ADS)

    Sluse, D.; Hutsemékers, D.; Anguita, T.; Braibant, L.; Riaud, P.

    2015-10-01

    Testing the standard Shakura-Sunyaev model of accretion is a challenging task because the central region of quasars where accretion takes place is unresolved with telescopes. The analysis of microlensing in gravitationally lensed quasars is one of the few techniques that can test this model, yielding to the measurement of the size and of temperature profile of the accretion disc. We present spectroscopic observations of the gravitationally lensed broad absorption line quasar H1413+117, which reveal partial microlensing of the continuum emission that appears to originate from two separated regions: a microlensed region, corresponding the compact accretion disc; and a non-microlensed region, more extended and contributing to at least 30% of the total UV-continuum flux. Because this extended continuum is occulted by the broad absorption line clouds, it is not associated with the host galaxy, but rather with light scattered in the neighbourhood of the central engine. We measure the amplitude of microlensing of the compact continuum over the rest-frame wavelength range 1000-7000 Å. Following a Bayesian scheme, we confront our measurements to microlensing simulations of an accretion disc with a temperature varying as T ∝ R-1/ν. We find a most likely source half-light radius of R1/2 = 0.61 × 1016cm (i.e., 0.002 pc) at 0.18 μm, and a most-likely index of ν = 0.4. The standard disc (ν = 4/3) model is not ruled out by our data, and is found within the 95% confidence interval associated with our measurements. We demonstrate that, for H1413+117, the existence of an extended continuum in addition to the disc emission only has a small impact on the inferred disc parameters, and is unlikely to solve the tension between the microlensing source size and standard disc sizes, as previously reported in the literature. Based on observations made with ESO Telescopes at the Paranal Observatory (Chile). ESO program ID: 386.B-0337.Appendices A and B are available in electronic form

  20. IMPROVED AND QUALITY-ASSESSED EMISSION AND ABSORPTION LINE MEASUREMENTS IN SLOAN DIGITAL SKY SURVEY GALAXIES

    SciTech Connect

    Oh, Kyuseok; Yi, Sukyoung K.; Sarzi, Marc; Schawinski, Kevin

    2011-08-01

    We present a new database of absorption and emission-line measurements based on the entire spectral atlas from the Sloan Digital Sky Survey (SDSS) 7th data release of galaxies within a redshift of 0.2. Our work makes use of the publicly available penalized pixel-fitting (pPXF) and gas and absorption line fitting (gandalf) IDL codes, aiming to improve the existing measurements for stellar kinematics, the strength of various absorption-line features, and the flux and width of the emissions from different species of ionized gas. Our fit to the stellar continuum uses both standard stellar population models and empirical templates obtained by combining a large number of stellar spectra in order to fit a subsample of high-quality SDSS spectra for quiescent galaxies. Furthermore, our fit to the nebular spectrum includes an exhaustive list of both recombination and forbidden lines. Foreground Galactic extinction is implicitly treated in our models, whereas reddening in the SDSS galaxies is included in the form of a simple dust screen component affecting the entire spectrum that is accompanied by a second reddening component affecting only the ionized gas emission. In order to check for systematic departures from the rather standard set of assumptions that enters our models, we provide a quality assessment for our fit to the SDSS spectra in our sample, for both the stellar continuum and the nebular emissions and across different wavelength regions. This quality assessment also allows the identification of objects with either problematic data or peculiar features. We hope to foster the discovery potential of our database; therefore, our spectral fit is available to the community. For example, based on the quality assessment around the H{alpha} and [N II] {lambda}6584 lines, approximately 1% of the SDSS spectra classified as 'galaxies' by the SDSS pipeline do in fact require additional broad lines to be matched, even though they do not show a strong continuum from an active

  1. Constraining the Variation of the Fine-structure Constant with Observations of Narrow Quasar Absorption Lines

    NASA Astrophysics Data System (ADS)

    Songaila, A.; Cowie, L. L.

    2014-10-01

    The unequivocal demonstration of temporal or spatial variability in a fundamental constant of nature would be of enormous significance. Recent attempts to measure the variability of the fine-structure constant α over cosmological time, using high-resolution spectra of high-redshift quasars observed with 10 m class telescopes, have produced conflicting results. We use the many multiplet (MM) method with Mg II and Fe II lines on very high signal-to-noise, high-resolution (R = 72, 000) Keck HIRES spectra of eight narrow quasar absorption systems. We consider both systematic uncertainties in spectrograph wavelength calibration and also velocity offsets introduced by complex velocity structure in even apparently simple and weak narrow lines and analyze their effect on claimed variations in α. We find no significant change in α, Δα/α = (0.43 ± 0.34) × 10-5, in the redshift range z = 0.7-1.5, where this includes both statistical and systematic errors. We also show that the scatter in measurements of Δα/α arising from absorption line structure can be considerably larger than assigned statistical errors even for apparently simple and narrow absorption systems. We find a null result of Δα/α = (- 0.59 ± 0.55) × 10-5 in a system at z = 1.7382 using lines of Cr II, Zn II, and Mn II, whereas using Cr II and Zn II lines in a system at z = 1.6614 we find a systematic velocity trend that, if interpreted as a shift in α, would correspond to Δα/α = (1.88 ± 0.47) × 10-5, where both results include both statistical and systematic errors. This latter result is almost certainly caused by varying ionic abundances in subcomponents of the line: using Mn II, Ni II, and Cr II in the analysis changes the result to Δα/α = (- 0.47 ± 0.53) × 10-5. Combining the Mg II and Fe II results with estimates based on Mn II, Ni II, and Cr II gives Δα/α = (- 0.01 ± 0.26) × 10-5. We conclude that spectroscopic measurements of quasar absorption lines are not yet capable of

  2. Absorption-Line Probes of Gas and Dust in Galactic Superwinds

    NASA Astrophysics Data System (ADS)

    Heckman, Timothy M.; Lehnert, Matthew D.; Strickland, David K.; Armus, Lee

    2000-08-01

    We have obtained moderate resolution (R=few thousand) spectra of the Na I λλ5890, 5896 (Na D) absorption line in a sample of 32 far-IR-bright starburst galaxies. In 18 cases, the Na D line in the nucleus is produced primarily by interstellar gas, while cool stars contribute significantly in the others. In 12 of the 18 ``interstellar-dominated'' cases the Na D line is blueshifted by over 100 km s-1 relative to the galaxy systemic velocity (the ``outflow sources''), while no case shows a net redshift of more than 100 km s-1. The absorption-line profiles in these outflow sources span the range from near the galaxy systemic velocity to a maximum blueshift of ~400-600 km s-1. The outflow sources are galaxies systematically viewed more nearly face-on than the others. We therefore argue that the absorbing material consists of ambient interstellar material that has been entrained and accelerated along the minor axis of the galaxy by a hot starburst-driven superwind. The Na D lines are optically thick, but indirect arguments imply total hydrogen column densities of NH~few×1021 cm-2. This implies that the superwind is expelling matter at a rate comparable to the star formation rate. This outflowing material is evidently very dusty: we find a strong correlation between the depth of the Na D profile and the line-of-sight reddening. Typical implied values are E(B-V)=0.3-1 over regions several-to-10 kpc in size. We briefly consider some of the potential implications of these observations. The estimated terminal velocities of superwinds inferred from the present data and extant X-ray data are typically 400-800 km-1, are independent of the galaxy rotation speed, and are comparable to (substantially exceed) the escape velocities for L* (dwarf) galaxies. The resulting selective loss of metals from shallower potential wells can establish the mass-metallicity relation in spheroids, produce the observed metallicity in the intracluster medium, and enrich a general IGM to of order 10

  3. Probing the Early Universe with the Epoch of Reionization and QSO Spectroscopy

    NASA Astrophysics Data System (ADS)

    Matejek, Michael Scott

    2012-06-01

    We present results from the first systematic survey for Mg II absorption lines at z > 2.5. Using 46 infrared QSO spectra we discovered 111 Mg II systems, including five with z > 5---the most distant systems now known. The comoving line density for weaker systems is statistically consistent with no evolution from z = 0.4 to z = 5.5. The density for stronger systems increases three-fold until z ˜ 3 before declining towards higher redshifts, suggesting a connection to star formation. The weaker systems' lack of evolution does not fit within this interpretation, but may be reproduced by extrapolating low redshift scaling relations between host galaxy luminosity and absorbing halo radius to earlier epochs. Using new measurements from optical spectra of the same targets and low redshift control samples we study evolutionary trends in the chemical composition of Mg II systems from z = 0 → 5.33. We observe a significant strengthening in the characteristic N(H I) for fixed Mg II strength as one moves toward higher redshift. We set lower limits on the metallicity where we can measure H I, and find that systems with Wl27960 = 0.3 - 1.0A are quite metal rich at ˜ 0.1 Solar. We speculate that if weaker Mg II systems represent accreting gas, then their high metal abundance suggests re-accretion of recently ejected material rather than first-time infall from the metal-poor IGM, even at early times. We present a new technique for simultaneously fitting bright point sources in ungridded visibility data called the side lobe matrix technique. We provide computational speedups which allow for real time implementation. We derive analytic approximations for the error distributions of fit intensities in the presence of thermal noise, imperfect calibration, and ionospheric errors. We find that the intensity errors of the brightest sources with imperfect calibration and ionospheric errors are dominated by 'self errors' that exist independent of sidelobe contamination. We demonstrate

  4. Locking distributed feedback laser diode frequency to gas absorption lines based on genetic programming

    NASA Astrophysics Data System (ADS)

    Quan, Wei; Li, Guanghui; Fang, Zishan; Zhai, Yueyang; Li, Xinyi; Liu, Feng

    2017-01-01

    Distributed feedback laser is widely used as the pump beam and probe beam in atomic physical and quantum experiments. As the frequency stability is a vital characteristic to the laser diode in these experiments, a saturated absorption frequency stabilization method assisted with the function of current and frequency is proposed. The relationship between the current and frequency is acquired based on the genetic programming (GP) algorithm. To verify the feasibility of the method, the frequency stabilization system is comprised of two parts that are modeling the relation between the current and frequency by GP and processing the saturated absorption signal. The results of the frequency stabilization experiment proved that this method can not only narrow the frequency searching range near the atomic line center but also compensate for the phase delay between the saturated absorption peak and the zero crossing point of the differential error signal. The reduced phase delay increases the locking probability and makes the wavelength drift only 0.015 pm/h, which converted to frequency drift is 7 MHz/h after frequency locking on the Rb absorption line.

  5. High-resolution IUE observations of interstellar absorption lines in the Vela supernova remnant

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Wallerstein, G.; Silk, J.

    1984-01-01

    Ultraviolet spectra of 45 stars in the vicinity of the Vela supernova remnant were recorded by the short-wavelength echelle spectrograph aboard the International Ultraviolet Explorer (IUE). Over one-third of the stars show interstellar absorption lines at large radial velocities (greater than 60 km/s). The mapping of these high-velocity components in the sky suggests the motions are chaotic, rather than from a coherent expansion of the remnant material. In accord with earlier conclusions from Copernicus data, the gas at high velocity exhibits higher than normal ionization and shows substantially less depletion of nonvolatile elements than normal interstellar material at low velocities. Relatively strong lines from neutral carbon in the two excited fine-structure states indicate that the neutral clouds within the remnant have had their pressures enhanced by the passage of the blast wave from the supernova. Also, the remnant seems to show a significant enhancement in the abundances of low-velocity Si IV, C IV, and N V over those found in the general interstellar medium.

  6. Atlas of Absorption Lines from 0 to 17900 Cm (sup)-1

    NASA Technical Reports Server (NTRS)

    Park, J. H.; Rothman, L. S.; Rinsland, C. P.; Pickett, H. M.; Richardson, D. J.; Namkung, J. S.

    1987-01-01

    Plots of logarithm (base 10) of absorption line strength versus wavenumber from 0 to 17900/cm(sup)-1 are shown for the 28 atmospheric gases (H2O, CO2, O3, N2O, CO, CH4, O2, NO, SO2, NO2, NH3, HNO3, OH, HF, HCl, HBr, HI, ClO, OCS, H2CO, HOCl, N2, HCN, CH3Cl, H2O2, C2H2, C2H6, PH3), which appear in the 1986 Air Force Geophysics Laboratory high-resolution transmission molecular absorption data base (HITRAN) compilation, and for O(P-3), O-18 isotopic ozone, and HO2 from the 1984 JPL compilation in the 0- to 200/cm(sup)-1 region, and infrared solar CO lines at 4500 K. Also shown are plots of logarithm (base 10) of approximate infrared absorption cross sections of 11 heavy molecules versus wavenumber. The cross-section data cover 700 to 1800/cm(sup)-1 and are included as a separate data file in the 1986 HITRAN database.

  7. C IV Broad Absorption Line Acceleration in Sloan Digital Sky Survey Quasars

    NASA Astrophysics Data System (ADS)

    Grier, C. J.; Brandt, W. N.; Hall, P. B.; Trump, J. R.; Filiz Ak, N.; Anderson, S. F.; Green, Paul J.; Schneider, D. P.; Sun, M.; Vivek, M.; Beatty, T. G.; Brownstein, Joel R.; Roman-Lopes, Alexandre

    2016-06-01

    We present results from the largest systematic investigation of broad absorption line (BAL) acceleration to date. We use spectra of 140 quasars from three Sloan Digital Sky Survey programs to search for global velocity offsets in BALs over timescales of ≈2.5-5.5 years in the quasar rest frame. We carefully select acceleration candidates by requiring monolithic velocity shifts over the entire BAL trough, avoiding BALs with velocity shifts that might be caused by profile variability. The C iv BALs of two quasars show velocity shifts consistent with the expected signatures of BAL acceleration, and the BAL of one quasar shows a velocity-shift signature of deceleration. In our two acceleration candidates, we see evidence that the magnitude of the acceleration is not constant over time; the magnitudes of the change in acceleration for both acceleration candidates are difficult to produce with a standard disk-wind model or via geometric projection effects. We measure upper limits to acceleration and deceleration for 76 additional BAL troughs and find that the majority of BALs are stable to within about 3% of their mean velocities. The lack of widespread acceleration/deceleration could indicate that the gas producing most BALs is located at large radii from the central black hole and/or is not currently strongly interacting with ambient material within the host galaxy along our line of sight.

  8. Is there a connection between broad absorption line quasars and narrow-line Seyfert 1 galaxies?

    SciTech Connect

    Grupe, Dirk; Nousek, John A.

    2015-02-01

    We consider whether broad absorption line quasars (BAL QSOs) and narrow-line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt and Gallagher and Boroson. For this purpose, we constructed a sample of 11 BAL QSOs from existing Chandra and Swift observations. We found that BAL QSOs and NLS1s both operate at high Eddington ratios L/L{sub Edd}, although BAL QSOs have slightly lower L/L{sub Edd}. BAL QSOs and NLS1s in general have high Fe ii/Hβ and low [O iii]/Hβ ratios following the classic “Boroson and Green” eigenvector 1 relation. We also found that the mass accretion rates M-dot of BAL QSOs and NLS1s are more similar than previously thought, although some BAL QSOs exhibit extreme mass accretion rates of more than 10 M{sub ⊙} yr{sup −1}. These extreme mass accretion rates may suggest that the black holes in BAL QSOs are relativistically spinning. Black hole masses in BAL QSOs are a factor of 100 larger than NLS1s. From their location on a M−σ plot, we find that BAL QSOs contain fully developed black holes. Applying a principal component analysis to our sample, we find eigenvector 1 to correspond to the Eddington ratio L/L{sub Edd}, and eigenvector 2 to black hole mass.

  9. Surprises from a Deep ASCA Spectrum of the Broad Absorption Line Quasar PHL 5200

    NASA Technical Reports Server (NTRS)

    Mathur, Smita; Matt, G.; Green, P. J.; Elvis, M.; Singh, K. P.

    2002-01-01

    We present a deep (approx. 85 ks) ASCA observation of the prototype broad absorption line quasar (BALQSO) PHL 5200. This is the best X-ray spectrum of a BALQSO yet. We find the following: (1) The source is not intrinsically X-ray weak. (2) The line-of-sight absorption is very strong, with N(sub H) = 5 x 10(exp 23)/sq cm. (3) The absorber does not cover the source completely; the covering fraction is approx. 90%. This is consistent with the large optical polarization observed in this source, implying multiple lines of sight. The most surprising result of this observation is that (4) the spectrum of this BALQSO is not exactly similar to other radio-quiet quasars. The hard X-ray spectrum of PHL 5200 is steep, with the power-law spectral index alpha approx. 1.5. This is similar to the steepest hard X-ray slopes observed so far. At low redshifts, such steep slopes are observed in narrow-line Seyfert 1 (NLS1) galaxies, believed to be accreting at a high Eddington rate. This observation strengthens the analogy between BALQSOs and NLS1 galaxies and supports the hypothesis that BALQSOs represent an early evolutionary state of quasars. It is well accepted that the orientation to the line of sight determines the appearance of a quasar: age seems to play a significant role as well.

  10. FR-II Broad Absorption Line Quasars and the Life Cycle of Quasars

    SciTech Connect

    Gregg, M D; Becker, R H; de Vries, W

    2006-01-05

    By combining the Sloan Digitized Sky Survey Third Data Release quasar list with the VLA FIRST survey, we have identified five objects having both broad absorption lines in their optical spectra and FR-II radio morphologies. We identify an additional example of this class from the FIRST Bright Quasar Survey, J1408+3054. Including the original FR-II-BAL object, J1016+5209, brings the number of such objects to eight. These quasars are relatively rare; finding this small handful has required the 45,000-large quasar sample of SDSS. The FR-II-BAL quasars exhibit a significant anti-correlation between radio-loudness and the strength of the BAL features. This is easily accounted for by the evolutionary picture in which quasars emerge from cocoons of BAL-producing material which stifle the development of radio jets and lobes. There is no such simple explanation for the observed properties of FR-II-BALs in the unification-by-orientation model of quasars. The rarity of the FR-II-BAL class implies that the two phases do not coexist for very long in a single quasar, perhaps less than 10{sup 5} years, with the combined FR-II, high ionization broad absorption phase being even shorter by another factor of 10 or more.

  11. Isotopic ratios at z = 0.68 from molecular absorption lines toward B 0218+357

    NASA Astrophysics Data System (ADS)

    Wallström, S. H. J.; Muller, S.; Guélin, M.

    2016-11-01

    Isotopic ratios of heavy elements are a key signature of the nucleosynthesis processes in stellar interiors. The contribution of successive generations of stars to the metal enrichment of the Universe is imprinted on the evolution of isotopic ratios over time. We investigate the isotopic ratios of carbon, nitrogen, oxygen, and sulfur through millimeter molecular absorption lines arising in the z = 0.68 absorber toward the blazar B 0218+357. We find that these ratios differ from those observed in the Galactic interstellar medium, but are remarkably close to those in the only other source at intermediate redshift for which isotopic ratios have been measured to date, the z = 0.89 absorber in front of PKS 1830-211. The isotopic ratios in these two absorbers should reflect enrichment mostly from massive stars, and they are indeed close to the values observed toward local starburst galaxies. Our measurements set constraints on nucleosynthesis and chemical evolution models. The reduced spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/595/A96

  12. Fast outflows in broad absorption line quasars and their connection with CSS/GPS sources

    NASA Astrophysics Data System (ADS)

    Bruni , G.; Mack, K.-H.; Montenegro-Montes, F. M.; Brienza, M.; González-Serrano, J. I.

    2016-02-01

    Broad absorption line quasars are among the objects presenting the fastest outflows. The launching mechanism itself is not completely understood. Models in which they could be launched from the accretion disk, and then curved and accelerated by the effect of the radiation pressure, have been presented. We conducted an extensive observational campaign, from radio to optical band, to collect information about their nature and test the models present in the literature, the main dichotomy being between a young scenario and an orientation one. We found a variety of possible orientations, morphologies, and radio ages, not converging to a particular explanation for the BAL phenomenon. From our latest observations in the m- and mm-band, we obtained an indication of a lower dust abundance with respect to normal quasars, thus suggesting a possible feedback process on the host galaxy. Also, in the low-frequency regime we confirmed the presence of CSS components, sometime in conjunction with a GPS one already detected at higher frequencies. Following this, about 70 % of our sample turns out to be in a GPS or CSS+GPS phase. We conclude that fast outflows, responsible for the BAL features, can be more easily present among objects going through a restarting or just-started radio phase, where radiation pressure can substantially contribute to their acceleration.

  13. MOSFIRE ABSORPTION LINE SPECTROSCOPY OF z > 2 QUIESCENT GALAXIES: PROBING A PERIOD OF RAPID SIZE GROWTH

    SciTech Connect

    Belli, Sirio; Ellis, Richard S.; Konidaris, Nick P.; Newman, Andrew B.

    2014-06-20

    Using the MOSFIRE near-infrared multi-slit spectrograph on the Keck 1 Telescope, we have secured high signal-to-noise ratio absorption line spectra for six massive galaxies with redshift 2 < z < 2.5. Five of these galaxies lie on the red sequence and show signatures of passive stellar populations in their rest-frame optical spectra. By fitting broadened spectral templates we have determined stellar velocity dispersions and, with broad-band Hubble Space Telescope and Spitzer photometry and imaging, stellar masses and effective radii. Using this enlarged sample of galaxies, we confirm earlier suggestions that quiescent galaxies at z > 2 have small sizes and large velocity dispersions compared to local galaxies of similar stellar mass. The dynamical masses are in very good agreement with stellar masses (log M {sub *}/M {sub dyn} = –0.02 ± 0.03), although the average stellar-to-dynamical mass ratio is larger than that found at lower redshift (–0.23 ± 0.05). By assuming evolution at fixed velocity dispersion, not only do we confirm a surprisingly rapid rate of size growth but we also consider the necessary evolutionary track on the mass-size plane and find a slope α = dlog R{sub e} /dlog M {sub *} ≳ 2 inconsistent with most numerical simulations of minor mergers. Both results suggest an additional mechanism may be required to explain the size growth of early galaxies.

  14. The velocity distribution of interstellar gas observed in strong UV absorption lines

    NASA Technical Reports Server (NTRS)

    Cowie, L. L.; York, D. G.

    1978-01-01

    Observations of three strong interstellar UV absorption lines of N I (1199 A), N II (1083 A), and Si III (1206 A) in 47 stars of widely varying distance and a variety of spectral types are analyzed to obtain a velocity distribution function for the interstellar gas. A technique based on the maximum and minimum velocities observed along a line of sight is adopted because of heavy line blending, and results are discussed for both power-law and exponential distribution functions. The expected distribution of radiative-phase supernova remnants (SNRs) in the interstellar medium is calculated as a function of SNR birthrate and of the interstellar density in which they evolve. The results are combined with observed distance estimates, and it is shown that an interstellar density in excess of 0.1 per cu cm would be required to keep the SNRs sufficiently confined so that their cross sections are consistent with the observed number of components. The alternative possibility is considered that SNRs do not enter the radiative phase before escaping from the Galaxy or colliding with neighboring remnants.

  15. Discovery of Hα Absorption in the Unusual Broad Absorption Line Quasar SDSS J083942.11+380526.3

    NASA Astrophysics Data System (ADS)

    Aoki, Kentaro; Iwata, Ikuru; Ohta, Kouji; Ando, Masataka; Akiyama, Masayuki; Tamura, Naoyuki

    2006-11-01

    We discovered Hα absorption in the broad Hα emission line of an unusual broad absorption line quasar, SDSS J083942.11+380526.3, at z=2.318, through near-infrared spectroscopy with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) on the Subaru telescope. The presence of nonstellar Hα absorption is known only in the Seyfert galaxy NGC 4151 to date; thus, our discovery is the first case for quasars. The Hα absorption line is blueshifted by 520 km s-1 relative to the Hα emission line, and its redshift almost coincides with those of UV low-ionization metal absorption lines. The width of the Hα absorption (~340 km s-1) is similar to those of the UV low-ionization absorption lines. These facts suggest that the Hα and low-ionization metal absorption lines are produced by the same low-ionization gas, which has a substantial amount of neutral gas. The column density of the neutral hydrogen is estimated to be ~1018 cm-2 by assuming a gas temperature of 10,000 K from the analysis of the curve of growth. The continuum spectrum is reproduced by a reddened [E(B-V)~0.15 mag for the SMC-like reddening law] composite quasar spectrum. Furthermore, the UV spectrum of SDSS J083942.11+380526.3 shows a remarkable similarity to that of NGC 4151 in its low state, suggesting that the physical condition of the absorber in SDSS J083942.11+380526.3 is similar to that of NGC 4151 in the low state. As proposed for NGC 4151, SDSS J083942.11+380526.3 may also be seen through the edge of the obscuring torus. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  16. Optical imaging of the low redshift superluminous QSO 1821 + 643

    SciTech Connect

    Hutchings, J.B.; Neff, S.G. NASA, Goddard Space Flight Center, Greenbelt, MD )

    1991-06-01

    Optical imaging is presented of the luminous z = 0.3 QSO 1821 + 643, with resolution 1.0 and 0.4 arcsec. The host galaxy is resolved and seen to be large, featureless, and red, with slightly displaced outer isophotes. The nucleus is unusually red. There is a rich cluster of galaxies in the field which is probably at a much higher redshift, and extended nebulosity from a nearby star. These results and the IR properties are discussed in terms of a mature merger of a luminous galaxy in which there is still a considerable amount of central dust and molecular clouds. 8 refs.

  17. Optical imaging of the low redshift superluminous QSO 1821 + 643

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Optical imaging is presented of the luminous z = 0.3 QSO 1821 + 643, with resolution 1.0 and 0.4 arcsec. The host galaxy is resolved and seen to be large, featureless, and red, with slightly displaced outer isophotes. The nucleus is unusually red. There is a rich cluster of galaxies in the field which is probably at a much higher redshift, and extended nebulosity from a nearby star. These results and the IR properties are discussed in terms of a mature merger of a luminous galaxy in which there is still a considerable amount of central dust and molecular clouds.

  18. NIR flaring of the QSO PKS 2233-148

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Luna, A.; Mayya, D. Y.; Porras, A.; Recillas, E.; Carraminana, A.

    2012-10-01

    We have observed a recent NIR brightening of the flat spectrum QSO PKS2233-148 (z=0.325), a gamma ray source 2FGL J2236.5-1431. On September 26th, 2012, epoch JD2456196.813507, we determined the flux in the H band to be 13.096 +/- 0.04. That is 2 magnitudes brighter than the flux determined by the 2mass survey. Observations were carried out with the 2.1m telescope of the Guillermo Haro Observatory operated by the National Institute for Astrophysics, Optics and Electronics (Mexico), equipped with the instrument CANICA a NIR camera.

  19. A Variable Energy, Redshifted, Iron Absorption Line in a recoiling Black Hole

    NASA Astrophysics Data System (ADS)

    Civano, Francesca

    The aim of this proposal is to maximize the scientific return of a medium deep (123 ksec) XMM-Newton observation, awarded during the AO10 call for proposal, to obtain a high quality X-ray spectrum of CID-42, a very peculiar source discovered in the COSMOS survey. CID-42 is exceptional in many respects showing a redshifted, variable energy absorption line plus an emission line at ~ 6 keV forming an inverted P-Cygni profile. These features were never observed before in the X-rays. The peculiar nature of CID-42 extends well beyond the X-ray spectrum. First, two optical sources in a common envelope are clearly seen in the HST data. They are separated by about 2.45 kpc. Thanks to the unrivaled Chandra HRC resolution it was possible to unambiguously associate the X-ray emission to only one of the two optical sources. Second, a high velocity (1100 km/s) offset, between the broad and narrow component of the H-beta line is measured in the VLT/Magellan/Keck optical spectra. The velocity offset observed is unlikely to be due to a ongoing merger because too high. Third, the above mentioned inverted P-Cygni profile in the hard X-ray spectrum would be naturally explained by an high velocity (v~0.02-0.14c) gas infall in the innermost region of the accreting Black Hole. All together the observed properties support the interpretation of a Black Hole kicked from the center of the galaxy by asymmetric emission of gravitational waves produced during a major merger. The Black Hole is caught while still active, at ~10^6 yrs after the kick and at a substantial distance from the center of the galaxy. The theoretical expectations suggest that they are extremely rare and just 1 or 2 gravitational wave recoiling Black Holes are expected in a survey like COSMOS. CID- 42 thus represents a ``Rosetta stone'' for the study of SMBH mergers that are believed to occur during galaxy-galaxy mergers, and their fate after the merging. The detailed study of the hard X-ray XMM-Newton spectrum, in the

  20. Quasar Absorption Lines: The Evolution of Galactic Gas Over Cosmic Time

    NASA Astrophysics Data System (ADS)

    Charlton, J.

    1996-12-01

    A view of the formation and evolution of galaxies and structure over the whole history of the Universe requires observations both of stars and of gas. From the stars in galaxies, now observed in deep images back in time to less than a billion years past the Big Bang, we can study the evolution of galaxy morphology and of star formation rates. Direct observation of gas in the Universe at all epochs is also possible, using absorption spectra of quasars as a probe of intervening material. This absorption arises not only from the gas in developed galaxies and in their environments, but also from the clumps of gas that will eventually combine to form galaxies, and from the gas spread through the Universe that is gradually flowing into the galaxies. This study of gas through quasar absorption lines has opened the possibility of observing directly the formation of galaxies through the assembly of their gas over time. Furthermore, with high resolution spectroscopy, the substructures observed in absorption profiles provide information about the internal workings of galaxies. This talk will present an overview of progress toward a comprehensive picture of the formation and evolution of galaxies through quasar absorption line studies. The absorption profiles that are observed due to the passage of the quasar light through a given structure are a convolution of several properties of the gas, including its spatial and kinematic distribution, its chemical composition, and its state of ionization. Illustrative models will be utilized to show how these various factors affect the appearance of synthetic spectra. Beginning with the philosophy ``what you see is what you get'', the kinematic spectral signatures of higher redshift absorbers will be modeled by familiar components of nearby galaxies: a rotating disk, an isothermal halo, and gas in radial inflow. A combination of these basic models goes a long way toward producing a variety of complex absorption profiles which are in fact

  1. X-ray-selected broad absorption line quasi-stellar objects

    NASA Astrophysics Data System (ADS)

    Page, M. J.; Carrera, F. J.; Ceballos, M.; Corral, A.; Ebrero, J.; Esquej, P.; Krumpe, M.; Mateos, S.; Rosen, S.; Schwope, A.; Streblyanska, A.; Symeonidis, M.; Tedds, J. A.; Watson, M. G.

    2017-02-01

    We study a sample of six X-ray-selected broad absorption line (BAL) quasi-stellar objects (QSOs) from the XMM-Newton Wide Angle Survey. All six objects are classified as BALQSOs using the classic balnicity index, and together they form the largest sample of X-ray-selected BALQSOs. We find evidence for absorption in the X-ray spectra of all six objects. An ionized absorption model applied to an X-ray spectral shape that would be typical for non-BAL QSOs (a power law with energy index α = 0.98) provides acceptable fits to the X-ray spectra of all six objects. The optical to X-ray spectral indices, αOX, of the X-ray-selected BALQSOs, have a mean value of <αOX> = 1.69 ± 0.05, which is similar to that found for X-ray-selected and optically selected non-BAL QSOs of a similar ultraviolet luminosity. In contrast, optically selected BALQSOs typically have much larger αOX and so are characterized as being X-ray weak. The results imply that X-ray selection yields intrinsically X-ray bright BALQSOs, but their X-ray spectra are absorbed by a similar degree to that seen in optically selected BALQSO samples; X-ray absorption appears to be ubiquitous in BALQSOs, but X-ray weakness is not. We argue that BALQSOs sit at one end of a spectrum of X-ray absorption properties in QSOs related to the degree of ultraviolet absorption in C IV 1550 Å.

  2. BROAD ABSORPTION LINE VARIABILITY ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE

    SciTech Connect

    Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.; Hall, P. B.; Anderson, S. F.; Hamann, F.; Lundgren, B. F.; Myers, Adam D.; Pâris, I.; Petitjean, P.; Ross, Nicholas P.; Shen, Yue; York, Don

    2013-11-10

    We present a detailed investigation of the variability of 428 C IV and 235 Si IV broad absorption line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations primarily sample rest-frame timescales of 1-3.7 yr over which significant rearrangement of the BAL wind is expected. We derive a number of observational results on, e.g., the frequency of BAL variability, the velocity range over which BAL variability occurs, the primary observed form of BAL-trough variability, the dependence of BAL variability upon timescale, the frequency of BAL strengthening versus weakening, correlations between BAL variability and BAL-trough profiles, relations between C IV and Si IV BAL variability, coordinated multi-trough variability, and BAL variations as a function of quasar properties. We assess implications of these observational results for quasar winds. Our results support models where most BAL absorption is formed within an order-of-magnitude of the wind-launching radius, although a significant minority of BAL troughs may arise on larger scales. We estimate an average lifetime for a BAL trough along our line-of-sight of a few thousand years. BAL disappearance and emergence events appear to be extremes of general BAL variability, rather than being qualitatively distinct phenomena. We derive the parameters of a random-walk model for BAL EW variability, finding that this model can acceptably describe some key aspects of EW variability. The coordinated trough variability of BAL quasars with multiple troughs suggests that changes in 'shielding gas' may play a significant role in driving general BAL variability.

  3. Investigating the radio-loud phase of broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Bruni, G.; González-Serrano, J. I.; Pedani, M.; Benn, C. R.; Mack, K.-H.; Holt, J.; Montenegro-Montes, F. M.; Jiménez-Luján, F.

    2014-09-01

    Context. Broad absorption lines (BALs) are present in the spectra of ~20% of quasars (QSOs); this indicates fast outflows (up to 0.2c) that intercept the observer's line of sight. These QSOs can be distinguished again into radio-loud (RL) BAL QSOs and radio-quiet (RQ) BAL QSOs. The first are very rare, even four times less common than RQ BAL QSOs. The reason for this is still unclear and leaves open questions about the nature of the BAL-producing outflows and their connection with the radio jet. Aims: We explored the spectroscopic characteristics of RL and RQ BAL QSOs with the aim to find a possible explanation for the rarity of RL BAL QSOs. Methods: We identified two samples of genuine BAL QSOs from SDSS optical spectra, one RL and one RQ, in a suitable redshift interval (2.5 < z < 3.5) that allowed us to observe the Mg ii and Hβ emission lines in the adjacent near-infrared (NIR) band. We collected NIR spectra of the two samples using the Telescopio Nazionale Galileo (TNG, Canary Islands). By using relations known in the literature, we estimated the black-hole mass, the broad-line region radius, and the Eddington ratio of our objects and compared the two samples. Results: We found no statistically significant differences from comparing the distributions of the cited physical quantities. This indicates that they have similar geometries, accretion rates, and central black-hole masses, regardless of whether the radio-emitting jet is present or not. Conclusions: These results show that the central engine of BAL QSOs has the same physical properties with and without a radio jet. The reasons for the rarity of RL BAL QSOs must reside in different environmental or evolutionary variables. Figure 3 is available in electronic form at http://www.aanda.org

  4. A variable P v broad absorption line and quasar outflow energetics

    NASA Astrophysics Data System (ADS)

    Capellupo, D. M.; Hamann, F.; Barlow, T. A.

    2014-10-01

    Broad absorption lines (BALs) in quasar spectra identify high-velocity outflows that might exist in all quasars and could play a major role in feedback to galaxy evolution. The viability of BAL outflows as a feedback mechanism depends on their kinetic energies, as derived from the outflow velocities, column densities, and distances from the central quasar. We estimate these quantities for the quasar, Q1413+1143 (redshift ze = 2.56), aided by the first detection of P V λλ1118, 1128 BAL variability in a quasar. In particular, P V absorption at velocities where the C IV trough does not reach zero intensity implies that the C IV BAL is saturated and the absorber only partially covers the background continuum source (with characteristic size <0.01 pc). With the assumption of solar abundances, we estimate that the total column density in the BAL outflow is log NH ≳ 22.3 cm-2. Variability in the P V and saturated C IV BALs strongly disfavours changes in the ionization as the cause of the BAL variability, but supports models with high column density BAL clouds moving across our lines of sight. The observed variability time of 1.6 yr in the quasar rest frame indicates crossing speeds >750 km s-1 and a radial distance from the central black hole of ≲ 3.5 pc, if the crossing speeds are Keplerian. The total outflow mass is ˜4100 M⊙, the kinetic energy ˜4 × 1054 erg, and the ratio of the outflow kinetic energy luminosity to the quasar bolometric luminosity is ˜0.02 (at the minimum column density and maximum distance), which might be sufficient for important feedback to the quasar's host galaxy.

  5. A new perspective on the interstellar cloud surrounding the Sun from UV absorption line results

    NASA Astrophysics Data System (ADS)

    Gry, Cecile; Jenkins, Edward B.

    2015-01-01

    We offer a new, more inclusive, picture of the local interstellar medium, where it is composed of a single, monolithic cloud that surrounds the Sun in all directions. Our study of velocities based on Mg II and Fe II ultraviolet absorption lines indicates that the cloud has an average motion consistent with the velocity vector of gas impacting the heliosphere and does not behave like a rigid body: gas within the cloud is being differentially decelerated in the direction of motion, and the cloud is expanding in directions perpendicular to this flow, much like the squashing of a balloon. The outer boundary of the cloud is in average 10 pc away from us but is highly irregular, being only a few parsecs away in some directions, with possibly a few extensions up to 20 pc. Average H I volume densities vary between 0.03 and 0.1 cm3 over different sight lines. Metals appear to be significantly depleted onto grains, and there is a steady increase in this effect from the rear of the cloud to the apex of motion. There is no evidence that changes in the ionizing radiation influence the apparent abundances. Additional, secondary velocity components are detected in 60% of the sight lines. Almost all of them appear to be interior to the volume holding the gas that we identify with the main cloud. Half of the sight lines exhibit a secondary component moving at about - 7.2 km/s with respect to the main component, which may be the signature of an implosive shock propagating toward the cloud's interior.

  6. Variation of Ionizing Continuum: The Main Driver of Broad Absorption Line Variability

    NASA Astrophysics Data System (ADS)

    He, Zhicheng; Wang, Tinggui; Zhou, Hongyan; Bian, Weihao; Liu, Guilin; Yang, Chenwei; Dou, Liming; Sun, Luming

    2017-04-01

    We present a statistical analysis of the variability of broad absorption lines (BALs) in quasars using the large multi-epoch spectroscopic data set of the Sloan Digital Sky Survey Data Release 12 (SDSS DR12). We divide the sample into two groups according to the pattern of the variation of C iv BAL with respect to that of a continuum: the equivalent widths (EW) of the BAL decreases (increases) when the continuum brightens (dims) as group T1; and the variation of the EW and the continuum in the opposite relation of group T2. We find that T2 has significantly ({P}{{T}}< {10}-6, Students T Test) higher EW ratios (R) of Si iv to C iv BAL than T1. Our result agrees with the prediction of photoionization models that {C}+3 column density increases (decreases) if there is a (or no) {C}+3 ionization front, while R decreases with the incident continuum. We show that BAL variabilities in at least 80% of quasars are driven by the variation of an ionizing continuum, while other models that predict uncorrelated BAL and continuum variability contribute less than 20%. Considering large uncertainty in the continuum flux calibration, the latter fraction may be much smaller. When the sample is binned into different time intervals between the two observations, we find significant difference in the distribution of R between T1 and T2 in all time-bins down to {{Δ }}T< 6 days, suggesting that the BAL outflow in a fraction of quasars has a recombination timescale of only a few days.

  7. Formation of a Giant Galactic Gaseous Halo: Metal-Absorption Lines and High-Velocity Clouds

    NASA Astrophysics Data System (ADS)

    Li, Fan

    1992-04-01

    A Galactic gaseous halo formed through the interstellar disk-halo connection is simulated by means of a two-dimensional axisymmetric hydrodynamic code based upon the chimney model of the interstellar medium, a new version of the galactic fountain. Galactic rotation, heating processes by diffuse UV flux, and radiative cooling processes are taken into account. The resulting gaseous halo can be divided into three categories, i.e., wind-type halo, bound-type halo, and cooled-type halo. In this way, we try to reproduce the column densities of C IV, N V, O VI, and Si IV in the observed absorption lines of halo stars. Assuming that the radiatively cooled halo gas condenses into clouds due to thermal instabilities, we can calculate their distribution and ballistic motions in the Galactic gravitational field. These correspond to the high- and intermediate-velocity clouds observed at high Galactic latitudes. We find that a cooled-type halo with a gas temperature between 5 X 10^5 and 10^6 K and a density between 10^-3 and 10^-2 cm^-3 at the disk-halo interface can reproduce the observational facts about our Galaxy. Supposing that the metal-absorption-line systems of QSOs arise from the halos of intervening galaxies formed by similar processes, we calculate features of the Ca II, Mg II, C IV, and Si IV absorption lines in various stages of galactic evolution. We conclude that C IV systems which are greater than 50 kpc in size correspond to the wind-type halo. On the other hand, Mg II and Ca II systems can only be detected in a very restricted region ( Metaxa, SMALL FAINT CLUSTERS IN THE LMC This is a short review of the main results of my Ph.D. thesis concerning some important problems on the dynamical properties of the LMC star clusters. The topic of this thesis was to find and study the dynamical paramters (tidal radius r_t core radius r_c concentration parameters log (r_t/r_c), and total mass M) for a large sample of small LMC clusters and to define their location in the

  8. On the Formation of Molecular Clumps in QSO Outflows

    NASA Astrophysics Data System (ADS)

    Ferrara, A.; Scannapieco, E.

    2016-12-01

    We study the origin of the cold molecular clumps in quasar outflows, recently detected in CO and HCN emission. We first describe the physical properties of such radiation-driven outflows and show that a transition from a momentum- to an energy-driven flow must occur at a radial distance of R≈ 0.25 {kpc}. During this transition, the shell of swept-up material fragments due to Rayleigh-Taylor instabilities, but these clumps contain little mass and are likely to be rapidly ablated by the hot gas in which they are immersed. We then explore an alternative scenario in which clumps form from thermal instabilities at R≳ 1 {kpc}, possibly containing enough dust to catalyze molecule formation. We investigate this process with 3D two-fluid (gas+dust) numerical simulations of a kpc3 patch of the outflow, including atomic and dust cooling, thermal conduction, dust sputtering, and photoionization from the QSO radiation field. In all cases, dust grains are rapidly destroyed in ≈ {10}4 years; and while some cold clumps form at later times, they are present only as transient features, which disappear as cooling becomes more widespread. In fact, we only find a stable two-phase medium with dense clumps if we artificially enhance the QSO radiation field by a factor of 100. This result, together with the complete destruction of dust grains, renders the interpretation of molecular outflows a very challenging problem.

  9. X-Ray Spectrum of a Narrow-Line QSO

    NASA Technical Reports Server (NTRS)

    Halpern, Jules P.

    1998-01-01

    During the reporting period, seven papers using ASCA data, supported in whole or in part by this grant, were published or submitted to refereed journals. Their abstracts are given in this report, and the complete bibliographic references are listed in the Appendix. Titles include (1) A Broad-Band X-ray Study of the Geminga Pulsar; (2) ASCA Observations of PSR 1920+10 and PSR 0950+08; (3) X-ray and Optical Spectroscopy of IRAS 20181-2244: Not a Type 2 QSO, but a I Zw I Object; (4) Models for X-ray Emission from Isolated Pulsars; (5) Optical and X-ray Spectroscopy of 1E 0449.4-1823: Demise of the Original Type 2 QSO; (6) The ASCA Spectrum of the Broad-Line Radio Galaxy Pictor A: A Simple Power Law with No Fe Ka Line; and (7) ASCA Spectra of NGC 4388 and ESO 103-G35: Absorption, Reflection, and Variability in Intermediate Type Seyfert Galaxies.

  10. Water-vapor absorption line measurements in the 940-nm band by using a Raman-shifted dye laser

    NASA Technical Reports Server (NTRS)

    Chu, Zhiping; Wilkerson, Thomas D.; Singh, Upendra N.

    1993-01-01

    We report water-vapor absorption line measurements that are made by using the first Stokes radiation (930-982 nm) with HWHM 0.015/cm generated by a narrow-linewidth, tunable dye laser. Forty-five absorption line strengths are measured with an uncertainty of 6 percent and among them are fourteen strong lines that are compared with previous measurements for the assessment of spectral purity of the light source. Thirty air-broadened linewidths are measured with 8 percent uncertainty at ambient atmospheric pressure with an average of 0.101/cm. The lines are selected for the purpose of temperature-sensitive or temperature-insensitive lidar measurements. Results for these line strengths and linewidths are corrected for broadband radiation and finite laser linewidth broadening effects and compared with the high-resolution transmission molecular absorption.

  11. Recovery of acetylene absorption line profile basing on tunable diode laser spectroscopy with intensity modulation and photoacoustic spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Li; Thursby, Graham; Stewart, George; Arsad, Norhana; Uttamchandani, Deepak; Culshaw, Brian; Wang, Yiding

    2010-04-01

    A novel and direct absorption line recovery technique based on tunable diode laser spectroscopy with intensity modulation is presented. Photoacoustic spectroscopy is applied for high sensitivity, zero background and efficient acoustic enhancement at a low modulation frequency. A micro-electromechanical systems (MEMS) mirror driven by an electrothermal actuator is used for generating laser intensity modulation (without wavelength modulation) through the external reflection. The MEMS mirror with 10μm thick structure material layer and 100nm thick gold coating is formed as a circular mirror of 2mm diameter attached to an electrothermal actuator and is fabricated on a chip that is wire-bonded and placed on a PCB holder. Low modulation frequency is adopted (since the resonant frequencies of the photoacoustic gas cell and the electrothermal actuator are different) and intrinsic high signal amplitude characteristics in low frequency region achieved from measured frequency responses for the MEMS mirror and the gas cell. Based on the property of photoacoustic spectroscopy and Beer's law that detectable sensitivity is a function of input laser intensity in the case of constant gas concentration and laser path length, a Keopsys erbium doped fibre amplifier (EDFA) with opto-communication C band and high output power up to 1W is chosen to increase the laser power. High modulation depth is achieved through adjusting the MEMS mirror's reflection position and driving voltage. In order to scan through the target gas absorption line, the temperature swept method is adopted for the tunable distributed feed-back (DFB) diode laser working at 1535nm that accesses the near-infrared vibration-rotation spectrum of acetylene. The profile of acetylene P17 absorption line at 1535.39nm is recovered ideally for ~100 parts-per-million (ppm) acetylene balanced by nitrogen. The experimental signal to noise ratio (SNR) of absorption line recovery for 500mW laser power was ~80 and hence the

  12. Absorption lines from magnetically driven winds in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Chakravorty, S.; Petrucci, P.-O.; Ferreira, J.; Henri, G.; Belmont, R.; Clavel, M.; Corbel, S.; Rodriguez, J.; Coriat, M.; Drappeau, S.; Malzac, J.

    2016-05-01

    Context. High resolution X-ray spectra of black hole X-ray binaries (BHBs) show blueshifted absorption lines suggesting the presence of outflowing winds. Furthermore, observations show that the disk winds are equatorial and they occur in the Softer (disk dominated) states of the outburst and are less prominent or absent in the Harder (power-law dominated) states. Aims: We want to test whether the self-similar magneto-hydrodynamic (MHD) accretion-ejection models can explain the observational results for accretion disk winds in BHBs. In our models, the density at the base of the outflow from the accretion disk is not a free parameter. This mass loading is determined by solving the full set of dynamical MHD equations without neglecting any physical term. Thus, the physical properties of the outflow depend on and are controlled by the global structure of the disk. Methods: We studied different MHD solutions characterized by different values of the disk aspect ratio (ɛ) and the ejection efficiency (p). We also generate two kinds of MHD solutions depending on the absence (cold solution) or presence (warm solution) of heating at the disk surface. Such heating could be either from dissipation of energy due to MHD turbulence in the disk or from illumination of the disk surface. Warm solutions can have large (>0.1) values of p, which would imply larger wind mass loading at the base of the outflow. We use each of these MHD solutions to predict the physical parameters (distance, density, velocity, magnetic field, etc.) of an outflow. Motivated by observational results, we have put limits on the ionization parameter (ξ), column density, and timescales. Further constraints were derived for the allowed values of ξ from thermodynamic instability considerations, particularly for the Hard SED. These physical constraints were imposed on each of these outflows to select regions within it, which are consistent with the observed winds. Results: The cold MHD solutions are found to be

  13. The hydration dependence of CaCO3 absorption lines in the Far IR

    NASA Astrophysics Data System (ADS)

    Powell, Johnny; Emery, Logan P

    2014-06-01

    The far infrared (FIR) absorption lines of CaCO3 have been measured at a range of relative humidities (RH) between 33 and 92% RH using a Bruker 66v/S spectrometer. Hydration measurements on CaCO3 have been made in the mid-infrared (MIR) by [Al-Hosney, H.A. and Grassian, V.H., 2005, Phys. Chem. Chem. Phys., 7, 1266], and astrophysically-motivated temperature-dependent FIR measurements of CaCO3 in vacuum have also been reported [Posch, T., et al., 2007, Ap. J., 668, 993]. The custom sample cell constructed for these hydrated-FIR spectra is required because the 66v/S bench is under vacuum (3 mbar) during typical measurements. Briefly, the sample cell consists of two Thalium Bromoiodide (KRS-5) windows, four O-rings, a plastic ring for separating the windows and providing a volume for the saturated atmosphere. CaCO3 was deposited on KRS-5 windows using doubly-distilled water as an intermediary. The KRS-5 window with sample and assembled sample cell were placed in a desiccator with the appropriated saturated salt solution [Washburn, E.W. (Ed.), International Critical Tables of Numerical Data, Physics Chemistry and Technology, Vol. 1, (McGraw-Hill, New York, 1926), p. 67-68] and allowed to hydrate for 23 hours. For spectroscopy the desiccator was quickly opened and the second KRS-5 window placed in the cell to seal the chamber. A spectrum was then taken of the sample at the appropriate RH. The spectra taken characterize the adsorption of water vapor and CaCO3 that might occur in circumstellar environments [Melnick, G.J., et al. 2001, Nature, 412, 160].The MIR and FIR reflectance spectra of calcite (CaCO3) have been thoroughly studied by [Hellwege, K.H., et al., 1970, Z. Physik, 232, 61]. Five Lorentzian curves were fit to our data in the range from 378-222 cm-1/SUP> and each was able to be assigned to a known mode of CaCO3. The data does not support the conclusion of a hydration effect on these modes of CaCO3, but it does suggest a possible broadening of three modes

  14. Dependence of the Broad Absorption Line Quasar Fraction on Radio Luminosity

    NASA Astrophysics Data System (ADS)

    Shankar, Francesco; Dai, Xinyu; Sivakoff, Gregory R.

    2008-11-01

    We find that the fraction of classical broad absorption line quasars (BALQSOs) among the FIRST radio sources in the Sloan Data Release 3, is 20.5+ 7.3-5.9% at the faintest radio powers detected (L1.4 GHz ~ 1032 erg s-1), and rapidly drops to lesssim8% at L1.4 GHz ~ 3 × 1033 erg s-1. Similarly, adopting the broader absorption index (AI) definition of Trump et al., we find the fraction of radio BALQSOs to be 44+ 8.1-7.8%, reducing to 23.1+ 7.3-6.1% at high luminosities. While the high fraction at low radio power is consistent with the recent near-IR estimates by Dai et al., the lower fraction at high radio powers is intriguing and confirms previous claims based on smaller samples. The trend is independent of the redshift range, the optical and radio flux selection limits, or the exact definition of a radio match. We also find that at fixed optical magnitude, the highest bins of radio luminosity are preferentially populated by non-BALQSOs, consistent with the overall trend. We do find, however, that those quasars identified as AI-BALQSOs but not under the classical definition do not show a significant drop in their fraction as a function of radio power, further supporting independent claims that these sources, characterized by lower equivalent width, may represent an independent class from the classical BALQSOs. We find the balnicity index, a measure of the absorption trough in BALQSOs, and the mean maximum wind velocity to be roughly constant at all radio powers. We discuss several plausible physical models which may explain the observed fast drop in the fraction of the classical BALQSOs with increasing radio power, although none is entirely satisfactory. A strictly evolutionary model for the BALQSO and radio emission phases requires a strong fine-tuning to work, while a simple geometric model, although still not capable of explaining polar BALQSOs and the paucity of FRII BALQSOs, is statistically successful in matching the data if part of the apparent radio

  15. The radio core and jet in the broad absorption-line quasar PG 1700+518

    NASA Astrophysics Data System (ADS)

    Yang, J.; Wu, F.; Paragi, Z.; An, T.

    2012-01-01

    The blueshifted broad absorption lines (BAL) or troughs are observed in active galactic nuclei (AGNs) when our line of sight is intercepted by a high-speed outflow (wind), likely originating in the accretion disc. The outflow or wind can shed light on the internal structure obscured by the AGN torus. Recently, it has been shown that this outflow is rotating in the BAL quasar PG 1700+518, further supporting the accretion disc origin of the wind. With the purpose of giving independent constraints on the wind geometry, we performed high-resolution European very long baseline interferometry (VLBI) Network (EVN) observations at 1.6 GHz in 2010. Combining the results with the Very Large Array (VLA) archival data at 8.4 GHz, we present its jet structure on scales of parsec (pc) to kiloparsec (kpc) for the first time. The source shows two distinct jet features in east-west direction with a separation of around 4 kpc. The eastern feature, which has so far been assumed to hide the core, is a kpc-scale hotspot, which is completely resolved out in the EVN image. In the western jet feature, we find a compact jet component, which pinpoints the position of the central black hole in the galaxy. Jet components on both sides of the core are additionally detected in the north-west-south-east direction, and they show a symmetric morphology on scale of <1 kpc. This two-sided jet feature is not common in the known BAL quasars and indicates that the jet axis is far away from the line of sight. Furthermore, it is nearly parallel to the scattering plane revealed earlier by optical polarimetry. By analogy to polar-scattered Seyfert 1 galaxies, we conclude that the jet likely has a viewing angle around 45°. The analogy is further supported by the recent report of significant cold absorption in the soft X-rays, a nearly unique feature to polar-scattered Seyfert galaxies. Finally, our observations have confirmed the earlier finding that the majority of radio emission in this galaxy arises

  16. No Evidence for Variability of Intervening Absorption Lines toward GRB 060206: Implications for the MgII Incidence Problem

    NASA Astrophysics Data System (ADS)

    Aoki, Kentaro; Totani, Tomonori; Hattori, Takashi; Ohta, Kouji; Kawabata, Koji S.; Kobayashi, Naoto; Iye, Masanori; Nomoto, Ken'ichi; Kawai, Nobuyuki

    2009-02-01

    We examined the variability of absorption line strength of intervening systems along the line of sight to GRB 060206 at z = 4.05, utilizing low-resolution optical spectra obtained by the Subaru telescope from six to ten hours after the burst. Strong variabilities of FeII and MgII lines at z = 1.48 during t = 5--8hr have been reported for this GRB, and those have been used to support the idea of clumpy MgII cloudlets, which was originally proposed to explain the anomalously high incidence of MgII absorbers in the GRB spectra compared to quasars. However, our spectra with a higher signal-to-noise ratio do not show any evidence for variability in t = 6--10hr. There is a clear discrepancy between our data and those of Hao et al. (2007, ApJ, 659, L99) in the overlapping time interval. Furthermore, the line strengths in our data are in agreement with those observed at t ˜ 2hr by Thöne et al. (2008, A&A, 489, 37). We also detected FeII and MgII absorption lines for a system at z = 2.26; these lines do not show evidence for variability either. Therefore, we conclude that there is no strong evidence for the variability in the intervening absorption lines toward GRB 060206, offering poor support for the MgII cloudlet hypothesis by the GRB 060206 data.

  17. A ghostly damped Ly α system revealed by metal absorption lines

    NASA Astrophysics Data System (ADS)

    Fathivavsari, H.; Petitjean, P.; Zou, S.; Noterdaeme, P.; Ledoux, C.; Krühler, T.; Srianand, R.

    2017-03-01

    We report the discovery of the first 'ghostly' damped Ly α absorption system (DLA), which is identified by the presence of absorption from strong low-ion species at zabs = 1.704 65 along the line of sight to the quasar SDSS J113341.29-005740.0 with zem = 1.704 41. No Ly α absorption trough is seen associated with these absorptions because the DLA trough is filled with the leaked emission from the broad emission-line region of the quasar. By modelling the quasar spectrum and analysing the metal lines, we derive log N(H I)(cm-2) ∼21.0 ± 0.3. The DLA cloud is small (≤0.32 pc), thus not covering entirely the broad-line region and is located at ≥39 pc from the central active galactic nucleus (AGN). Although the DLA is slightly redshifted relative to the quasar, its metallicity ([S/H] = -0.41 ± 0.30) is intermediate between what is expected from infalling and outflowing gas. It could be possible that the DLA is part of some infalling material accreting on to the quasar host galaxy through filaments, and that its metallicity is raised by mixing with the enriched outflowing gas emanating from the central AGN. Current DLA surveys miss these 'ghostly' DLAs, and it would be important to quantify the statistics of this population by searching the Sloan Digital Sky Survey (SDSS) data base using metal absorption templates.

  18. FOS Observations of the QSO 1442+101 (OQ 172)

    NASA Astrophysics Data System (ADS)

    Lyons, R. W.; Beaver, E. A.; Burbidge, E. M.; Cohen, R. D.; Junkkarinen, V. T.

    1992-12-01

    Low resolution far-UV spectra of the high redshift (zem=3.54) QSO OQ172 have been obtained with the prism and the G160L grating of the Faint Object Spectrograph on board the Hubble Space Telescope. Light is detected down to a rest wavelength near 323 Angstroms where the spectrum appears to be cut off, possibly by a Lyman limit system. This cutoff is only 18000 km sec(-1) in velocity units longward of the predicted He II lambda 304 feature (the He II lambda 304 Gunn-Peterson effect and the He II lambda 304 forest). A partial Lyman limit is observed near 2800 Angstroms. The UV spectra have been combined with Lick CCD optical spectra to determine the shape of the continuum short of Lyalpha and the applicability to it of the ``Lyman valley'' model presented by M\\o ller and Jakobsen (A&A 228, 299, 1990).

  19. Morphology of QSO host galaxies --- a look at the SED

    NASA Astrophysics Data System (ADS)

    Andrei, A.; Coelho, B.; Anton, S.

    2015-08-01

    The Gaia Initial QSO Catalogue presents several characteristics of its 1,248,372 listed objects, among which the optical morphological type. From this a program studies the host galaxies of QSOs present in the SDSS up to its 8th release, based on retrieving a data bank of images in the five ugriz colors for the 105,783 objects spectroscopically found as QSOs. The first scope of this program is to study QSOs for which the isophotes of the host galaxy are not pronounced, so that the centroid determination is not affected for those fundamental grid-points of the Gaia Celestial Reference Frame. Since the target images come from relatively short exposures, we developed an approach to access disturbances of the target PSF relatively to the nearby stars. Here we focus on the first results for absolute magnitude of QSOs combining the SDSS colors and the SED library from Gaia.

  20. APM Z >=4 QSO Survey: Spectra and Intervening Absorption Systems

    NASA Astrophysics Data System (ADS)

    Storrie-Lombardi, L. J.; McMahon, R. G.; Irwin, M. J.; Hazard, C.

    1996-09-01

    The APM multicolor survey for bright z > 4 objects, covering 2500 deg^2^ of sky to m_r_ ~ 19, resulted in the discovery of 31 quasars with z ~> 4. High signal-to-noise optical spectrophotometry at 5 A resolution has been obtained for the 28 quasars easily accessible from the northern hemisphere. These spectra have been surveyed to create new samples of high-redshift Lyman-limit systems, damped Lyα absorbers, and metal absorption systems (e.g., C IV and Mg II). In this paper we present the spectra, together with line lists of the detected absorption systems. The QSOs display a wide variety of emission- and absorption-line characteristics, with five exhibiting broad absorption lines and one with extremely strong emission lines (BR 2248 - 1242). Eleven candidate damped Lyα absorption systems have been identified covering the redshift range 2.8 <= z <= 4.4 (eight with z > 3.5). An analysis of the measured redshifts of the high-ionization emission lines with the low-ionization lines shows them to be blueshifted by 430 +/- 60 km s^-1^. In a previous paper (by Storrie-Lombardi et al.) we discussed the redshift evolution of the Lyman limit systems cataloged here. In subsequent papers we will discuss the properties of the Lyα forest absorbers and the redshift and column density evolution of the damped Lyα absorbers.

  1. Interstellar Absorption Lines in the Spectrum of the Starburst Galaxy NGC 1705

    NASA Astrophysics Data System (ADS)

    Sahu, M. S.

    1998-09-01

    A Goddard High Resolution Spectrograph archival study of the interstellar absorption lines in the line of sight to the H i-rich, starburst dwarf galaxy NGC 1705 in the 1170 to 1740 Å range at ~120 km s^-1 resolution is presented. The absorption features arising because of photospheric lines are distinctly different from the interstellar lines: the photospheric lines are weak, broad (equivalent widths >1 Å), asymmetric, and centered around the systemic LSR velocity of NGC 1705 (~610 km s^-1). The interstellar lines consist of three relatively narrow components at LSR velocities of -20, 260, and 540 km s^-1, and include absorption by neutral atoms (N i lambda1200 triplet and O i lambda1302), singly ionized atoms (Si ii lambdalambda1190, 1193, 1260, 1304, and 1526, S ii lambda1253, C ii lambda1334, C ii^* lambda1336, Fe ii lambda1608, and Al ii lambda1670), and atoms in higher ionization states (Si iii lambda1206, Si iv lambdalambda1393, 1402, and C iv lambdalambda1548, 1550). The Si iv and C iv absorption features have both interstellar and photospheric contributions. In an earlier study, Sahu & Blades identified the absorption system at -20 km s^-1 with Milky Way disk/halo gas, and the 260 km s^-1 system with a small, isolated high-velocity cloud HVC 487, which is probably associated with Magellanic Stream gas. The 540 km s^-1 absorption system is associated with a kiloparsec-scale expanding, ionized supershell centered on the super-star cluster NGC 1705-1. The analysis presented in this paper consists of (1) a list of all interstellar absorption features with greater than 3 sigma significance and their measured equivalent widths, (2) plots of the lines in the various atomic species together with the results of nonlinear least-squares fit profiles to the observed data, and (3) unpublished 21 cm maps from the Wakker & van Woerden survey showing the large-scale H i distribution in the region near the NGC 1705 sight line and HVC 487. Furthermore, weak N i lambda1200

  2. Confining hot spots in 3C 196 - Implications for QSO-companion galaxies

    NASA Technical Reports Server (NTRS)

    Brown, R. L.; Broderick, J. J.; Mitchell, K. J.

    1986-01-01

    VLBI observations of the extremely compact hot spot in the northern radio lobe of the QSO 3C 196 reveal the angular size of its smallest substructure to be 0.065 arcsec x 0.045 arcsec or about 300 pc at the redshift distance. The morphology of the hot spot and its orientation relative to the more diffuse radio emission suggest that it is formed by an oblique interaction between the nuclear QSO jet and circum-QSO cloud. The inferred density in this cloud, together with its apparent size, imply that the cloud contains a galactic mass, greater than a billion solar masses of gas. The effect of the jet will be to hasten gravitational collapse of the cloud. If many QSOs such as 3C 196 are formed or found in gas-rich environments, the QSO radio phase may commonly stimulate the metamorphosis of circum-QSO gas to QSO-companion galaxies or it may play a significant part in catalyzing star formation in existing companions.

  3. Confining hot spots in 3C 196 - implications for QSO-companion galaxies

    SciTech Connect

    Brown, R.L.; Broderick, J.J.; Mitchell, K.J.

    1986-07-01

    VLBI observations of the extremely compact hot spot in the northern radio lobe of the QSO 3C 196 reveal the angular size of its smallest substructure to be 0.065 arcsec x 0.045 arcsec or about 300 pc at the redshift distance. The morphology of the hot spot and its orientation relative to the more diffuse radio emission suggest that it is formed by an oblique interaction between the nuclear QSO jet and circum-QSO cloud. The inferred density in this cloud, together with its apparent size, imply that the cloud contains a galactic mass, greater than a billion solar masses of gas. The effect of the jet will be to hasten gravitational collapse of the cloud. If many QSOs such as 3C 196 are formed or found in gas-rich environments, the QSO radio phase may commonly stimulate the metamorphosis of circum-QSO gas to QSO-companion galaxies or it may play a significant part in catalyzing star formation in existing companions. 30 references.

  4. Broad absorption line variability on multi-year timescales in a large quasar sample

    NASA Astrophysics Data System (ADS)

    Filiz Ak, Nurten

    Outflows launched near the central supermassive black holes (SMBHs) are a common and important component of active galactic nuclei (AGNs). Outflows in luminous AGNs (i.e., quasars) play a key role in mass accretion onto SMBH as well as in the feedback into host galaxies. The most prominent signature of such outflows appears as broad absorption lines (BALs) that are blueshifted from the emission line with a few thousands km s--1 velocities. In this dissertation, I place further constrains upon the size scale, internal structure, dynamics, and evolution of the outflows investigating profiles, properties, and variation characteristics of BAL troughs. I present observational results on BAL troughs in a large quasar sample utilizing spectroscopic observations from the Sloan Digital Sky Survey spanning on multi-year timescales. The results presented here, for the first time, provide a large and well-defined variability data base capable of discriminating between time-dependent hydrodynamic wind calculations in a statistically powerful manner. In a study of 582 quasars, I present 21 examples of BAL trough disappearance. Approximately 3.3% of BAL quasars show disappearing C IV trough on rest-frame timescales of 1.1--3.9 yr. BAL disappearance appears to occur mainly for shallow and weak or moderate-strength absorption troughs but not the strongest ones. When one BAL trough in a quasar spectrum disappears, the other present troughs usually weaken. Possible causes of such coordinated variations could be disk-wind rotation or variations of shielding gas that lead to variations of ionizing-continuum radiation. I present a detailed study on the variability of 428 C IV and 235 Si IV BAL troughs using a systematically observed sample of 291 BAL quasars. BAL variation distributions indicate that BAL disappearance is an extreme type of general BAL variability, rather than a qualitatively distinct phenomenon. The high observed frequency of BAL variability on multi-year timescales is

  5. A new limit on the variation of the fine-structure constant using absorption line multiplets in the early universe

    NASA Astrophysics Data System (ADS)

    Thong, Le Duc

    2015-08-01

    One of the key questions of modern physics concerns the possibility that physical constants vary over space and time during the history of the universe. The Standard Model of physics is built on these constants, but it does not provide any explanation for their values, nor requires their constancy over space and time. Here we set a new limit on possible spatial and temporal variations of the fine-structure constant , by comparing transitions line multiplets in an ensemble of Fe II 1608, 2344, 2374, 2383, 2587 and 2600 observed in the early universe with those measured in the laboratory. Based on the optical spectra observations of QSO HE 0515-4414, we deduced a constraint of at redshift z = 1.15. This is at present the tightest limit on at early cosmological epochs compared to the published results in the literature.

  6. No Evidence for Variability of Intervening Absorption Lines toward GRB 060206: Implications for the Mg II Incidence Problem

    NASA Astrophysics Data System (ADS)

    Aoki, K.; Totani, T.; Hattori, T.; Ohta, K.; Kawabata, K. S.; Kobayashi, N.; Iye, M.; Nomoto, K.; Kawai, N.

    2009-05-01

    We examine variability of absorption line strength of intervening systems along the line of sight to GRB 060206 at z = 4.05, by the low-resolution optical spectra obtained by the Subaru telescope from six to ten hours after the burst. Strong variabilities of Fe II and Mg II lines at z = 1.48 during t = 5-8 hours have been reported for this GRB [8], and this has been used to support the idea of clumpy Mg II cloudlets that was originally proposed to explain the anomalously high incidence of Mg II absorbers in GRB spectra compared with quasars. However, our spectra with higher signal-to-noise ratio do not show any evidence for variability in t = 6-10 hours. There is a clear discrepancy between our data and Hao et al. data in the overlapping time interval. Furthermore, the line strengths in our data are in good agreement with those observed at t~2 hours by Thone et al. [22]. Therefore we conclude that there is no strong evidence for variability of intervening absorption lines toward GRB 060206, significantly weakening the support to the Mg II cloudlet hypothesis by the GRB 060206 data.

  7. Intergalactic medium emission observations with the cosmic web imager. I. The circum-QSO medium of QSO 1549+19, and evidence for a filamentary gas inflow

    SciTech Connect

    Martin, D. Christopher; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.

    2014-05-10

    The Palomar Cosmic Web Imager (PCWI), an integral field spectrograph designed to detect and map low surface brightness emission, has obtained imaging spectroscopic maps of Lyα from the circum-QSO medium (CQM) of QSO HS1549+19 at redshift z = 2.843. Extensive extended emission is detected from the CQM, consistent with fluorescent and pumped Lyα produced by the ionizing and Lyα continuum of the QSO. Many features present in PCWI spectral images match those detected in narrow-band images. Filamentary structures with narrow line profiles are detected in several cases as long as 250-400 kpc. One of these is centered at a velocity redshifted with respect to the systemic velocity, and displays a spatially collimated and kinematically cold line profile increasing in velocity width approaching the QSO. This suggests that the filament gas is infalling onto the QSO, perhaps in a cold accretion flow. Because of the strong ionizing flux, the neutral column density is low, typically N(H I)∼10{sup 12}--10{sup 15} cm{sup −2}, and the line center optical depth is also low (typically τ{sub 0} < 10), insufficient to display well separated double peak emission characteristic of higher line optical depths. With a simple ionization and cloud model we can very roughly estimate the total gas mass (log M {sub gas} = 12.5 ± 0.5) and the total (log M {sub tot} = 13.3 ± 0.5). We can also calculate a kinematic mass from the total line profile (2 × 10{sup 13} M {sub ☉}), which agrees with the mass estimated from the gas emission. The intensity-binned spectrum of the CQM shows a progression in kinematic properties consistent with heirarchical structure formation.

  8. INVISIBLE ACTIVE GALACTIC NUCLEI. II. RADIO MORPHOLOGIES AND FIVE NEW H i 21 cm ABSORPTION LINE DETECTORS

    SciTech Connect

    Yan, Ting; Stocke, John T.; Darling, Jeremy; Momjian, Emmanuel; Sharma, Soniya; Kanekar, Nissim

    2016-03-15

    This is the second paper directed toward finding new highly redshifted atomic and molecular absorption lines at radio frequencies. To this end, we selected a sample of 80 candidates for obscured radio-loud active galactic nuclei (AGNs) and presented their basic optical/near-infrared (NIR) properties in Paper I. In this paper, we present both high-resolution radio continuum images for all of these sources and H i 21 cm absorption spectroscopy for a few selected sources in this sample. A-configuration 4.9 and 8.5 GHz Very Large Array continuum observations find that 52 sources are compact or have substantial compact components with size <0.″5 and flux densities >0.1 Jy at 4.9 GHz. The 36 most compact sources were then observed with the Very Long Baseline Array at 1.4 GHz. One definite and 10 candidate Compact Symmetric Objects (CSOs) are newly identified, which is a detection rate of CSOs ∼three times higher than the detection rate previously found in purely flux-limited samples. Based on possessing compact components with high flux densities, 60 of these sources are good candidates for absorption-line searches. Twenty-seven sources were observed for H i 21 cm absorption at their photometric or spectroscopic redshifts with only six detections (five definite and one tentative). However, five of these were from a small subset of six CSOs with pure galaxy optical/NIR spectra (i.e., any AGN emission is obscured) and for which accurate spectroscopic redshifts place the redshifted 21 cm line in a radio frequency intereference (RFI)-free spectral “window” (i.e., the percentage of H i 21 cm absorption-line detections could be as high as ∼90% in this sample). It is likely that the presence of ubiquitous RFI and the absence of accurate spectroscopic redshifts preclude H i detections in similar sources (only 1 detection out of the remaining 22 sources observed, 13 of which have only photometric redshifts); that is, H i absorption may well be present but is masked by

  9. H{beta} LINE WIDTHS AS AN ORIENTATION INDICATOR FOR LOW-IONIZATION BROAD ABSORPTION LINE QUASARS

    SciTech Connect

    Punsly, Brian; Zhang Shaohua E-mail: brian.punsly@comdev-usa.co

    2010-12-20

    There is evidence from radio-loud quasars to suggest that the distribution of the H{beta} broad emission line (BEL) gas is arranged in a predominantly planar orientation, and this result may well also apply to radio-quiet quasars. This would imply that the observed FWHM of the H{beta} BELs is dependent on the orientation of the line of sight to the gas. If this view is correct then we propose that the FWHM can be used as a surrogate, in large samples, to determine the line of sight to the H{beta} BELs in broad absorption line quasars (BALQSOs). The existence of broad UV absorption lines (BALs) means that the line of sight to BALQSOs must also pass through the BAL out-flowing gas. It is determined that there is a statistically significant excess of narrow-line profiles in the SDSS DR7 archival spectra of low-ionization broad absorption line quasars (LoBALQSOs), indicating that BAL gas flowing close to the equatorial plane does not commonly occur in these sources. We also find that the data is not well represented by random lines of sight to the BAL gas. Our best fit indicates two classes of LoBALQSOs, the majority ({approx}2/3) are polar outflows that are responsible for the enhanced frequency of narrow-line profiles, and the remainder are equatorial outflows. We further motivated the line of sight explanation of the narrow-line excess in LoBALQSOs by considering the notion that the skewed distribution of line profiles is driven by an elevated Eddington ratio in BALQSOs. We constructed a variety of control samples comprised of non-LoBALQSOs matched to a de-reddened LoBALQSO sample in redshift, luminosity, black hole mass, and Eddington ratio. It is demonstrated that the excess of narrow profiles persists within the LoBALQSO sample relative to each of the control samples with no reduction of the statistical significance. Thus, we eliminate the possibility that the excess narrow lines seen in the LoBALQSOs arise from an enhanced Eddington ratio.

  10. The x ray properties of a large, uniform QSO sample: Einstein observations of the LBQS

    NASA Technical Reports Server (NTRS)

    Margon, B.; Anderson, S. F.; Xu, X.; Green, P. J.; Foltz, C. B.

    1992-01-01

    Although there are large numbers of Quasi Stellar Objects (QSO's) now observed in X rays, extensive X-ray observations of uniformly selected, 'complete' QSO samples are more rare. The Large Bright QSO Survey (LBQS) consists of about 1000 objects with well understood properties, most brighter than B = 18.8 and thus amenable to X-ray detections in relatively brief exposures. The sample is thought to be highly complete in the range 0.2 less than z less than 3.3, a significantly broader interval than many other surveys. The Einstein IPC observed 150 of these objects, mostly serendipitously, during its lifetime. We report the results of an analysis of these IPC data, considering not only the 20 percent of the objects we find to have positive X-ray detections, but also the ensemble X-ray properties derived by 'image stacking'.

  11. Monitoring of the extreme alpha_ox variations in the luminous NL QSO PHL 1092

    NASA Astrophysics Data System (ADS)

    Miniutti, Giovanni

    2009-10-01

    During a 2008 XMM-Newton observation the luminous Narrow-Line quasar PHL 1092 showed a dramatic X-ray flux drop by a factor ~200 with respect to previous X-ray observations, becoming one of the most extreme X-ray weak QSO (alpha_ox = -2.44), after being X-ray "normal" (alpha_ox = -1.56) only 4.5 years earlier. Note that the extreme 2008 X-ray weakness corresponds to a factor ~320 with respect to the expected X-ray flux of QSO with the given luminosity. The aim of this proposal is to continue our UV and X-ray monitoring of this extreme source with two 25 ks exposures (one for each visibility window, hence separated by about 6 months) to unveil the timescale over which transitions from X-ray weak to normal QSO states take place in this most extraordinary AGN.

  12. Detection of neutral hydrogen emission and optical nebulosity in the low redshift QSO 0351+026

    NASA Technical Reports Server (NTRS)

    Bothun, G. D.; Chanan, G. A.; Romanishin, W.; Margon, B.; Schommer, R. A.

    1982-01-01

    Spectroscopy, photometry, and imaging of the X-ray source 0351+026 are consistent with an active nucleus with the spectrum of a QSO or type I Seyfert, embedded in a low luminosity host galaxy of colors similar to M31. The H I observations reveal a tremendous amount of neutral gas associated with the system, M(H I)/L(B) = 15 in solar units, and the velocity width of the feature is 1500 km/s. Both parameters substantially exceed those seen in other galaxies and interacting pairs. The unique H I properties of the system combined with the presence of an active nucleus with QSO-like features is a tantalizing, but poorly understood, combination. At slightly larger redshift and thus inferior angular scale, this object would be indistinguishable from a QSO in its optical and X-ray characteristics.

  13. Optical frequency standard by using a 1560 nm diode laser locked to saturated absorption lines of rubidium vapor

    SciTech Connect

    Masuda, Shin; Seki, Atsushi; Niki, Shoji

    2007-07-20

    A robust, compact, highly accurate rubidium optical frequency standard module was developed to overcome the delicate performance of conventional frequency stabilized lasers. A frequency doubled1560 nm distributed feedback diode laser locked to a rubidium D2 saturated absorption line without using an optical amplifier was demonstrated, and dithering-free optical output was obtained. In addition, the sensitivity of the developed optical frequency standard to magnetic fields was investigated. We confirmed that the influence of the magnetic fields on the optical frequency standard can be almost negligible when using appropriate magnetic-shield films. As a result, the magnetic-field-insensitive optical frequency standard, which can be embedded in optical systems,exhibiting uncertainty less than at least 100 kHz, was successfully realized for the first time to the best of our knowledge.

  14. Dramatically Variable C IV Mini-Broad Absorption Line System in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, T.; Eracleous, M.; Charlton, J. C.; Chartas, G.; Kashikawa, N.

    2008-10-01

    We observed the quasar HS 1603+3820 (z_{em} = 2.542, first discovered by Dobrzycki et al. 1996) six times over an interval of 4.2 yrs (1.2 yrs in the quasar rest frame) using the High Dispersion Spectrograph on Subaru telescope. The purpose was to study the mini-broad absorption line (mini-BAL; FWHM ˜ 1,000 km s^{-1}) that is blue-shifted from the quasar by ˜ 9,500 km s^{-1}. We found significant time variability, which supported the physical association of the mini-BAL gas with an outflow from the quasar. We have narrowed down the cause of the variability to two possible scenarios. We also used archival Chandra x-ray data to study the x-ray properties of this quasar. The results constrain the location of the absorbing gas relative to the overall outflow.

  15. Time-averaging approximation in the interaction picture: absorption line shapes for coupled chromophores with application to liquid water.

    PubMed

    Yang, Mino; Skinner, J L

    2011-10-21

    The time-averaging approximation (TAA), originally developed to calculate vibrational line shapes for coupled chromophores using mixed quantum/classical methods, is reformulated. In the original version of the theory, time averaging was performed for the full one-exciton Hamiltonian, while herein the time averaging is performed on the coupling (off-diagonal) Hamiltonian in the interaction picture. As a result, the influence of the dynamic fluctuations of the transition energies is more accurately described. We compare numerical results of the two versions of the TAA with numerically exact results for the vibrational absorption line shape of the OH stretching modes in neat water. It is shown that the TAA in the interaction picture yields theoretical line shapes that are in better agreement with exact results.

  16. HIGHLY IONIZED Fe-K ABSORPTION LINE FROM CYGNUS X-1 IN THE HIGH/SOFT STATE OBSERVED WITH SUZAKU

    SciTech Connect

    Yamada, S.; Yoshikawa, A.; Makishima, K.; Torii, S.; Noda, H.; Mineshige, S.; Ueda, Y.; Kubota, A.; Gandhi, P.; Done, C.

    2013-04-20

    We present observations of a transient He-like Fe K{alpha} absorption line in Suzaku observations of the black hole binary Cygnus X-1 on 2011 October 5 near superior conjunction during the high/soft state, which enable us to map the full evolution from the start to the end of the episodic accretion phenomena or dips for the first time. We model the X-ray spectra during the event and trace their evolution. The absorption line is rather weak in the first half of the observation, but instantly deepens for {approx}10 ks, and weakens thereafter. The overall change in equivalent width is a factor of {approx}3, peaking at an orbital phase of {approx}0.08. This is evidence that the companion stellar wind feeding the black hole is clumpy. By analyzing the line with a Voigt profile, it is found to be consistent with a slightly redshifted Fe XXV transition, or possibly a mixture of several species less ionized than Fe XXV. The data may be explained by a clump located at a distance of {approx}10{sup 10-12} cm with a density of {approx}10{sup (-13)-(-11)} g cm{sup -3}, which accretes onto and/or transits the line of sight to the black hole, causing an instant decrease in the observed degree of ionization and/or an increase in density of the accreting matter. Continued monitoring for individual events with future X-ray calorimeter missions such as ASTRO-H and AXSIO will allow us to map out the accretion environment in detail and how it changes between the various accretion states.

  17. A SURVEY OF METAL LINES AT HIGH REDSHIFT. II. SDSS ABSORPTION LINE STUDIES-O VI LINE DENSITY, SPACE DENSITY, AND GAS METALLICITY AT z{sub abs} {approx} 3.0

    SciTech Connect

    Frank, S.; Mathur, S.; Pieri, M.; York, D. G.

    2010-09-15

    studies. These results demonstrate that large spectroscopic data sets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution.

  18. A Stringent Limit on Variation of the Fine-Structure Constant Using Absorption Line Multiplets in the Early Universe

    NASA Astrophysics Data System (ADS)

    Le, T. D.

    2016-06-01

    One of the key questions of modern physics concerns the possibility that physical constants have varied throughout the history of the Universe. The standard model of physics is built on these constants, but it does not provide any explanation for their values, nor does it require their constancy over space and time. Here, we set a new limit on possible spatial and temporal variations of the fine-structure constant α = e 2/4πɛ0 ħc by comparing transitions and line multiplets in an ensemble of Fe II λ 1608, λ 2344, λ 2374, λ 2383, λ 2587, and λ 2600 observed in the early Universe with those measured in the laboratory. Based on the optical spectrum observations of QSO HE 0515-4414, we deduce a constraint of Δα/α = (-0.157± 0.300)×10-6 at redshift z = 1.15. At present, this represents the tightest limit on Δα/α in early cosmological epochs compared to the published results in the literature.

  19. Beyond the single-atom response in absorption line shapes: probing a dense, laser-dressed helium gas with attosecond pulse trains.

    PubMed

    Liao, Chen-Ting; Sandhu, Arvinder; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2015-04-10

    We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently, to the appearance of new, narrow features in the absorption line.

  20. The z = 1.6748 C I Absorber Toward the QSO PKS 1756+237

    NASA Astrophysics Data System (ADS)

    Roth, Katherine C.; Bauer, James M.; Jim, Kevin T. C.

    We have detected C I ground-state absorption at zabs = 1.6748 toward the QSO PKS 1756+237 (zem = 1.725), making this only the fourth known C I QSO absorber. The absence of excited-state fine-structure C I lines is compatible with the redshifted Cosmic Microwave Background Radiation at an expected temperature of TCMBR (1+z) = 7.291 K (Mather et al. 1994, ApJ, 354, L37). We find a 2 σ upper-limit on the C I excitation temperature of Tex <= 7.73(+0.53, -0.46) K (Roth & Bauer 1999, ApJ, submitted). Our Keck HIRES spectra (8.3 km s-1 FWHM) obtained in May 1997 also reveal the existence of Ni II and Fe II lines with a sub-solar Ni/Fe abundance ratio, presumably indicative of dust. We have obtained deep, high resolution (0.3'' FWHM) images in H+K' with the UH 2.2m Tip-Tilt system of the QSO field in order to identify the system responsible for the zabs = 1.6748 absorption. We detect two faint candidate systems within 1.5'' and 3'' (≅ 15 and 30 kpc, Hcirc = 65) of the QSO.

  1. A NIR Flare of the QSO [HB89] 0234+285

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Porras, A.; Recillas, E.; Chavushyan, V.; Mayya, D. Y.

    2017-02-01

    We report on the recent NIR flare of the high redshift QSO (z=1.213) [hb89]0234+285 also known as BZQJ0237+2848, cross correlated with the radio source 4C+28.07 and the Gamma-ray source 2FGLJ0237.4+2846.

  2. Evidence for the presence of dust in intervening QSO absorbers from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Khare, P.; York, D. G.; vanden Berk, D.; Kulkarni, V. P.; Crotts, A. P. S.; Welty, D. E.; Lauroesch, J. T.; Richards, G. T.; Alsayyad, Y.; Kumar, A.; Lundgren, B.; Shanidze, N.; Vanlandingham, J.; Baugher, B.; Hall, P. B.; Jenkins, E. B.; Menard, B.; Rao, S.; Turnshek, D.; Yip, C. W.

    2005-03-01

    We find evidence for dust in the intervening QSO absorbers from the spectra of QSOs in the Sloan Digital Sky Survey Data Release 1. No evidence is found for the 2175 Å feature which is present in the Milky Way dust extinction curve.

  3. Infrared flaring of the potential gamma-ray source QSO B0133+47

    NASA Astrophysics Data System (ADS)

    Carramiñana, A.; Carrasco, L.; Recillas, E.; Chavushyan, V.

    2008-12-01

    We call attention on our recent observations of QSO B0133+47 with the Cananea NIR camera (CANICA) on the 2.1m telescope at the Observatorio Astrofísico Guillermo Haro. We found this quasar to show fluxes 2.5 magnitudes brighter than 2MASS values, of epoch 1999, but undergoing a rapid decline.

  4. GEMINI 3D spectroscopy of BAL + IR + FeII QSOs - I. Decoupling the BAL, QSO, starburst, NLR, supergiant bubbles and galactic wind in Mrk 231

    NASA Astrophysics Data System (ADS)

    Lipari, S.; Sanchez, S. F.; Bergmann, M.; Terlevich, R.; Garcia-Lorenzo, B.; Punsly, B.; Mediavilla, E.; Taniguchi, Y.; Ajiki, M.; Zheng, W.; Acosta, J.; Jahnke, K.

    2009-02-01

    In this paper we present the first results of a study of BAL QSOs (at low and high redshift), based on very deep Gemini GMOS integral field spectroscopy. In particular, the results obtained for the nearest BAL IR-QSO Mrk 231 are presented. For the nuclear region of Mrk 231, the QSO and host galaxy components were modelled, using a new technique of decoupling 3D spectra. From this study, the following main results were found: (i) in the pure host galaxy spectrum an extreme nuclear starburst component was clearly observed, as a very strong increase in the flux, at the blue wavelengths; (ii) the BAL system I is observed in the spectrum of the host galaxy; (iii) in the clean/pure QSO emission spectrum, only broad lines were detected. 3D GMOS individual spectra (specially in the near-infrared CaII triplet) and maps confirm the presence of an extreme and young nuclear starburst (8 < age < 15 Myr), which was detected in a ring or toroid with a radius r = 0.3arcsec ~ 200 pc, around the core of the nucleus. The extreme continuum blue component was detected only to the south of the core of the nucleus. This area is coincident with the region where we previously suggested that the galactic wind is cleaning the nuclear dust. Very deep 3D spectra and maps clearly show that the BAL systems I and II - in the strong `absorption lines' NaIDλ5889-95 and CaII Kλ3933 - are extended (reaching ~1.4-1.6 arcsec ~ 1.2-1.3 kpc, from the nucleus) and clearly elongated at the position angle (PA) close to the radio jet PA, which suggest that the BAL systems I and II are `both' associated with the radio jet. The physical properties of the four expanding nuclear bubbles were analysed, using the GMOS 3D spectra and maps. In particular, we found strong multiple LINER/OF emission-line systems and Wolf-Rayet features in the main knots of the more external super bubble S1 (r = 3.0 kpc). The kinematics of these knots - and the internal bubbles - suggest that they are associated with an area of

  5. A Census of Intrinsic Narrow Absorption Lines in the Spectra of Quasars at z = 2-4

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Charlton, Jane C.; Eracleous, Michael; Ganguly, Rajib; Tytler, David; Kirkman, David; Suzuki, Nao; Lubin, Dan

    2007-07-01

    We use Keck HIRES spectra of 37 optically bright quasars at z=2-4 to study narrow absorption lines that are intrinsic to the quasars (intrinsic NALs, produced in gas that is physically associated with the quasar central engine). We identify 150 NAL systems, which contain 124 C IV, 12 N V, and 50 Si IV doublets, of which 18 are associated systems (within 5000 km s-1 of the quasar redshift). We use partial coverage analysis to separate intrinsic NALs from NALs produced in cosmologically intervening structures. We find 39 candidate intrinsic systems (28 reliable determinations and 11 that are possibly intrinsic). We estimate that 10%-17% of C IV systems at blueshifts of 5000-70,000 km s-1 relative to quasars are intrinsic. At least 32% of quasars contain one or more intrinsic C IV NALs. Considering N V and Si IV doublets showing partial coverage as well, at least 50% of quasars host intrinsic NALs. This result constrains the solid angle subtended by the absorbers to the background source(s). We identify two families of intrinsic NAL systems, those with strong N V absorption and those with negligible absorption in N V but with partial coverage in the C IV doublet. We discuss the idea that these two families represent different regions or conditions in accretion disk winds. Of the 26 intrinsic C IV NAL systems, 13 have detectable low-ionization absorption lines at similar velocities, suggesting that these are two-phase structures in the wind rather than absorbers in the host galaxy. We also compare possible models for quasar outflows, including radiatively accelerated disk-driven winds, magnetocentrifugally accelerated winds, and pressure-driven winds, and we discuss ways of distinguishing between these models observationally. The data presented here 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

  6. Atmospheric Profiling Combining the Features of GPS ro & Mls: Satellite to Satellite Occultations Near Water & Ozone Absorption Lines

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Reed, H.; Erickson, D.

    2015-12-01

    Assessing climate models & their predictions requires observations that determine the state of the real climate system precisely and unambiguously, independently from models. For this purpose, we have been developing a new orbiting remote sensing system called the Active Temperature, Ozone & Moisture Microwave Spectrometer (ATOMMS) which is a cross between GPS RO and the Microwave Limb Sounder. ATOMMS actively probes water vapor, ozone & other absorption lines at cm & mm wavelengths in a satellite to satellite occultation geometry to simultaneously profile temperature, pressure, water vapor and ozone as well as other important constituents. Individual profiles of water vapor, temperature & pressure heights will extend from near the surface into the mesosphere with ~1%, 0.4K and 10 m precision respectively and still better accuracy, with 100 m vertical resolution. Ozone profiles will extend upward from the upper troposphere. Line of sight wind profiles will extend upwards from the mid-stratosphere. ATOMMS is a doubly differential absorption system which eliminates drift and both sees clouds and sees thru them, to deliver performance in clouds within a factor of 2 of the performance in clear skies. This all-weather sampling combined with insensitivity to surface emissivity avoids sampling biases that limit most existing satellite records. ATOMMS will profile slant liquid water in clouds & rain and as well as turbulence via scintillations ("twinkling of a star"). Using prototype ATOMMS instrumentation that we developed with funding from NSF, several ATOMMS ground field campaigns precisely measured water vapor, cloud amount, rainfall, turbulence and absorption line spectroscopy. ATOMMS's dynamic range was demonstrated as water vapor was derived to 1% precision in optical depths up to 17. We are developing high altitude aircraft to aircraft instrumentation to further demonstrate ATOMMS performance, refine spectroscopy & support future field campaigns. Our vision is a

  7. Imaging Polarimetry of Scattered Light from the Buried QSO in IRAS F15307+3252

    NASA Astrophysics Data System (ADS)

    Gerber, Jeffrey; Hines, D. C.

    2013-01-01

    We present new imaging polarimetry observations of the Hyperluminous Infrared Galaxy and Type 2 QSO IRAS F15307+3252 (z = 0.9257). The observations were obtained with the High-Resolution Camera (HRC) of the Advance Camera for Surveys (ACS) aboard the Hubble Space Telescope (HST). The images show strongly polarized (p ≥ 20%) light extending ~8 kpc southwest from the center of the galaxy. The overall shape suggests that the extended emission has a single-sided, conical structure of apparent half-opening angle ~16 degrees and apex centered at the galaxy nucleus. The polarization position angle (at each resolution element) is perpendicular to the axis of the extended emission, implying that the structure is illuminated by a central source in the galaxy nucleus that is not seen directly. F15307+3252 is known to harbor a buried QSO that was revealed in a polarized spectrum by Hines et al. (1995); the degree of polarization and position angle of this polarized spectrum match those of the extended structure seen in our new HST/ACS data. We thus conclude that this extended emission is light from the buried QSO that is scattered (thus polarized) into our line of sight, and importantly, this object would be classified optically as a Type 1 QSO if viewed from the vantage point of the scattering material. The conical structure of the scattered light suggests that the material blocking our direct line of sight to the QSO has a spatial distribution similar to the dusty torus in lower redshift Active Galactic Nuclei (AGNs). Assuming that the scattered-light-cone half-opening angle is the same as the dusty torus half-opening angle, we derive a dust-covering fraction of ≥ 95%. This, and comparison between the observed spectral energy distribution of F15307+3252 and that of a composite Type 1 QSO, suggests that the majority of the luminosity in F15307+3252 is powered by the central QSO. Deep HST/ACS images in total light also show clearly that F15307+3252 sits at the center of a

  8. Effect of buffer gases on broadening of the Iodine-127 resonance absorption line at a 633-nm He-Ne laser wavelength

    SciTech Connect

    Kireev, S.V.; Shnyrev, S.L.; Zaspa, Yu.P.

    1995-04-01

    Collisional broadening coefficients are measured for iodine-127 resonance absorption lines in several rare cases of atmospheric air and CO{sub 2}. The results obtained are used to determine the optimum pressure of a gaseous mixture in a measuring cell for detecting iodine-127 by a helium-neon (633 nm) laser-induced fluorescence technique of monitoring iodine in atmospheric air.

  9. Ca II AND Na I QUASAR ABSORPTION-LINE SYSTEMS IN AN EMISSION-SELECTED SAMPLE OF SDSS DR7 GALAXY/QUASAR PROJECTIONS. I. SAMPLE SELECTION

    SciTech Connect

    Cherinka, B.; Schulte-Ladbeck, R. E.

    2011-10-15

    The aim of this project is to identify low-redshift host galaxies of quasar absorption-line systems by selecting galaxies that are seen in projection onto quasar sightlines. To this end, we use the Seventh Data Release of the Sloan Digital Sky Survey to construct a parent sample of 97,489 galaxy/quasar projections at impact parameters of up to 100 kpc to the foreground galaxy. We then search the quasar spectra for absorption-line systems of Ca II and Na I within {+-}500 km s{sup -1} of the galaxy's velocity. This yields 92 Ca II and 16 Na I absorption systems. We find that most of the Ca II and Na I systems are sightlines through the Galactic disk, through high-velocity cloud complexes in our halo, or Virgo Cluster sightlines. Placing constraints on the absorption line rest equivalent width significance ({>=}3.0{sigma}), the local standard of rest velocity along the sightline ({>=}345 km s{sup -1}), and the ratio of the impact parameter to the galaxy optical radius ({<=}5.0), we identify four absorption-line systems that are associated with low-redshift galaxies at high confidence, consisting of two Ca II systems (one of which also shows Na I) and two Na I systems. These four systems arise in blue, {approx}L*{sub r} galaxies. Tables of the 108 absorption systems are provided to facilitate future follow-up.

  10. Selection of the optimal combination of water vapor absorption lines for detection of temperature in combustion zones of mixing supersonic gas flows by diode laser absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Mironenko, V. R.; Kuritsyn, Yu. A.; Bolshov, M. A.; Liger, V. V.

    2016-12-01

    Determination of a gas medium temperature by diode laser absorption spectrometry (DLAS) is based on the measurement of integral intensities of the absorption lines of a test molecule (generally water vapor molecule). In case of local thermodynamic equilibrium temperature is inferred from the ratio of the integral intensities of two lines with different low energy levels. For the total gas pressure above 1 atm the absorption lines are broadened and one cannot find isolated well resolved water vapor absorption lines within relatively narrow spectral interval of fast diode laser (DL) tuning range (about 3 cm-1). For diagnostics of a gas object in the case of high temperature and pressure DLAS technique can be realized with two diode lasers working in different spectral regions with strong absorption lines. In such situation the criteria of the optimal line selection differs significantly from the case of narrow lines. These criteria are discussed in our work. The software for selection the optimal spectral regions using the HITRAN-2012 and HITEMP data bases is developed. The program selects spectral regions of DL tuning, minimizing the error of temperature determination δT/T, basing on the attainable experimental error of line intensity measurement δS. Two combinations of optimal spectral regions were selected - (1.392 & 1.343 μm) and (1.392 & 1.339 μm). Different algorithms of experimental data processing are discussed.

  11. VARIABLE REDDENING AND BROAD ABSORPTION LINES IN THE NARROW-LINE SEYFERT 1 GALAXY WPVS 007: AN ORIGIN IN THE TORUS

    SciTech Connect

    Leighly, Karen M.; Cooper, Erin; Grupe, Dirk; Terndrup, Donald M.; Komossa, S.

    2015-08-10

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ∼2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director’s Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the C iv emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variable scale height, and the BAL gas is blown from the torus material like spray from the crest of a wave. As the obscuring material passes into our line of sight, we alternately see high-velocity broad absorption lines and a clear view to the central engine, or low-velocity broad absorption lines and strong reddening. WPVS 007 has a small black hole mass, and correspondingly short timescales, and so we may be observing behavior that is common in BALQSOs, but is not typically observable.

  12. Atmospheric profiling via satellite to satellite occultations near water and ozone absorption lines for weather and climate

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Stovern, M.; Sammler, K.; Reed, H.; Erickson, D.; McCormick, C.; Griggs, E.

    2016-05-01

    Significantly reducing weather and climate prediction uncertainty requires global observations with substantially higher information content than present observations provide. While GPS occultations have provided a major advance, GPS observations of the atmosphere are limited by wavelengths chosen specifically to minimize interaction with the atmosphere. Significantly more information can be obtained via satellite to satellite occultations made at wavelengths chosen specifically to characterize the atmosphere. Here we describe such a system that will probe cm- and mmwavelength water vapor absorption lines called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). Profiling both the speed and absorption of light enables ATOMMS to profile temperature, pressure and humidity simultaneously, which GPS occultations cannot do, as well as profile clouds and turbulence. We summarize the ATOMMS concept and its theoretical performance. We describe field measurements made with a prototype ATOMMS instrument and several important capabilities demonstrated with those ground based measurements including retrieving temporal variations in path-averaged water vapor to 1%, in clear, cloudy and rainy conditions, up to optical depths of 17, remotely sensing turbulence and determining rain rates. We conclude with a vision of a future ATOMMS low Earth orbiting satellite constellation designed to take advantage of synergies between observational needs for weather and climate, ATOMMS unprecedented orbital remote sensing capabilities and recent cubesat technological innovations that enable a constellation of dozens of very small spacecraft to achieve many critical, but as yet unfulfilled, monitoring and forecasting needs.

  13. XMM-NEWTON OBSERVATIONS OF THE RADIO-LOUD BROAD ABSORPTION LINE QUASAR FBQS J131213.5+231958

    SciTech Connect

    Mathur, Smita; Dai Xinyu E-mail: dai@nhn.ou.ed

    2010-12-15

    We present XMM-Newton observations of the broad absorption line (BAL) quasar FBQS J131213.5+231958. The X-ray spectrum of the source can be well described by an absorbed power-law model in which the absorber is either ionized or only partially covers the continuum source. This can explain the apparent lack of absorption observed in the Chandra spectrum with low signal-to-noise ratio. While the power-law slope of the spectrum is similar to that of non-BAL radio-loud quasars, the Eddington luminosity ratio is likely to be significantly higher than the mean. This shows that in high-mass black holes (BHs), high Eddington accretion may not result in as steep of a spectrum as in lower-mass BHs. This provides important constraints for accretion disk models. It also provides support to the idea that BAL quasars, at least their radio-loud subclass, represent an early evolutionary stage of quasars.

  14. Highly Ionized Iron Absorption Lines from Outflowing Gases in the X-ray Spectrum of NGC 1365

    NASA Technical Reports Server (NTRS)

    Risaliti, G.; Bianchi, S.; Matt, G.; Baldi, A.; Elvis, M.; Fabbiano, G.; Zezas, A.

    2006-01-01

    We present the discovery of four absorption lines in the X-ray spectrum of the Seyfert galaxy NGC 1365, at energies between 6.7 and 8.3 keV. The lines are detected with high statistical confidence (from >20 sigma for the strongest to -4 sigma for the weakest) in two XMM-Newton observations 60 ks long. We also detect the same lines, with a lower signal-to-noise ratio (but still >2 sigma for each line), in two previous shorter (-10 ks) XMM-Newton observations. The spectral analysis identifies these features as Fe XXV and Fe XXVI Kalpha and Kbeta lines, outflowing with velocities varying between -1000 and -5000 km/s among the observations. These are the highest quality detections of such lines so far. The high equivalent widths [EW (Kalpha) approximately 100 eV] and the Kalpha/Kbeta ratios imply that the lines are due to absorption of the AGN continuum by a highly ionized gas with column density NH-5?1023 cm(exp -2) at a distance of -(50-100)RS from the continuum source.

  15. X-ray absorption lines suggest matter infalling onto the central black-hole of Mrk 509

    NASA Astrophysics Data System (ADS)

    Dadina, M.; Cappi, M.; Malaguti, G.; Ponti, G.; de Rosa, A.

    2005-11-01

    Evidence for both red- and blue-shifted absorption lines due to ionized Fe in the X-ray spectrum of the Seyfert 1 galaxy Mrk 509 is reported. These features appear to be transient on time-scales as short as ~20 ks, and have been observed with two different satellites, BeppoSAX and XMM-Newton. The red- and blue-shifted lines are found at E˜5.5 keV and ~8.1-8.3 keV (rest-frame), respectively. The first is seen in one out of six BeppoSAX observations, the latter is seen by both satellites. Under the assumption that the absorption is due to either H- or He-like Iron, the implied velocities for the absorbing matter are v˜0.15-0.2 c, in both outward and inward directions. An alternative explanation in terms of gravitational red-shift for the ~5.5 keV line cannot be ruled out with the current data. We argue, however, that the temporal patterns and sporadic nature of the lines are more easily reconciled with models that predict important radial motions close to the central black hole, such as the "aborted jet" model, the "thundercloud" model, or magneto-hydrodynamical models of jets and accretion-disks.

  16. The KMOS GTO Cluster Program: Absorption Line Spectroscopy of Cluster Galaxies at z˜1.5

    NASA Astrophysics Data System (ADS)

    Houghton, R. C. W.; Davies, R. L.; Bender, R.; Beifiori, A.; Chan, J.; Cappellari, M.; Galametz, A.; Lewis, I.; Mendel, J. T.; Prichard, L.; Saglia, R. P.; Sharples, R.; Smith, R.; Stott, J.; Wilman, D.; Wegner, M.

    2016-10-01

    The GTO KMOS cluster program (P.I.s Davies & Bender) is investigating the absorption line spectra of individual cluster galaxies during the peak epoch of star formation at 1.3< z<2. The multiplexed nature of KMOS increases the observing efficiency by more than an order-of-magnitude compared to single integral field units, which is essential for obtaining deep spectra of many faint targets. Furthermore, the NIR capabilities of KMOS produce observations of the well understood rest-frame V-band indices at these redshifts, providing reliable measures of age and composition for the stellar populations. The kinematics coupled with archival HST photometry allow us to construct the fundamental plane and study the evolution in size and mass-to-light when the Universe was less than 5 Gyrs old. The program has already obtained spectra of ˜60 galaxies in three clusters with on-source exposure times of 15-20 hrs per galaxy. We present early results from these data and provide an overview of the project.

  17. Ratio of Dust to Metal Abundance in Quasar Absorption Line Systems from 1.9 < z < 3.3

    NASA Astrophysics Data System (ADS)

    Stawinski, Stephanie; Malhotra, Sangeeta

    2017-01-01

    Measuring the ratio of dust to metal abundance in quasar absorption line systems will provide insight to the chemical evolution of galaxies, dust formation, and dust properties in the early universe. Quasar absorption systems allow us to study the abundance of dust from many different redshifts, in this project up to z ~ 3.3 for absorber redshift. The absorption bump at 2175 Å is a broad, but strong, dust feature within the UV-optical wavelength range. This feature, if detected, can be directly related to the optical depth of the dust in the absorbing systems. However, the 2175 Å bump is very broad, having a full-width half-maximum approximately 350 * (1 + z) Å, and therefore hard to distinguish from a single spectrum. To find this bump, it is important to co-add many quasar spectra. In this project, we look at how the abundance of dust compares to that of metals for 105 quasar spectra with strong damped Lyman alpha systems with absorber redshifts ranging from 1.9 < z < 3.3. From these spectra, we created a composite spectrum to analyze the 2175 Å bump and the absorption of heavy elements. We will present the results including the strength of the 2175 Å feature found in our composite spectrum.

  18. Intersstellar absorption lines between 2000 and 3000 A in nearby stars observed with BUSS. [Balloon Borne Ultraviolet Spectrophotometer

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Lenhart, H.; Van Der Hucht, K. A.; Kamperman, T. M.; Kondo, Y.

    1986-01-01

    Spectra obtained between 2000 and 3000 A with the Balloon Borne Ultraviolet Spectrophotometer (BUSS) payload were examined for interstellar absorption lines. In bright stars, with spectral types between O9V and F5V, such lines were measured of Mg I, Mg II, Cr II, Mn II, Fe II and Zn II, with Cr II and Zn II data of especially high quality. Column densities were derived and interstellar abundances were determined for the above species. It was found that metal depletion increases with increasing E(B-V); Fe was most affected and Zn showed a small depletion for E(B-V) greater than 0.3 towards Sco-Oph. The metal column densities, derived for Alpha-And, Kappa-Dra, Alpha-Com, Alpha-Aql, and 29 Cyg were used to infer N(H I). It was shown that the ratio of Mg I to Na I is instrumental in determining the ionization structure along each line of sight. The spectra of Aql stars confirms the presence of large gas densities near Alpha-Oph. Moreover, data indicated that the Rho-Oph N(H I) value needs to be altered to 35 x 10 to the 20th/sq cm, based on observed ion ratios and analysis of the Copernicus L-alpha profile.

  19. CHARACTERIZING THE CIRCUMGALACTIC MEDIUM OF NEARBY GALAXIES WITH HST/COS AND HST/STIS ABSORPTION-LINE SPECTROSCOPY

    SciTech Connect

    Stocke, John T.; Keeney, Brian A.; Danforth, Charles W.; Shull, J. Michael; Froning, Cynthia S.; Green, James C.; Penton, Steven V.; Savage, Blair D.

    2013-02-15

    The circumgalactic medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z {<=} 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph (COS) and {approx}60 serendipitous absorber/galaxy pairs at z {<=} 0.2 with the Space Telescope Imaging Spectrograph. CGM warm cloud properties are derived, including volume filling factors of 3%-5%, cloud sizes of 0.1-30 kpc, masses of 10-10{sup 8} M {sub Sun }, and metallicities of {approx}0.1-1 Z {sub Sun }. Almost all warm CGM clouds within 0.5 R {sub vir} are metal-bearing and many have velocities consistent with being bound, 'galactic fountain' clouds. For galaxies with L {approx}> 0.1 L*, the total mass in these warm CGM clouds approaches 10{sup 10} M {sub Sun }, {approx}10%-15% of the total baryons in massive spirals and comparable to the baryons in their parent galaxy disks. This leaves {approx}> 50% of massive spiral-galaxy baryons 'missing'. Dwarfs (<0.1 L*) have smaller area covering factors and warm CGM masses ({<=}5% baryon fraction), suggesting that many of their warm clouds escape. Constant warm cloud internal pressures as a function of impact parameter (P/k {approx} 10 cm{sup -3} K) support the inference that previous COS detections of broad, shallow O VI and Ly{alpha} absorptions are of an extensive ({approx}400-600 kpc), hot (T Almost-Equal-To 10{sup 6} K), intra-cloud gas which is very massive ({>=}10{sup 11} M {sub Sun }). While the warm CGM clouds cannot account for all the 'missing baryons' in spirals, the hot intra-group gas can, and could account for {approx}20% of the cosmic baryon census at z {approx} 0 if this hot gas is ubiquitous among spiral groups.

  20. UNSHIFTED METASTABLE He I* MINI-BROAD ABSORPTION LINE SYSTEM IN THE NARROW-LINE TYPE 1 QUASAR SDSS J080248.18+551328.9

    SciTech Connect

    Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Wang, Huiyuan; Liu, Wenjuan; Yang, Chenwei; Ge, Jian; Hamann, Fred; Komossa, S.; Yuan, Weimin; Zuther, Jens; Lu, Honglin; Zuo, Wenwen

    2015-02-10

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ∼ 1500 km s{sup –1} centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n {sub H} ∼ (1.0-2.5) × 10{sup 5} cm{sup –3} and a column density of N {sub H} ∼ (1.0-3.2) × 10{sup 21} cm{sup –2} and is located at R ∼100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

  1. X-RAYS FROM A RADIO-LOUD COMPACT BROAD ABSORPTION LINE QUASAR 1045+352 AND THE NATURE OF OUTFLOWS IN RADIO-LOUD BROAD ABSORPTION LINE QUASARS

    SciTech Connect

    Kunert-Bajraszewska, Magdalena; Katarzynski, Krzysztof; Siemiginowska, Aneta; Janiuk, Agnieszka

    2009-11-10

    We present new results on X-ray properties of radio-loud broad absorption line (BAL) quasars and focus on broadband spectral properties of a high-ionization BAL (HiBAL) compact steep spectrum (CSS) radio-loud quasar 1045+352. This HiBAL quasar has a very complex radio morphology indicating either strong interactions between a radio jet and the surrounding interstellar medium or a possible re-start of the jet activity. We detected 1045+352 quasar in a short 5 ksec Chandra ACIS-S observation. We applied theoretical models to explain spectral energy distribution of 1045+352 and argue that non-thermal, inverse-Compton (IC) emission from the innermost parts of the radio jet can account for a large fraction of the observed X-ray emission. In our analysis, we also consider a scenario in which the observed X-ray emission from radio-loud BAL quasars can be a sum of IC jet X-ray emission and optically thin corona X-ray emission. We compiled a sample of radio-loud BAL quasars that were observed in X-rays to date and report no correlation between their X-ray and radio luminosity. However, the radio-loud BAL quasars show a large range of X-ray luminosities and absorption columns. This is consistent with the results obtained earlier for radio-quiet BAL quasars and may indicate an orientation effect in BAL quasars or more complex dependence between X-ray emission, radio emission, and an orientation based on the radio morphology.

  2. Absorption-line Spectroscopy of Gravitationally Lensed Galaxies: Further Constraints on the Escape Fraction of Ionizing Photons at High Redshift

    NASA Astrophysics Data System (ADS)

    Leethochawalit, Nicha; Jones, Tucker A.; Ellis, Richard S.; Stark, Daniel P.; Zitrin, Adi

    2016-11-01

    The fraction of ionizing photons escaping from high-redshift star-forming galaxies is a key obstacle in evaluating whether galaxies were the primary agents of cosmic reionization. We previously proposed using the covering fraction of low-ionization gas, measured via deep absorption-line spectroscopy, as a proxy. We now present a significant update, sampling seven gravitationally lensed sources at 4 < z < 5. We show that the absorbing gas in our sources is spatially inhomogeneous, with a median covering fraction of 66%. Correcting for reddening according to a dust-in-cloud model, this implies an estimated absolute escape fraction of ≃19% ± 6%. With possible biases and uncertainties, collectively we find that the average escape fraction could be reduced to no less than 11%, excluding the effect of spatial variations. For one of our lensed sources, we have sufficient signal-to-noise ratio to demonstrate the presence of such spatial variations and scatter in its dependence on the Lyα equivalent width, consistent with recent simulations. If this source is typical, our lower limit to the escape fraction could be reduced by a further factor ≃2. Across our sample, we find a modest anticorrelation between the inferred escape fraction and the local star formation rate, consistent with a time delay between a burst and leaking Lyman continuum photons. Our analysis demonstrates considerable variations in the escape fraction, consistent with being governed by the small-scale behavior of star-forming regions, whose activities fluctuate over short timescales. This supports the suggestion that the escape fraction may increase toward the reionization era when star formation becomes more energetic and burst-like.

  3. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    SciTech Connect

    Pascucci, I.; Simon, M. N.; Edwards, S.; Heyer, M.; Rigliaco, E.; Hillenbrand, L.; Gorti, U.; Hollenbach, D.

    2015-11-20

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.

  4. Nustar Reveals an Intrinsically X-ray Weak Broad Absorption Line Quasar in the Ultraluminous Infrared Galaxy Markarian 231

    NASA Technical Reports Server (NTRS)

    Teng, Stacy H.; Brandt. W. N.; Harrison, F. A.; Luo, B.; Alexander, D. M.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W.; Fabian, A. C.; Farrah, D.; Fiore, F.; Gandhi, P.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R. C.; Madsen, K. K.; Ptak, A. F.; Rigby, Jane Rebecca; Risaliti, G.; Saz, C.; Stern, D.; Veilleux, S.; Walton, D. J.; Wik, D. R.; Zhang, W. W.

    2014-01-01

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin N(sub H) approx. 1.2(sup +0.3) sub-0.3) x 10(exp 23) / sq cm) column. The intrinsic X-ray luminosity L(sub 0.5-30 Kev) approx. 1.0 x 10(exp 43) erg /s) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is approx. 0.03% compared to the typical values of 2-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope alpha(sub 0X) approx. -1.7. It is a local example of a low-ionization broad absorption line (LoBAL) quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  5. Unveiling the Intrinsic X-Ray Properties of Broad Absorption Line Quasars with a Relatively Unbiased Sample

    NASA Astrophysics Data System (ADS)

    Morabito, Leah K.; Dai, Xinyu; Leighly, Karen M.; Sivakoff, Gregory R.; Shankar, Francesco

    2014-05-01

    There is growing evidence of a higher intrinsic fraction of broad absorption line quasars (BALQSOs) than that obtained in optical surveys, on which most previous X-ray studies of BALQSOs have focused. Here we present Chandra observations of 18 BALQSOs at z ~ 2, selected from a near-infrared (Two Micron All Sky Survey) sample, where the BALQSO fraction is likely to be close to the intrinsic fraction. We measure photon indices using the stacked spectra of the optically faint (i - Ks >= 2.3 mag) and optically bright (i - Ks < 2.3 mag) samples to be Γ ~= 1.5-2.1. We constrain their intrinsic column density by modeling the X-ray fractional hardness ratio, finding a mean column density of 3.5 × 1022 cm-2 assuming neutral absorption. We incorporate Sloan Digital Sky Survey optical measurements (rest frame UV) to study the broadband spectral index between the X-ray and UV bands, and compare this to a large sample of normal quasars. We estimate that the optically faint BALQSOs are X-ray weaker than the optically bright ones, and the entire sample of BALQSOs are intrinsically X-ray weak when compared to normal active galactic nuclei (AGNs). Correcting for magnification of X-ray emission via gravitational lensing by the central black hole viewed at large inclination angles makes these BALQSOs even more intrinsically X-ray weak. Finally, we estimate AGN kinetic feedback efficiencies of a few percent for an X-ray wind of 0.3c in high-ionization BALQSOs. Combined with energy carried by low-ionization BALQSOs and UV winds, the total kinetic energy in BALQSOs can be sufficient to provide AGN kinetic feedback required to explain the co-evolution between black holes and host galaxies.

  6. Intervening Metal Systems in GRB and QSO Sight Lines: The Mg II and C IV Question

    NASA Astrophysics Data System (ADS)

    Sudilovsky, Vladimir; Savaglio, Sandra; Vreeswijk, Paul; Ledoux, Cédric; Smette, Alain; Greiner, Jochen

    2007-11-01

    Prochter and coworkers recently found that the number density of strong intervening 0.5QSO spectra. We have conducted a similar study using C IV absorbers. Our C IV sample, consisting of a total of 19 systems, is drawn from three high-resolution and high to moderate signal-to-noise ratio VLT UVES spectra of three long-duration GRB afterglows, covering the redshift interval 1.6QSO spectra. We discuss several possibilities for the discrepancy between C IV and Mg II absorbers and conclude that a higher dust extinction in the Mg II QSO samples studied up to now would give the most straightforward solution. However, this effect is only important for the strong Mg II absorbers. Regardless of the reasons for this discrepancy, this result confirms once more that GRBs can be used to detect a side of the universe that was unknown before, not necessarily connected with GRBs themselves, providing an alternative and fundamental investigative tool of the cosmic evolution of the universe. Based on observations collected at the European Southern Observatory, Chile; proposals 75.A-0385, 75.A-0603, and 77.D-0661.

  7. The MUSE QSO Blind Survey: A Census of Absorber Host Galaxies

    NASA Astrophysics Data System (ADS)

    Straka, Lorrie A.

    2017-03-01

    Understanding the distribution of gas in galaxies and its interaction with the IGM is crucial to complete the picture of galaxy evolution. At all redshifts, absorption features seen in QSO spectra serve as a unique probe of the gaseous content of foreground galaxies and the IGM, extending out to 200 kpc. Studies show that star formation history is intimately related to the co-evolution of galaxies and the IGM. In order to study the environments traced by absorption systems and the role of inflows and outflows, it is critical to measure the emission properties of host galaxies and their halos. We overcome the challenge of detecting absorption host galaxies with the MUSE integral field spectrograph on VLT. MUSE's large field of view and sensitivity to emission lines has allowed a never-before seen match between the number density of absorbers along QSO sightlines and the number density of emission line galaxies within 200 kpc of the QSO. These galaxies represent a sample for which previously elusive connections can be made between mass, metallicity, SFR, and absorption.

  8. Abundances of O, Mg, S, Cr, Mn, Ti, Ni and Zn from absorption lines of neutral gas in the Large Magellanic Cloud in front of R136

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Fitzpatrick, E. L.; Savage, B. D.

    1985-01-01

    Weak absorption lines of C I, O I, Mg I, Mg II, Si I, Si II, P I, Cl I, Cr II, Mn II, Fe I, Ni II, Zn II, CO and C2 are detected in neutral gas in front of the 30 Doradus H II region by IUE spectra of R 136. The Large Magellanic Cloud abundances from the absorption lines are a factor of 2 or 3 below those of the Milky Way, in agreement with emission line study results. Neutral gas density and temperature are estimated from the observed excitation and ionization to be about 300/cu cm and 100 K, respectively; this implies a gas pressure of 30,000/cu cm K.

  9. Variable Reddening and Broad Absorption Lines in the Narrow-line Seyfert 1 Galaxy WPVS 007: An Origin in the Torus

    NASA Astrophysics Data System (ADS)

    Leighly, Karen M.; Cooper, Erin; Grupe, Dirk; Terndrup, Donald M.; Komossa, S.

    2015-08-01

    We report the discovery of an occultation event in the low-luminosity narrow-line Seyfert 1 galaxy WPVS 007 in 2015 February and March. In concert with longer timescale variability, these observations place strong constraints on the nature and location of the absorbing material. Swift monitoring has revealed a secular decrease since ∼2010 accompanied by flattening of the optical and UV photometry that suggests variable reddening. Analysis of four Hubble Space Telescope COS observations since 2010, including a Director’s Discretionary time observation during the occultation, shows that the broad-absorption-line velocity offset and the C iv emission-line width both decrease as the reddening increases. The occultation dynamical timescale, the BAL variability dynamical timescale, and the density of the BAL gas show that both the reddening material and the broad-absorption-line gas are consistent with an origin in the torus. These observations can be explained by a scenario in which the torus is clumpy with variable scale height, and the BAL gas is blown from the torus material like spray from the crest of a wave. As the obscuring material passes into our line of sight, we alternately see high-velocity broad absorption lines and a clear view to the central engine, or low-velocity broad absorption lines and strong reddening. WPVS 007 has a small black hole mass, and correspondingly short timescales, and so we may be observing behavior that is common in BALQSOs, but is not typically observable. Based on observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with programs 11733, 13015, and 14058.

  10. Spectral anomalies of the light-induced drift effect caused by the velocity dependence of the collision broadening and shift of the absorption line

    NASA Astrophysics Data System (ADS)

    Parkhomenko, A. I.; Shalagin, Anatolii M.

    2013-02-01

    We have theoretically investigated the spectral features of the light-induced drift (LID) effect, arising due to the dependence of the collision broadening γ and shift Δ of the absorption line on the velocity of resonance particles, ν. It is shown that under certain conditions, account of this dependence can radically change the spectral shape of the LID signal, up to the appearance of additional zeros in the dependence of the drift velocity on the radiation frequency.

  11. Spectral anomalies of the light-induced drift effect caused by the velocity dependence of the collision broadening and shift of the absorption line

    SciTech Connect

    Parkhomenko, A I; Shalagin, Anatolii M

    2013-02-28

    We have theoretically investigated the spectral features of the light-induced drift (LID) effect, arising due to the dependence of the collision broadening {gamma} and shift {Delta} of the absorption line on the velocity of resonance particles, {nu}. It is shown that under certain conditions, account of this dependence can radically change the spectral shape of the LID signal, up to the appearance of additional zeros in the dependence of the drift velocity on the radiation frequency. (nonlinear optical phenomena)

  12. EMERGENCE OF A BROAD ABSORPTION LINE OUTFLOW IN THE NARROW-LINE SEYFERT 1 GALAXY WPVS 007

    SciTech Connect

    Leighly, Karen M.; Casebeer, Darrin A.; Hamann, Fred; Grupe, Dirk

    2009-08-10

    We report results from a 2003 Far Ultraviolet Spectroscopic Explorer (FUSE) observation and reanalysis of a 1996 Hubble Space Telescope (HST) observation of the unusual X-ray transient Narrow-line Seyfert 1 galaxy WPVS 007. The HST Faint Object Spectrograph (FOS) spectrum revealed mini-BALs (broad absorption lines) with V {sub max} {approx} 900 km s{sup -1} and FWHM {approx}550 km s{sup -1}. The FUSE spectrum showed that an additional BAL outflow with V {sub max} {approx} 6000 km s{sup -1} and FWHM {approx}3400 km s{sup -1} had appeared. WPVS 007 is a low-luminosity object in which such a high-velocity outflow is not expected; therefore, it is an outlier on the M{sub V} /v {sub max} relationship. Template spectral fitting yielded apparent ionic columns, and a Cloudy analysis showed that the presence of P V requires a high-ionization parameter log(U) {>=} 0 and high-column density log(N {sub H}) {>=} 23 assuming solar abundances and a nominal spectral energy distribution (SED) for low-luminosity NLS1s with {alpha} {sub ox} = -1.28. A recent long Swift observation revealed the first hard X-ray detection and an intrinsic (unabsorbed) {alpha} {sub ox} {approx} -1.9. Using this SED in our analysis yielded lower column density constraints (log(N {sub H}) {>=} 22.2 for Z = 1, or log(N {sub H}) {>=} 21.6 if Z = 5). The X-ray weak continuum, combined with X-ray absorption consistent with the UV lines, provides the best explanation for the observed Swift X-ray spectrum. The large column densities and velocities implied by the UV data in any of these scenarios could be problematic for radiative acceleration. We also point out that since the observed P V absorption can be explained by lower total column densities using an intrinsically X-ray weak spectrum, we might expect to find P V absorption preferentially more often (or stronger) in quasars that are intrinsically X-ray weak.

  13. Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness

    SciTech Connect

    Luo, B.; Brandt, W. N.; Scott, A. E.; Alexander, D. M.; Gandhi, P.; Stern, D.; Teng, S. H.; Arévalo, P.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Farrah, D.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Ogle, P.; Puccetti, S.; Saez, C.; and others

    2014-10-10

    We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with ≲ 45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γ{sub eff} ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (≳ 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.

  14. A CHANDRA SURVEY OF THE X-RAY PROPERTIES OF BROAD ABSORPTION LINE RADIO-LOUD QUASARS

    SciTech Connect

    Miller, B. P.; Brandt, W. N.; Garmire, G. P.; Gibson, R. R.; Shemmer, O. E-mail: niel@astro.psu.edu E-mail: rgibson@astro.washington.edu

    2009-09-10

    This work presents the results of a Chandra study of 21 broad absorption line (BAL) radio-loud quasars (RLQs). We conducted a Chandra snapshot survey of 12 bright BAL RLQs selected from Sloan Digital Sky Survey Data/Faint Images of the Radio Sky data and possessing a wide range of radio and C IV absorption properties. Optical spectra were obtained nearly contemporaneously with the Hobby-Eberly Telescope; no strong flux or BAL variability was seen between epochs. In addition to the snapshot targets, we include in our sample nine additional BAL RLQs possessing archival Chandra coverage. We compare the properties of (predominantly high-ionization) BAL RLQs to those of non-BAL RLQs as well as to BAL radio-quiet quasars (RQQs) and non-BAL RQQs for context. All 12 snapshots and 8/9 archival BAL RLQs are detected, with observed X-ray luminosities less than those of non-BAL RLQs having comparable optical/UV luminosities by typical factors of 4.1-8.5. (BAL RLQs are also X-ray weak by typical factors of 2.0-4.5 relative to non-BAL RLQs having both comparable optical/UV and radio luminosities.) However, BAL RLQs are not as X-ray weak relative to non-BAL RLQs as are BAL RQQs relative to non-BAL RQQs. While some BAL RLQs have harder X-ray spectra than typical non-BAL RLQs, some have hardness ratios consistent with those of non-BAL RLQs, and there does not appear to be a correlation between X-ray weakness and spectral hardness, in contrast to the situation for BAL RQQs. RLQs are expected to have X-ray continuum contributions from both accretion-disk corona and small-scale jet emission. While the entire X-ray continuum in BAL RLQs cannot be obscured to the same degree as in BAL RQQs, we calculate that the jet is likely partially covered in many BAL RLQs. We comment briefly on implications for geometries and source ages in BAL RLQs.

  15. High Dust Depletion in two Intervening Quasar Absorption Line Systems with the 2175 Å Extinction Bump at z ~ 1.4

    NASA Astrophysics Data System (ADS)

    Jiang, Peng; Ge, Jian; Prochaska, J. Xavier; Wang, Junfeng; Zhou, Hongyan; Wang, Tinggui

    2010-12-01

    We present the column densities of heavy elements and dust depletion studies in two strong Mg II absorption systems at z ~ 1.4 displaying the 2175 Å dust extinction feature. Column densities are measured from low-ionization absorption lines using an Apparent Optical Depth Method on the Keck/ESI spectra. We find that the dust depletion patterns resemble that of cold diffuse clouds in the Milky Way (MW). The values, [Fe/Zn] ≈-1.5 and [Si/Zn]<-0.67, are among the highest dust depletion measured for quasar absorption line systems. In another 2175 Å absorber at z = 1.64 toward the quasar SDSS J160457.50+220300.5, Noterdaeme et al. reported a similar dust depletion measurement ([Fe/Zn] = -1.47 and [Si/Zn] = -1.07) and detected C I and CO absorption lines on its VLT/UVES spectrum. We conclude that heavy dust depletion (i.e., a characteristic of cold dense clouds in MW) is required to produce a pronounced 2175 Å extinction bump. 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.

  16. Discovery of two broad absorption line quasars at redshift about 4.75 using the Lijiang 2.4 m telescope

    NASA Astrophysics Data System (ADS)

    Yi, WeiMin; Wu, XueBing; Wang, FeiGe; Yang, JinYi; Yang, Qian; Bai, JinMing

    2015-09-01

    The ultraviolet broad absorption lines have been seen in the spectra of quasars at high redshift, and are generally considered to be caused by outflows with velocities from thousands kilometers per second to one tenth of the speed of light. They provide crucial implications for the cosmological structures and physical evolutions related to the feedback of active galactic nuclei (AGNs). Recently, through a dedicated program of optically spectroscopic identifications of selected quasar candidates at redshift 5 by using the Lijiang 2.4 m telescope, we discovered two luminous broad absorption line quasars (BALQSOs) at redshift about 4.75. One of them may even have the potentially highest absorption Balnicity Index (BI) ever found to date, which is remarkably characterized by its deep, broad absorption lines and sub-relativistic outflows. Further physical properties, including the metal abundances, variabilities, evolutions of the supermassive black holes (SMBH) and accretion disks associated with the feedback process, can be investigated with multi-wavelength follow-up observations in the future.

  17. Evidence for ultra-fast outflows in radio-quiet AGNs. I. Detection and statistical incidence of Fe K-shell absorption lines

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Yaqoob, T.; Braito, V.; Dadina, M.

    2010-10-01

    Context. Blue-shifted Fe K absorption lines have been detected in recent years between 7 and 10 keV in the X-ray spectra of several radio-quiet AGNs. The derived blue-shifted velocities of the lines can often reach mildly relativistic values, up to 0.2-0.4c. These findings are important because they suggest the presence of a previously unknown massive and highly ionized absorbing material outflowing from their nuclei, possibly connected with accretion disk winds/outflows. Aims: The scope of the present work is to statistically quantify the parameters and incidence of the blue-shifted Fe K absorption lines through a uniform analysis on a large sample of radio-quiet AGNs. This allows us to assess their global detection significance and to overcome any possible publication bias. Methods: We performed a blind search for narrow absorption features at energies greater than 6.4 keV in a sample of 42 radio-quiet AGNs observed with XMM-Newton. A simple uniform model composed by an absorbed power-law plus Gaussian emission and absorption lines provided a good fit for all the data sets. We derived the absorption lines parameters and calculated their detailed detection significance making use of the classical F-test and extensive Monte Carlo simulations. Results: We detect 36 narrow absorption lines on a total of 101 XMM-Newton EPIC pn observations. The number of absorption lines at rest-frame energies higher than 7 keV is 22. Their global probability to be generated by random fluctuations is very low, less than 3 × 10-8, and their detection have been independently confirmed by a spectral analysis of the MOS data, with associated random probability <10-7. We identify the lines as Fe XXV and Fe XXVI K-shell resonant absorption. They are systematically blue-shifted, with a velocity distribution ranging from zero up to ~0.3c, with a peak and mean value at ~0.1c. We detect variability of the lines on both EWs and blue-shifted velocities among different XMM-Newton observations

  18. The Hubble Space Telescope quasar absorption line key project. 6: Properties of the metal-rich systems

    NASA Technical Reports Server (NTRS)

    Bergeron, Jacqueline; Petitjean, Patrick; Sargent, W. L. W.; Bahcall, John N.; Boksenberg, Alec; Hartig, George F.; Jannuzi, Buell T.; Kirhakos, Sofia; Savage, Blair D.; Schneider, Donald P.

    1994-01-01

    We present an analysis of the properties of a sample of 18 metal-rich, low-redshift z(sub abs) much less than z(sub em) absorbers seen in low- and medium-resolution spectra obtained for the Quasar Absorption Line Key Project with the Hubble Space Telescope Faint Object Spectrograph (HST/FOS). For most of the C IV and Lyman-limit systems, observations in the optical wavelength range of the expected associated Mg II absorption are available. As at high redshift (z approximately 2), there are two subclasses of absorbers which are characterized by the presence or absence of MG II absorption. However, some low-redshift Mg II and Fe absorptions originate from regions optically thin to UV ionizing photons and thus, at low redshift, the low-ionization systems do not always trace high opacities, as is the case at high redshift. This implies that the mean ionization state of metal-rich, optically thin absorbing clouds falls with decreasing redshift, which is consistent with the hypothesis that the gas is photoionized by the metagalactic UV background radiation field. Two main constraints are derived from the analysis of the Lyman-limit sample, assuming photoionization models are valid. First, a low opacity to ionizing photons (tau(sub LL) approximately less than 1), as observed for several Mg II-Fe II systems at z approximately 0.5, sets limits on the ionization level of hydrogen, thus on the total hydrogen column density and the heavy element abundances, (Z/H) approximately -0.5 to -0.3. Second, the dimensions of individual Mg II clouds are smaller than at high redshift by a factor 3-10. At z approximately greater than 0.6, the O VI absorption doublet is detected in four of the five z(sub abs) much less than z(sub em) systems for which the O VI wavelength range has been observed, whereas the associated N V doublet is detected in only two cases. This suggests that the presence of a high-ionization O VI phase is a general property of z approximately 0.6-1 absorption systems

  19. WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope

    NASA Astrophysics Data System (ADS)

    Pieri, M. M.; Bonoli, S.; Chaves-Montero, J.; Pâris, I.; Fumagalli, M.; Bolton, J. S.; Viel, M.; Noterdaeme, P.; Miralda-Escudé, J.; Busca, N. G.; Rahmani, H.; Peroux, C.; Font-Ribera, A.; Trager, S. C.

    2016-12-01

    In these proceedings we describe the WEAVE-QSO survey, which will observe around 400,000 high redshift quasars starting in 2018. This survey is part of a broader WEAVE survey to be conducted at the 4.2m William Herschel Telescope. We will focus on chiefly on the science goals, but will also briefly summarise the target selection methods anticipated and the expected survey plan. Understanding the apparent acceleration in the expansion of the Universe is one of the key scientific challenges of our time. Many experiments have been proposed to study this expansion, using a variety of techniques. Here we describe a survey that can measure this acceleration and therefore help elucidate the nature of dark energy: a survey of the Lyα forest (and quasar absorption in general) in spectra towards z>2 quasars (QSOs). Further constraints on neutrino masses and warm dark matter are also anticipated. The same data will also shed light on galaxy formation via study of the properties of inflowing/outflowing gas associated with nearby galaxies and in a cosmic web context. Gas properties are sensitive to density, temperature, UV radiation, metallicity and abundance pattern, and so constraint galaxy formation in a variety of ways. WEAVE-QSO will study absorbers with a dynamic range spanning more than 8 orders of magnitude in column density, their thermal broadening, and a host of elements and ionization species. A core principal of the WEAVE-QSO survey is the targeting of QSOs with near 100% efficiency principally through use of the J-PAS (r < 23.2) and Gaia (r ≲ 20) data.

  20. Results of Monitoring the Dramatically Variable C IV Mini-Broad Absorption Line System in the Quasar HS 1603+3820

    NASA Astrophysics Data System (ADS)

    Misawa, Toru; Eracleous, Michael; Charlton, Jane C.; Kashikawa, Nobunari

    2007-05-01

    We present six new and two previously published high-resolution spectra of the quasar HS 1603+3820 (zem=2.542) taken over an interval of 4.2 yr (1.2 yr in the quasar rest frame). The observations were made with the High Dispersion Spectrograph on the Subaru telescope and the Medium Resolution Spectrograph on the Hobby-Eberly Telescope. The purpose was to study the narrow absorption lines (NALs). We use time variability and coverage fraction analysis to separate intrinsic absorption lines, which are physically related to the quasar, from intervening absorption lines. By fitting models to the line profiles, we derive the parameters of the respective absorbers as a function of time. Only the mini-BAL system at zabs~2.43 (vshift~9500 km s-1) shows both partial coverage and time variability, although two NAL systems possibly show evidence of partial coverage. We find that all the troughs of the mini-BAL system vary in concert and its total equivalent width variations resemble those of the coverage fraction. However, no other correlations are seen between the variations of different model parameters. Thus, the observed variations cannot be reproduced by a simple change of ionization state or by motion of a homogeneous parcel of gas across the cylinder of sight. We propose that the observed variations are a result of rapid continuum fluctuations, coupled with coverage fraction fluctuations caused by a clumpy screen of variable optical depth located between the continuum source and the mini-BAL gas. An alternative explanation is that the observed partial coverage signature is the result of scattering of continuum photons around the absorber, thus the equivalent width of the mini-BAL can vary as the intensity of the scattered continuum changes. Based on data collected at the Subaru telescope, which is operated by the National Astronomical Observatory of Japan.

  1. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    NASA Technical Reports Server (NTRS)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  2. A Candidate for an Intrinsic Dusty Absorber with a Metal-rich Damped Lyα Absorption Line System in the Quasar J170542.91+354340.2

    NASA Astrophysics Data System (ADS)

    Pan, Xiang; Zhou, Hongyan; Ge, Jian; Jiang, Peng; Yang, Bin; Lu, Honglin; Ji, Tuo; Zhang, Shaohua; Shi, Xiheng

    2017-02-01

    We present a detailed analysis of the unusual damped Lyα absorption line system (DLA) toward the quasar SDSS J170542.91+354340.2 at a redshift of 2, previously reported by Noterdaeme et al. as one of the very few CO absorbers known to date at high z. This DLA is exceptional in that: (1) its extinction curve is similar to peculiar Milky Way sightlines penetrating star formation regions; (2) its absorption components are redshifted at a speed of several hundred km s‑1 compared to broad Balmer emission lines; (3) its gas-phase metallicity is super-solar as evaluated from more than 30 absorption lines; (4) detection of residual flux in the DLA trough and variability of {{C}} {{IV}} absorption is possible. Based on these facts, we argue that this dusty DLA is a good candidate for an intrinsic quasar 2175 Å absorber, and can originate from star formation regions of the quasar’s host galaxy. We discuss in detail the gas and dust properties, and the dust depletion. Follow-up observations, such as spectropolarimetry and optical/infrared spectroscopy, will help to confirm the system’s intrinsic nature and to explore how dust grains behave in the extreme environments proximate to quasars.

  3. Adaptive optics imaging of QSO host galaxies with Hokupa'a on the Gemini North telescope

    NASA Astrophysics Data System (ADS)

    Guyon, O.; Sanders, D. B.; Stockton, A.; Baudoz, P.; Potter, D.

    2001-05-01

    We report the initial results of a new near-infrared imaging survey of quasar hosts using the University of Hawaii Hokupa'a Adaptive Optics system on the 8.2m Gemini-North telescope. J,H,K' images of a complete subsample ( 25) of nearby (z <0.3), "bona-fide" optically selected (MB < -23; Ho = 50, qo=0; Schmidt & Green 1983) QSOs are being taken in order to obtain accurate host galaxy magnitudes and colors and to determine two-dimensional structure. In the initial phase of our observations we found that PSF subtraction residuals were severely limiting our ability to characterize the host galaxy. However we were able to obtain a significant increase in stability of the PSF by turning off the Cassegrain rotator during observations (see Roth et al. contribution at this meeting). Our sample of Palomar-Green Bright QSOs includes both radio quiet and radio loud objects plus objects spanning the full range of observed "infrared excess" continuum emission. One of the most surprising results has been the detection of modest scale (3-5" 5 kpc diameter) "bars" and/or circumnuclear "disks" that were not evident in previous one-dimensional profile analyses. These structures may be related to the reservoir of fuel needed to power the QSO and may provide important clues concerning the origin and evolution of QSO hosts.

  4. Spitzer Observations of a Gravitationally Lensed Quasar, QSO 2237+0305

    NASA Astrophysics Data System (ADS)

    Agol, Eric; Gogarten, Stephanie M.; Gorjian, Varoujan; Kimball, Amy

    2009-06-01

    The four-image gravitationally lensed quasar QSO 2237+0305 is microlensed by stars in the lens galaxy. The amplitude of microlensing variability can be used to infer the relative size of the quasar as a function of wavelength; this provides a test of quasar models. Toward this end, we present Spitzer Space Telescope Infrared Spectrograph and Infrared Array Camera (IRAC) observations of QSO 2237+0305, finding the following. (1) The infrared (IR) spectral energy distribution (SED) is similar to that of other bright radio-quiet quasars, contrary to an earlier claim. (2) A dusty torus model with a small opening angle fits the overall shape of the IR SED well, but the quantitative agreement is poor due to an offset in wavelength of the silicate feature. (3) The flux ratios of the four lensed images can be derived from the IRAC data despite being unresolved. We find that the near-IR fluxes are increasingly affected by microlensing toward shorter wavelengths. (4) The wavelength dependence of the IRAC flux ratios is consistent with the standard quasar model in which an accretion disk and a dusty torus both contribute near 1 μm in the rest frame. This is also consistent with recent IR spectropolarimetry of nearby quasars.

  5. BREAKING THE OBSCURING SCREEN: A RESOLVED MOLECULAR OUTFLOW IN A BURIED QSO

    SciTech Connect

    Rupke, David S. N.; Veilleux, Sylvain

    2013-09-20

    We present Keck laser guide star adaptive optics observations of the nearby buried quasi-stellar object (QSO) F08572+3915:NW. We use near-infrared integral field data taken with the OH-Suppressing Infra-Red Imaging Spectrograph to reveal a compact disk and molecular outflow using Paα and H{sub 2} rotational-vibrational transitions at a spatial resolution of 100 pc. The outflow emerges perpendicular to the disk into a bicone of one-sided opening angle 100° up to distances of 400 pc from the nucleus. The integrated outflow velocities, which reach at least –1300 km s{sup –1}, correspond exactly to those observed in (unresolved) OH absorption, but are smaller (larger) than those observed on larger scales in the ionized (neutral atomic) outflow. These data represent a factor of >10 improvement in the spatial resolution of molecular outflows from mergers/QSOs, and plausibly represent the early stages of the excavation of the dust screen from a buried QSO.

  6. Observations of QSO J2233-606 in the Southern Hubble Deep Field

    NASA Astrophysics Data System (ADS)

    Sealey, K. M.; Drinkwater, M. J.; Webb, J. K.

    1998-06-01

    The Hubble Deep Field South (HDF-S) Hubble Space Telescope (HST) observations are expected to begin in 1998 October. We present a composite spectrum of the QSO in the HDF-S field covering UV/optical/near-IR wavelengths, obtained by combining data from the Australian National University 2.3 m telescope with STIS on the HST.1 This intermediate-resolution spectrum covers the range 1600-10000 Å and allows us to derive some basic information on the intervening absorption systems which will be important in planning future higher resolution studies of this QSO. The QSO J2233-606 coordinates are α = 22h33m37.6s, δ = -60°33'29" (J2000), the magnitude is B = 17.5, and its redshift is zem = 2.238, derived by simultaneously fitting several emission lines. The spectral index is α = -0.7 +/- 0.1, measured between the Lyα and Mg II emission lines. Many absorption systems are present, including systems with metal lines redward of the Lyα emission line at zabs = 2.204, 1.942, 1.870, 1.787 and a few very strong Lyα features at zabs = 2.077, 1.928, without similarly strong metal lines. There is a conspicuous Lyman limit (LL) absorption system that is most likely associated with the zabs = 1.942 system with a neutral hydrogen column density of NH I = (3.1 +/- 1.0) × 1017 cm-2. There is some evidence for the presence of a second LL absorber just to the blue of the conspicuous system at z = 1.870. We have employed a new technique, based on an analysis of the shape of the observed spectrum in the region of the LL absorption, to explore the properties of the gas. We tentatively conclude that this system might have suitable characteristics for measuring the deuterium-to-hydrogen (D/H) ratio.

  7. Discovery of a cyclotron absorption line in the spectrum of the binary X-ray pulsar 4U 1538 - 52 observed by Ginga

    NASA Technical Reports Server (NTRS)

    Clark, George W.; Woo, Jonathan W.; Nagase, Fumiaki; Makishima, Kazuo; Sakao, Taro

    1990-01-01

    A cyclotron absorption line near 20 keV has been found in the spectrum of the massive eclipsing binary X-ray pulsar 4U 1538 - 52 in observations with the Ginga observatory. The line is detected throughout the 529 s pulse cycle with a variable equivalent width that has its maximum value during the smaller peak of the two-peak pulse profile. It is found that the profile of the pulse and the phase-dependence of the cyclotron line can be explained qualitatively by a pulsar model based on recent theoretical results on the properties of pencil beams emitted by accretion-heated slabs of magnetized plasma at the magnetic poles of a neutron star. The indicated field at the surface of the neutron star is 1.7 (1 + z) x 10 to the 12th G, where z is the gravitational redshift.

  8. First laboratory detection of an absorption line of the first overtone electric quadrupolar band of N2 by CRDS near 2.2 μm

    NASA Astrophysics Data System (ADS)

    Čermák, P.; Vasilchenko, S.; Mondelain, D.; Kassi, S.; Campargue, A.

    2017-01-01

    The extremely weak 2-0 O(14) electric quadrupole transition of N2 has been detected by very high sensitivity Cavity Ring Down spectroscopy near 4518 cm-1. It is the first N2 absorption line in the first overtone band reported so far from laboratory experiments. By combining a feedback narrowed Distributed Feedback laser diode with a passive cell tracking technique, a limit of detection of αmin ∼ 1.2 × 10-11 cm-1 was achieved after one day of spectra averaging. The N2 2-0 O(14) line position and line intensity (about 1.5 × 10-30 cm/molecule) agree with calculated values provided in the HITRAN2012 database.

  9. Gravitationally Redshifted Absorption Lines in the Burst Spectra of the Neutron Star in the X-Ray Binary EXO 0748-676

    NASA Technical Reports Server (NTRS)

    Cottoam, J.; Paerels, F.; Mendez, M.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    The most straightforward manner of determining masses and radii of neutron stars is by measuring the gravitational redshift of spectral lines produced in the neutron star photosphere; such a measurement would provide direct constraints on the mass-to-radius ratio of the neutron star, and therefore on the equation of state for neutron star matter. Using data taken with the Reflection Grating Spectrometer on board the XMM-Newton observatory we identify, for the first time, significant absorption lines in the spectra of 28 bursts of the low-mass X-ray binary EXO 0748-676. The most significant features are consistent with the Fe XXVI and XXV n=2-3 and O VIII n=1-2 transitions, with a redshift of z=0.35, identical within small uncertainties for the different transitions. This constitutes the first direct and unambiguous measurement of the gravitational redshift in a neutron star.

  10. Evaluation of the absorption line blackbody distribution function of CO2 and H2O using the proper orthogonal decomposition and hyperbolic correlations

    NASA Astrophysics Data System (ADS)

    Liu, F.; Chu, H.; Zhou, H.; Smallwood, G. J.

    2013-10-01

    Databases of the absorption line blackbody distribution function (ALBDF) of CO2 and H2O were generated over a wide range of gas and blackbody temperatures and the full range of gas concentration from line-by-line (LBL) calculations using the latest version of HITEMP. Proper orthogonal decomposition (POD) and the hyperbolic correlations (HC) were then used for rapid calculation the ALBDF value at an arbitrary combination of gas and blackbody temperatures and gas concentration. A novel hyperbolic correlation for H2O was proposed to fully account for the self-broadening effect. The accuracy of POD and the HC was evaluated by comparing the ALBDF values and the total gas emissivities from these two approximate methods at several selected conditions against those from LBL calculations. POD is significantly more accurate than HC at essentially no extra computational costs.

  11. New aspects of absorption line formation in intervening turbulent clouds - II. Monte Carlo simulation of interstellar H+D Lyalpha absorption profiles

    NASA Astrophysics Data System (ADS)

    Levshakov, Sergei A.; Kegel, Wilhelm H.; Mazets, Igor E.

    1997-07-01

    Stochastic velocity fields with finite correlation lengths affect the formation of interstellar (intergalactic) absorption lines in a way not accounted for in the standard analysis procedure in which Voigt profiles are fitted to the observed line profiles. We investigate these effects, accounting in particular for the fact that interstellar absorption spectra reflect only one realization of the velocity field, since (i) actually only one line of sight is observed and (ii) the velocity structure of the cloud has to be considered to be `frozen' over the exposure time. This paper presents results of Monte Carlo calculations. In this technique an ensemble of line profiles is computed, each one of which corresponds to one realization of the random velocity field. The most important results are the following. (1) The individual line profiles may deviate substantially from each other and from the ensemble average. (2) Correlated velocity fields may cause complex multicomponent absorption features which in a traditional analysis would be attributed to several clouds, i.e. to density and/or kinetic temperature inhomogeneities. (3) Each line of sight has its own curve-of-growth. (4) Applying the standard analysis to such line profiles may produce misleading results concerning the physical parameters of the cloud. (5) In particular, the apparent scatter of the D/H ratio revealed in the ISM on the basis of the Copernicus, IUE, and HST observations may be caused by an inadequate analysis. Finally, we discuss under which conditions cloud characteristics may be derived from absorption lines without relying on a particular physical model.

  12. XMM-Newton Observation of Fe K(alpha) Emission from a BAL QSO: Mrk 231

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; Kraemer, S. B.

    2003-01-01

    We present results from a 20 ksec XMM-Newton observation of Mrk 231. EPIC spectral data reveal strong line emission due to Fe K alpha, which has rarely been detected in this class, as BAL QSOs are very faint in the X-ray band. The line energy is consistent with an origin in neutral Fe. The width of the line is equivalent to a velocity dispersion approximately 18,000 kilometers per second and thus the line may be attributed to transmission and/or reflection from a distribution of emitting clouds. If, instead, the line originates in the accretion disk then the line strength and flat X-ray continuum support some contribution from a reflected component, although the data disfavor a model where the hard X-ray band is purely reflected X-rays. The line parameters are similar to those obtained for the Fe Ka line detected in another BAL QSO, H1413 + 117.

  13. IUE and ROSAT monitoring of the bright QSO H1821+643

    NASA Technical Reports Server (NTRS)

    Halpern, Jules; Kolman, Michiel; Shrader, Chris; Filippenko, Alexei

    1991-01-01

    The analysis is presented of IUE observations of the bright QSO H1821+643, obtained during the ROSAT All Sky Survey (the RIASS program). The objectives were: (1) to establish whether the UV and soft X ray radiation have the same physical origin; and (2) to determine if this physical origin is an accretion disk. Supporting ground based spectrophotometry was also obtained. The analysis shows that the shape and flux level of the UV continuum did not vary among the seven IUE observation spanning one month, to an upper limit of about 8 percent. So it is of great interest to determine whether the soft X ray flux varied during this period. Since X ray variability in AGNs is often more rapid and of higher amplitude than in the UV, detection of X ray variability in the ROSAT data could severely challenge the accretion disk model for the soft X ray excess.

  14. The TESIS Project: Are Type 2 QSO Hidden in X-Ray Emitting EROs?

    NASA Astrophysics Data System (ADS)

    Severgnini, P.; Della Ceca, R.; Braito, V.; Saracco, P.; Longhetti, M.; Bender, R.; Drory, N.; Feulner, G.; Hopp, U.; Mannucci, F.; Maraston, C.

    X-ray selected EROs are, on average, the hardest X-ray sources in medium and deep X-ray fields. This coupled with their extremely red colors (R-K > 5) suggest that they represent one of the most promising population where looking for high-luminosity (LX > 1044 erg s-1) and X-ray obscured (NH > 1022 cm-2) type2 AGNs, the so called QSO2 (e.g., [5]; [4]; Mignoli et al. submitted to A&A). These latter are predicted in large density by the synthesis model of the Cosmic X-ray background [9] even if only few observational evidences have been found so far (e.g., [1] and references therein; Caccianiga et al. A&A accepted).

  15. Near IR flare of the QSO B2 1732+38A

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Carraminana, A.; Escobedo, G.; Recillas, E.; Porras, A.; Mayya, D. Y.

    2011-07-01

    We carried out NIR Photometry of the QSO B2 1732+38A also known as CGRaBS J1734+3857 and BZQ J1734+3857, and found that on July 1st 2011 (JD 5743.947095) the object was brighter (H = 15.08 ± 0.07) than our previous determination on JD 5360.891620 when it had a flux corresponding to H = 16.28 ± 0.09. That is a significant flux increase in this time lapse. Observations were carried out with the 2.1m telescope of the Guillermo Haro Observatory operated by the National Institute for Astrophysics, Optics and Electronics (Mexico), equipped with the instrument CANICA a NIR camera.

  16. The Damped Lyalpha Absorber Toward the Double QSO HE 1104-1805

    NASA Astrophysics Data System (ADS)

    Roth, K. C.; Songaila, A.; Jim, K. T. C.

    1998-05-01

    We recently obtained two hours of Keck HIRES data for the gravitational lens candidate HE 1104-1805A,B (z_QSO=2.303). We observed with a fixed position angle so that both quasar images (separation ~ 3'') fell on the slit simultaneously. The resulting high-resolution spectra (FWHM = 8 km/s) have a signal-to-noise ratio of 30 for the brighter component (A) while the fainter B component has S/N ~ 10 at 6000 Angstroms. Lower resolution spectra had previously revealed the presence of a damped Lyalpha absorber (z_damped=1.665) toward A which was absent in the spectrum of B (Wisotzki et al. 1993). Our spectra cover numerous weak low-ionization lines including Fe II, Zn II, Cr II, Ni II and Ti II which we use for abundance and dust depletion analyses. There also is a metal-line system at lower redshift (z_metal=1.321) which does cover both lines of sight, although the velocity profiles of the Fe II lines are significantly different. To complement the spectral data and verify the nature of the damped and metal-line absorbers, we have imaged the system with the UH 2.2m Tip-Tilt system and QUIRC infrared array. Our images have excellent image quality (FWHM = 0.3'') and cover ~ 1.5' centered on the QSO. This corresponds to a diameter of ~ 750 kpc at the absorption redshift of the damped Lyalpha system (Omega =0.3, H_deg=65 km s(-1) Mpc(-1) ). A 10 kpc galactic disk at this redshift would have an angular extent of 1.2''. This data was obtained as part of an ongoing program designed to relate the absorption characteristics of damped Lyalpha absorbers to the ISM of nearby galaxies and image the intervening systems responsible (see Jim & Roth, Bauer et al., & Kolhatkar et al. also presenting at this session).

  17. Variable X-Ray Absorption in the Mini-BAL QSO PG 1126-041

    NASA Technical Reports Server (NTRS)

    Giustini, M.; Cappi, M.; Chartas, G.; Dadina, M.; Eracleous, M.; Ponti, G.; Proga, D.; Tombesi, F.; Vignali, C.; Palumbo, G. G. C.

    2011-01-01

    Context. X-ray studies of AGN with powerful nuclear winds are important to constrain the physics of the inner accretion/ejection flow around SMBH, and to understand the impact of such winds on the AGN environment. Aims. Our main scientific goal is to constrain the properties of a variable outflowing absorber that is thought to be launched near the SMBH of the mini-BAL QSO PG 1126-041 using a multi-epoch observational campaign performed with XMM-Newton. Methods. We performed temporally resolved X-ray spectroscopy and simultaneous UV and X-ray photometry on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Results. We found complex X-ray spectral variability on time scales of both months and hours, best reproduced by means of variable massive ionized absorbers along the line of sight. As a consequence, the observed optical-to-X-ray spectral index is found to be variable with time. In the highest signal-to-noise observation we detected highly ionized X-ray absorbing material outflowing much faster (u(sub X) approx. 16 500 km/s) than the UV absorbing one (u(sub uv) approx. 5,000 km/s). This highly ionized absorber is found to be variable on very short (a few kiloseconds) time scales. Conclusions. Our findings are qualitatively consistent with line driven accretion disk winds scenarios. Our observations have opened the time-resolved X-ray spectral analysis field for mini-BAL QSOs; only with future deep studies will we be able to map the dynamics of the inner flow and understand the physics of AGN winds and their impact on the environment.

  18. Suzaku observations of the type 2 QSO in the central galaxy of the Phoenix cluster

    SciTech Connect

    Ueda, Shutaro; Hayashida, Kiyoshi; Anabuki, Naohisa; Nakajima, Hiroshi; Koyama, Katsuji; Tsunemi, Hiroshi

    2013-11-20

    We report the Suzaku/XIS and HXD and Chandra/ACIS-I results on the X-ray spectra of the Phoenix cluster at the redshift z = 0.596. The spectrum of the intracluster medium (ICM) is well reproduced with the emissions from low-temperature (∼3.0 keV and ∼0.76 solar) and high-temperature (∼11 keV and ∼0.33 solar) plasmas; the former is localized at the cluster core, while the latter distributes over the cluster. In addition to these ICM emissions, a strongly absorbed power-law component is found, which is due to an active galactic nucleus (AGN) in the cluster center. The absorption column density and unobscured luminosity of the AGN are ∼3.2 × 10{sup 23} cm{sup –2} and ∼4.7 × 10{sup 45} erg s{sup –1} (2-10 keV), respectively. Furthermore, a neutral iron (Fe I) K-shell line is discovered for the first time with the equivalent width (EW) of ∼150 eV at the rest frame. The column density and the EW of the Fe I line are exceptionally large for such a high-luminosity AGN, and hence the AGN is classified as a type 2 quasi-stellar object (QSO). We speculate that a significant fraction of the ICM cooled gas would be consumed to maintain the torus and to activate the type 2 QSO. The Phoenix cluster has a massive starburst in the central galaxy, indicating that suppression in the cooling flow is less effective. This may be because the onset of the latest AGN feedback has occurred recently and has not yet been effective. Alternatively, the AGN feedback is predominantly in radiative mode, not in kinetic mode, and the torus may work as a shield to reduce its effect.

  19. Tomography of the intergalactic medium with Lyα forests in close QSO pairs

    NASA Astrophysics Data System (ADS)

    D'Odorico, V.; Viel, M.; Saitta, F.; Cristiani, S.; Bianchi, S.; Boyle, B.; Lopez, S.; Maza, J.; Outram, P.

    2006-11-01

    We study the three-dimensional distribution of non-virialized matter at z ~ 2 using high-resolution spectra of quasi-stellar object (QSO) pairs and simulated spectra drawn from cosmological hydrodynamical simulations. We have collected the largest sample of QSO pairs ever observed with Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT), with angular separations between ~1 and 14arcmin. The observed correlation functions of the transmitted flux in the HI Lyman α forest along and transverse to the lines of sight are in good agreement implying that the distortions in redshift space due to peculiar velocities are small. The clustering signal is significant up to velocity separations of ~200kms-1, or about 3h-1 comoving Mpc. The regions at lower overdensity are still clustered but on smaller scales (Δv <~ 100kms-1). The observed and simulated correlation functions are compatible at the 3σ level. A better concordance is obtained when only the low overdensity regions are selected for the analysis or when the effective optical depth of the simulated spectra is increased artificially, suggesting a deficiency of strong lines in the simulated spectra. We found that also a lower value of the power-law index of the temperature-density relation for the Lyman α forest gas improves the agreement between observed and simulated results. If confirmed, this would be consistent with other observations favouring a late HeII reionization epoch (at z ~ 3). We remark the detection of a significant clustering signal in the cross-correlation coefficient at a transverse velocity separation Δv⊥ ~ 500kms-1 whose origin needs further investigation. Based on observations collected at the European Southern Observatory Very Large Telescope, Cerro Paranal, Chile - Programs 65.O-0299(A), 68.A-0216(A), 69.A-0204(A), 69.A-0586(A), 70.A-0031(A), 166.A-0106(A). E-mail: dodorico@oats.inaf.it

  20. A study of ultraviolet absorption lines through the complete Galactic halo by the analysis of HST faint object spectrograph spectra of active Galactic nuclei, 1

    NASA Technical Reports Server (NTRS)

    Burks, Geoffrey S.; Bartko, Frank; Shull, J. Michael; Stocke, John T.; Sachs, Elise R.; Burbidge, E. Margaret; Cohen, Ross D.; Junkkarinen, Vesa T.; Harms, Richard J.; Massa, Derck

    1994-01-01

    The ultraviolet (1150 - 2850 A) spectra of a number of active galactic nuclei (AGNs) observed with the Hubble Space Telescope (HST) Faint Object Spectrograph (FOS) have been used to study the properties of the Galactic halo. The objects that served as probes are 3C 273, PKS 0454-220, Pg 1211+143, CSO 251, Ton 951, and PG 1351+640. The equivalent widths of certain interstellar ions have been measured, with special attention paid to the C IV/C II and Si IV/Si II ratios. These ratios have been intercompared, and the highest values are found in the direction of 3C 273, where C IV/C II = 1.2 and Si IV/Si II greater than 1. These high ratios may be due to a nearby supernova remnant, rather than to ionized gas higher up in the Galactic halo. Our data give some support to the notion that QSO metal-line systems may arise from intervening galaxies which contain high supernova rates, galactic fountains, and turbulent mixing layers.

  1. Search for alpha variation in UVES spectra: Analysis of C IV and Si IV doublets towards QSO 1101-264

    NASA Astrophysics Data System (ADS)

    Martínez Fiorenzano, A. F.; Vladilo, G.; Bonifacio, P.

    Motivated by previous studies of QSO spectra that reported a variation of the fine structure constant alpha , a search for C IV and Si IV doublets was conducted in the absorption spectrum toward QSO 1101-264, obtained by VLT-UVES during the Science Verification. Seven C IV and two Si IV systems were identified and accurate measurements of wavelengths over the redshift range 1.1862 < z < 1.8377 were performed. After a careful selection of pairs of lines, the ``Alkali Doublet" method with a derived analitical expression for the error analysis was applied to compute the alpha variation. The result according in magnitud order with previous doublets measurements, corresponds to one Si IV system: Delta alpha /alpha = (- 3.09 +/- 8.46) x 10-5. Data from UVES-VLT.

  2. Narrow-band forbidden O III imaging of the QSO 4C 18.68 - A tidal tail revealed?

    NASA Technical Reports Server (NTRS)

    Shara, M. M.; Moffat, A. F. J.; Albrecht, R.

    1985-01-01

    The z = 0.313 quasar 4C 18.68 and its surroundings in the light of redshifted forbidden O III were imaged. The QSO appears much more extended than in broad-band images, with a large halo and possibly a faint tidal tail discerned. A broad-band I CCD image taken in 1 - 1.2 arcsec seeing resolves the QSO from a companion galaxy 3.6 arcsec distant, similar to many others seen in the field. It is suggested that the elongated and asymmetric shapes of some QSOs may be due to not-quite-resolved companion galaxies, and that caution be exercised in interpreting luminosity and color profiles as evidence for underlying spiral or elliptical structure.

  3. A study of the discrepant QSO X-ray luminosity function from the HEAO-2 data archive

    NASA Technical Reports Server (NTRS)

    Margon, B.

    1986-01-01

    Sensitive X-ray information for approximately 90 previously uncataloged Quasi-Stellar Objects (QSOs) in the redshift range 1.8 is less than or equal to z which is less than or equal to 3. Even with the longest esixting Einstein Observatory X-ray exposures, only 25% of these objects are positively detected in X-rays. The data were used to investigate the ensemble X-ray properties of high redshift QSOs, and the QSO population in general.

  4. Evidence for Ultra-Fast Outflows in Radio-Quiet AGNs. 2; Detailed Photoionization Modeling of Fe K-Shell Absorption Lines

    NASA Technical Reports Server (NTRS)

    Tombesi, Francesco; Clapp, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.; Dadina, M.

    2011-01-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet AGNs. In the previous paper of this series we defined UFOs as those absorbers with an outflow velocity higher than 10,000km/s and assessed the statistical significance of the associated blue shifted FeK absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. In the present paper we report a detailed curve of growth analysis and directly model the FeK absorbers with the Xstar photo-ionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35%. The outflow velocity distribution spans from \\sim10,000km/s (\\sim0.03c) up to \\siml00,000kmis (\\sim0.3c), with a peak and mean value of\\sim42,000km/s (\\sim0.14c). The ionization parameter is very high and in the range log\\xi 3-6 erg s/cm, with a mean value of log\\xi 4.2 erg s/cm. The associated column densities are also large, in the range N_H\\siml0(exp 22)-10(exp 24)/sq cm, with a mean value of N_H\\siml0(exp23)/sq cm. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected cosmological feedback from AGNs and their study can provide important clues on the connection between accretion disks, winds and jets.

  5. CHANDRA VIEW OF THE WARM-HOT INTERGALACTIC MEDIUM TOWARD 1ES 1553+113: ABSORPTION-LINE DETECTIONS AND IDENTIFICATIONS. I

    SciTech Connect

    Nicastro, F.; Zappacosta, L.; Elvis, M.; Krongold, Y.; Mathur, S.; Gupta, A.; Danforth, C.; Shull, J. M.; Barcons, X.; Borgani, S.; Branchini, E.; Cen, R.; Dave, R.; Kaastra, J.; Paerels, F.; Piro, L.; Takei, Y.

    2013-06-01

    We present the first results from our pilot 500 ks Chandra Low Energy Transmission Grating Large Program observation of the soft X-ray brightest source in the z {approx}> 0.4 sky, the blazar 1ES 1553+113, aimed to secure the first uncontroversial detections of the missing baryons in the X-rays. We identify a total of 11 possible absorption lines, with single-line statistical significances between 2.2{sigma} and 4.1{sigma}. Six of these lines are detected at high single-line statistical significance (3.6 {<=} {sigma} {<=} 4.1), while the remaining five are regarded as marginal detections in association with either other X-ray lines detected at higher significance and/or far-ultraviolet (FUV) signposts. Three of these lines are consistent with metal absorption at z {approx_equal} 0, and we identify them with Galactic O I and C II. The remaining eight lines may be imprinted by intervening absorbers and are all consistent with being high-ionization counterparts of FUV H I and/or O VI intergalactic medium signposts. In particular, five of these eight possible intervening absorption lines (single-line statistical significances of 4.1{sigma}, 4.1{sigma}, 3.9{sigma}, 3.8{sigma}, and 2.7{sigma}), are identified as C V and C VI K{alpha} absorbers belonging to three WHIM systems at z{sub X} = 0.312, z{sub X} = 0.237, and (z{sub X} ) = 0.133, which also produce broad H I (and O VI for the z{sub X} = 0.312 system) absorption in the FUV. For two of these systems (z{sub X} = 0.312 and 0.237), the Chandra X-ray data led the a posteriori discovery of physically consistent broad H I associations in the FUV (for the third system the opposite applies), so confirming the power of the X-ray-FUV synergy for WHIM studies. The true statistical significances of these three X-ray absorption systems, after properly accounting for the number of redshift trials, are 5.8{sigma} (z{sub X} = 0.312; 6.3{sigma} if the low-significance O V and C V K{beta} associations are considered), 3.9{sigma} (z

  6. Evidence for Ultra-fast Outflows in Radio-quiet Active Galactic Nuclei. II. Detailed Photoionization Modeling of Fe K-shell Absorption Lines

    NASA Astrophysics Data System (ADS)

    Tombesi, F.; Cappi, M.; Reeves, J. N.; Palumbo, G. G. C.; Braito, V.; Dadina, M.

    2011-11-01

    X-ray absorption line spectroscopy has recently shown evidence for previously unknown Ultra-fast Outflows (UFOs) in radio-quiet active galactic nuclei (AGNs). These have been detected essentially through blueshifted Fe XXV/XXVI K-shell transitions. In the previous paper of this series we defined UFOs as those highly ionized absorbers with an outflow velocity higher than 10,000 km s-1 and assessed the statistical significance of the associated blueshifted absorption lines in a large sample of 42 local radio-quiet AGNs observed with XMM-Newton. The present paper is an extension of that work. First, we report a detailed curve of growth analysis of the main Fe XXV/XXVI transitions in photoionized plasmas. Then, we estimate an average spectral energy distribution for the sample sources and directly model the Fe K absorbers in the XMM-Newton spectra with the detailed Xstar photoionization code. We confirm that the frequency of sources in the radio-quiet sample showing UFOs is >35% and that the majority of the Fe K absorbers are indeed associated with UFOs. The outflow velocity distribution spans from ~10,000 km s-1 (~0.03c) up to ~100,000 km s-1 (~0.3c), with a peak and mean value of ~42,000 km s-1 (~0.14c). The ionization parameter is very high and in the range log ξ ~ 3-6 erg s-1 cm, with a mean value of log ξ ~ 4.2 erg s-1 cm. The associated column densities are also large, in the range N H ~ 1022-1024 cm-2, with a mean value of N H ~ 1023 cm-2. We discuss and estimate how selection effects, such as those related to the limited instrumental sensitivity at energies above 7 keV, may hamper the detection of even higher velocities and higher ionization absorbers. We argue that, overall, these results point to the presence of extremely ionized and possibly almost Compton-thick outflowing material in the innermost regions of AGNs. This also suggests that UFOs may potentially play a significant role in the expected cosmological feedback from AGNs and their study can

  7. The Redshifted Hydrogen Balmer and Metastable He 1 Absorption Line System in Mini-FeLoBAL Quasar SDSS J112526.12+002901.3: A Parsec-scale Accretion Inflow?

    NASA Astrophysics Data System (ADS)

    Shi, Xi-Heng; Jiang, Peng; Wang, Hui-Yuan; Zhang, Shao-Hua; Ji, Tuo; Liu, Wen-Juan; Zhou, Hong-Yan

    2016-10-01

    The accretion of the interstellar medium onto central super-massive black holes is widely accepted as the source of the gigantic energy released by the active galactic nuclei. However, few pieces of observational evidence have been confirmed directly demonstrating the existence of the inflows. The absorption line system in the spectra of quasar SDSS J112526.12+002901.3 presents an interesting example in which the rarely detected hydrogen Balmer and metastable He i absorption lines are found redshifted to the quasar's rest frame along with the low-ionization metal absorption lines Mg ii, Fe ii, etc. The repeated SDSS spectroscopic observations suggest a transverse velocity smaller than the radial velocity. The motion of the absorbing medium is thus dominated by infall. The He i* lines present a powerful probe to the strength of ionizing flux, while the Balmer lines imply a dense environment. With the help of photoionization simulations, we find that the absorbing medium is exposed to the radiation with ionization parameter U ≈ 10-1.8, and the density is n({{H}})≈ {10}9 {{cm}}-3. Thus the absorbing medium is located ˜4 pc away from the central engine. According to the similarity in the distance and physical conditions between the absorbing medium and the torus, we strongly propose the absorption line system as a candidate for the accretion inflow, which originates in the inner surface of the torus.

  8. An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2012-01-01

    We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

  9. H2O and O2 Absorption-Line Abundances in the Coma of Comet 67P/Churyumov-Gerasimenko Measured by the R-Alice Ultraviolet Spectrograph

    NASA Astrophysics Data System (ADS)

    Keeney, Brian A.; Stern, S. Alan; Schindhelm, Eric; A'Hearn, Michael F.; Bertaux, Jean-Loup; Bieler, Andre; Feaga, Lori M.; Feldman, Paul D.; Parker, Joel Wm; Steffl, Andrew Joseph; Weaver, Harold A.

    2016-10-01

    The Alice far-UV spectrograph, aboard the ESA Rosetta spacecraft, has observed emissions in the wavelength range 800-2000 Å from the coma of Comet 67P/Churyumov-Gerasimenko since before orbital insertion in September 2014. We present novel observations of the cometary coma in absorption against the stellar continuum of UV-bright stars that were targeted or serendipitously observed near the comet's nucleus between April 2015 and February 2016 at heliocentric radii ranging from 1.2 to 2.4 AU. These spectra show clear signatures of absorption from gaseous H2O and O2. The observed H2O column densities agree well with values found by Rosetta's VIRTIS instrument (Bockelée-Morvan et al. 2015, A&A, 583, A6) and can be reasonably described by a simple Haser model. However, the absorption-derived O2/H2O ratio is somewhat larger than the 1-10% range reported by Rosetta's ROSINA mass spectrometer (Bieler et al. 2015, Nature, 526, 678) from September 2014 through March 2015 at heliocentric radii of 2.1-3.2 AU. We explore potential causes for this discrepancy, including systematic biases in the absorption-line measurements and seasonal variations in O2/H2O as the comet approaches perihelion.

  10. The dependence of C IV broad absorption line properties on accompanying Si IV and Al III absorption: relating quasar-wind ionization levels, kinematics, and column densities

    SciTech Connect

    Filiz Ak, N.; Brandt, W. N.; Schneider, D. P.; Trump, J. R.; Hall, P. B.; Anderson, S. F.; Hamann, F.; Myers, Adam D.; Pâris, I.; Petitjean, P.; Ross, Nicholas P.; Shen, Yue; York, Don

    2014-08-20

    We consider how the profile and multi-year variability properties of a large sample of C IV Broad Absorption Line (BAL) troughs change when BALs from Si IV and/or Al III are present at corresponding velocities, indicating that the line of sight intercepts at least some lower ionization gas. We derive a number of observational results for C IV BALs separated according to the presence or absence of accompanying lower ionization transitions, including measurements of composite profile shapes, equivalent width (EW), characteristic velocities, composite variation profiles, and EW variability. We also measure the correlations between EW and fractional-EW variability for C IV, Si IV, and Al III. Our measurements reveal the basic correlated changes between ionization level, kinematics, and column density expected in accretion-disk wind models; e.g., lines of sight including lower ionization material generally show deeper and broader C IV troughs that have smaller minimum velocities and that are less variable. Many C IV BALs with no accompanying Si IV or Al III BALs may have only mild or no saturation.

  11. STAR CLUSTERS IN M31. IV. A COMPARATIVE ANALYSIS OF ABSORPTION LINE INDICES IN OLD M31 AND MILKY WAY CLUSTERS

    SciTech Connect

    Schiavon, Ricardo P.; Caldwell, Nelson; Morrison, Heather; Harding, Paul; Courteau, Stephane; MacArthur, Lauren A.

    2012-01-15

    We present absorption line indices measured in the integrated spectra of globular clusters both from the Galaxy and from M31. Our samples include 41 Galactic globular clusters, and more than 300 clusters in M31. The conversion of instrumental equivalent widths into the Lick system is described, and zero-point uncertainties are provided. Comparison of line indices of old M31 clusters and Galactic globular clusters suggests an absence of important differences in chemical composition between the two cluster systems. In particular, CN indices in the spectra of M31 and Galactic clusters are essentially consistent with each other, in disagreement with several previous works. We reanalyze some of the previous data, and conclude that reported CN differences between M31 and Galactic clusters were mostly due to data calibration uncertainties. Our data support the conclusion that the chemical compositions of Milky Way and M31 globular clusters are not substantially different, and that there is no need to resort to enhanced nitrogen abundances to account for the optical spectra of M31 globular clusters.

  12. NONLINEAR COLOR-METALLICITY RELATIONS OF GLOBULAR CLUSTERS. V. NONLINEAR ABSORPTION-LINE INDEX VERSUS METALLICITY RELATIONS AND BIMODAL INDEX DISTRIBUTIONS OF M31 GLOBULAR CLUSTERS

    SciTech Connect

    Kim, Sooyoung; Yoon, Suk-Jin; Chung, Chul; Lee, Young-Wook; Caldwell, Nelson; Schiavon, Ricardo P.; Kang, Yongbeom; Rey, Soo-Chang

    2013-05-10

    Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We take this as a close analogy to the recent view that metallicity-color nonlinearity is primarily responsible for observed GC color bimodality. We also demonstrate that the metallicity-sensitive magnesium line displays non-negligible metallicity-index nonlinearity and Balmer lines show rather strong nonlinearity. This gives rise to bimodal index distributions, which are routinely interpreted as bimodal metallicity distributions, not considering metallicity-index nonlinearity. Our findings give a new insight into the constitution of M31's GC system, which could change much of the current thought on the formation of GC systems and their host galaxies.

  13. A Comparison of the Circumgalactic Medium of Present-Day Dwarf and Milky Way Galaxies using Absorption Line Analysis through Hydrodynamic Cosmological Simulations

    NASA Astrophysics Data System (ADS)

    Vander Vliet, Jacob R.; Churchill, C. W.; Trujillo-Gomez, S.; Klimek, E. S.; Klypin, A. A.

    2014-01-01

    Dwarf galaxies are predicted to have a unique halo structure. They experience the same feedback as more massive galaxies but lack the strong gravitational potential. The structure and composition of gas around dwarfs should be different than for gas around massive galaxies. These differences would show up in quasar absorption spectra. We test this idea by examining mock quasar spectra of the circumgalactic medium of two simulated dwarf galaxies to determine the extent of their metal halos at redshift zero. The galaxies are from a cosmological zoom-in simulation using Eulerian Gasdynamics plus N-body Adaptive Refinement Tree (ART) code. Both galaxies have the same initial conditions but are simulated with different physical conditions. One uses only supernova feedback while the other adds in radiative pressure and an increase in star formation efficiency to recreate the correct stellar properties. We measure the absorption lines of several ions including MgII, CIV, OVI, SiIV, and Ly beta and compare the covering fraction, equivalent width distribution and the velocity distribution for both simulations. These are then compared to more massive halos to explore how the galaxy's mass affects their CGM structure.

  14. A Deep Search For Faint Galaxies Associated With Very Low-redshift C IV Absorbers. II. Program Design, Absorption-line Measurements, and Absorber Statistics

    NASA Astrophysics Data System (ADS)

    Burchett, Joseph N.; Tripp, Todd M.; Prochaska, J. Xavier; Werk, Jessica K.; Tumlinson, Jason; O'Meara, John M.; Bordoloi, Rongmon; Katz, Neal; Willmer, C. N. A.

    2015-12-01

    To investigate the evolution of metal-enriched gas over recent cosmic epochs as well as to characterize the diffuse, ionized, metal-enriched circumgalactic medium, we have conducted a blind survey for C iv absorption systems in 89 QSO sightlines observed with the Hubble Space Telescope Cosmic Origins Spectrograph. We have identified 42 absorbers at z < 0.16, comprising the largest uniform blind sample size to date in this redshift range. Our measurements indicate an increasing C iv absorber number density per comoving path length (d{N}/{dX}= 7.5 ± 1.1) and modestly increasing mass density relative to the critical density of the universe (ΩC iv = 10.0 ± 1.5 × 10-8) from z ˜ 1.5 to the present epoch, consistent with predictions from cosmological hydrodynamical simulations. Furthermore, the data support a functional form for the column density distribution function that deviates from a single power law, also consistent with independent theoretical predictions. As the data also probe heavy element ions in addition to C iv at the same redshifts, we identify, measure, and search for correlations between column densities of these species where components appear to be aligned in velocity. Among these ion-ion correlations, we find evidence for tight correlations between C ii and Si ii, C ii and Si iii, and C iv and Si iv, suggesting that these pairs of species arise in similar ionization conditions. However, the evidence for correlations decreases as the difference in ionization potential increases. Finally, when controlling for observational bias, we find only marginal evidence for a correlation (86.8% likelihood) between the Doppler line width b(C iv) and column density N(C iv).

  15. The X-ray spectrum of QSO 0241+622. [OSO-8 observations

    NASA Technical Reports Server (NTRS)

    Worrall, D. M.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

    1980-01-01

    Proportional counters on the OsO-8 spacecraft measured the X-ray spectrum of QSR 0241+622 in the range 2-50 keV. The best power law fit has a proton spectral index and 90 percent errors gamma = 1.93 (+0.5, -0.3) and low energy absorption consistent with reported gas column densities, but a thermal bremsstrahlung form with temperature 13.1 keV cannot be excluded. No indication of spectral variability is found in three observations of the source with HEAO-A2, although a possible 15-30 percent intensity change over a period of 6 months was observed. The quasar is similar to 3C 273 in the proportion of energy emitted in various bands, excluding the radio, if reported radiation above 50 keV from its direction is indeed associated with QSO 0241+622. The two quasars are compared and possible energy generation scenarios are discussed. Implications concerning quasar contributions to the diffuse background are discussed.

  16. An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

    NASA Technical Reports Server (NTRS)

    Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

    2009-01-01

    We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

  17. NuSTAR reveals an intrinsically X-ray weak broad absorption line quasar in the ultraluminous infrared galaxy Markarian 231

    SciTech Connect

    Teng, Stacy H.; Rigby, J. R.; Brandt, W. N.; Luo, B.; Harrison, F. A.; Grefenstette, B. W.; Madsen, K. K.; Alexander, D. M.; Gandhi, P.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Fabian, A. C.; Farrah, D.; Fiore, F.; Hailey, C. J.; Hickox, R. C.; Ptak, A. F.; and others

    2014-04-10

    We present high-energy (3-30 keV) NuSTAR observations of the nearest quasar, the ultraluminous infrared galaxy (ULIRG) Markarian 231 (Mrk 231), supplemented with new and simultaneous low-energy (0.5-8 keV) data from Chandra. The source was detected, though at much fainter levels than previously reported, likely due to contamination in the large apertures of previous non-focusing hard X-ray telescopes. The full band (0.5-30 keV) X-ray spectrum suggests the active galactic nucleus (AGN) in Mrk 231 is absorbed by a patchy and Compton-thin (N{sub H}∼1.2{sub −0.3}{sup +0.3}×10{sup 23} cm{sup –2}) column. The intrinsic X-ray luminosity (L {sub 0.5–30} {sub keV} ∼ 1.0 × 10{sup 43} erg s{sup –1}) is extremely weak relative to the bolometric luminosity where the 2-10 keV to bolometric luminosity ratio is ∼0.03% compared to the typical values of 2%-15%. Additionally, Mrk 231 has a low X-ray-to-optical power law slope (α{sub OX} ∼ –1.7). It is a local example of a low-ionization broad absorption line quasar that is intrinsically X-ray weak. The weak ionizing continuum may explain the lack of mid-infrared [O IV], [Ne V], and [Ne VI] fine-structure emission lines which are present in sources with otherwise similar AGN properties. We argue that the intrinsic X-ray weakness may be a result of the super-Eddington accretion occurring in the nucleus of this ULIRG, and may also be naturally related to the powerful wind event seen in Mrk 231, a merger remnant escaping from its dusty cocoon.

  18. Mars Ozone Absorption Line Shapes from Infrared Heterodyne Spectra Applied to GCM-Predicted Ozone Profiles and to MEX/SPICAM Column Retrievals

    NASA Technical Reports Server (NTRS)

    Fast, Kelly E.; Kostiuk, T.; Annen, J.; Hewagama, T.; Delgado, J.; Livengood, T. A.; Lefevre, F.

    2008-01-01

    We present the application of infrared heterodyne line shapes of ozone on Mars to those produced by radiative transfer modeling of ozone profiles predicted by general circulation models (GCM), and to contemporaneous column abundances measured by Mars Express SPICAM. Ozone is an important tracer of photochemistry Mars' atmosphere, serving as an observable with which to test predictions of photochemistry-coupled GCMs. Infrared heterodyne spectroscopy at 9.5 microns with spectral resolving power >1,000,000 is the only technique that can directly measure fully-resolved line shapes of Martian ozone features from the surface of the Earth. Measurements were made with Goddard Space Flight Center's Heterodyne instrument for Planetary Wind And Composition (HIPWAC) at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii on February 21-24 2008 UT at Ls=35deg on or near the MEX orbital path. The HIPWAC observations were used to test GCM predictions. For example, a GCM-generated ozone profile for 60degN 112degW was scaled so that a radiative transfer calculation of its absorption line shape matched an observed HIPWAC absorption feature at the same areographic position, local time, and season. The RMS deviation of the model from the data was slightly smaller for the GCM-generated profile than for a line shape produced by a constant-with-height profile, even though the total column abundances were the same, showing potential for testing and constraining GCM ozone-profiles. The resulting ozone column abundance from matching the model to the HIPWAC line shape was 60% higher than that observed by SPICAM at the same areographic position one day earlier and 2.5 hours earlier in local time. This could be due to day-to-day, diurnal, or north polar region variability, or to measurement sensitivity to the ozone column and its distribution, and these possibilities will be explored. This work was supported by NASA's Planetary Astronomy Program.

  19. ORIGIN OF THE COMPLEX RADIO STRUCTURE IN BAL QSO 1045+352

    SciTech Connect

    Kunert-Bajraszewska, Magdalena; Gawronski, Marcin P.; Janiuk, Agnieszka; Siemiginowska, Aneta

    2010-08-01

    We present new, more sensitive, high-resolution radio observations of a compact broad absorption line (BAL) quasar, 1045+352, made with the EVN+MERLIN at 5 GHz. These observations allowed us to trace the connection between the arcsecond structure and the radio core of the quasar. The radio morphology of 1045+352 is dominated by a knotty jet showing several bends. We discuss possible scenarios that could explain such a complex morphology: galaxy merger, accretion disk instability, precession of the jet, and jet-cloud interactions. It is possible that we are witnessing an ongoing jet precession in this source due to internal instabilities within the jet flow; however, a dense environment detected in the submillimeter band and an outflowing material suggested by the X-ray absorption could strongly interact with the jet. It is difficult to establish the orientation between the jet axis and the observer in 1045+352 because of the complex structure. Nevertheless, taking into account the most recent inner radio structure, we conclude that the radio jet is oriented close to the line of sight, which can mean that the opening angle of the accretion disk wind can be large in this source. We also suggest that there is no direct correlation between the jet-observer orientation and the possibility of observing BALs.

  20. Origin of the Complex Radio Structure in BAL QSO 1045+352

    NASA Astrophysics Data System (ADS)

    Kunert-Bajraszewska, Magdalena; Janiuk, Agnieszka; Gawroński, Marcin P.; Siemiginowska, Aneta

    2010-08-01

    We present new, more sensitive, high-resolution radio observations of a compact broad absorption line (BAL) quasar, 1045+352, made with the EVN+MERLIN at 5 GHz. These observations allowed us to trace the connection between the arcsecond structure and the radio core of the quasar. The radio morphology of 1045+352 is dominated by a knotty jet showing several bends. We discuss possible scenarios that could explain such a complex morphology: galaxy merger, accretion disk instability, precession of the jet, and jet-cloud interactions. It is possible that we are witnessing an ongoing jet precession in this source due to internal instabilities within the jet flow; however, a dense environment detected in the submillimeter band and an outflowing material suggested by the X-ray absorption could strongly interact with the jet. It is difficult to establish the orientation between the jet axis and the observer in 1045+352 because of the complex structure. Nevertheless, taking into account the most recent inner radio structure, we conclude that the radio jet is oriented close to the line of sight, which can mean that the opening angle of the accretion disk wind can be large in this source. We also suggest that there is no direct correlation between the jet-observer orientation and the possibility of observing BALs.

  1. Resolving the inner structure of QSO discs through fold-caustic-crossing events

    NASA Astrophysics Data System (ADS)

    Abolmasov, P.; Shakura, N. I.

    2012-06-01

    Although the bulk of the observed optical flux from the discs of intermediate-redshift lensed quasars is formed well outside the region of strong relativistic boosting and light bending, relativistic effects have an important influence on microlensing curves. The reason lies in the divergent nature of amplification factors near fold caustics, which are increasingly sensitive to small spatial size details. Higher-order disc images produced by strong light bending around the black hole may affect the amplification curves, making a contribution of up to several per cent near maximum amplification. In accordance with theoretical predictions, some of the observed high-amplification events possess fine structure. Here we consider three putative caustic-crossing events, one by SBS J1520+530 and two events for individual images of Einstein's cross (QSO J2237+0305). Using relativistic disc models allows us to improve the fits but the required inclinations are high, ?. Such high inclinations apparently contradict the absence of any strong absorption that is likely to arise if a disc is observed edge-on through a dust torus. Still, high inclinations are required only for the central parts of the disc, which allows the disc itself initially to be tilted by 60-90° with respect to the black hole and aligned toward the black hole equatorial plane near the last stable orbit radius. For SBS J1520+530, an alternative explanation for the observed amplification curve is a superposition of two subsequent fold-caustic crossings. While relativistic disc models favour black hole masses ˜1010 M⊙ (several times higher than the virial estimates) or small Eddington ratios, this model is consistent with the observed distribution of galaxies over peculiar velocities only if the black hole mass is ?.

  2. Coronal properties of the luminous radio-quiet quasar QSO B2202-209

    NASA Astrophysics Data System (ADS)

    Kammoun, E. S.; Risaliti, G.; Stern, D.; Jun, H. D.; Graham, M.; Celotti, A.; Behar, E.; Elvis, M.; Harrison, F. A.; Matt, G.; Walton, D. J.

    2017-02-01

    We present an analysis of the joint XMM-Newton and NuSTAR observations of the radio-quiet quasar QSO B2202-209. Using an optical observation from the Hale Telescope at the Palomar Observatory, we revise the redshift of the source from the previously reported z = 1.77 to z = 0.532, and we estimate the mass of the central black hole, log (MBH/M⊙) = 9.08 ± 0.18. The X-ray spectrum of this source can be well described by a power law of photon index Γ = 1.82 ± 0.05 with E_cut = 152_{-54}^{+103} keV, in the rest frame of the source. Assuming a Comptonization model, we estimate the coronal temperature to be kTe = 42 ± 3 keV and kTe = 56 ± 3 keV for a spherical and a slab geometry, respectively. The coronal properties are comparable to the ones derived for local active galactic nuclei, despite a difference of around one order of magnitude in black hole mass and X-ray luminosity (L2 - 10 = 1.93 × 1045 erg s-1). The quasar is X-ray loud, with an unusually flat observed optical-to-X-ray spectral slope αOX = 1.00 ± 0.02, and has an exceptionally strong optical [O III] line. Assuming that both the X-ray emission and the [O III] line are isotropic, these two extreme properties can be explained by a nearly edge-on disc, leading to a reduction in the observed ultraviolet continuum light.

  3. On the QSO Content of the First Byurakan Survey and the Completeness of the Palomar Green Survey

    NASA Astrophysics Data System (ADS)

    Véron, Philippe; Mickaelian, A. M.; Gonçalves, A. C.; Véron-Cetty, M.-P.

    The second part of the First Byurakan Survey is aimed at detecting all bright (B < 16.5) UV-excess starlike objects in a large area of the sky. By comparison with major X-ray and radio surveys we tentatively identified as QSOs 11 FBS objects. We made spectroscopic observations of nine of them. We found six new QSOs bringing the total number of known QSOs in this survey to 42. By comparison with the Palomar Green (PG) QSO survey, we found that the completeness of this last survey is of the order of 70% rather than 30-50% as suggested by several authors.

  4. The radiation pressure-driven Rayleigh-Taylor instability - Analysis and application to QSO emission line clouds

    NASA Technical Reports Server (NTRS)

    Krolik, J. H.

    1979-01-01

    The growth of perturbations in a photoionized gas slab accelerated by radiation pressure under conditions like those in QSO emission-line regions is analyzed. A linear dispersion relation is derived, and numerical radiation-transfer calculations are performed to evaluate the coefficients and roots of that dispersion relation for L-alpha optical depths between 0.1 and 10,000. The nonlinear growth of the waves is estimated, and it is concluded that complete dispersal of the clouds is likely. On the basis of qualitative arguments it is suggested that clouds of greater optical depth are linearly stable.

  5. Weak Hard X-Ray Emission from Two Broad Absorption Line Quasars Observed with NuStar: Compton-Thick Absorption or Intrinsic X-Ray Weakness?

    NASA Technical Reports Server (NTRS)

    Luo, B.; Brandt, W. N.; Alexander, D. M.; Harrison, F. A.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Christensen, F. E.; Comastri, A.; Craig, W. W..; Fabian, A. C.; Farrah, D.; Fiore, F.; Fuerst, F.; Grefenstette, B. W.; Hailey, C. J.; Hickox, R.; Madsen, K. K.; Matt, G.; Ogle, P.; Risaliti, G.; Saez, C.; Teng, S. H.; Walton, D. J.; Zhang, W. W.

    2013-01-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain approx. or equal to 400-600 hard X-ray (is greater than or equal to 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed N(sub H) is less than or equal to 10(exp24) cm(exp-2). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N(sub H) 7 × 10(exp 24) cm(exp-2) if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe Ka line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  6. WEAK HARD X-RAY EMISSION FROM TWO BROAD ABSORPTION LINE QUASARS OBSERVED WITH NuSTAR: COMPTON-THICK ABSORPTION OR INTRINSIC X-RAY WEAKNESS?

    SciTech Connect

    Luo, B.; Brandt, W. N.; Alexander, D. M.; Hickox, R.; Harrison, F. A.; Fuerst, F.; Grefenstette, B. W.; Madsen, K. K.; Stern, D.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Fabian, A. C.; Farrah, D.; Fiore, F.; Hailey, C. J.; Matt, G.; Ogle, P.; and others

    2013-08-01

    We present Nuclear Spectroscopic Telescope Array (NuSTAR) hard X-ray observations of two X-ray weak broad absorption line (BAL) quasars, PG 1004+130 (radio loud) and PG 1700+518 (radio quiet). Many BAL quasars appear X-ray weak, probably due to absorption by the shielding gas between the nucleus and the accretion-disk wind. The two targets are among the optically brightest BAL quasars, yet they are known to be significantly X-ray weak at rest-frame 2-10 keV (16-120 times fainter than typical quasars). We would expect to obtain Almost-Equal-To 400-600 hard X-ray ({approx}> 10 keV) photons with NuSTAR, provided that these photons are not significantly absorbed (N{sub H} {approx}< 10{sup 24} cm{sup -2}). However, both BAL quasars are only detected in the softer NuSTAR bands (e.g., 4-20 keV) but not in its harder bands (e.g., 20-30 keV), suggesting that either the shielding gas is highly Compton-thick or the two targets are intrinsically X-ray weak. We constrain the column densities for both to be N{sub H} Almost-Equal-To 7 Multiplication-Sign 10{sup 24} cm{sup -2} if the weak hard X-ray emission is caused by obscuration from the shielding gas. We discuss a few possibilities for how PG 1004+130 could have Compton-thick shielding gas without strong Fe K{alpha} line emission; dilution from jet-linked X-ray emission is one likely explanation. We also discuss the intrinsic X-ray weakness scenario based on a coronal-quenching model relevant to the shielding gas and disk wind of BAL quasars. Motivated by our NuSTAR results, we perform a Chandra stacking analysis with the Large Bright Quasar Survey BAL quasar sample and place statistical constraints upon the fraction of intrinsically X-ray weak BAL quasars; this fraction is likely 17%-40%.

  7. Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph Observations of Intervening O VI Absorption Line Systems in the Spectrum of PG 0953+415

    NASA Astrophysics Data System (ADS)

    Savage, B. D.; Sembach, K. R.; Tripp, T. M.; Richter, P.

    2002-01-01

    We present Far Ultraviolet Spectroscopic Explorer (FUSE) and Space Telescope Imaging Spectrograph (STIS) observations of the intergalactic medium toward the bright QSO PG 0953+415 (zem=0.239). The FUSE spectra extend from 905 to 1187 Å and have a resolution of 25 km s-1, while the STIS spectra cover 1150-1730 Å and have a resolution of 7 km s-1. Additional STIS observations at 30 km s-1 are obtained in selected wavelength ranges. An O VI system at z=0.06807 is detected in H I Lyα, Lyβ, Lyγ, O VI λλ1031.93, 1037.62, N V λλ1238.82, 1242.80, C IV λλ1548.20, 1550.77, and C III λ977.02. The observed column densities can be modeled as a low-density intervening gas with a metallicity of 0.4+0.6-0.2 times solar in photoionization equilibrium with the ionizing extragalactic background radiation. The best fit is achieved with an ionization parameter, logU=-1.35, which implies nH~10-5 cm-3 and a path length of ~80 kpc through the absorbing gas. H I Lyα absorption at z=0.14232 spans a velocity range of 410 km s-1 with the strongest components near 0 and 80 km s-1 in the z=0.14232 rest frame. In this system, O VI λλ1031.93, 1037.62 absorption is strong near 0 km s-1 and not detected at 80 km s-1. C III λ977.02 absorption is marginally detected at 80 km s-1 but is not detected at 0 km s-1. The observations place constraints on the properties of the z=0.14232 system but do not discriminate between collisional ionization in hot gas versus photoionization in a very low density medium with an ionization parameter logU>-0.74. The z=0.06807 and 0.14232 O VI systems occur at redshifts where there are peaks in the number density of intervening galaxies along the line of sight determined from WIYN redshift measurements of galaxies in the ~1° field centered on PG 0953+415. We combine our observations of PG 0953+415 with those for other QSOs to update the estimate of the low-redshift number density of intervening O VI systems. Over a total unobscured redshift path of Δz=0

  8. A Monster At Any Other Epoch: Are Intermediate Redshift ULIRGs the Progenitors of QSO Host Galaxies?

    NASA Astrophysics Data System (ADS)

    Rothberg, Barry; Fischer, Jackie; Rodrigues, Myriam; Pirzkal, Nor

    2015-08-01

    There is a clear progression from merger-induced SF to QSO activity via Ultraluminous Infrared Galaxies (ULIRGs). While not all mergers are ULIRGs, multi-wavelength imaging confirms that all local ULIRGs are mergers. At 0.4 < z < 1.0, the star-formation rates, gas fractions, and masses are believed to be significantly higher than in the local universe (i.e. due to "Downsizing"). ULIRGs begin to dominate the SF activity in the Universe at z˜0.7, and at z>1 are responsible for ˜ 70% of the co-moving IR density. At these earlier epochs ULIRGs contained more gas, formed stars faster, and their number density was much higher. At z>1 there are conflicting conclusions about ULIRGs. Many studies conclude they are massive star-forming galaxies, not major mergers nor AGN. Nearly all studies of ULIRGs at z > 0.4 have selected these systems via scaling observed 24μm or 170μm Spitzer fluxes to integrated 8-1000μm fluxes and inferring masses from scaling photometric fluxes or millimeter observations of CO gas emission. These methods often rely heavily on uncertain assumptions (e.g. gas conversions, SED fitting and templates). Instead, we have assembled a representative sample of "classically" selected ULIRGs (60 and 100μm IRAS fluxes and 12 and 25μm WISE fluxes) for 0.4 < z < 1.0 and obtained optical and near-IR imaging and spectroscopy from Hubble Space Telescope, Keck, and the Large Binocular Telescope. We use the same techniques for measuring the dynamical and BH masses of ULIRGs in the local Universe to measure these parameters in more distant systems. Unlike other methods, we directly measure the mass at an epoch when galaxy formation and evolution appears to have changed dramatically from what we see today and compare these intermediate redshift ULIRGs with their counterparts in the local Universe. Our restframe optical and UV spectroscopy also allow us to directly probe gas-metallicities, outflows, and measure the properties of their stellar populations. Our

  9. Detection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Arcaro, C.; Babic, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Bretz, T.; Buson, S.; Carosi, A.; Chatterjee, A.; Clavero, R.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Oña Wilhelmi, E.; Di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Idec, W.; Kodani, K.; Konno, Y.; Kubo, H.; Kushida, J.; La Barbera, A.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Coto, R.; Majumdar, P.; Makariev, M.; Mallot, K.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Miranda, J. M.; Mirzoyan, R.; Moralejo, A.; Moretti, E.; Nakajima, D.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Poutanen, J.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Toyama, T.; Treves, A.; Vanzo, G.; Verguilov, V.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zanin, R.; Desiante, R.

    2016-11-01

    Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components that are spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. Aims: The spectral energy distribution of QSO B0218+357 can give information on the energetics of z 1 very high energy gamma-ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z 1. Methods: MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and sub-TeV data obtained by Fermi-LAT and MAGIC are used to set constraints on the extragalactic background light. Results: Very high energy gamma-ray emission was detected from the direction of QSO B0218+357 by the MAGIC telescopes during the expected time of arrival of the trailing component of the flare, making it the farthest very high energy gamma-ray source detected to date. The observed emission spans the energy range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy distribution of QSO B0218+357 is consistent with current extragalactic background light models. The broadband emission can be modeled in the framework of a two-zone external Compton scenario, where the GeV emission comes from an emission region in the jet, located outside the broad line region.

  10. HST/COS observations of a new population of associated QSO absorbers

    NASA Astrophysics Data System (ADS)

    Muzahid, S.; Srianand, R.; Arav, N.; Savage, B. D.; Narayanan, A.

    2013-05-01

    . However, detection of absorption line variability with repeat HST/COS observations will allow us to (i) distinguish between these alternatives, (ii) establish the location of the absorbing gas and (iii) understand the mechanism that provides stability to the multiphase medium. These are important for understanding the contribution of associated Ne VIII absorbers to the AGN feedback.

  11. PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

    SciTech Connect

    Vayner, Andrey; Wright, Shelley A.; Do, Tuan; Larkin, James E.; Armus, Lee; Gallagher, S. C.

    2016-04-10

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ∼ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ∼0.″2 (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (z{sub Hα} = 2.182) and SDSS J0925+0655 (z{sub Hα} = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M{sub ⊙} yr{sup −1} originating from a compact region that is kinematically offset by 290–350 km s{sup −1}. For SDSS J0925+0655 we infer a SFR of 29 M{sub ⊙} yr{sup −1} distributed over three clumps that are spatially offset by ∼7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M{sub ⊙} yr{sup −1} kpc{sup −2}. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M{sub ⊙} yr{sup −1} kpc{sup −2}. These IFS observations indicate that while the central black hole is accreting mass at 10%–40% of the Eddington rate, if

  12. The primordial deuterium abundance: subDLA system at zabs = 2.437 towards the QSO J 1444+2919

    NASA Astrophysics Data System (ADS)

    Balashev, S. A.; Zavarygin, E. O.; Ivanchik, A. V.; Telikova, K. N.; Varshalovich, D. A.

    2016-05-01

    We report a new detection of neutral deuterium in the sub-Damped Lyman Alpha system with low metallicity [O/H] = -2.042 ± 0.005 at zabs = 2.437 towards QSO J 1444+2919. The hydrogen column density in this system is logN(H I) =19.983 ± 0.010 and the measured value of deuterium abundance is log(D/H) = -4.706 ± 0.007stat ± 0.067syst. This system meets the set of strict selection criteria stated recently by Cooke et al. 2014 and, therefore, widens the Precision Sample of D/H. However, possible underestimation of systematic errors can bring a bias into the mean D/H value (especially if one uses a weighted mean). Hence, it might be reasonable to relax these selection criteria and thus increase the number of acceptable absorption systems with measured D/H values. The unweighted mean value of 15 robust D/H measurements gives a conservative value of the primordial deuterium abundance (D/H)p = (2.54 ± 0.19) × 10-5 which is in good agreement with the prediction given by analysis of the cosmic microwave background radiation for the standard big bang nucleosynthesis. By means of the derived unweighted mean (D/H)p value the baryon density of the Universe Ωbh2 = 0.0218 ± 0.0010 and the baryon-to-photon ratio η = (5.96 ± 0.27) × 10-10 have been deduced. These values have confidence intervals which are less stringent than that obtained for the Precision Sample and, thus, leave a broader window for new physics. The latter is particularly important in the light of the lithium problem.

  13. The Stellar Initial Mass Function in Early-type Galaxies from Absorption Line Spectroscopy. IV. A Super-Salpeter IMF in the Center of NGC 1407 from Non-parametric Models

    NASA Astrophysics Data System (ADS)

    Conroy, Charlie; van Dokkum, Pieter G.; Villaume, Alexa

    2017-03-01

    It is now well-established that the stellar initial mass function (IMF) can be determined from the absorption line spectra of old stellar systems, and this has been used to measure the IMF and its variation across the early-type galaxy population. Previous work focused on measuring the slope of the IMF over one or more stellar mass intervals, implicitly assuming that this is a good description of the IMF and that the IMF has a universal low-mass cutoff. In this work we consider more flexible IMFs, including two-component power laws with a variable low-mass cutoff and a general non-parametric model. We demonstrate with mock spectra that the detailed shape of the IMF can be accurately recovered as long as the data quality is high (S/N ≳ 300 Å‑1) and cover a wide wavelength range (0.4–1.0 μm). We apply these flexible IMF models to a high S/N spectrum of the center of the massive elliptical galaxy NGC 1407. Fitting the spectrum with non-parametric IMFs, we find that the IMF in the center shows a continuous rise extending toward the hydrogen-burning limit, with a behavior that is well-approximated by a power law with an index of ‑2.7. These results provide strong evidence for the existence of extreme (super-Salpeter) IMFs in the cores of massive galaxies.

  14. The short- and long-term frequency stabilization of an injection-locked Nd:YAG laser in reference to a Fabry-Perot cavity and an iodine saturated absorption line

    NASA Astrophysics Data System (ADS)

    Musha, Mitsuru; Kanaya, Takeshi; Nakagawa, Ken'ichi; Ueda, Ken-ichi

    2000-09-01

    We have developed a wideband frequency-stabilized injection-locked Nd:YAG laser as a light source for the laser interferometric gravitational wave detector, in which short-term frequency stability of the laser improves the sensitivity of the interferometer and the long-term frequency stability aims for the stable long-time operation of the interferometer. The frequency of a 2-W injection-locked laser is locked to both a rigid Fabry-Perot cavity with ULE spacer and saturated absorption line of 127I2 simultaneously with two nested servo loops, and the long-term as well as short-term frequency stability are obtained. The drift of the resonant frequency of the rigid Fabry-Perot cavity is measured and the stability of the Fabry-Perot cavity is estimated to be 20× f-1 [Hz/√Hz]. The predicted frequency stabilities of the present dual-reference-locked laser are numerically simulated. Our wideband frequency-stabilized laser is also available for the high-resolution spectroscopy.

  15. Quasar Absorption Lines and SDSS Galaxies

    NASA Astrophysics Data System (ADS)

    Shoemaker, Emileigh Suzanne; Scott, Jennifer E.; Oldak, Katarzyna

    2017-01-01

    We present the results of a study of the sightlines of 45 low redshift quasars (0.06 < z < 0.85) observed with HST/COS that lie within the footprint of the Sloan Digital Sky Survey. We use both the SDSS DR12 galaxy photometric data, including photometric redshifts, and the measured properties of the absorbers along with the known absorption characteristics of the intergalactic medium and the circumgalactic medium of galaxies to assign the most probable galaxy matches for each absorber in the sample, using estimated galaxy luminosities and virial radii as a discriminator. We show that the scheme can recover known galaxy-absorber matches found from spectroscopic data and thus provides a method for identifying likely pairs in photometric data sets as well as targets for spectroscopic follow up.

  16. Variability of GeV gamma-ray emission in QSO B0218+357 due to microlensing on intermediate size structures

    NASA Astrophysics Data System (ADS)

    Sitarek, J.; Bednarek, W.

    2016-06-01

    Strong gravitational lensing leads to an occurrence of multiple images, with different magnifications, of a lensed source. Those magnifications can in turn be modified by microlensing on smaller mass scales within the lens. Recently, measurements of the changes in the magnification ratio of the individual images have been proposed as a powerful tool for estimation of the size and velocity of the emission region in the lensed source. The changes of the magnification ratios in blazars PKS1830-211 and QSO B0218+357, if interpreted as caused by a microlensing on individual stars, put strong constraints on those two variables. These constraints are difficult to accommodate with the current models of gamma-ray emission in blazars. In this paper we study if similar changes in the magnification ratio can be caused by microlensing on intermediate size structures in the lensing galaxy. We investigate in details three classes of possible lenses: globular clusters (GCs), open clusters (OCs) and giant molecular clouds (GMCs). We apply this scenario to the case of QSO B0218+357. Our numerical simulations show that changes in magnifications with similar time-scales can be obtained for relativistically moving emission regions with sizes up to 0.01 pc in the case of microlensing on the cores of GCs or clumps in GMCs. From the density of such structures in spiral galaxies we estimate however that lensing in GMCs would be more common.

  17. The low-metallicity QSO HE 2158 - 0107: a massive galaxy growing by accretion of nearly pristine gas from its environment?

    NASA Astrophysics Data System (ADS)

    Husemann, B.; Wisotzki, L.; Jahnke, K.; Sánchez, S. F.

    2011-11-01

    The metallicities of active galactic nuclei (AGN) are usually well above solar in their narrow-line regions, often reaching up to several times solar in their broad-line regions independent of redshift. Low-metallicity AGN are rare objects that have so far always been associated with low-mass galaxies hosting low-mass black holes (MBH106M⊙). We present integral field spectroscopy data of the low-redshift (z = 0.212) quasi-stellar object (QSO) HE 2158 - 0107 for which we find strong evidence of sub-solar NLR metallicities associated with a massive black hole (MBH ~ 3 × 108M⊙). The QSO is surrounded by a large extended emission-line region reaching out to 30 kpc from the QSO in a tail-like geometry. We present optical and near-infrared images and investigate the properties of the host galaxy. The host of HE 2158 - 0107 is most likely a very compact bulge-dominated galaxy with a size of re ~ 1.4 kpc. The multi-colour spectral energy distribution (SED) of the host is quite blue, indicative of a significant young age stellar population formed within the last 1 Gyr. A 3σ upper limit of Lbulge,H < 4.5 × 1010L ⊙ ,H for the H-band luminosity and a corresponding stellar mass upper limit of Mbulge < 3.4 × 1010M⊙ show that the host is offset from the local black hole-bulge relations. This is independently supported by the kinematics of the gas. Although the stellar mass of the host galaxy is lower than expected, it cannot explain the exceptionally low metallicity of the gas. We suggest that the extended emission-line region and the galaxy growth are caused by the infall of nearly pristine gas from the environment of the QSO host. Minor mergers of low-metallicity dwarf galaxies or the theoretically predicted smooth accretion of cold (~ 104 K) gas are both potential drivers behind that process. Because the metallicity of the gas in the QSO narrow-line region is much lower than expected, we suspect that the external gas has already reached the galaxy centre and may

  18. METALLICITIES, DUST, AND MOLECULAR CONTENT OF A QSO-DAMPED Ly{alpha} SYSTEM REACHING log N(H I) = 22: AN ANALOG TO GRB-DLAs

    SciTech Connect

    Guimaraes, R.; Noterdaeme, P.; Petitjean, P.; Ledoux, C.; Srianand, R.; Rahmani, H.; Lopez, S.

    2012-06-15

    We present the elemental abundance and H{sub 2} content measurements of a damped Ly{alpha} (DLA) system with an extremely large H I column density, log N(H I) (cm{sup -2}) = 22.0 {+-} 0.10, at z{sub abs} = 3.287 toward the QSO SDSS J081634+144612. We measure column densities of H{sub 2}, C I, C I*, Zn II, Fe II, Cr II, Ni II, and Si II from a high signal-to-noise and high spectral resolution VLT-UVES spectrum. The overall metallicity of the system is [Zn/H] = -1.10 {+-} 0.10 relative to solar. Two molecular hydrogen absorption components are seen at z = 3.28667 and 3.28742 (a velocity separation of Almost-Equal-To 52 km s{sup -1}) in rotational levels up to J = 3. We derive a total H{sub 2} column density of log N(H{sub 2}) (cm{sup -2}) = 18.66 and a mean molecular fraction of f = 2N(H{sub 2})/[2N(H{sub 2}) + N(H I)] = 10{sup -3.04{+-}0.37}, typical of known H{sub 2}-bearing DLA systems. From the observed abundance ratios we conclude that dust is present in the interstellar medium of this galaxy, with an enhanced abundance in the H{sub 2}-bearing clouds. However, the total amount of dust along the line of sight is not large and does not produce any significant reddening of the background QSO. The physical conditions in the H{sub 2}-bearing clouds are constrained directly from the column densities of H{sub 2} in different rotational levels, C I and C I*. The kinetic temperature is found to be T Almost-Equal-To 75 K and the particle density lies in the range n{sub H} = 50-80 cm{sup -3}. The neutral hydrogen column density of this DLA is similar to the mean H I column density of DLAs observed at the redshift of {gamma}-ray bursts (GRBs). We explore the relationship between GRB-DLAs and the high column density end of QSO-DLAs finding that the properties (metallicity and depletion) of DLAs with log N(H I) > 21.5 in the two populations do not appear to be significantly different.

  19. XMM-Newton reveals a Seyfert-like X-ray spectrum in the z = 3.6 QSO B1422+231

    NASA Astrophysics Data System (ADS)

    Dadina, M.; Vignali, C.; Cappi, M.; Lanzuisi, G.; Ponti, G.; De Marco, B.; Chartas, G.; Giustini, M.

    2016-08-01

    Context. Matter flows from the central regions of quasi-stellar objects (QSOs) during their active phases are probably responsible for the properties of the super-massive black holes and those of the bulges of host galaxies. To understand how this mechanism works, we need to characterize the geometry and the physical state of the accreting matter at cosmological redshifts, when QSO activity is at its peak. Aims: We aim to use X-ray data to probe the matter inflow at the very center of a QSO at z = 3.62. While complex absorption, the iron K emission line, reflection hump, and high-energy cutoff are known to be almost ubiquitous in nearby active galactic nuclei (AGN), only a few distant objects are known to exhibit some of them. Methods: The few high-quality spectra of distant QSO were collected by adding sparse pointings of single objects obtained during X-ray monitoring campaigns. This could have introduced spurious spectral features due to source variability and/or microlensing. To avoid such problems, we decided to collect a single-epoch and high-quality X-ray spectrum of a distant AGN. We thus picked up the z = 3.62 QSO B1422+231, whose flux, enhanced by gravitationally lensing, is proven to be among the brightest lensed QSOs in X-rays (F2-10 keV ~ 10-12 erg s-1 cm-2). Results: The X-ray spectrum of B1422+231 is found to be very similar to the one of a typical nearby Seyfert galaxy. Neutral absorption is clearly detected (NH ~ 5 × 1021 cm-2 at the redshift of the source), while a strong absorption edge is measured at E ~ 7.5 keV with an optical depth of τ ~ 0.14. We also find hints of the FeKα line in emission at E ~ 6.4 keV line (EW ≲ 70 eV), and a hump is detected in the E ~ 15 - 20 keV energy band (rest frame) in excess of what is predicted by a simple absorbed power-law. Conclusions: The spectrum can best be modeled with two rather complex models; one assumes ionized and partially covering matter along the line of sight, the other is characterized by a

  20. A low-luminosity type-1 QSO sample . IV. Molecular gas contents and conditions of star formation in three nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Moser, Lydia; Krips, Melanie; Busch, Gerold; Scharwächter, Julia; König, Sabine; Eckart, Andreas; Smajić, Semir; García-Marin, Macarena; Valencia-S., Mónica; Fischer, Sebastian; Dierkes, Jens

    2016-03-01

    We present a pilot study of ~3'' resolution observations of low CO transitions with the Submillimeter Array in three nearby Seyfert galaxies, which are part of the low-luminosity quasi-stellar object (LLQSOs) sample consisting of 99 nearby (z = 0.06) type-1 active galactic nuclei (AGN) taken from the Hamburg/ESO quasi-stellar object (QSO) survey. Two sources were observed in 12CO(2-1) and 13CO(2-1) and the third in 12CO(3-2) and HCO+(4-3). None of the sources is detected in continuum emission. More than 80% of the 12CO detected molecular gas is concentrated within a diameter (FWHM) < 1.8 kpc. 13CO is tentatively detected, while HCO+ emission could not be detected. All three objects show indications of a kinematically decoupled central unresolved molecular gas component. The molecular gas masses of the three galaxies are in the range Mmol = (0.7-8.7) × 109M⊙. We give lower limits for the dynamical masses of Mdyn> 1.5 × 109M⊙ and for the dust masses of Mdust> 1.6 × 106M⊙. The R21 = 12CO/13CO(2-1) line luminosity ratios show Galactic values of R21 ~ 5-7 in the outskirts and R21 ≳ 20 in the central region, similar to starbursts and (ultra)luminous infrared galaxies ((U)LIRGs; i.e. LIRGs and ULIRGs), implying higher temperatures and stronger turbulence. All three sources show indications of 12CO(2-1)/12CO(1-0) ratios of ~0.5, suggesting a cold or diffuse gas phase. Strikingly, the 12CO(3-2)/(1-0) ratio of ~1 also indicates a higher excited phase. Since these galaxies have high infrared luminosities of LIR ≥ 1011L⊙ and seem to contain a circumnuclear starburst with minimum surface densities of gas and star formation rate (SFR) around Σmol = 50-550 M⊙pc-2 and ΣSFR = 1.1-3.1 M⊙ kpc-2 yr-1, we conclude that the interstellar medium in the centers of these LIRG Seyferts is strongly affected by violent star formation and better described by the ULIRG mass conversion factor.

  1. Exploiting enzyme catalysis in ultra-low ion strength media for impedance biosensing of avian influenza virus using a bare interdigitated electrode.

    PubMed

    Fu, Yingchun; Callaway, Zachary; Lum, Jacob; Wang, Ronghui; Lin, Jianhan; Li, Yanbin

    2014-02-18

    Enzyme catalysis is broadly used in various fields but generally applied in media with high ion strength. Here, we propose the exploitation of enzymatic catalysis in ultra-low ion strength media to induce ion strength increase for developing a novel impedance biosensing method. Avian influenza virus H5N1, a serious worldwide threat to poultry and human health, was adopted as the analyte. Magnetic beads were modified with H5N1-specific aptamer to capture the H5N1 virus. This was followed by binding concanavalin A (ConA), glucose oxidase (GOx), and Au nanoparticles (AuNPs) to create bionanocomposites through a ConA-glycan interaction. The yielded sandwich complex was transferred to a glucose solution to trigger an enzymatic reaction to produce gluconic acid, which ionized to increase the ion strength of the solution, thus decreasing the impedance on a screen-printed interdigitated array electrode. This method took advantages of the high efficiency of enzymatic catalysis and the high susceptibility of electrochemical impedance on the ion strength and endowed the biosensor with high sensitivity and a detection limit of 8 × 10(-4) HAU in 200 μL sample, which was magnitudes lower than that of some analogues based on biosensing methods. Furthermore, the proposed method required only a bare electrode for measurements of ion strength change and had negligible change on the surficial properties of the electrode, though some modification of magnetic beads/Au nanoparticles and the construction of a sandwich complex were still needed. This helped to avoid the drawbacks of commonly used electrode immobilization methods. The merit for this method makes it highly useful and promising for applications. The proposed method may create new possibilities in the broad and well-developed enzymatic catalysis fields and find applications in developing sensitive, rapid, low-cost, and easy-to-operate biosensing and biocatalysis devices.

  2. MASTER: QSO flare and OTs

    NASA Astrophysics Data System (ADS)

    Gress, O.; Shumkov, V.; Pogrosheva, T.; Lipunov, V.; Rebolo, R.; Serra-Ricart, M.; Podesta, R.; Levato, H.; Gorbovskoy, E.; Tiurina, N.; Balanutsa, P.; Kuznetsov, A.; Kornilov, V.; Ivanov, K.; Vladimirov, V.; Lopez, C.; Podesta, F.; Saffe, C.

    2016-10-01

    MASTER-OAFA auto-detection system (Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 01h 50m 52.97s -45d 10m 15.9s on 2016-10-06.21896 UT with unfiltered m_OT=17.4m (limit 20.6m).

  3. Ultraviolet absorption lines associated with the Vela supernova remnant

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.; Wallerstein, G.; Silk, J.

    1976-01-01

    Two stars behind the Vela supernova remnant and two stars offset from the remnant have been observed with the UV spectrometer aboard the Copernicus satellite. Over 200 interstellar atomic and molecular absorption features between 1000 and 1400 A have been identified and measured for radial velocity and equivalent width. In many cases, additional information was obtained by studying the detailed shapes of the recorded profiles. Most of the stars show several absorption components, with clouds of the highest radial velocity appearing in the spectra of stars behind the remnant. For each component, column densities were derived using velocity dispersion parameters which yielded the most self-consistent results. Qualitatively, the gas toward the remnant exhibits a number of unusual properties, when compared with normal interstellar material. First, abnormally high radial velocities were evident. Second, the degree of ionization of some elements suggested the existence of ionizing processes significantly more potent than those found in general regions of space. Finally, an investigation of electron densities shows that much of the gas, especially that at high velocity, must exist in the form of relatively thin sheets or filaments. If cosmic abundances prevail, the column densities of high-velocity excited material suggest that H-alpha emission measures could be as large as 100 sq cm/cu pc.

  4. Pressure dependence of Se absorption lines in AlSb

    SciTech Connect

    Hsu, L. |; Haller, E.E.; Ramdas, A.K.

    1996-09-01

    Using far infrared absorption spectroscopy, the authors have investigated electronic transition spectra of Se donors in AlSb as a function of hydrostatic pressure. At least two distinct ground to bound excited state transition lines, which depend quadratically on the pressure, can be seen. At pressures between 30 and 50 kbar, evidence of an anti-crossing between one of the electronic transitions and a peak which they attribute to the 2 zone center LO phonon mode can be seen.

  5. Study of Water Absorption Lines in the Near Infrared

    DTIC Science & Technology

    1975-02-17

    the absorption coefficient is better approximated by the sum of Matcha -N«. oec short range contribution and W-BB dispersion contribution. The...and W. Byers Brown, Molecular Physics 2S, 1105 (1973). 5. R. L. Matcha and R. K. Nesbet, Phys. Rev. 1_6_0, 72 (1967). I H. B. Levine, Phys. Rev...reasurcrents of Ouren, ^eltqen Gaide, Helbing and Pauly. The dipole moment function is taken from ab initio 9 calculations of Matcha and Nesbet. With

  6. Atlas of Absorption Lines from 0 to 17900 cm-1

    DTIC Science & Technology

    1987-09-01

    u—, J i i , j : 1 .’ lllll:! 1 ;, U h’,1 i L’lllll 111 ’ lilll lillh i 50 51 52 53 WAV t NUMBER 55 : ( 57...jiilli III 111 III, llll II III N,0 ’ NH, l-ICN C2H2 cm 700 55 14.2857 14.1844 140845 13.9860 13.8889 � 13.6986 13.6054 13.5135...1 1 1 1 2 3 - 4 - 5 - 6 /UITI CO CH4 OH HF H CO SUN 4250 4255 4260 4265 WAVENUMBER 4270 4275 4280 4285 4290 4295 4300 129 2 3256

  7. Interpreting the convergence of Lyman series absorption lines

    NASA Technical Reports Server (NTRS)

    Jenkins, Edward B.

    1990-01-01

    Spectra of quasars at high z often show absorption at the Lyman limit from intervening gas systems at intermediate z having N(H) approx. greater than 10(exp 7) cm(-2). In some circumstances, N(H) can be determined by measuring the strength of the Lyman limit absorption or the damping wings of Lyman - alpha. With a spectrum taken at low wavelength resolution, say, lambda/delta lambda approx. 10(exp 3), it is usually not possible to distinguish individual Lyman series lines near the limit, yet one can still discern how rapidly the average intensity drops off as the limit is approached from the long wavelength side. The purpose here is to point out the information which is available from measurements of this series convergence.

  8. Effects of velocity averaging on the shapes of absorption lines

    NASA Technical Reports Server (NTRS)

    Pickett, H. M.

    1980-01-01

    The velocity averaging of collision cross sections produces non-Lorentz line shapes, even at densities where Doppler broadening is not apparent. The magnitude of the effects will be described using a model in which the collision broadening depends on a simple velocity power law. The effect of the modified profile on experimental measures of linewidth, shift and amplitude will be examined and an improved approximate line shape will be derived.

  9. What Drives the Outflows in Broad Absorption Line QSOs?

    NASA Technical Reports Server (NTRS)

    Begelman, Mitchell C.

    1997-01-01

    We have made progress in the areas related to the propulsion and confinement of gas responsible for broad absorption troughts in QSOs: Radiative Acceleration in BALQSOs; The "Ghost" of Lyman (alpha); and Magnetic Confinement of Absorbing Gas.

  10. Pressure broadening of H(2)O absorption lines in the 1.3 microm region measured by continuous wave-cavity ring-down spectroscopy: application in the trace detection of water vapor in N(2), SiH(4), CF(4), and PH(3).

    PubMed

    Fiadzomor, Phyllis A Y; Baker, Derek M; Keen, Anthony M; Grant, Robert B; Orr-Ewing, Andrew J

    2008-12-01

    A continuous wave cavity ring-down (cw-CRD) spectrometer has been developed for the measurement of trace levels of water vapor by absorption spectroscopy at wavelengths in the vicinity of 1358 nm and 1392 nm. The speed of data acquisition and selectivity make cavity ringdown spectroscopy potentially more useful than current techniques for measurement of trace water in process gases and vacuum environments used for semiconductor manufacture where water vapor contamination has a detrimental effect on the final product. The pressure broadening coefficients (gamma) for bath gases N(2), air, and Ar and semiconductor process gases SiH(4), PH(3), and CF(4) were determined for a range of absorption lines in the 2nu(1) and nu(1) + nu(3) bands of H(2)O. For the transitions investigated, the concentration of water vapor in the sample gas varied from 1.7 x 10(12) to 2.9 x 10(15) molecule cm(-3) in N(2) at a total pressure of <10 mbar and was mixed with the bath gas of increasing pressure up to approximately 200 mbar. The values of gamma quantify the reduction in peak absorption cross-sections with bath gas pressure and, thus, their effects on the detection limit of water vapor. For a CRD spectrometer with a ring-down time of tau = 12.0 mus measured with a precision of 0.6%, detection limits for the measurement of water vapor in 1 atm N(2) and of CF(4) were estimated to be 18 and 14 ppbv, respectively. Competing absorption by SiH(4) and PH(3) in the 1.3 mum wavelength region results in respective detection limits for water vapor of 98 and 319 ppbv (relative to 1 atm) in 0.2 atm SiH(4) and 0.37 atm PH(3).

  11. Gemini 3D spectroscopy of BAL+IR+FeII QSOs - II. IRAS 04505-2958, an explosive QSO with hypershells and a new scenario for galaxy formation and galaxy end phase

    NASA Astrophysics Data System (ADS)

    Lípari, S.; Bergmann, M.; Sanchez, S. F.; Garcia-Lorenzo, B.; Terlevich, R.; Mediavilla, E.; Taniguchi, Y.; Zheng, W.; Punsly, B.; Ahumada, A.; Merlo, D.

    2009-09-01

    From a study of broad absorption line (BAL) + infrared (IR) + FeII quasi-stellar objects (QSOs) [using deep Gemini Multi-Object Spectrograph Integral Field Unit (GMOS-IFU) spectroscopy], new results are presented for IRAS 04505-2958. Specifically, we have studied in detail the outflow (OF) process at two large galactic scales: (i) two blobs/shells at radius r ~ 1.1 and 2.2 kpc, and (ii) an external hypergiant shell at r ~ 11 kpc. In addition, the presence of two very extended hypergiant shells at r ~ 60-80 kpc is also discussed. From this GMOS study the following main results were obtained. (i) For the external hypergiant shell, the kinematics GMOS maps of the ionized gas ([OII], [NeIII], [OIII], Hβ) show a small-scale bipolar OF, with similar properties to those observed in the prototype of exploding external supershells: NGC 5514. (ii) Three main knots - of this hypershell S3 - show the presence of a young starburst. (iii) The two internal shells show OF components with typical properties of nuclear shells. (iv) The two blobs and the hypershell are aligned at PA ~ 131° showing bipolar OF shape at ~10-15 kpc scale. In addition, the more external shells (at ~60-80 kpc scale) are aligned at PA ~ 40° also with bipolar OF shape (perpendicular to the more internal OF). (v) A strong blue continuum and multiple emission-line components were detected in all the GMOS fields. The new GMOS data show a good agreement with an extreme + explosive OF scenario for IRAS 04505-2958, in which part of the interstellar medium (ISM) of the host galaxy was ejected (in multiple shells). This extreme OF could also be associated with two main processes in the evolution of QSOs: (i) the formation of companion/satellite galaxies by giant explosions; and (ii) to define the final mass of the host galaxy, and even if the explosive nuclear OF is extremely energetic, this process could disrupt an important fraction of the host galaxy. Finally, the generation of ultra-high-energy cosmic rays

  12. MASTER: new OT and QSO flare

    NASA Astrophysics Data System (ADS)

    Balanutsa, P.; Lipunov, V.; Buckley, D.; Budnev, N.; Gress, O.; Gorbovskoy, E.; Tiurina, N.; Vladimirov, V.; Kornilov, V.; Kuvshinov, D.; Pogrosheva, T.; Ivanov, K.

    2017-02-01

    MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 09h 45m 05.87s -65d 43m 43.3s on 2017-02-15.91771 UT. The OT unfiltered magnitude is (mlim=18.6).

  13. QSO color selection in the SDSS

    SciTech Connect

    Newberg, H.J.; Yanny, B.

    1998-01-01

    The Sloan Digital Sky Survey (SDSS) will image 10,000 square degrees in the north galactic cap in five filters. We hope to identify and obtain spectra for about 100,000 quasars brighter than 20th magnitude in this area. The selection will be primarily on the basis of point spread function and colors, but we will also identify quasars from a catalog of FIRST radio sources. The selection areas in color space must be determined during the testing period prior to the official start of the survey. This task may determine the length of the test period. In anticipation of this becoming the critical path, we have written a body of software that will allow us to quickly analyze a set of multicolor data and make a first cut at the selection limits.

  14. PSD analysis of optical QSO light curves

    NASA Astrophysics Data System (ADS)

    Simm, Torben; Salvato, M.; Saglia, R.; Ponti, G.; Lanzuisi, G.; Trakhtenbrot, B.; Nandra, K.; Bender, R.

    2016-08-01

    One of the elementary properties of quasar activity is continuous variability in the UV/optical bands. The power spectral density (PSD) potentially contains information about the underlying processes connected to variability. We applied a novel method based on continuous-time autoregressive moving average (CARMA) models (Kelly et al. 2014) to derive the PSD even for irregularly sampled light curves. Using a sample of ~100 X-ray selected non-local QSOs from the XMM-COSMOS catalog and optical light curves provided by the Pan-STARRS1 MDF survey we find that the PSD resembles a broken power-law with a high-frequency slope significantly steeper than observed in X-ray studies. The PSD normalization is observed to scale inversely with bolometric luminosity and Eddington ratio, whereas there is no correlation between the characteristic bend timescale and black hole mass. We find a weak tendency for QSOs with higher black hole mass to have steeper high-frequency PSD slopes. In an ongoing work we extend these studies employing a sample of ~700 variable broad-line QSOs with high-quality black hole mass estimates and well-sampled light curves from the SDSS-RM project.

  15. Effect of a partial coverage of quasar broad-line regions by intervening -bearing clouds

    NASA Astrophysics Data System (ADS)

    Ofengeim, D. D.; Balashev, S. A.; Ivanchik, A. V.; Kaminker, A. D.; Klimenko, V. V.

    2015-09-01

    We consider the effect of a partial coverage of quasar broad-line regions (QSO BLRs) by intervening -bearing clouds when a part of quasar (QSO) radiation passes by a cloud not taking part in absorption-line system formation of the QSO spectrum. That leads to modification of observable absorption line profiles and consequently to a bias in physical parameters derived from standard absorption line analysis. In application to the absorption systems the effect has been revealed in the analysis of absorption system in the spectrum of Q 1232+082 (see Ivanchik et al. in Mon. Not. R. Astron. Soc. 404:1583, 2010, Balashev et al. in Mon. Not. R. Astron. Soc. 418:357, 2011). We estimate a probability of the effect to be detected in QSO spectra. To do this we derive distribution of BLR sizes of high-z QSOs from Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9) catalogue and assume different distributions of cloud sizes. We conclude that the low limit of the probability is about 11 %. The latest researches shows that about a fifth of observed absorption systems can be partially covered. Accounting of the effect may allow to revise significantly physical parameters of interstellar clouds obtained by the spectral analysis.

  16. The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines.

    PubMed

    Bignami, G F; Caraveo, P A; De Luca, A; Mereghetti, S

    2003-06-12

    Isolated neutron stars are highly magnetized, fast-rotating objects that form as an end point of stellar evolution. They are directly observable in X-ray emission, because of their high surface temperatures. Features in their X-ray spectra could in principle reveal the presence of atmospheres, or be used to estimate the strength of their magnetic fields through the cyclotron process, as is done for X-ray binaries. Almost all isolated neutron star spectra observed so far appear as featureless thermal continua. The only exception is 1E1207.4-5209 (refs 7-9), where two deep absorption features have been detected, but with insufficient definition to permit unambiguous interpretation. Here we report a long X-ray observation of the same object in which the star's spectrum shows three distinct features, regularly spaced at 0.7, 1.4 and 2.1 keV, plus a fourth feature of lower significance, at 2.8 keV. These features vary in phase with the star's rotation. The logical interpretation is that they are features from resonant cyclotron absorption, which allows us to calculate a magnetic field strength of 8 x 10(10) G, assuming the absorption arises from electrons.

  17. Limits on variations in fundamental constants from 21-cm and ultraviolet Quasar absorption lines.

    PubMed

    Tzanavaris, P; Webb, J K; Murphy, M T; Flambaum, V V; Curran, S J

    2005-07-22

    Quasar absorption spectra at 21-cm and UV rest wavelengths are used to estimate the time variation of x [triple-bond] alpha(2)g(p)mu, where alpha is the fine structure constant, g(p) the proton g factor, and m(e)/m(p) [triple-bond] mu the electron/proton mass ratio. Over a redshift range 0.24 < or = zeta(abs) < or = 2.04, (Deltax/x)(weighted)(total) = (1.17 +/- 1.01) x 10(-5). A linear fit gives x/x = (-1.43 +/- 1.27) x 10(-15) yr(-1). Two previous results on varying alpha yield the strong limits Deltamu/mu = (2.31 +/- 1.03) x 10(-5) and Deltamu/mu=(1.29 +/- 1.01) x10(-5). Our sample, 8 x larger than any previous, provides the first direct estimate of the intrinsic 21-cm and UV velocity differences 6 km s(-1).

  18. Wavelength Locking to CO2 Absorption Line-Center for 2-Micron Pulsed IPDA Lidar Application

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Petros, Mulugeta; Antill, Charles W.; Singh, Upendra N.; Yu, Jirong

    2016-01-01

    An airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This IPDA lidar system targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements. Independent wavelength control of each of the transmitted laser pulses is a key feature for the success of this instrument. The wavelength control unit provides switching, tuning and locking for each pulse in reference to a 2-micron CW (Continuous Wave) laser source locked to CO2 line-center. Targeting the CO2 R30 line center, at 2050.967 nanometers, a wavelength locking unit has been integrated using semiconductor laser diode. The CO2 center-line locking unit includes a laser diode current driver, temperature controller, center-line locking controller and CO2 absorption cell. This paper presents the CO2 center-line locking unit architecture, characterization procedure and results. Assessment of wavelength jitter on the IPDA measurement error will also be addressed by comparison to the system design.

  19. Heterodyne detection of the 752.033-GHz H2O rotational absorption line

    NASA Astrophysics Data System (ADS)

    Dionne, G. F.; Fitzgerald, J. F.; Chang, T. S.; Litvak, M. M.; Fetterman, H. R.

    1980-08-01

    A tunable high resolution two stage heterodyne radiometer was developed for the purpose of investigating the intensity and lineshape of the 752.033 GHz rotational transition of water vapor. Single-sideband system noise temperatures of approximately 45,000 K were obtained using a sensitive GaAs Schottky diode as the first stage mixer. First local oscillator power was supplied by a CO2 laser pumped formic acid laser (761.61 GHz), generating an X-band IF signal with theoretical line center at 9.5744 GHz. Second local oscillator power was provided by means of a 3 GHz waveguide cavity filter with only 9 dB insertion loss. In absorption measurements of the H2O taken from a laboratory simulation of a high altitude rocket plume, the center frequency of the 752 GHz line was determined to within 1 MHz of the reported value. A rotational temperature 75 K, a linewidth 5 MHz and a Doppler shift 3 MHz were measured with the line-of-sight intersecting the simulated-plume axis at a distance downstream of 30 nozzle diameters. These absorption data were obtained against continuum background radiation sources at temperatures of 1175 and 300 K.

  20. Heterodyne detection of the 752.033-GHz H2O rotational absorption line

    NASA Technical Reports Server (NTRS)

    Dionne, G. F.; Fitzgerald, J. F.; Chang, T. S.; Litvak, M. M.; Fetterman, H. R.

    1980-01-01

    A tunable high resolution two stage heterodyne radiometer was developed for the purpose of investigating the intensity and lineshape of the 752.033 GHz rotational transition of water vapor. Single-sideband system noise temperatures of approximately 45,000 K were obtained using a sensitive GaAs Schottky diode as the first stage mixer. First local oscillator power was supplied by a CO2 laser pumped formic acid laser (761.61 GHz), generating an X-band IF signal with theoretical line center at 9.5744 GHz. Second local oscillator power was provided by means of a 3 GHz waveguide cavity filter with only 9 dB insertion loss. In absorption measurements of the H2O taken from a laboratory simulation of a high altitude rocket plume, the center frequency of the 752 GHz line was determined to within 1 MHz of the reported value. A rotational temperature 75 K, a linewidth 5 MHz and a Doppler shift 3 MHz were measured with the line-of-sight intersecting the simulated-plume axis at a distance downstream of 30 nozzle diameters. These absorption data were obtained against continuum background radiation sources at temperatures of 1175 and 300 K.

  1. Probing low-redshift galaxies using quasar absorption lines with an emphasis on Ca II absorption

    NASA Astrophysics Data System (ADS)

    Sardane, Gendith M.

    2016-05-01

    We searched for intervening CaII absorption in nearly 95,000 quasar spectra with i≤20 from the Sloan Digital Sky Survey(SDSS) data releases DR7+DR9. Our identification of >400 CaII systems is the largest compilation of CaII absorbers in a blind search. (Abstract shortened by ProQuest.).

  2. The SLUGGS survey: globular cluster stellar population trends from weak absorption lines in stacked spectra

    NASA Astrophysics Data System (ADS)

    Usher, Christopher; Forbes, Duncan A.; Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Conroy, Charlie; Foster, Caroline; Pastorello, Nicola; Pota, Vincenzo; Arnold, Jacob A.

    2015-01-01

    As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ˜90 Å-1. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the Hα and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.

  3. Narrow absorption lines with two observations from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei; Cao, Yue

    2015-07-01

    We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow C IV λ λ 1548,1551 and Mg II λ λ 2796,2803 absorption doublets in spectral regions shortward of 7000 Å in the observed frame, which corresponds to time-scales of about 150-2643 d in the quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with zabs = 1.5188-3.5212 and 1809 Mg II absorption systems with zabs = 0.3948-1.7167. In term of the absorber velocity (β) distribution in the quasar rest frame, we find a substantial number of C IV absorbers with β < 0.06, which might be connected to absorption of quasar outflows. The outflow absorption peaks at υ ≈ 2000 km s^{-1} and drops rapidly below this peak value. Among 3580 C IV absorption systems, 52 systems (˜1.5 per cent) show obvious variations in equivalent widths in the absorber rest frame (Wr): 16 enhanced, 16 emerged, 12 weakened and 8 disappeared systems, respectively. We find that changes in Wrλ1548 are related neither to the time-scales of the two SDSS observations nor to absorber velocities in the quasar rest frame. Variable absorption in low-ionization species is important to constrain the physical conditions of the absorbing gas. There are two variable Mg II absorption systems measured from SDSS spectra detected by Hacker et al. However, in our Mg II absorption sample, we find that neither shows variable absorption with confident levels of >4σ for λ2796 lines and >3σ for λ2803 lines.

  4. An STIS Atlas of Ca II Triplet Absorption Line Kinematics in Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Batcheldor, D.; Axon, D.; Valluri, M.; Mandalou, J.; Merritt, D.

    2013-09-01

    The relations observed between supermassive black holes and their host galaxies suggest a fundamental link in the processes that cause these two objects to evolve. A more comprehensive understanding of these relations could be gained by increasing the number of supermassive black hole mass (M •) measurements. This can be achieved, in part, by continuing to model the stellar dynamics at the centers of galactic bulges using data of the highest possible spatial resolution. Consequently, we present here an atlas of galaxies in the Space Telescope Imaging Spectrograph (STIS) data archive that may have spectra suitable for new M • estimates. Archived STIS G750M data for all non-barred galactic bulges are co-aligned and combined, where appropriate, and the radial signal-to-noise ratios calculated. The line-of-sight velocity distributions from the Ca II triplet are then determined using a maximum penalized likelihood method. We find 19 out of 42 galaxies may provide useful new M • estimates since they are found to have data that is comparable in quality with data that has been used in the past to estimate M •. However, we find no relation between the signal-to-noise ratio in the previously analyzed spectra and the uncertainties of the black hole masses derived from the spectra. We also find that there is a very limited number of appropriately observed stellar templates in the archive from which to estimate the effects of template mismatching. 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 NAS5-26555.

  5. AN STIS ATLAS OF Ca II TRIPLET ABSORPTION LINE KINEMATICS IN GALACTIC NUCLEI

    SciTech Connect

    Batcheldor, D.; Mandalou, J.; Axon, D.; Valluri, M.; Merritt, D.

    2013-09-15

    The relations observed between supermassive black holes and their host galaxies suggest a fundamental link in the processes that cause these two objects to evolve. A more comprehensive understanding of these relations could be gained by increasing the number of supermassive black hole mass (M{sub .}) measurements. This can be achieved, in part, by continuing to model the stellar dynamics at the centers of galactic bulges using data of the highest possible spatial resolution. Consequently, we present here an atlas of galaxies in the Space Telescope Imaging Spectrograph (STIS) data archive that may have spectra suitable for new M{sub .} estimates. Archived STIS G750M data for all non-barred galactic bulges are co-aligned and combined, where appropriate, and the radial signal-to-noise ratios calculated. The line-of-sight velocity distributions from the Ca II triplet are then determined using a maximum penalized likelihood method. We find 19 out of 42 galaxies may provide useful new M{sub .} estimates since they are found to have data that is comparable in quality with data that has been used in the past to estimate M{sub .}. However, we find no relation between the signal-to-noise ratio in the previously analyzed spectra and the uncertainties of the black hole masses derived from the spectra. We also find that there is a very limited number of appropriately observed stellar templates in the archive from which to estimate the effects of template mismatching.

  6. Ultraviolet interstellar absorption lines in the LMC: Searching for hidden SNRs

    NASA Technical Reports Server (NTRS)

    Chu, You-Hua; Wakker, Bart; Low, Mordecai-Mark Mac; Garcia-Segura, Guillermo

    1994-01-01

    Strong x-ray emission detected in Large Magellanic Cloud (LMC) superbubbles has been explained as the result of interior supernova remnants (SNRs) hitting the dense superbubble shell. Such SNRs cannot be found using conventional criteria. We thus investigate the possibility of using the interstellar absorption properties in the ultraviolet (UV) as a diagnostic of hidden SNR shocks. The International Ultraviolet Explorer (IUE) archives provide the database for this pilot study. They contain high-dispersion spectra of several stars in x-ray bright superbubbles. To distinguish the effects of SNR shocks from those of local stellar winds and a global hot halo around the LMC, we included control objects in different environments. We find that almost all interstellar absorption properties can be explained by the interstellar environment associated with the objects. Summarizing the two most important results of this study: (1) a large velocity shift between the high-ionization species (C IV and Si IV) and the low-ionization species (S II, Si II, and C II*) is a diagnostic of hidden SNR shocks; however, the absence of a velocity shift does not preclude the existence of SNR shocks; (2) there is no evidence that the LMC is uniformly surrounded by hot gas; hot gas is preferentially found associated with large interstellar structures like superbubbles and supergiant shells, which may extend to large distances from the plane.

  7. The assembly histories of quiescent galaxies since z = 0.7 from absorption line spectroscopy

    SciTech Connect

    Choi, Jieun; Conroy, Charlie; Moustakas, John; Graves, Genevieve J.; Holden, Bradford P.; Brown, Michael J. I.; Van Dokkum, Pieter G.

    2014-09-10

    We present results from modeling the optical spectra of a large sample of quiescent galaxies between 0.1 < z < 0.7 from the Sloan Digital Sky Survey (SDSS) and the AGN and Galaxy Evolution Survey (AGES). We examine how the stellar ages and abundance patterns of galaxies evolve over time as a function of stellar mass from 10{sup 9.6}-10{sup 11.8} M {sub ☉}. Galaxy spectra are stacked in bins of mass and redshift and modeled over a wavelength range from 4000 Å to 5500 Å. Full spectrum stellar population synthesis modeling provides estimates of the age and the abundances of the elements Fe, Mg, C, N, and Ca. We find negligible evolution in elemental abundances at fixed stellar mass over roughly 7 Gyr of cosmic time. In addition, the increase in stellar ages with time for massive galaxies is consistent with passive evolution since z = 0.7. Taken together, these results favor a scenario in which the inner ∼0.3-3 R {sub e} of massive quiescent galaxies have been passively evolving over the last half of cosmic time. Interestingly, the derived stellar ages are considerably younger than the age of the universe at all epochs, consistent with an equivalent single-burst star formation epoch of z ≲ 1.5. These young stellar population ages coupled with the existence of massive quiescent galaxies at z > 1 indicate the inhomogeneous nature of the z ≲ 0.7 quiescent population. The data also permit the addition of newly quenched galaxies at masses below ∼10{sup 10.5} M {sub ☉} at z < 0.7. Additionally, we analyze very deep Keck DEIMOS spectra of the two brightest quiescent galaxies in a cluster at z = 0.83. There is tentative evidence that these galaxies are older than their counterparts in low-density environments. In the Appendix, we demonstrate that our full spectrum modeling technique allows for accurate and reliable modeling of galaxy spectra to low S/N (∼20 Å{sup –1}) and/or low spectral resolution (R ∼ 500).

  8. Detection of carbon monoxide and water absorption lines in an exoplanet atmosphere.

    PubMed

    Konopacky, Quinn M; Barman, Travis S; Macintosh, Bruce A; Marois, Christian

    2013-03-22

    Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging--spatially resolving the planet from its parent star--which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet's chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet's formation.

  9. Diurnal and Interannual Variation in Absorption Lines of Isotopic Carbon Dioxide in Mars Atmosphere

    NASA Astrophysics Data System (ADS)

    Livengood, Timothy A.; Kostiuk, Theodor; Hewagama, Tilak; Kolasinski, John R.; Henning, Wade G.

    2015-11-01

    Groundbased observations of Mars in 2003, 2007, 2012, and 2014 have detected transitions of carbon dioxide containing the stable minor isotopes of oxygen and carbon as well as the primary isotopes, using the ultrahigh resolution spectrometer HIPWAC at the NASA Infrared Telescope Facility. The most well characterized minor isotope is O-18, due to strong lines and observational opportunities. The average estimated O-18/O-16 isotope ratio is roughly consistent with other in situ and remote spectroscopic measurements but demonstrates an additional feature in that the retrieved ratio appears to increase with greater ground surface temperature. These conclusions primarily come from analyzing a subset of the 2007 data. Additional observations have been acquired over a broad range of local time and meridional position to evaluate variability with respect to ground surface temperature. These additional observations include one run of measurements with C-13. These observations can be compared to local in situ measurements by the Curiosity rover to narrow the uncertainty in absolute isotope ratio and extend isotopic measurements to other regions and seasons on Mars. The relative abundance of carbon dioxide heavy isotopes on Mars is central to estimating the primordial atmospheric inventory on Mars. Preferential freeze-distillation of heavy isotopes means that any measurement of the isotope ratio can be only a lower limit on heavy isotope enrichment due to past and current loss to space.

  10. Probing the interstellar medium in Puppis-Vela through optical absorption line spectroscopy

    NASA Astrophysics Data System (ADS)

    Cha, Alexandra Nicole Stuehler

    2000-06-01

    The interstellar medium (ISM) toward Puppis-Vela (l = 245° to 275°, b = -15° to +5°) has been studied using high resolution, R ~ 75,000-90,000, high signal-to-noise, S/N ~ 100, optical Na I and Ca II absorption spectra along several hundred lines of sight. The distance of the Vela supernova remnant was found to be at d ~ 250 pc, a factor of two less than the canonical value. Lines of sight passing through the Vela supernova remnant were seen to have optical spectra that varied over epochs of a few years, including those toward HD 72089, HD 72127, HD 72997, HD 73658, HD 74455, HD 75309, and HD 75821. The variability of the first three lines of sight had been previously documented, but variability in the spectra toward the latter four stars had not been observed. An analysis of the Local ISM (d < 200 pc) toward Puppis-Vela is presented, and using both Na I absorption features and accurate distances to the stars, courtesy of Hipparcos trigonometric parallax data, spatially compact, homogeneous velocity components were mapped. In the Local ISM, the Puppis-Vela region abuts the apparent extension of the Local Bubble (or Cavity) known as the β CMa tunnel, and the compiled Na I lines of sight suggest that within 200 pc, the extent of the tunnel is confined to a region smaller than was previously thought. The technique of identifying and mapping individual velocity components in three dimensions was extended to the Puppis-Vela ISM out to d ~ 1 kpc, and a total of 7 velocity components were identified. Gas with velocities higher than that expected in the ambient ISM combined with higher than normal reddening was detected toward two regions, (l ~ 254°, b ~ -1°) and (l ~ 251°, b ~ -7°), suggesting the presence of previously unidentified structures. Nearby, gas associated with the IRAS Vela Shell was detected in Na I at distances >~ 300 pc. The Na I velocity components from IRAS Vela Shell sight lines were fit with a model of a spherically expanding filled sphere with an average expansion rate of ~12 km s-1, consistent with previous studies which used other ions. In addition to a thorough analysis of the gaseous component of the ISM in Puppis-Vela, a correlation between the gas and dust was sought. Using column densities of Na I and color excesses, E(B - V), as indicators of the respective amounts of gas and dust present along each line of sight, a linear empirical relationship was found: N(Na I) = -1.9 × 1012 + 4.6 × 1013 E(B - V).

  11. A Bayesian Method For Finding Galaxies That Cause Quasar Absorption Lines

    NASA Astrophysics Data System (ADS)

    Shoemaker, Emileigh Suzanne; Laubner, David Andrew; Scott, Jennifer E.

    2016-01-01

    We present a study of candidate absorber-galaxy pairs for 39 low redshift quasar sightlines (0.06 < z < 0.85) using a statistical approach to match absorbers with galaxies near the quasar lines of sight. Of the 75 quasars observed with HST/Cosmic Origins Spectrograph (COS) and archived on the Mikulski Archive for Space Telescopes (MAST), 39 overlap with the footprint of the Sloan Digital Sky Survey (SDSS). We downloaded the COS linelists for these quasar spectra from MAST and queried the SDSS DR12 database for photometric data on all galaxies within 1 Mpc of each of these quasar lines of sight. We calculated photometric redshifts for all the SDSS galaxies using the Bayesian Photometric Redshift code. We used all these absorber and galaxy data as input into an absorber-galaxy matching code which also employs a Bayesian scheme, along with known statistics of the intergalactic medium and circumgalactic media of galaxies, for finding the most probable galaxy match for each absorber. We compare our candidate absorber-galaxy matches to existing studies in the literature and explore trends in the absorber and galaxy properties among the matched and non-matched populations. This method of matching absorbers and galaxies can be used to find targets for follow up spectroscopic studies.

  12. Double troughs in broad absorption line quasars and Ly-alpha-N V line-locking

    NASA Technical Reports Server (NTRS)

    Korista, Kirk T.; Voit, G. M.; Morris, Simon L.; Weymann, Ray J.

    1993-01-01

    It was investigated whether the double trough (DT) structure in the mean C IV BAL trough reported by Weymann et al. (1991) is real or due to statistical fluctuations of BAL troughs over random outflow velocities in a limited sample. A sample of 72 BAL QSOs with C IV BAL troughs was analyzed. It is found that only 22 percent of the sample explicitly exhibits the DT feature; when present the DTs are deep. A Monte Carlo simulation of the mean C IV BAL suggests that the DT feature is real at only the 95-98 percent level.

  13. A summary of transition probabilities for atomic absorption lines formed in low-density clouds

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Smith, W. H.

    1973-01-01

    A table of wavelengths, statistical weights, and excitation energies is given for 944 atomic spectral lines in 221 multiplets whose lower energy levels lie below 0.275 eV. Oscillator strengths were adopted for 635 lines in 155 multiplets from the available experimental and theoretical determinations. Radiation damping constants also were derived for most of these lines. This table contains the lines most likely to be observed in absorption in interstellar clouds, circumstellar shells, and the clouds in the direction of quasars where neither the particle density nor the radiation density is high enough to populate the higher levels. All ions of all elements from hydrogen to zinc are included which have resonance lines longward of 912 A, although a number of weaker lines of neutrals and first ions have been omitted.

  14. Contribution to the ultraviolet metagalactic background from radiative recombination in intervening absorbers

    NASA Astrophysics Data System (ADS)

    Liu, J. M.

    1997-05-01

    Recently, Haardt & Madau (HM) showed that QSO absorption-line systems are not only sinks of the ultraviolet metagalactic background (UMB), but also significant sources of the UMB due to recombination radiation within photoionized absorbers. We demonstrate that the contribution to the UMB from H I and He II recombination radiation may be less than Haardt & Madau's by a factor of about 0.4 if intervening absorbers are modeled as a slab illuminated isotropically on two sides and the recombination radiation is assumed to be isotropic. This is the case which most closely approximates QSOs absorption-line systems.

  15. QSOs and Intervening Absorbers around the Hubble Deep Field

    NASA Astrophysics Data System (ADS)

    Vanden Berk, D. E.; Stoughton, C.; Crotts, A. P. S.; Tytler, D.; Kirkman, D.

    1999-12-01

    We have imaged a 45 arcmin by 45 arcmin area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to respective limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2 and 21.2. The principal goals of the survey are to identify QSOs and to map structure traced by luminous galaxies and QSO absorption line systems in a wide volume containing the HDF. The area surveyed is 400 times that of the HDF, and 40 times that of the HDF Flanking Fields. We have selected QSO candidates from color space, and identified four QSOs and two narrow emission-line galaxies (NELGs) which have not previously been discovered, bringing the total number of known QSOs in the area to 20. The bright z=1.31 QSO only 12 arcmin away from the HDF fulfills for the northern HDF the design goal of HDFS, which was selected for its proximity to a bright QSO. About half of the QSO candidates remain for spectroscopic verification. Absorption line spectroscopy has been obtained for three bright QSOs in the field, using the Keck 10m, McDonald 2.7m, and MDM 2.4m telescopes. Five heavy-element absorption line systems have been identified, three of which overlap the well-explored redshift range covered by deep galaxy redshift surveys towards the HDF. The two absorbers occur at the same redshift as the second most populated redshift peak in the galaxy distribution, but each is more than 7/h Mpc (comoving) away from the HDF line of sight in the transverse dimension, indicating large sheet-like structures traversing the HDF at high redshift.

  16. New Probes with Deep of Gas Flows within Galaxies at Intermediate Redshifts

    NASA Astrophysics Data System (ADS)

    Koo, D. C.

    2012-09-01

    Instead of using background QSO's, we suggest using the light from galaxies to probe cool gas flows within their own halos. We highlight two DEEP projects based on this idea, one by Sato et al. (2009) that uses NaD absorption lines of galaxies at low redshifts z < 0.6 and another by Weiner et al. (2009) that uses MgII lines seen in galaxies at higher redshifts z ˜ 1.4.

  17. The ionization conditions in the Milky Way halo - Infalling gas toward the North Galactic Pole

    NASA Technical Reports Server (NTRS)

    Danly, Laura

    1992-01-01

    Observations of gas in the Milky Way halo are studied with an eye toward the theoretical predictions of the Galactic Fountain model for the production of halo gas. Data are shown that indicate significant variations in the ionization conditions in infalling halo gas in the northern galactic hemisphere. Understanding the nature of Milky Way halo gas plays a critical role in interpreting QSO absorption lines in the investigation of galaxies at high redshift.

  18. Explore Full Range of QSO/AGN Properties

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald (Technical Monitor); Wilkes, Belinda

    2005-01-01

    The goal of the proposal is to perform ISO spectroscopic studies, including data analysis and modeling, of star formation regions using an ensemble of archival space-based data from the Infrared Space Observatory s Long Wavelength Spectrometer and Short Wavelength Spectrometer, but including as well some other spectroscopic databases. Four kinds of regions are considered in the studies: (1) disks around more evolved objects; (2) young, low or high mass pre-main sequence stars in star formation regions; (3) star formation in external, bright IR galaxies; and (4) the galactic center. One prime focus of the program is the OH lines in the far infrared. The program had the following goals: 1) Refine the data analysis of IS0 observations to obtain deeper and better SNR results on selected sources. The IS0 data itself underwent "pipeline 10" reductions in early 2001, and additional "hands-on data reduction packages" were supplied by the IS0 teams in 2001. The Fabry-Perot database is particularly sensitive to noise and slight calibration errors. 2) Model the atomic and molecular line shapes, in particular the OH lines, using revised monte- carlo techniques developed by the SWAS team at the Center for Astrophysics; 3) Attend scientific meetings and workshops; 4) Do E&PO activities related to infrared astrophysics and/or spectroscopy.

  19. MASTER discoveries: bright PSN, new dwarf novae and QSO flare

    NASA Astrophysics Data System (ADS)

    Shumkov, V.; Balanutsa, P.; Gress, O.; Popova, E.; Lipunov, V.; Buckley, D.; Rebolo, R.; Serra-Ricart, M.; Tlatov, A.; Budnev, N.; Ivanov, K.; Podesta, R.; Levato, H.; Gorbovskoy, E.; Tiurina, N.; Kuznetsov, A.; Vladimirov, V.; Kornilov, V.; Chazov, V.; Pogrosheva, T.; Potter, S.; Senik, V.; Dormidontov, D.; Parkhomenko, A.; Shurpakov, S.

    2016-10-01

    MASTER-Kislovodsk auto-detection system (Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L) discovered OT source at (RA, Dec) = 11h 05m 33.80s +19d 41m 18.7s on 2016-10-23.06338 UT. The OT unfiltered magnitude is 16.7m (mlim=18.8m).

  20. The time delay in the twin QSO Q0957 + 561

    SciTech Connect

    Schild, R.E. )

    1990-12-01

    From 10 yr of brightness monitoring of the two gravitational mirage components of Q0957 + 561 A,B it is shown that the time delay is 1.11 yr. An intensive program of daily brightness monitoring suggests a further refinement of the time delay to 404 days. Careful superposition of the phased brightness records shows that small differences are seen. These differences are attributed to microlensing by a star or stars in the lens galaxy. 5 refs.

  1. MASTER: QSO flares, PSN and dwarf novae outbursts

    NASA Astrophysics Data System (ADS)

    Gress, O.; Pogrosheva, T.; Shumkov, V.; Balanutsa, P.; Popova, E.; Lipunov, V.; Rebolo, R.; Serra-Ricart, M.; Budnev, N.; Gorbovskoy, E.; Tiurina, N.; Kornilov, V.; Vladimirov, V.; Gorbuynov, I.; Kuvshinov, D.; Ivanov, K.; Shurpakov, S.

    2017-03-01

    MASTER-Tunka auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 13h 42m 40.29s +09d 39m 11.1s on 2017-03-31.75039 UT. The OT unfiltered magnitude is 17.5m (limit 20.0m).

  2. Interstellar H I and H2 in the Magellanic Clouds: An Expanded Sample Based on Ultraviolet Absorption-line Data

    NASA Astrophysics Data System (ADS)

    Welty, Daniel E.; Xue, Rui; Wong, Tony

    2012-02-01

    We have determined column densities of H I and/or H2 for sight lines in the Magellanic Clouds from archival Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer spectra of H I Lyα and H2 Lyman-band absorption. Together with some similar data from the literature, we now have absorption-based N(H I) and/or N(H2) for 285 Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) sight lines (114 with a detection or limit for both species)—enabling more extensive, direct, and accurate determinations of molecular fractions, gas-to-dust ratios, and elemental depletions in these two nearby, low-metallicity galaxies. For sight lines where the N(H I) estimated from 21 cm emission is significantly higher than the value derived from Lyα absorption (presumably due to emission from gas beyond the target stars), integration of the 21 cm profile only over the velocity range seen in Na I or H2 absorption generally yields much better agreement. Conversely, N(21 cm) can be lower than N(Lyα) by factors of 2-3 in some LMC sight lines—suggestive of small-scale structure within the 21 cm beam(s) and/or some saturation in the emission. The mean gas-to-dust ratios obtained from N(Htot)/E(B - V) are larger than in our Galaxy, by factors of 2.8-2.9 in the LMC and 4.1-5.2 in the SMC—i.e., factors similar to the differences in metallicity. The N(H2)/E(B - V) ratios are more similar in the three galaxies, but with considerable scatter within each galaxy. These data may be used to test models of the atomic-to-molecular transition at low metallicities and predictions of N(H2) based on comparisons of 21 cm emission and the IR emission from dust. ), the MAST archive at STScI (FUSE data), and the University of Bonn (LAB and GASS 21 cm surveys).

  3. Upper limits on the 21 cm power spectrum at z = 5.9 from quasar absorption line spectroscopy

    NASA Astrophysics Data System (ADS)

    Pober, Jonathan C.; Greig, Bradley; Mesinger, Andrei

    2016-11-01

    We present upper limits on the 21 cm power spectrum at z = 5.9 calculated from the model-independent limit on the neutral fraction of the intergalactic medium of x_{H I} < 0.06 + 0.05 (1σ ) derived from dark pixel statistics of quasar absorption spectra. Using 21CMMC, a Markov chain Monte Carlo Epoch of Reionization analysis code, we explore the probability distribution of 21 cm power spectra consistent with this constraint on the neutral fraction. We present 99 per cent confidence upper limits of Δ2(k) < 10-20 mK2 over a range of k from 0.5 to 2.0 h Mpc-1, with the exact limit dependent on the sampled k mode. This limit can be used as a null test for 21 cm experiments: a detection of power at z = 5.9 in excess of this value is highly suggestive of residual foreground contamination or other systematic errors affecting the analysis.

  4. QED Theory of Radiation Emission and Absorption Lines for Atoms and Ions in a Strong Laser Field

    SciTech Connect

    Glushkov, A. V.

    2008-10-22

    The results of numerical calculating the multi-photon resonance shift and width for transition 6S-6F in the atom of Cs (wavelength 1059nm) in a laser pulse of the Gaussian and soliton-like shapes are presented. QED theory of radiation atomic lines is used.

  5. Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines.

    PubMed

    Abrams, M C; Gunson, M R; Lowes, L L; Rinsland, C P; Zander, R

    1996-06-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m. The total uncertainty is limited primarily by the quality of the spectra and ranges between 4% and 6% (280-420 m) for spectra with signal-to-noise ratios of 300:1 and between 4% and 10% for spectra with signal-to-noise ratios of 100:1. The retrieval of atmospheric pressure increases the accuracy of the retrieved-gas concentrations by minimizing the effect of systematic errors introduced by climatological pressure data, ephemeris parameters, and the uncertainties in instrumental pointing.

  6. Pressure Sounding of the Middle Atmosphere from ATMOS Solar Occultation Measurements of Atmospheric CO(sub 2) Absorption Lines

    NASA Technical Reports Server (NTRS)

    Abrams, M.; Gunson, M.; Lowes, L.; Rinsland, C.; Zander, R.

    1994-01-01

    A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(sub 2) lines with temperature-insensitive intensities. Tangent pressures are determined with a spectroscopic precision of 1-3%, corresponding to a tangent point height precision, depending on the scale height, of 70-210 meters.

  7. A New Catalog of Homogenized Absorption Line Indices for Milky Way Globular Clusters from High-resolution Integrated Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, Hak-Sub; Cho, Jaeil; Sharples, Ray M.; Vazdekis, Alexandre; Beasley, Michael A.; Yoon, Suk-Jin

    2016-12-01

    We perform integrated spectroscopy of 24 Galactic globular clusters (GGCs). Spectra are observed from one core radius for each cluster with a high wavelength resolution of ˜2.0 Å FWHM. In combination with two existing data sets from Puzia et al. and Schiavon et al., we construct a large database of Lick spectral indices for a total of 53 GGCs with a wide range of metallicities, -2.4 ≲ [Fe/H] ≲ 0.1, and various horizontal-branch morphologies. The empirical index-to-metallicity conversion relationships are provided for the 20 Lick indices for the use of deriving metallicities for remote, unresolved stellar systems.

  8. Rest-UV Absorption Lines as Metallicity Estimator: The Metal Content of Star-forming Galaxies at z ~ 5

    NASA Astrophysics Data System (ADS)

    Faisst, A. L.; Capak, P. L.; Davidzon, I.; Salvato, M.; Laigle, C.; Ilbert, O.; Onodera, M.; Hasinger, G.; Kakazu, Y.; Masters, D.; McCracken, H. J.; Mobasher, B.; Sanders, D.; Silverman, J. D.; Yan, L.; Scoville, N. Z.

    2016-05-01

    We measure a relation between the depth of four prominent rest-UV absorption complexes and metallicity for local galaxies and verify it up to z˜ 3. We then apply this relation to a sample of 224 galaxies at 3.5\\lt z\\lt 6.0 (< z> =4.8) in the Cosmic Evolution Survey (COSMOS), for which unique UV spectra from the Deep Imaging Multi-object Spectrograph (DEIMOS) and accurate stellar masses from the Spitzer Large Area Survey with Hyper-Suprime-Cam (SPLASH) are available. The average galaxy population at z˜ 5 and {log}(M/{M}⊙ )\\gt 9 is characterized by 0.3-0.4 dex (in units of 12+{log}({{O/H}})) lower metallicities than at z ˜ 2, but comparable to z˜ 3.5. We find galaxies with weak or no Lyα emission to have metallicities comparable to z ˜ 2 galaxies and therefore may represent an evolved subpopulation of z˜ 5 galaxies. We find a correlation between metallicity and dust in good agreement with local galaxies and an inverse trend between metallicity and star-formation rate consistent with observations at z ˜ 2. The relation between stellar mass and metallicity (MZ relation) is similar to z˜ 3.5, but there are indications of it being slightly shallower, in particular for the young, Lyα-emitting galaxies. We show that, within a “bathtub” approach, a shallower MZ relation is expected in the case of a fast (exponential) build-up of stellar mass with an e-folding time of 100-200 Myr. Because of this fast evolution, the process of dust production and metal enrichment as a function of mass could be more stochastic in the first billion years of galaxy formation compared to later times.

  9. First detection of ionized helium absorption lines in infrared K band spectra of O-type stars

    NASA Technical Reports Server (NTRS)

    Conti, Peter S.; Block, David L.; Geballe, T. R.; Hanson, Margaret M.

    1993-01-01

    We have obtained high SNR, moderate-resolution K band spectra of two early O-type main sequence stars, HD 46150 O5 V, and HD 46223 O4 V, in the Rosette Nebula. We report the detection, for the first time, of the 2.189 micron He II line in O-type stars. Also detected is the 2.1661 micron Br-gamma line in absorption. The 2.058 micron He I line appears to be present in absorption in both stars, although its appearance at our resolution is complicated by atmospheric features. These three lines can form the basis for a spectral classification system for hot stars in the K band that may be used at infrared wavelengths to elucidate the nature of those luminous stars in otherwise obscured H II and giant H II regions.

  10. Phase-Dependent Observations of Intermediate Polars and The Broad Emission and Absorption Line Region in NGC 3516

    NASA Technical Reports Server (NTRS)

    Koratkar, Anuradha; Bond, Howard E.

    1995-01-01

    The Intermediate Polars (IP's) constitute a class of Cataclysmic Variables (CV's), which are binary star systems in which mass is transferred from a late-type main-sequence star to a white dwarf via Roche lobe overflow. In the IP's, the inner accretion disk is evidently disrupted by the magnetic field of the white dwarf. High-temperature shocks at the white dwarf's magnetic poles (where accretion occurs) produce X-rays, which are reprocessed into photons over a broad energy band across the electromagnetic spectrum. Because the white dwarf typically spins rapidly (rotation periods a few 10s to a few 100s of seconds), the signals due to both the X-rays and reprocessed photons are pulsed. The shape of the spectrum of pulse amplitude as a function of wavelength yields information about both the temperature and size of the pulse-emitting region. It has been noted by several investigators that the optical pulsation amplitudes rise steeply toward short wavelengths. It is therefore a fair surmise that pulsation amplitudes peak in the ultraviolet. The scientific goal of this project was to observe a representative sample of IP's, using IUE, in search of the expected strong UV pulsations, and hence to further our understanding of pulse-producing mechanisms.

  11. Wavelength locking to CO2 absorption line-center for 2-μm pulsed IPDA lidar application

    NASA Astrophysics Data System (ADS)

    Refaat, Tamer F.; Petros, Mulugeta; Antill, Charles W.; Singh, Upendra N.; Yu, Jirong

    2016-05-01

    An airborne 2-m triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This IPDA lidar system targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements. Independent wavelength control of each of the transmitted laser pulses is a key feature for the success of this instrument. The wavelength control unit provides switching, tuning and locking for each pulse in reference to a 2-μm CW laser source locked to CO2 line-center. Targeting the CO2 R30 line center, at 2050.967 nm, a wavelength locking unit has been integrated using semiconductor laser diode. The CO2 center-line locking unit includes a laser diode current driver, temperature controller, center-line locking controller and CO2 absorption cell. This paper presents the CO2 center-line locking unit architecture, characterization procedure and results. Assessment of wavelength jitter on the IPDA measurement error will also be addressed by comparison to the system design.

  12. VizieR Online Data Catalog: Narrow MgII absorption lines from SDSS-DR9Q (Chen+, 2015)

    NASA Astrophysics Data System (ADS)

    Chen, Z.-F.; Gu, Q.-S.; Chen, Y.-M.

    2016-01-01

    The Baryonic Oscillation Spectroscopic Survey (BOSS) project (Dawson et al. 2013AJ....145...10D) of SDSS-III (Eisenstein et al. 2011AJ....142...72E) uses upgraded versions of the SDSS spectrographs mounted on the Sloan 2.5m telescope at Apache Point, New Mexico. The spectra are taken through 2" diameter fibers and cover a wavelength range from 3600 to 10400Å with a resolution of R~2000 and a dispersion of 69km/s/pixel. (1 data file).

  13. Assessing the link between chlorophyll concentration and absorption line height at 676 nm over a broad range of water types.

    PubMed

    Nardelli, Schuyler C; Twardowski, Michael S

    2016-10-31

    The relationship between absorption at 676 nm normalized to chlorophyll-a, i.e., specific absorption aph*(676), and various optical and environmental properties is examined in extensive data sets from Case I and Case II waters found globally to assess drivers of variability such as pigment packaging. A better understanding of this variability could lead to more accurate estimates of chlorophyll concentrations from in situ optical measurements that may be made autonomously. Values of aph*(676) ranged from 0.00006 to 0.0944 m2/mg Chl a across all sites studied, but converged on median and mean values (n = 563) of 0.0108 and 0.0139 m2/mg Chl a respectively, with no apparent relationship with various optical properties, latitude, coastal or open ocean environment, depth, temperature, salinity, photoadaptation, ecosystem health, or albedo. Relative consistency in aph* across such diverse water types and the full range in chlorophyll concentration suggests a single aph* may be used to estimate chlorophyll concentration from absorption measurements with better accuracy than currently thought.

  14. Broadening of the infrared absorption lines at reduced temperatures. II - Carbon monoxide in an atmosphere of carbon dioxide.

    NASA Technical Reports Server (NTRS)

    Tubbs, L. D.; Williams, D.

    1972-01-01

    The strengths of the rotational lines in the R branch of the CO fundamental have been determined at temperatures of 298, 202, and 132 K by means of a high-resolution spectrograph. The results can be used to determine line strengths at other temperatures by means of the Herman-Wallis relation or by considerations of the populations of the rotational levels in the ground vibrational state. Parameters describing the self-broadening and carbon dioxide broadening of CO lines have been determined at 298 and 202 K. The results are compared with other recent experimental and theoretical studies.

  15. Crystal-field analysis and calculation of two-photon absorption line strengths of dicesium sodium hexachlorogadolinate(III).

    PubMed

    Duan, Chang-Kui; Tanner, Peter A

    2010-03-31

    The crystal-field energy level calculation of the 4f(7) ion Gd(3+) in the crystal Cs(2)NaGdCl(6) has fitted 45 levels with standard deviation 12 cm(-1), with the energy parameters being consistent with those from other studies. The resulting eigenvectors have been employed in the calculation of two-photon absorption (TPA) intensities of transitions from the electronic ground state (8)S(7/2) to the crystal-field levels of excited (6)P, (6)I and (6)D multiplet terms. The TPA line strengths are highly polarization dependent and exhibit striking differences for linearly polarized incident radiation compared with circularly polarized radiation. The relative intensities are compared with those available from previous experimental studies and some reassignments have been made. Good agreement of calculated and experimental TPA spectra is found, except for the intensity ratio of the transitions to (6)P(7/2) or (6)P(5/2) compared with that to (6)P(3/2), for linear and circular polarizations, where the calculation overestimates the ratio. Reasons for this disagreement are presented.

  16. UV Absorption Lines as Metallicity Estimator and the Metal Content of Star-forming Galaxies at z=5

    NASA Astrophysics Data System (ADS)

    Faisst, Andreas; Capak, Peter L.; Davidson, Iary; Kakazu, Yuko; Salvato, Mara; Laigle, Clotilde; Onodera, Masato; Masters, Daniel; COSMOS Team

    2016-01-01

    Probing the metal content of high redshift galaxies is essential to study their formation and evolution in the early universe. However, the spectral features used to measure the metallicity are shifted out of the wavelength range of current spectrographs at high-z and therefore alternative methods must be used.We measure the relation between four prominent UV absorption complexes and metallicity for more than 50 local galaxies and, by using a sample of more than 20 galaxies at z ~ 2 - 3, verify that this relation holds up to z ˜ 3. We then apply this method to a sample of ˜ 220 galaxies at 3.5 < z < 6.0 in COSMOS, for which unique UV spectra from DEIMOS and accurate stellar mass estimates from SPLASH are available. The z ~ 5 galaxies at 9 < log(m/M⊙) < 11 are characterized by 0.3 - 0.4 dex (in units of 12 + log(O/H)) lower metallicities than galaxies at z ˜ 2 but comparable to z ˜ 3 - 3.5 galaxies. In the same stellar mass range, we do not find a significant relation between stellar mass and metallicity (MZ relation), suggesting that the MZ relation at z ~ 5 is very shallow or breaking down. Since we verify a correlation between dust obscuration (measured by β) and UV absorption strength (i.e., metallicity), we argue that the process of dust production and metal enrichment in the first billion years of galaxy formation is more stochastic than at later times. Using a "bathtub" model approach, we find that an exponential build up of stellar mass within a short time of several 100 Myr can explain a shallow MZ relation at z ˜ 5. Furthermore, we find a weak anti-correlation between star-formation rates and UV absorption strength (i.e., metallicity), indicative of these galaxies being fueled by the inflow of pristine (metal-poor) gas. The galaxy sample presented in this work is unique to further test these scenarios using ALMA and the upcoming James Webb Space Telescope.

  17. ME-CAGEBIRDr,X-CPMG-HSQMBC. A phase sensitive, multiplicity edited long range HSQC with absorptive line shapes

    NASA Astrophysics Data System (ADS)

    Koskela, Harri; Kilpeläinen, Ilkka; Heikkinen, Sami

    2016-11-01

    ME-CAGEBIRDr,X-CPMG-HSMBC pulse sequence is a phase sensitive, carbon multiplicity edited 2D-experiment for detecting heteronuclear correlations originating from long-range 1H, 13C-couplings, nJCH. The presented method allows measurement of nJCH-values as well as is capable of separating different carbon types in subspectra (13C/13CH2 and 13CH/13CH3) with minimal amount of cross talk i.e. cross peaks from wrong carbon multiplicity. Pure lineshapes and clean subspectra are achieved by utilizing CPMG in polarization transfer period, CRISIS-approach in multiplicity editing period and zero-quantum filtration. The obtained spectral properties together with simple setup of the experiment make ME-CAGEBIRDr,X-CPMG-HSMBC a useful addition into synthetic organic chemistry oriented NMR-tool collection.

  18. Low-redshift quasars in the SDSS Stripe 82: associated companion galaxies and signature of star formation

    NASA Astrophysics Data System (ADS)

    Bettoni, D.; Falomo, R.; Kotilainen, J. K.; Karhunen, K.

    2017-04-01

    We obtained optical spectroscopy of close (<80 kpc) companion objects of a sample of 12 low-redshift quasars (z < 0.3) selected from the SDSS Stripe82 area and that are in the subsample of 52 QSOs for which both multicolour host galaxies properties and galaxy environment were recently investigated in detail. We found that for 8 out of 12 sources the companion galaxy is associated with the QSO having a difference of radial velocity that is less than 400 km s-1. Many of these associated companions exhibit [OII] λ3727 Å emission lines suggestive of episodes of (recent) star formation possibly induced by past interactions. The star formation rate of the companion galaxies as derived from [O II] line luminosity is, however, modest, with a median value of 1.0 ± 0.8 M⊙ yr-1, and the emission lines are barely consistent with expectation from gas ionization by the QSO. The role of the QSO for inducing star formation in close companion galaxies appears meager. For three objects we also detect the starlight spectrum of the QSO host galaxy, which is characterized by absorption lines of old stellar population and [O II] emission line.

  19. Galaxy-environment Interactions as Revealed by the Circumgalactic Medium

    NASA Astrophysics Data System (ADS)

    Burchett, Joseph; Tripp, Todd M.; Wang, Daniel; Willmer, Christopher; Prochaska, Jason X.; Werk, Jessica; Bordoloi, Rongmon; Katz, Neal; Tumlinson, Jason

    2017-01-01

    Galaxies do not live in isolation, and their star formation activity and gas supply are closely tied to the density of the environment in which they reside. The circumgalactic medium (CGM) serves as the point of first contact between a galaxy and its environment and mediates the gas accretion and outflow processes that regulate the galaxy ecosystem. Employing a combination of ultraviolet QSO spectroscopy, optical galaxy surveys, and X-ray imaging and spectroscopy, I will show that the metal-enriched gas and cool, photoionized H I in the CGM gas reflect the galaxy’s large-scale environment from scales of modest groups to clusters. Thus, QSO absorption line spectroscopy provides uniquely sensitive multiphase gas diagnostics of the physical conditions at the sites of galaxy-environment interactions. By shock-heating or stripping the CGM gas, as is indicated by its absorption, these interactions may deplete or deprive the galaxy's gas supply and quench its star formation.

  20. Studies of Quasar Outflows

    NASA Technical Reports Server (NTRS)

    Arav, Nahum

    2002-01-01

    The main aim of this research program is to determine the ionization equilibrium and abundances in quasar outflows. Especially in the broad absorption line QSO PG 0946+301. We find that the outflow's metalicity is consistent with being solar, while the abundance ratio of phosphorus to other metals is at least ten times solar. These findings are based on diagnostics that are not sensitive to saturation and partial covering effects in the BALs (Broad Adsorption Lines), which considerably weakened previous claims for enhanced metalicity. Ample evidence for these effects is seen in the spectrum.

  1. IUE observations of extragalactic objects

    NASA Technical Reports Server (NTRS)

    Boksenberg, A.; Snijders, M. A. J.; Wilson, R.; Benvenuti, P.; Clavell, J.; Macchetto, F.; Penston, M.; Boggess, A.; Gull, T. R.; Gondhalekar, P.

    1978-01-01

    During the commissioning phase of IUE several extragalactic objects were observed spectrally at low dispersion in the UV range lambda lambda 1150-3200: the Seyfert galaxies NGC4151 and NGC1068, the QSO 3C273, the BL Lacertae object B2 1101+38, the giant elliptical galaxy M87 and the spiral galaxy M81. The results obtained are presented and a preliminary analysis given for all six objects, discussing the continuous spectrum, extinction, emission line spectrum and absorption line spectrum, where possible for each case. Several new or confirmatory astrophysical results are obtained.

  2. Interstellar Mg II and C IV absorption by 1 1/2 galaxies along the sightline to MrK 205

    NASA Technical Reports Server (NTRS)

    Bowen, David V.; Blades, J. Chris

    1993-01-01

    The first results of our HST survey designed to search for Mg 2 and C 4 absorption lines from the disks and halos of low-redshift galaxies using background QSO's and supernovae as probes are presented. Our survey utilizes the high resolution of the Goddard High Resolution Spectrograph enabling us to calculate the column densities and doppler parameters of individual components within an absorption complex, and hence determine the physical conditions of the absorbing gas. Observing the complexity of the absorption line profiles i.e., the velocity distribution and total velocity extent of the constituent components, offers an important description of the kinematics of the absorbing gas, and hence an understanding of its origin. Focus is on one sight line in particular, that towards Mrk 205, which passes 3-5 kpc from the intervening galaxy NGC 4319. Mg 2 and C 4 absorption from both local Milky Way halo gas and from NGC 4319 is detected.

  3. Metallicity and nature of zabs

    NASA Astrophysics Data System (ADS)

    Moller, P.

    1995-05-01

    Of the various types of heavy element absorption lines that appear in quasar spectra, considerable controversy has surrounded the interpretation of the so-called {z_abs ~ z_em} systems, defined as C{\\small IV} doublets at redshifts within Delta v=+/-5000 km s(-1) \\ of the emission redshift. As reviewed most recently by Foltz, Chaffee, Weymann, and Anderson, 1988, in QSO Absorption Lines: Probing the Universe Cambridge University Press, Cambridge, p.53, it is not presently clear whether this class of absorption system is external or intrinsic in nature. One possibility is that such systems arise in the halos of galaxies located in a cluster that includes the host galaxy of the quasar (Weymann, Williams, Peterson, and Turnshek, 1979, ApJ, 234, 33). Alternatively, such systems could be related to the so-called broad absorption-line systems, and caused by absorption in matter ejected by the quasar itself (Turnshek, 1988, in QSO Absorption Lines: Probing the Universe Cambridge University Press, Cambridge, p.17. Recent studies of {z_abs ~ z_em} systems (Savaglio, D'Odorico, and M{\\o}ller, 1994, A&A, 281, 331; Petitjean, Rauch, and Carswell, 1994, A&A, 291, 29; M{\\o}ller, Jakobsen, and Perryman, 1994, A&A, 287, 719) have revealed that the {z_abs ~ z_em} systems are in fact distinctly different from corresponding intervening systems, in that they generally have extremely high metallicities. This suggests that those systems are more likely to be related to BAL systems, rather than to intervening absorbers. I shall briefly review the evidence for the metallicities of those systems, as well as the inverse luminosity correlation (M{\\o}ller, Jakobsen, 1987, ApJ-Lett 320, L75). Both of these results may provide important clues to the distribution, nature, and history of the absorbing gas in the AGN environment.

  4. On local ionization equilibrium and disk winds in QSOs

    SciTech Connect

    Pereyra, Nicolas A.

    2014-11-01

    We present theoretical C IV λλ1548,1550 absorption line profiles for QSOs calculated assuming the accretion disk wind (ADW) scenario. The results suggest that the multiple absorption troughs seen in many QSOs may be due to the discontinuities in the ion balance of the wind (caused by X-rays), rather than discontinuities in the density/velocity structure. The profiles are calculated from a 2.5-dimensional time-dependent hydrodynamic simulation of a line-driven disk wind for a typical QSO black hole mass, a typical QSO luminosity, and for a standard Shakura-Sunyaev disk. We include the effects of ionizing X-rays originating from within the inner disk radius by assuming that the wind is shielded from the X-rays from a certain viewing angle up to 90° ({sup e}dge on{sup )}. In the shielded region, we assume constant ionization equilibrium, and thus constant line-force parameters. In the non-shielded region, we assume that both the line-force and the C IV populations are nonexistent. The model can account for P-Cygni absorption troughs (produced at edge on viewing angles), multiple absorption troughs (produced at viewing angles close to the angle that separates the shielded region and the non-shielded region), and for detached absorption troughs (produced at an angle in between the first two absorption line types); that is, the model can account for the general types of broad absorption lines seen in QSOs as a viewing angle effect. The steady nature of ADWs, in turn, may account for the steady nature of the absorption structure observed in multiple-trough broad absorption line QSOs. The model parameters are M {sub bh} = 10{sup 9} M {sub ☉} and L {sub disk} = 10{sup 47} erg s{sup –1}.

  5. Size estimates for intervening CIV absorbers from high-resolution spectroscopy of APM 0827+5255

    NASA Astrophysics Data System (ADS)

    Tzanavaris, Panayiotis; Carswell, Robert F.

    2003-04-01

    A new analysis of Keck/HIRES observations of the broad absorption line quasi-stellar object (QSO) APM 0827+5255 indicates that a number of intervening CIV absorbers give rise to absorption lines for which the observed optical depths for the 1548, 1550 Å doublet components are not in the expected 2:1 ratio. To compensate for the effect, a local adjustment of the zero-level is required. We model this effect as coverage of one line of sight to this gravitationally lensed QSO and perform a set of simulations to select a sample of lines for which our model provides an explanation for the effect. We use lines in this sample to obtain estimates for minimum CIV absorber sizes from total coverage and the separations of the lines of sight for a range of lens redshifts, zl, and two cosmologies. We also obtain best estimates for overall sizes from a statistical `hit and miss' approach. For zl= 0.7 our results set a lower limit to sizes of CIV absorbers of ~0.3 h-172 kpc (~0.5 h-172 kpc) for ΩM= 1, ΩΛ= 0 (ΩM= 0.3, ΩΛ= 0.7), in agreement with other results from similar work but are limited by sample size and the uncertainty in zl. Our method can be used to detect lensed QSOs and to probe absorber sizes when separate spectra cannot be obtained for each line of sight.

  6. An adaptive optics package designed for astronomical use with a laser guide star tuned to an absorption line of atomic sodium

    SciTech Connect

    Salmon, J.T.; Avicola, K.; Brase, J.M.

    1994-04-11

    We present the design and implementation of a very compact adaptive optic system that senses the return light from a sodium guide-star and controls a deformable mirror and a pointing mirror to compensate atmospheric perturbations in the wavefront. The deformable mirror has 19 electrostrictive actuators and triangular subapertures. The wavefront sensor is a Hartmann sensor with lenslets on triangular centers. The high-bandwidth steering mirror assembly incorporates an analog controller that samples the tilt with an avalanche photodiode quad cell. An {line_integral}/25 imaging leg focuses the light into a science camera that can either obtain long-exposure images or speckle data. In laboratory tests overall Strehl ratios were improved by a factor of 3 when a mylar sheet was used as an aberrator. The crossover frequency at unity gain is 30 Hz.

  7. New aspects of absorption-line formation in intervening turbulent clouds - III. The inverse problem in the study of H+D profiles

    NASA Astrophysics Data System (ADS)

    Levshakov, Sergei A.; Kegel, Wilhelm H.; Takahara, Fumio

    1999-02-01

    A new method, based on a reverse Monte Carlo technique and aimed at the inverse problem in the analysis of intergalactic (interstellar) H+D absorption profiles, is presented. We consider the process of line formation in media with a stochastic velocity field accounting for correlation effects (mesoturbulence). This approach generalizes the standard microturbulent approximation, which is commonly used to model the formation of absorption spectra in turbulent media. The method allows one to estimate, from an observed spectrum, both the physical parameters of the absorbing gas and an appropriate structure of the distribution of the velocity component parallel to the line of sight. The validity of the computational procedure is demonstrated using a series of synthetic spectra that emulate the up-to-date best quality data. The H+D Lyα, Lyβ and H I Ly-14 lines were fitted simultaneously. The confidence regions calculated for the `NH i-D/H' plane show that the difference between the recovered and adopted values does not exceed the 3σ level.

  8. INFRARED ABSORPTION LINES TOWARD NGC 7538 IRS 1: ABUNDANCES OF H{sub 2}, H{sub 3}{sup +}, AND CO

    SciTech Connect

    Goto, Miwa; Geballe, T. R.; Usuda, Tomonori E-mail: tgeballe@gemini.edu

    2015-06-10

    We report high-resolution near-infrared absorption spectroscopy of H{sub 2}, H{sub 3}{sup +}, and CO toward the young high mass object NGC 7538 IRS 1. The v = 1–0 H{sub 2} S(0) line and lines in the CO v = 2–0 band were detected; the v = 1–0 H{sub 2} S(1) line and the v = 1–0 H{sub 3}{sup +} lines [R(1, 1){sup l}, R(1, 0), R(1, 1){sup u}] were not detected. The line of sight traverses two clouds, with temperatures 45 and 259 K and with roughly equal column densities of CO. Assuming that H{sub 2} is at the same temperature as CO and that the two species are uniformly mixed, [H{sub 2}]/[CO] = 3600 ± 1200. NGC 7538 is the most distant object from the Galactic center for which [H{sub 2}]/[CO] has been directly measured using infrared absorption spectroscopy.

  9. Circulation of the Venus upper mesosphere/lower thermosphere: Doppler wind measurements from 2001-2009 inferior conjunction, sub-millimeter CO absorption line observations

    NASA Astrophysics Data System (ADS)

    Clancy, R. Todd; Sandor, Brad J.; Moriarty-Schieven, Gerald

    2012-02-01

    Sub-millimeter 12CO (346 GHz) and 13CO (330 GHz) line absorptions, formed within the mesospheric to lower thermospheric altitude (70-120 km) region of the Venus atmosphere, have been mapped across the nightside disk of Venus during 2001-2009 inferior conjunctions, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis of these thermal line absorptions supports temperature and CO mixing profile retrievals, as described in a companion paper ( Clancy et al., 2012). Here, we consider the analysis of the sharp line absorption cores of these CO spectra in terms of accurate Doppler wind profile measurements at 95-115 km altitudes versus local time (˜8 pm-4 am) and latitude (˜60N-60S). These Doppler wind measurements support determinations of the nightside zonal and subsolar-to-antisolar (SSAS) circulation components over a variety of timescales. The average behavior fitted from 21 retrieved maps of 12CO Doppler winds (obtained over hourly, daily, weekly, and interannual intervals) indicates stronger average zonal (85 m/s retrograde) versus SSAS (65 m/s) circulation at the 1 μbar pressure (108-110 km altitude) level. However, the absolute and relative magnitudes of these circulation components exhibit extreme variability over daily to weekly timescales. Furthermore, the individual Doppler wind measurements within each nightside mapping observation generally show significant deviations (20-50 m/s, averaged over 5000 km horizontal scales) from the simple zonal/SSAS solution, with distinct local time and latitudinal characters that are also time variable. These large scale residual circulations contribute 30-70% of the observed nightside Doppler winds at any given time, and may be most responsible for global variations in nightside lower thermospheric trace composition and temperatures, as coincidentally retrieved CO abundance and temperature distributions do not correlate with solution retrograde zonal and SSAS winds (see companion paper, Clancy et al., 2012). Limited comparisons of these nightside submillimeter results with dayside infrared Doppler wind measurements suggest distinct dayside versus nightside circulations, in terms of zonal winds in particular. Combined 12CO and 13CO Doppler wind mapping observations obtained since 2004 indicate that the average zonal and SSAS wind components increase by 50-100% between altitudes of 100 and 115 km. If gravity waves originating from the cloud levels are responsible for the extension of zonal winds into the thermosphere (Alexander, M.J. [1992]. Geophys. Res. Lett. 19, 2207-2210), such waves deposit substantial momentum (i.e., break) in the lower nightside thermosphere.

  10. Thermal structure and CO distribution for the Venus mesosphere/lower thermosphere: 2001-2009 inferior conjunction sub-millimeter CO absorption line observations

    NASA Astrophysics Data System (ADS)

    Clancy, R. Todd; Sandor, Brad J.; Moriarty-Schieven, Gerald

    2012-02-01

    Sub-millimeter 12CO (346 GHz) and 13CO (330 GHz) line absorptions, formed in the mesosphere and lower thermosphere of Venus (70-120 km), have been mapped across the nightside Venus disk during 2001-2009 inferior conjunctions, employing the James Clerk Maxwell Telescope (JCMT). Radiative transfer analysis of these thermal line absorptions supports temperature and CO mixing profile retrievals, as well as Doppler wind fields (described in the companion paper, Clancy et al., 2012). Temporal sampling over the hourly, daily, weekly and interannual timescales was obtained over 2001-2009. On timescales inferred as several weeks, we observe changes between very distinctive CO and temperature nightside distributions. Retrieved nightside CO, temperature distributions for January 2006 and August 2007 observations display strong local time, latitudinal gradients consistent with early morning (2-3 am), low-to-mid latitude (0-40NS) peaks of 100-200% in CO and 20-30 K in temperature. The temperature increases are most pronounced above 100 km altitudes, whereas CO variations extend from 105 km (top altitude of retrieval) down to below 80 km in the mesosphere. In contrast, the 2004 and 2009 periods of observation display modest temperature (5-10 K) and CO (30-60%) increases, that are centered on antisolar (midnight) local times and equatorial latitudes. Doppler wind derived global (zonal and should be SSAS) circulations from the same data do not exhibit variations correlated with these CO, temperature short-term variations. However, large-scale residual wind fields not fit by the zonal, SSAS circulations are observed in concert with the strong temperature, CO gradients observed in 2006 and 2007 (Clancy et al., 2010). These short term variations in nightside CO, temperature distributions may also be related to observed nightside variations in O 2 airglow (Hueso, H., Sánchez-Lavega, A., Piccioni, G., Drossart, P., Gérard, J.C., Khatuntsev, I., Zasova, L., Migliorini, A. [2008]. J. Geophys. Res. 113, E00B02. doi:10.1029/2008JE003081) and upper mesospheric SO and SO 2 layers (Sandor, B.J., Clancy, R.T., Moriarty-Schieven, G.H., Mills, F.P. [2010]. Icarus 208, 49-60). The retrieved temperature profiles also exhibit 20 K long-term (2001-2009) variations in nightside (whole disk) average mesospheric (80-95 km) temperatures, similar to 1982-1991 variations identified in previous millimeter CO line observations (Clancy et al., 1991). Global average diurnal variations in lower thermospheric temperatures and mesospheric CO abundances decreased by a factor-of-two between 2000-2002 versus 2007-2009 periods of combined dayside and nightside observations. The infrequency and still limited temporal extent of the observations make it difficult to assign specific timescales to such longer term variations, which may be associated with longer term variations observed for cloud top SO 2 (Esposito, L.W., Bertaux, J.-L., Krasnopolsky, V., Moroz, V.I., Zasova, L.V. [1997]. Chemistry of lower atmosphere and clouds. In: Bougher, S.W., Hunten, D.M., Phillips, R.J. (Eds.), VENUS II, 1362pp) and mesospheric water vapor (Sandor, B.J., Clancy, R.T. [2005]. Icarus 177, 129-143) abundances.

  11. Radiometric observations of the 752.033-GHz rotational absorption line of H2O from a laboratory jet. [simulation of rocket plumes

    NASA Technical Reports Server (NTRS)

    Dionne, G. F.; Fitzgerald, J. F.; Chang, T.-S.; Fetterman, H. R.; Litvak, M. M.

    1980-01-01

    With the aid of a high-resolution two-stage heterodyne radiometer, spectral absorption measurements of the 752.033 GHz line of water vapor were carried out, using a blackbody continuum as a background radiation source for investigating the absorptive properties of the H2O content of high altitude rocket plumes. To simulate this physical situation in a laboratory environment, a small steam jet was operated within a large high-vacuum chamber, with the H2O jet plume traversing the radiometer line of sight. The experiments verified that this rotational line is optically thick, with excitation temperatures below 100 K, in the downstream part of the plume, as predicted by theoretical modelling.

  12. NuSTAR observations of the supergiant X-ray pulsar IGR J18027-2016: accretion from the stellar wind and possible cyclotron absorption line

    NASA Astrophysics Data System (ADS)

    Lutovinov, Alexander A.; Tsygankov, Sergey S.; Postnov, Konstantin A.; Krivonos, Roman A.; Molkov, Sergey V.; Tomsick, John A.

    2017-04-01

    We report on the first focused hard X-ray view of the absorbed supergiant system IGR J18027-2016 performed with the Nuclear Spectroscopic Telescope Array observatory. The pulsations are clearly detected with a period of Pspin = 139.866(1) s and a pulse fraction of about 50-60 per cent at energies from 3 to 80 keV. The source demonstrates an approximately constant X-ray luminosity on a time-scale of more than dozen years with an average spin-down rate of dot{P}≃ 6× 10^{-10} s s-1. This behaviour of the pulsar can be explained in terms of the wind accretion model in the settling regime. The detailed spectral analysis at energies above 10 keV was performed for the first time and revealed a possible cyclotron absorption feature at energy ∼23 keV. This energy corresponds to the magnetic field B ≃ 3 × 1012 G at the surface of the neutron star, which is typical for X-ray pulsars.

  13. Investigation of broadening and shift of vapour absorption lines of H{sub 2}{sup 16}O in the frequency range 7184 – 7186 cm{sup -1}

    SciTech Connect

    Nadezhdinskii, A I; Pereslavtseva, A A; Ponurovskii, Ya Ya

    2014-10-31

    We present the results of investigation of water vapour absorption spectra in the 7184 – 7186 cm{sup -1} range that is of particular interest from the viewpoint of possible application of the data obtained for monitoring water vapour in the Earth's stratosphere. The doublet of H{sub 2}{sup 16}O near ν = 7185.596 cm{sup -1} is analysed. The coefficients of broadening and shift of water vapour lines are found in the selected range in mixtures with buffer gases and compared to those obtained by other authors. (laser spectroscopy)

  14. Unveiling the X-ray/UV properties of disk winds in active galactic nuclei using broad and mini-broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Giustini, M.

    2016-05-01

    We present the results of the uniform analysis of 46 XMM-Newton observations of six BAL and seven mini-BAL QSOs belonging to the Palomar-Green Quasar catalogue. Moderate-quality X-ray spectroscopy was performed with the EPIC-pn, and allowed to characterise the general source spectral shape to be complex, significantly deviating from a power law emission. A simple power law analysis in different energy bands strongly suggests absorption to be more significant than reflection in shaping the spectra. If allowing for the absorbing gas to be either partially covering the continuum emission source or to be ionised, large column densities of the order of 1022-1024 cm-2 are inferred. When the statistics was high enough, virtually every source was found to vary in spectral shape on various time scales, from years to hours. All in all these observational results are compatible with radiation driven accretion disk winds shaping the spectra of these intriguing cosmic sources.

  15. More Constraints on the Physical Conditions of the Kinematically Complex, Multiphase Absorption Line System at z=0.93 toward PG1206+459

    NASA Astrophysics Data System (ADS)

    Rosenwasser, Ben; Muzahid, Sowgat; Norris, Jackson; Charlton, Jane C.

    2015-01-01

    We present the results of photo- and collisional ionization modeling of the strong MgII absorption system at redshift z~0.93 towards the quasar PG1206+459. This system has been extensively studied over the last two decades (Churchill & Charlton 1999; Ding et al. 2003; Tripp et al. 2011) using a combination of spectra from Keck/HIRES, HST/FOS, HST/STIS, and HST/COS. Here we present newconstraints using the most complete spectral coverage including more recent observations of OVI and the Lyman series from HST/COS. Numerous absorption components are seen over a large velocity spread (~1500km/s), and multiple ionization phases are required to account for the detected transitions, which include MgI, MgII, FeII, SiII, SiIII, SiIV, CII, CIII, CIV, SIII, SIV, SV, SVI, NIII, NIV, NV, OIII, OIV, OV, OVI, and NeVIII. Considering the new constraints, we revisit the question of the physical nature of the structures that produce this absorber.

  16. Terminal velocity of wind, mass loss, and absorption lines of the central star of the planetary nebula 75 + 35. 1 deg

    SciTech Connect

    Feibelman, W.A.; Bruhweiler, F.C. Catholic Univ. of America, Washington, DC )

    1989-12-01

    The high-galactic latitude planetary nebula 75 + 35.1 deg was observed in the high-dispersion mode of the International Ultraviolet Explorer (IUE) satellite in the wavelength range 1150-1950 A. The N V resonance doublet at 1240 A and O V subordinate line at 1371 A exhibit strong stellar P Cygni profiles with absorption extending to -2150 km/s and -1000 km/s, respectively. Application of the first moment method implies a mass-loss rate of M = (1-3) x 10 to the -8th solar mass/yr. The high ionization of the wind lines and the presence of strong Fe VI and Fe V lines in the stellar photosphere support that this object is quite hot. A Teff of 75,000 + or - 10,000 K was adopted, although Tc = 94,000 K was found previously from low-resolution IUE data. 18 refs.

  17. Terminal velocity of wind, mass loss, and absorption lines of the central star of the planetary nebula 75 + 35.1 deg

    NASA Technical Reports Server (NTRS)

    Feibelman, Walter A.; Bruhweiler, Frederick C.

    1989-01-01

    The high-galactic latitude planetary nebula 75 + 35.1 deg was observed in the high-dispersion mode of the International Ultraviolet Explorer (IUE) satellite in the wavelength range 1150-1950 A. The N V resonance doublet at 1240 A and O V subordinate line at 1371 A exhibit strong stellar P Cygni profiles with absorption extending to -2150 km/s and -1000 km/s, respectively. Application of the first moment method implies a mass-loss rate of M = (1-3) x 10 to the -8th solar mass/yr. The high ionization of the wind lines and the presence of strong Fe VI and Fe V lines in the stellar photosphere support that this object is quite hot. A Teff of 75,000 + or - 10,000 K was adopted, although Tc = 94,000 K was found previously from low-resolution IUE data.

  18. Water absorption lines, 931-961 nm - Selected intensities, N2-collision-broadening coefficients, self-broadening coefficients, and pressure shifts in air

    NASA Technical Reports Server (NTRS)

    Giver, L. P.; Gentry, B.; Schwemmer, G.; Wilkerson, T. D.

    1982-01-01

    Intensities were measured for 97 lines of H2O vapor between 932 and 961 nm. The lines were selected for their potential usefulness for remote laser measurements of H2O vapor in the earth's atmosphere. The spectra were obtained with several different H2O vapor abundances and N2 broadening gas pressures; the spectral resolution was 0.046/cm FWHM. Measured H2O line intensities range from 7 x 10 to the -25th to 7 x 10 to the -22nd/cm per (molecules/sq cm). H2O self-broadening coefficients were measured for 13 of these strongest lines; the mean value was 0.5/cm per atm. N2-collision-broadening coefficients were measured for 73 lines, and the average was 0.11 cm per atm HWHM. Pressure shifts in air were determined for a sample of six lines between 948 and 950 nm; these lines shift to lower frequency by an amount comparable to 0.1 of the collision-broadened widths measured in air or N2. The measured intensities of many lines of 300-000 band are much larger than expected from prior computations, in some cases by over an order of magnitude. Coriolis interactions with the stronger 201-000 band appear to be the primary cause of the enhancement of these line intensities.

  19. Hysteresis effects in the formation of a neutralizing beam plasma at low ion energy

    NASA Astrophysics Data System (ADS)

    Rafalskyi, Dmytro; Aanesland, Ane

    2013-11-01

    In this paper, the PEGASES II thruster prototype is used as an ion source generating low-energy (<300\\ \\text{eV}) positive Ar ion beam, extracted without an external neutralizer. The ions are extracted and accelerated from the source using a two-grid system. The extracted positive ion beam current is measured on a large beam target that can be translated along the acceleration axis. The ion beam current shows a stepwise transition from a low-current to a high-current extraction regime with hysteresis. The hysteresis region depends strongly upon the beam target position. Langmuir probe measurements in the plume show high plasma potentials and low plasma densities in the low-current mode, while the plasma potential drops and the density increases in the high-current mode. The ion energy distribution functions of the beam are measured for different regimes of ion extraction. The ion beam extracted in the high-current mode is indicated by the presence of an additional low-energy peak corresponding to ions from an ion-beam plasma created in the downstream chamber, as well as 10-20 times higher intensity of the primary ion beam peak. The hysteresis behavior is explained by the formation of a downstream neutralizing beam plasma, that depends on the target position and pressure in agreement with a Paschen-like breakdown by secondary electrons. The obtained results are of high relevance for further development of the PEGASES thruster, as well as for improving existing neutralizer-free concepts of the broad-beam ion sources.

  20. New regime of low ion collisionality in the neoclassical equilibrium of tokamak plasmas

    SciTech Connect

    Ramos, J. J.

    2015-07-15

    The neoclassical description of an axisymmetric toroidal plasma equilibrium is formulated for an unconventionally low ordering of the collisionality that suits realistic thermonuclear fusion conditions. This requires a drift-kinetic analysis to the second order of the ion Larmor radius, which yields a new contribution to the leading solution for the non-Maxwellian part of the ion distribution function if the equilibrium geometry is not up-down symmetric. An explicit geometrical factor weighs this second Larmor-radius order, low-collisionality effect that modifies the neoclassical ion parallel flow, and the ion contribution to the bootstrap current.

  1. Measurement of ultra-low ion energy of decelerated ion beam using a deflecting electric field

    NASA Astrophysics Data System (ADS)

    Thopan, P.; Suwannakachorn, D.; Tippawan, U.; Yu, L. D.

    2015-12-01

    In investigation on ultra-low-energy ion bombardment effect on DNA, an ion beam deceleration lens was developed for high-quality ultra-low-energy ion beam. Measurement of the ion energy after deceleration was necessary to confirm the ion beam really decelerated as theoretically predicted. In contrast to conventional methods, this work used a simple deflecting electrostatic field after the deceleration lens to bend the ion beam. The beam bending distance depended on the ion energy and was described and simulated. A system for the measurement of the ion beam energy was constructed. It consisted of a pair of parallel electrode plates to generate the deflecting electrical field, a copper rod measurement piece to detect ion beam current, a vernier caliper to mark the beam position, a stepping motor to translate the measurement rod, and a webcam-camera to read the beam bending distance. The entire system was installed after the ion-beam deceleration lens inside the large chamber of the bioengineering vertical ion beam line. Moving the measurement rod across the decelerated ion beam enabled to obtain beam profiles, from which the beam bending distance could be known and the ion beam energy could be calculated. The measurement results were in good agreement with theoretical and simulated results.

  2. Wavelength Calibration of the VLT-UVES Spectrograph

    NASA Astrophysics Data System (ADS)

    Whitmore, Jonathan B.; Murphy, Michael T.; Griest, Kim

    2010-11-01

    We attempt to measure possible miscalibration of the wavelength scale of the VLT-UVES spectrograph. We take spectra of QSO HE0515-4414 through the UVES iodine cell which contains thousands of well-calibrated iodine lines and compare these lines to the wavelength scale from the standard thorium-argon pipeline calibration. Analyzing three exposures of this z = 1.71 QSO, we find two distinct types of calibration shifts needed to correct the Th/Ar wavelength scale. First, there is an overall average velocity shift of between 100 m s-1 and 500 m s-1 depending upon the exposure. Second, within a given exposure, we find intra-order velocity distortions of 100 m s-1 up to more than 200 m s-1. These calibration errors are similar to, but smaller than, those found earlier in the Keck HIRES spectrometer. We discuss the possible origins of these two types of miscalibration. We also explore the implications of these calibration errors on the systematic error in measurements of Δ α \\over α, the change in the fine-structure constant derived from measurement of the relative redshifts of absorption lines in QSO absorption systems. The overall average, exposure-dependent shifts should be less relevant for fine-structure work, but the intra-order shifts have the potential to affect these results. Using either our measured calibration offsets or a Gaussian model with sigma of around 90 m s-1, Monte Carlo mock experiments find errors in Δ α \\over α of between 1 × 10-6 N -1/2 sys and 3 × 10-6 N -1/2 sys, where N sys is the number of systems used and the range is due to dependence on how many metallic absorption lines in each system are compared.

  3. First Detection of a Foreground Damped Ly-Alpha Absorber Along a GRB Line of Sight?

    NASA Technical Reports Server (NTRS)

    Vreeswijk, P. M.; Fruchter, A. S.; Pian, E.; Rol, E.; Wijers, R. A. M. J.; Kouveliotou, C.; Kaper, L.; Palazzi, E.; Masetti, N.; Frontera, F.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    We present a VLT spectrum of the optical afterglow of GRB 991216, taken 1.5 days after the burst, and HST (Hubble Space Telescope) imaging of the host galaxy, obtained four months later. The spectrum contains three metal absorption-line systems with redshifts z = 1.024, z = 0.803, and z = 0.771, where the highest redshift most likely reflects the distance to the host galaxy. For the z = 1.024 and z = 0.803 systems we tentatively detect MgI which suggests a dense environment at these redshifts. This and the strength of the z = 0.803 Fe lines indicate that this system very likely is a damped Ly-alpha absorber (DLA), which would be the first foreground DLA to be detected along a GRB afterglow sight line. The HST images are consistent with these findings: they show two blobs of light, one underneath the projected OT position, the presumed host galaxy, and the other 0.6" away, which is probably responsible for the absorption lines at z = 0.803. The lowest redshift system can be explained by either one of the two galaxies that are located roughly 2" away from the transient. Including these newly found systems, the total number of DLAS and Lyman limit systems along GRB afterglow sight lines is consistent with the number expected from QSO (quasi-stellar object) absorption line studies. We expect early spectroscopy of GRB afterglows to significantly increase the number of detected foreground absorption systems, and we discuss some advantages over QSO lines of sight.

  4. THE GALAXY ENVIRONMENT OF A QSO AT z {approx} 5.7

    SciTech Connect

    Banados, Eduardo; Venemans, Bram; Walter, Fabian; Kurk, Jaron; Overzier, Roderik; Ouchi, Masami

    2013-08-20

    High-redshift quasars are believed to reside in massive halos in the early universe and should therefore be located in fields with overdensities of galaxies, which are thought to evolve into galaxy clusters seen in the local universe. However, despite many efforts, the relationship between galaxy overdensities and z {approx} 6 quasars is ambiguous. This can possibly be attributed to the difficulty of finding galaxies with accurate redshifts in the vicinity of z {approx} 6 quasars. So far, overdensity searches around z {approx} 6 quasars have been based on studies of Lyman break galaxies (LBGs), which probe a redshift range of {Delta}z Almost-Equal-To 1. This range is large enough to select galaxies that may not be physically related to the quasar. We use deep narrow- and broadband imaging to study the environment of the z = 5.72 quasar ULAS J0203+0012. The redshift range probed by our narrow-band selection of Lyman alpha emitters (LAEs) is {Delta}z Almost-Equal-To 0.1, which is significantly narrower than the LBG searches. This is the first time that LAEs were searched for near a z {approx} 6 quasar, in an effort to provide clues about the environments of quasars at the end of the epoch of reionization. We find no enhancement of LAEs in the surroundings of ULAS J0203+0012 in comparison with blank fields. We explore different explanations and interpretations for this non-detection of a galaxy overdensity, including that (1) the strong ionization from the quasar may prevent galaxy formation in its immediate vicinity and (2) high-redshift quasars may not reside in the center of the most massive dark matter halos.

  5. VizieR Online Data Catalog: Photometric classification of QSO from RCS-2 (Carrasco+, 2015)

    NASA Astrophysics Data System (ADS)

    Carrasco, D.; Barrientos, L. F.; Pichara, K.; Anguita, T.; Murphy, D. N. A.; Gilbank, D. G.; Gladders, M. D.; Yee, H. K. C.; Hsieh, B. C.; Lopez, S.

    2015-08-01

    The catalogs contain the quasar candidates with their coordinates, magnitudes, respective errors, and an indicator of whether or not they were classified as quasars in the other two samples. We present three separate catalogs. Table1 corresponds to the candidates selected from DS1, matching the training set magnitude distribution and using only RCS-2 photometric information. Table2 contains the candidates from DS2, where objects with detection in the NUV GALEX band were used. Table3 includes the candidates from DS3, where information from W1 and W2 bands from WISE was used. (3 data files).

  6. More spectroscopy of the fuzz around QSOs - additional evidence for two types of QSO

    SciTech Connect

    Boroson, T.A.; Persson, S.E.; Oke, J.B.

    1985-06-01

    Spectroscopic observations of the nebulosity around a sample of optically selected, UV excess QSOs are reported. The spectra of QSOs observed by Boroson, Oke, and Green (1982) are also presented. These sets of objects strengthen the case that there are fundamental properties that distinguish two groups of objects which are both called QSOs. These differences include the equivalent width of the nuclear forbidden O III 5007 A emission, the width and shape of the nuclear broad lines, the equivalent width of the nuclear Fe II emission, and the radio morphology or the spectral index. Measurements of these properties are presented and the correlations and statistical significances are discussed. These distinctions are discussed in terms of a model in which the accretion rate onto a black hole is varied. 25 references.

  7. The large, bright QSO survey. II. QSOs in three equatorial fields

    SciTech Connect

    Foltz, C.B.; Chaffee, F.H.; Hewett, P.C.; Weymann, R.J.; Anderson, S.F. Cambridge Univ. Mount Wilson and Las Campanas Observatories, Pasadena, CA Washington Univ., Seattle )

    1989-12-01

    Results from the second observing season, in which 156 QSOs have been found in three equatorial UK Schmidt field covering an effective area of 85 sq deg, are described. Of the 31 QSOs listed in the Hewitt-Burbidge catalog, 22 are identified; one of the remaining nine has an overlapping objective prism spectrum and the rest were fainter than the derived magnitude limit at the epoch of the direct plate. Coordinates, magnitudes, redshifts, and spectra of moderate resolution and signal-to-noise ratio are presented for all 156 QSOs and 12 additional extragalactic objects. 12 refs.

  8. The Cold Dust Content of Broad and Narrow-Line, Optically Luminous, nearby QSO

    NASA Astrophysics Data System (ADS)

    Petric, A.

    2015-09-01

    Observations of the dynamics of stars and gas in the nuclear regions of nearby galaxies suggest that the overwhelming majority of spheroidal galaxies in the local Universe contain massive BHs and that, with some important caveats, the masses of those central BH correlate with the velocity dispersions of the stars in the spheroid and the bulge luminosities. Much research has been dedicated to understanding the mechanisms responsible for such a fundamental perhaps causal relation. An accurate census of the basic properties of the cold interstellar medium (ISM) in AGN host is pertinent to those investigations because cold molecular gas is the basic fuel for star-formation and black hole growth. We 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 and in a complementary sample of 85 narrow-line QSOs chosen to match the redshift and optical luminosity distribution of the broad-line targets. The FIR data are combined with near-infrared and mid-infrared 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 aggregate dust properties. We investigate the relation between star-formation rates (SFRs) estimated from the IR luminosities and SFRs determined from measurements of the 11.3 micron PAH. The differences between the cold dust properties of narrow and broad line AGN will be discussed in the context of models that envision that quasar activity is triggered by gas-rich galaxy mergers.

  9. A Morphological And Spectroscopic Atlas Of Emission Line Galaxies With QSO-Like Colors

    NASA Astrophysics Data System (ADS)

    Liu, Charles; Prescott, M.; Carroll, P.; Colon, A.; Roberts, R.; Wong, H.; Capak, P.; Impey, C.; Mobasher, B.; Scoville, N.; COSMOS Collaboration

    2007-12-01

    We present Hubble ACS I814 images, Subaru i images, and 3200A- 9000A optical spectroscopy for a sample of 139 narrow emission-line galaxies with quasar-like optical colors in the COSMOS Hubble Treasury field. These galaxies were all originally identified as quasar candidates in the Sloan Digital Sky Survey, primarily by their location in optical four-color space and secondarily by radio continuum emission. The sample shows the full range of galaxy morphologies, including very luminous galaxies and low surface brightness objects as well as compact dwarf galaxies. At least 17 of the galaxies (12% of the sample) have a close companion of comparable size and strong tidal features, indicating an ongoing merger or interaction. As an initial analysis, we compare the spectroscopic redshifts of these galaxies with their photometrically determined redshifts, and find no significant difference between the accuracy of this sample's photometric redshifts and that of the COSMOS galaxy population as a whole.

  10. MASTER: QSO flare (5BZQ J1312-0424) and OTs

    NASA Astrophysics Data System (ADS)

    Balanutsa, P.; Shumkov, V.; Pogrosheva, T.; Popova, E.; Lipunov, V.; Podesta, R.; Levato, H.; Lopez, C.; Podesta, F.; Tlatov, A.; Gorbovskoy, E.; Tiurina, N.; Kuznetsov, A.; Kornilov, V.; Vladimirov, V.; Ivanov, O. Gress K.; Chazov, V.

    2016-11-01

    MASTER-Kislovodsk auto-detection system ( Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L ) discovered OT source at (RA, Dec) = 13h 12m 50.91s -04d 24m 49.1s on 2016-11-20.11222 UT. The OT unfiltered magnitude is (mlim=18.2m).

  11. Two component model for X-ray emission of radio selected QSO's

    NASA Technical Reports Server (NTRS)

    Isobe, T.; Feigelson, E. D.; Singh, K. P.; Kembhavi, A.

    1986-01-01

    Using a large database of radio, optical, and x ray luminosities of AGNs with survival analysis, it was found that the x ray emission of the radio selected quasars has two components. One is related to the optical luminosity and the other is related to the radio luminosity.

  12. Cosmic Metal Production and the Contribution of QSO Absorption Systems to the Ionizing Background

    NASA Technical Reports Server (NTRS)

    Madau, Piero; Shull, J. Michael

    1996-01-01

    The recent discovery by Cowie et al. (1995) and Tytler et al. (1995) of metals in the Ly alpha clouds shows that the intergalactic medium (IGM) at high redshift is contaminated by the products of stars and suggests that ionizing photons from massive star formation may be a significant contributor to the UV background radiation at early epochs. We assess the validity of the stellar photoionization hypothesis. Based on recent computations of metal yields and 0-star Lyman continuum (Lyc) fluxes, we find that 0.2 percent of the rest-mass energy of the metals produced is radiated as Lyc. By modeling the transfer of ionizing radiation through the IGM and the rate of chemical enrichment, we demonstrate that the background intensity of photons at 1 ryd that accompanies the production of metals in the Ly alpha forest clouds may be significant, approaching 0.5 x 10(exp -21) ergs cm squared s(-1) Hz(-1) sr(-1) at z approximately equals 3 if the Lyc escape fraction is greater than of equal to 0.25. Together with quasars, massive stars could then, in principle, provide the hydrogen and helium Lyc photons required to ionize the universe at high redshifts. We propose that observations of the He2 Gunn-Peterson effect and of the metal ionization states of the Ly alpha forest and Lyman-limit absorbers should show the signature of a stellar spectrum. We also note that the stellar photoionization model fails if a large fraction of the UV radiation emitted from stars cannot escape into the IGM, as suggested by the recent Hopkins Ultraviolet Telescope observations by Leitherer et al. (1995) of low-redshift starburst galaxies, or if most of the metals observed at z is approximately 3 were produced at much earlier epochs.

  13. Discovery of low-redshift X-ray selected quasars - New clues to the QSO phenomenon

    NASA Technical Reports Server (NTRS)

    Grindlay, J. E.; Forman, W. R.; Steiner, J. E.; Canizares, C. R.; Mcclintock, J. E.

    1980-01-01

    The identification of six X-ray sources discovered by the Einstein Observatory with X-ray quasars is reported, and the properties of these X-ray selected quasars are discussed. The four high-latitude fields of 1 sq deg each in which the Einstein imaging proportional counter detected serendipitous X-ray sources at intermediate exposures of 10,000 sec were observed by 4-m and 1.5-m telescopes, and optical sources with uv excesses and emission line spectra typical of many low-redshift quasars and Seyfert 1 galaxies were found within the 1-arcsec error boxes of the X-ray sources. All six quasars identified were found to be radio quiet, with low redshift and relatively faint optical magnitudes, and to be similar in space density, colors and magnitude versus redshift relation to an optically selected sample at the same mean magnitude. X-ray luminosity was found to be well correlated with both continuum and broad-line emission luminosities for the known radio-quiet quasars and Seyfert 1 galaxies, and it was observed that the five objects with the lowest redshifts have very similar X-ray/optical luminosity ratios despite tenfold variations in X-ray luminosity. It is concluded that photoionization by a continuum extending to X-ray energies is the dominant excitation mechanism in radio-quiet quasars.

  14. [The backgroud sky subtraction around [OIII] line in LAMOST QSO spectra].

    PubMed

    Shi, Zhi-Xin; Comte, Georges; Luo, A-Li; Tu, Liang-Ping; Zhao, Yong-Heng; Wu, Fu-Chao

    2014-11-01

    At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around [OIII] line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-[OIII] line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei.

  15. A New NIR Flare of the QSO CGRaBS J1700+6830

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Carraminana, A.; Recillas, E.; Porras, A.; Mayya, D. Y.

    2013-08-01

    We call attention on our recent observation of the Gamma Ray source CGRaBS J1700+6830 also known as RGB J1700+685 with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofisico Guillermo Haro, located in Cananea, Mexico. On June 21th, 2013 (JD2456464.912), we found this blazar to be in a new outburst. On this date the source was found to have a flux corresponding to H = 12,112 +/- 0.05.

  16. A recent NIR brightening of the QSO CGRaBS J1700+6830

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Recillas, E.; Porras, A.; Mayya, D. Y.; Chavushyan, V.; Carraminana, A.

    2014-06-01

    We call your attention on our recent observation of the Gamma Ray source CGRaBS J1700+6830 also known as RGB J1700+685 with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofisico Guillermo Haro, located in Cananea, Mexico. ...

  17. A Recent NIR Flare of the QSO HB891803+784

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Porras, A.; Carraminana, A.; Recillas, E.; Chavushyan, V.; Mayya, D. Y.

    2014-08-01

    We call your attention on our recent observations in the NIR of the Gamma Ray source 2FGLJ1800.5+7829 related with the radio source S5 1803+78 and the quasar HB891803+784 (z=0.68) with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofisico Guillermo Haro, located in Cananea, Mexico.

  18. NIR Flaring of the QSO CGRaBS J1700+6830

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Carramiñana, A.; Recillas, E.; Porras, A.; Mayya, D. Y.; Escobedo, G.

    2010-06-01

    We call attention on our recent observation of the Gamma Ray source CGRaBS J1700+6830 also known as RGB J1700+685 with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofísico Guillermo Haro, located in Cananea, Mexico. On June 12th, 2010 (JD24555359.892), we found this blazar to be in outburst. It showed fluxes about 2.6 magnitudes brighter than previous NIR photometry. On this date the source was found to have a flux corresponding to K = 10.446 ± 0.05.

  19. Another recent NIR Flare of the QSO BZBJ1454+5124

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Porras, A.; Recillas, E.; Chavushyan, V.; Leon-Tavares, J.; Mayya, D. Y.

    2016-07-01

    We call attention on our recent observation of the Gamma Ray source 2FGLJ1454.4+5123 related with the quasar SBS1452+516 (z=1.0831) with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofisico Guillermo Haro, located in Cananea, Mexico.

  20. A Recent NIR Flare of the QSO SBS1452+516

    NASA Astrophysics Data System (ADS)

    Carrasco, L.; Porras, A.; Escobedo, G.; Carraminana, A.; Recillas, E.; Chavushyan, V.; Mayya, D. Y.

    2014-06-01

    We call attention on our recent observation of the Gamma Ray source 2FGLJ1454.4+5123 related with the quasar SBS1452+516 (z=1.0831) with the CANICA NIR camera on the 2.1m telescope at the Observatorio Astrofisico Guillermo Haro, located in Cananea, Mexico. ...

  1. Optical monitoring of QSO in the framework of the Gaia space mission

    NASA Astrophysics Data System (ADS)

    Taris, F.; Damljanovic, G.; Andrei, A.; Klotz, A.; Vachier, F.

    2015-08-01

    The Gaia astrometric mission of the European Space Agency has been launched the 19th December 2013. It will provide an astrometric catalogue of 500 000 extragalactic sources that could be the basis of a new optical reference frame. On the other hand, the current International Celestial Reference Frame (ICRF) is based on the observations of extragalactic sources at radio wavelength. The astrometric coordinates of sources in these two reference systems will have roughly the same uncertainty. It is then mandatory to observe a set of common targets at both optical and radio wavelength to link the ICRF with what could be called the GCRF (Gaia Celestial Reference Frame). We will show in this paper some results obtained with the TJO, Telescopi Juan Oro, from Observatori Astronomic del Montsec in Spain. It also presents some results obtained with the Lomb-Scargle and CLEAN algorithm methods applied to optical magnitude obtained with the TAROT telescopes.

  2. The Absorption Spectrum of PKS 1756+237

    NASA Astrophysics Data System (ADS)

    Bauer, J. M.; Roth, K. C.; Jim, K. T. C.

    1998-05-01

    We are involved in a program to investigate the relationship between damped Lyalpha absorption systems and the interstellar medium of our own galaxy and nearby galaxies. This ultimately requires the proper identification of the systems responsible for the absorption so that a connection may be drawn between the absorption characteristics and the physical characteristics of the absorber, such as galaxy morphology, size, brightness, and separation from the QSO line of sight (see Jim & Roth, Kolhatkar et al., and Roth et al. also presenting here). PKS 1756+237 is a relatively bright QSO (m_V~18.0) with an emission redshift of z=1.721. There are two strong intervening absorption line systems at redshifts of 1.426 and 1.673. Both systems exhibit strong low-ionization lines, and so are believed to originate in the inner regions of galactic systems at some stage of formation. We obtained two hours of high quality HIRES spectra on the Keck 10m telescope for this QSO in May, 1997. The 6.5 km/s (0.09 Angstroms FWHM) resolution of this data is a ten-fold improvement over existing data, providing kinematic information as well as significantly improved column density measurements. Preliminary analysis of the data suggests the existence of significant Ni II abundance at z=1.67, possibly indicating a damped absorber system. The spectra cover the C II and Si II lines, enabling us to search for associated fine-structure excitation. These spectra also cover several additional low and high-ionization species from which we derive abundance and kinematic information. Images of this QSO, acquired at the UH 2.2m telescope using the QUIRC infrared and Tek2048 optical cameras with UH's tip-tilt system, show possible candidates for absorber systems.

  3. The spatial extent of the z = 2. 04 absorber in the spectrum of PKS 0458-020

    SciTech Connect

    Briggs, F.H.; Wolfe, A.M.; Liszt, H.S.; Davis, M.M.; Turner, K.L.; Mount Wilson and Las Campanas Observatories, Pasadena, CA; National Radio Astronomy Observatory, Charlottesville, VA )

    1989-06-01

    Radio observations of the z = 2.29 QSO PKS 0458-020 are presented which probe the spatial extent of the gas that gives rise to damped Ly-alpha and 21 cm absorption lines at z = 2.04. Previous observations suggest an extended H I disk that would cover the large-scale structure of the background radio source, and are also consistent with smaller configurations of gas that only cover the compact core of the source. VLBI data of the line and continuum are presented which rule out small configurations such as dwarf galaxies or isolated, gravitationally bound clouds. Rather, the evidence points to an extended disklike structure with a radius of curvature larger than (8/h)kpc, where h = H(0)/100 km/s/Mpc. 21 refs.

  4. The unusual field of the quasar 3C 336 - Identification of three foreground Mg II absorbing galaxies

    NASA Technical Reports Server (NTRS)

    Steidel, Charles C.; Dickinson, Mark

    1992-01-01

    Imaging and spectroscopic observations of the field of the QSO 3C 336 (z = 0.927), whose absorption spectrum exhibits at least three Mg II 2796, 2803-A absorption systems with z sub abs less than z sub em, making it the richest low-redshift absorption spectrum observed in a recently completed absorption line survey. The most intrinsically faint Mg II absorbing galaxy yet discovered is tentatively identified. With z equal to 0.472 and B greater than 24, its properties strongly resemble those of the so-called faint blue galaxies found in deep imaging and spectroscopic surveys for field galaxies. The implications of this very complex field for the general properties of galaxies producing heavy element absorption systems in the spectra of QSOs are discussed.

  5. Element abundances at high redshift

    NASA Technical Reports Server (NTRS)

    Meyer, David M.; Welty, D. E.; York, D. G.

    1989-01-01

    Abundances of Si(+), S(+), Cr(+), Mn(+), Fe(_), and Zn(+) are considered for two absorption-line systems in the spectrum of the QSO PKS 0528 - 250. Zinc and sulfur are underabundant, relative to H, by a factor of 10 compared to their solar and Galactic interstellar abundances. The silicon-, chromium-, iron-, and nickel-to-hydrogen ratios are less than the solar values and comparable to the local interstellar ratios. A straightforward interpretation is that nucleosynthesis in these high-redshift systems has led to only about one-tenth as much heavy production as in the gas clouds around the sun, and that the amount of the observed underabundances attributable to grain depletion is small. The dust-to-gas ratio in these clouds is less than 8 percent of the Galactic value.

  6. Search for correlated UV and x ray absorption of NGC 3516

    NASA Technical Reports Server (NTRS)

    Martin, Christopher; Halpern, Jules P.; Kolman, Michiel

    1991-01-01

    NGC 3516, a low-luminosity Seyfert galaxy, is one of a small fraction of Seyfert galaxies that exhibit broad absorption in a resonance line. In order to determine whether the UV and x ray absorption in NGC 3516 are related, 5 IUE observations were obtained, quasi-simultaneously with 4 Ginga observations. The results are presented and discussed. The following subject areas are covered: short-term UV variability; emission lines; galactic absorption lines; the C IV, N V, and Si IV absorption features; lower limit on the carbon column density; estimate of the distance from the absorber to the continuum source; variability in the continuum and absorption; a comparison with BAL QSO's; and the x ray-UV connection.

  7. Warm and Hot Gases in and around Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Wang, Q. Daniel

    2012-10-01

    We propose a pilot joint XMM-Newton/HST observing program to study both warm and hot gases in two optically-selected galaxy clusters at z=0.1-0.2. Each cluster has a UV-bright background QSO projected within the expected strong accretion shock. We will measure the luminosity, temperature,and morphology of the hot gas component and observe UV absorption lines of the O VI doublet and other ion transitions of the clusters. These lines are sensitive to the thermal, kinetic, and chemical properties of warm gas, associated with the halos of individual galaxies and the intracluster medium. This joint study will thus allow us for the first time to characterize the heating/cooling and dynamic processes of the gases in the clusters.

  8. VizieR Online Data Catalog: XQ-100 survey neutral gas (Sanchez-Ramirez+, 2016)

    NASA Astrophysics Data System (ADS)

    Sanchez-Ramirez, R.; Ellison, S. L.; Prochaska, J. X.; Berg, T. A. M.; Lopez, S.; D'Odorico, V.; Becker, G. D.; Christensen, L.; Cupani, G.; Denney, K. D.; Paris, I.; Worseck, G.; Gorosabel, J.

    2016-10-01

    The XQ-100 survey is an ESO Large Program (ESO ID 189.A-0424, P.I. S. Lopez) which obtained X-shooter spectra of 100 3.5QSO absorption lines and emission features from the atmospheric cut-off to the near-IR. Based on the results of the XQ-100 survey, we report the detection of 38 intervening DLAs identified towards 100 z>3.5 QSOs. This sample has been combined, after exhaustive checking for duplications and errors, with a literature sample of DLA surveys spanning the last ~20 years. (2 data files).

  9. Development of a transparent, non-cytotoxic, silver ion-exchanged glass with antimicrobial activity and low ion elution.

    PubMed

    Shim, Gyu-In; Kim, Seong-Hwan; Eom, Hyung-Woo; Kim, Kwang-Mahn; Choi, Se-Young

    2015-05-01

    We investigated the antimicrobial, cytotoxicity, skin irritation, and ion elution behaviors of glass doped with silver ions with respect to its application to electronic equipment such as phones and tablet screens. The microbes tested were Escherichia coli, Staphylococcus aureus, and Penicillium funiculosum. AgNO3 powder was spread on both sides of aluminosilicate glass, and it was heated to 250-280°C for 10min. Under optimized heating conditions (260°C, 10min), the antimicrobial activity of ion-exchanged glass against bacteria and fungi was over 99.9% after 24 weeks. The glass failed to irritate the skin of experimental animals and was considered non-cytotoxic. The maximum amount of Ag ions that were eluted from the ion-exchanged glass into drinking water was measured at 0.037±0.003μgL(-1), an amount which is several orders of magnitude below the standard limit of 0.1mgL(-1) in drinking water. Ag ion-exchanged glass had characteristics suitable for use as a display screen, such as a light transmittance of 90% and a surface roughness of 0.704nm. Our findings suggest that glass doped with silver ions is more hygienic than non-doped glass is, and should be applied to display screens and glassware.

  10. ERRORS IN APPLYING LOW ION-STRENGTH ACTIVITY COEFFICIENT ALGORITHMS TO HIGHER IONIC-STRENGTH AQUATIC MEDIA

    EPA Science Inventory

    The toxicological and regulatory communities are currently exploring the use of free-ion-activity- models as a means of reducing uncertainties in current methods for assessing metals bioavailabi- lity from contaminated aquatic media. While most practitioners would support the des...

  11. Abundances in Star-forming Galaxies and Damped Lyman Alpha Systems

    NASA Astrophysics Data System (ADS)

    Schulte-Ladbeck, R.; Rao, S. M.; Hopkins, A. M.; König, B.; Turnshek, D. A.; Miller, C. J.; Vanden Berk, D.

    2004-12-01

    Our knowledge about the chemical properties of galaxies is based on measurements of emission lines from photo-ionized gas. The abundances of galaxies at high-z are inferred using absorption lines arising in neutral gas in Damped Lyman Alpha (DLA) systems. Do the results of emission and absorption experiments agree in cases of nearby star-forming galaxies (SFGs) causing DLAs? Schulte-Ladbeck et al. (2004a) examined the z=0.009 DLA/SFG SBS 1543+593. We derived [O/H]II=-0.54. The bright QSO HS 1543+5921 intercepts the disk at small impact parameter. We found a lower limit, [O/H]I>-2.14, using HST archival spectra. New HST observations by Bowen et al. are analyzed to yield a S abundance of [S/H]I=-0.54. Using S as a proxy for O this suggests [O/H]I=[O/H]II (or 0.29xsolar) for one genuine DLA. To investigate additional SFG/QSO pairs, we used the CMU-Pitt Value Added Catalog to assemble from the SDSS DR1 a database of about 13,000 SFGs with 0< z <0.36 (Schulte-Ladbeck 2004b). We applied the strong-line indices of Pettini & Pagel (2004), derived O/HII for all objects, and a median O/HII ratio of 0.74xsolar with a SIQR of 0.19. An O/H vs. z diagram is constructed by augmenting these data to z≈5 with O/HI ratios for DLAs (Prochaska et al. 2003). We matched our SFG catalog against the SDSS QSO catalog, then used the HST archive to determine the HI column densities and limits on O/HI for these SFGs. The results are discussed using the O/H vs. redshift diagram. We acknowledge support of HST archival funding to program ID 10282.

  12. Tomography of a Gamma-ray Burst Progenitor and its Host Galaxy

    NASA Technical Reports Server (NTRS)

    Castro-Tirado, Alberto J.; Moller, Palle; Garcia-Segura, Guillermo; Gorosabel, Javier; Perez, Enrique; deUgartePostigo, Antonio; Solano, Enrique; BarradoyNavascues, David; CastroCeron, Jose Marie; Kouveliotou, Chryssa

    2005-01-01

    We have obtained near-infrared and high-resolution optical spectroscopy of the bright afterglow of the very intense gamma-ray burst recorded on 2002, October 4 (GRB 021004). Besides of line emission in the near-IR allowing an independent measurement of the systemic redshift (z = 2.3304 plus or minus 0.0005), we find several absorption line groups spanning a range of about 3,000 kilometers per second in velocity relative to the redshift of the host galaxy. The absorption profiles are very complex with both velocity-broadened components extending over several 100 kilometers per second and narrow lines with velocity widths of only approximately 20 kilometers per second. By analogy with QSO absorption line studies, the relative velocities, widths, and degrees of ionization of the lines ("line-locking", "ionization-velocity correlation") show that the progenitor had both an extremely strong radiation field and several distinct mass loss phases (winds). These results are consistent with GRB progenitors being massive stars, such as Luminous Blue Variables (LBVs) or Wolf-Rayet stars, providing a detailed picture of the spatial and velocity structure of the GRB progenitor star at the time of explosion. The host galaxy is a prolific star-forming galaxy with a SFR of approximately 10 solar mass yr(sup -l).

  13. The X-ray Absorber in the X-ray Transient NLS1 WPVS 007

    NASA Astrophysics Data System (ADS)

    Grupe, Dirk

    This proposal is for a funding request for an approved XMM-Newton observations of the X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007. The request is for 4 month of salary for the PI for one year in order to do the data analysis, publish the results, and attend an international AGN meeting. XMM will observe WPVS 007 in June 2010 simultaneously with HST, Chandra, and Swift. The goal is to establish a tight connection between the UV broad absorption line troughs found in FUSE observations and the strong partial covering absorber feature found by Swift. WPVS 007 showed a dramatic transformation into a Broad Absorption line QSO like AGN between a 1996 HST observation and a 2003 FUSE observation. Several Swift monitoring observations have suggested that the absorber may have started to disappear. Therefore it is crucial for our HST COS UV spectroscopy to know what the status of the X-ray absorber is. The XMM observation will provide a well-exposed X-ray spectrum even if WPVS 007 will be in a low flux state. This spectrum will enable us to put constraints on the absorption column density and covering fraction of the partial covering absorber.

  14. Warm and Hot Gases in and around Cluster Galaxies at Z=0.1-0.2

    NASA Astrophysics Data System (ADS)

    Wang, Q.

    2013-10-01

    We propose a joint HST/XMM-Newton observing program to study both warm and hot gases in two optically-selected galaxy clusters at z=0.117-0.2108. Each cluster has a UV-bright background QSO projected within the expected strong accretion shock {< 2r_200}. We will observe UV absorption lines of the O VI doublet, HI Ly-alpha and Ly-beta, and other ion transitions in the rest frame of the clusters, using the HST/COS G130M grating. These absorption lines are sensitive to the thermal, kinetic, and chemical properties of warm {T < 10^6 K} gas, associated with the halos of individual galaxies and the intracluster medium. Chandra/ACIS observations will be used to measure the luminosity, temperature, and morphology of the hot gas component of the clusters, especially in their core regions. This joint study will thus allow us for the first time to characterize the heating/cooling and dynamic processes of these multiple gas phases in the clusters. The understanding of these processes is essential for understanding cluster galaxy evolution, the correct interpretation of X-ray and Sunyaev-Zeldovich effect measurements, and the use of clusters as cosmology probes.

  15. The FAST BAL Monitoring Campaign: Multi-epoch Constraints on Quasar Outflows

    NASA Astrophysics Data System (ADS)

    Arraki, Kenza S.; Haggard, D.; Anderson, S.; Green, P.; Aldcroft, T.

    2012-01-01

    Kinetic energy carried by AGN winds and jets may rival radiation as the dominant feedback mechanism regulating galaxy-SMBH co-evolution. Though outflows likely accompany all luminous accretion disks, broad absorption line quasars (BALQSOs) provide the most dramatic astrophysical examples; their massive outflows display P-Cygni profiles that span velocities up to 0.3c and are visible in the spectra of 15-40% of optically-selected quasars. Spectroscopic variability studies of BALQSOs probe the structure, stability, location, and dynamics of the emitting and absorbing gas near the SMBH and can provide insight into connections between AGN feedback and host galaxy formation and evolution. We report on a multi-year spectroscopic campaign that monitors seventeen BALQSOs (identified originally in the SDSS) using the Fred Lawrence Whipple Observatory's 1.5m telescope's FAST spectrograph. These targets have Chandra X-ray data and have been repeatedly observed with FAST, in regular cadences from one day to two years -- a 6 year cadence is planned for spring 2012. We identify variability in the broad absorption line region, assess its significance, magnitude, and frequency and discuss the constraints these investigations can place on QSO outflows

  16. A Highly Doppler Blueshifted Fe-K Emission Line in the High-Redshift QSO PKS 2149-306.

    PubMed

    Yaqoob; George; Nandra; Turner; Zobair; Serlemitsos

    1999-11-01

    We report the results from an ASCA observation of the high-luminosity, radio-loud quasar PKS 2149-306 (redshift 2.345), covering the approximately 1.7-30 keV band in the quasar frame. We find the source to have a luminosity approximately 6x1047 ergs s-1 in the 2-10 keV band (quasar frame). We detect an emission line centered at approximately 17 keV in the quasar frame. Line emission at this energy has not been observed in any other active galaxy or quasar to date. We present evidence rejecting the possibility that this line is the result of instrumental artifacts or a serendipitous source. The most likely explanation is blueshifted Fe-K emission (the equivalent width is EW approximately 300+/-200 eV, quasar frame). Bulk velocities of the order of 0.75c are implied by the data. We show that Fe-K line photons originating in an accretion disk and Compton scattering off a leptonic jet aligned along the disk axis can account for the emission line. Curiously, if the emission-line feature recently discovered in another quasar (PKS 0637-752, z=0.654) at 1.6 keV in the quasar frame is due to blueshifted O vii emission, the Doppler blueshifting factor in both quasars is similar ( approximately 2.7-2.8).

  17. A study of the discrepant QSO X-ray luminosity function from the HEAO-2 data archive

    NASA Technical Reports Server (NTRS)

    Margon, B.

    1984-01-01

    An in-progress investigation aimed at characterizing the X-ray luminosity of very faint QSOs is described. More than 100 faint, previously uncataloged QSOs which lie in areas imaged in X rays at very high sensitivity were discovered.

  18. VizieR Online Data Catalog: SDSS-RM project: z<1 QSO host galaxies (Matsuoka+, 2015)

    NASA Astrophysics Data System (ADS)

    Matsuoka, Y.; Strauss, M. A.; Shen, Y.; Brandt, W. N.; Greene, J. E.; Ho, L. C.; Schneider, D. P.; Sun, M.; Trump, J. R.

    2016-01-01

    We use the data acquired in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, in which a single spectroscopic field was repeatedly observed to explore the variability of quasars. The full technical details of the project are found in Shen et al. (2015, J/ApJS/216/4). SDSS-RM was conducted during the dark/gray time in the final season (2013-2014) of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS; Dawson et al. 2013AJ....145...10D). The target field (centered at RAJ2000=14:14:49.00, DEJ2000=+53:05:00.0) coincides with the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS 1; Kaiser et al. 2010SPIE.7733E..0EK) Medium Deep Field MD07, which lies within the Canada-France-Hawaii Telescope Legacy Survey W3 field. (1 data file).

  19. High-z QSO Absorption Systems: Metal-Poor Cold Flows and Mg II Absorber Host Galaxies

    NASA Astrophysics Data System (ADS)

    Cooper, Thomas; Simcoe, R. A.; Cooksey, K.; O'Meara, J.

    2014-01-01

    Cosmological simulations have suggested a new model for gas accretion in young galaxies, in which baryons flow into the star-forming disk along filamentary streams without shock heating at the dark matter halo virial radius. Observationally, these cold flows manifest as Lyman Limit Systems with low heavy element abundances. To search for cold flows in the early Universe, we have obtained echellette-resolution spectra of an HI-selected sample of LLS at z>3.5 from the Sloan Digital Sky Survey. The sightlines were selected to exhibit no heavy element absorption at the resolution afforded by SDSS, and the higher resolution data provides metallicity measurements precise enough to determine if they exhibit cold flow accretion characteristics. In a parallel program, we use the Magellan Telescopes and HST/WFC-3 to investigate the connection between Mg II absorbers and proximate galaxies at 3, extending fruitful studies of the circumgalactic medium to larger redshift.

  20. Ultraviolet-excess sources with a red/infrared counterpart: low-mass companions, debris discs and QSO selection

    NASA Astrophysics Data System (ADS)

    Verbeek, Kars; Groot, Paul J.; Scaringi, Simone; Casares, Jorge; Corral-Santana, Jesus M.; Deacon, Niall; Drew, Janet E.; Gänsicke, Boris T.; González-Solares, Eduardo; Greimel, Robert; Heber, Ulrich; Napiwotzki, Ralf; Østensen, Roy H.; Steeghs, Danny; Wright, Nicholas J.; Zijlstra, Albert

    2014-02-01

    We present the result of the cross-matching between ultraviolet (UV)-excess sources selected from the UV-Excess Survey of the Northern Galactic Plane (UVEX) and several infrared (IR) surveys (2MASS, UKIDSS and WISE). From the position in the (J - H) versus (H - K) colour-colour diagram, we select UV-excess candidate white dwarfs with an M-dwarf type companion, candidates that might have a lower mass, brown-dwarf type companion and candidates showing an IR-excess only in the K band, which might be due to a debris disc. Grids of reddened DA+dM and sdO+MS/sdB+MS model spectra are fitted to the U, g, r, i, z, J, H, K photometry in order to determine spectral types and estimate temperatures and reddening. From a sample of 964 hot candidate white dwarfs with (g - r) < 0.2, the spectral energy distribution fitting shows that ˜2-4 per cent of the white dwarfs have an M-dwarf companion, ˜2 per cent have a lower-mass companion, and no clear candidates for having a debris disc are found. Additionally, from WISE six UV-excess sources are selected as candidate quasi-stellar objects (QSOs). Two UV-excess sources have a WISE IR-excess showing up only in the mid-IR W3 band of WISE, making them candidate luminous infrared galaxies (LIRGs) or Sbc starburst galaxies.

  1. Communications via the radio artificial earth satellite: Design of the tracking diagram and features for conducting QSO

    NASA Technical Reports Server (NTRS)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

    A detailed examination is made of the operation of a transmitting artifical Earth satellite. A tracking diagram for the satellite is constructed. The zone of radio visibility can be determined based on the techniques proposed.

  2. THE QSO HE 0450-2958: SCANTILY DRESSED OR HEAVILY ROBED? A NORMAL QUASAR AS PART OF AN UNUSUAL ULIRG

    SciTech Connect

    Jahnke, Knud; Elbaz, David; Pantin, Eric; Lagage, Pierre-Olivier; Letawe, Geraldine; Chantry, Virginie

    2009-08-01

    The luminous z = 0.286 quasar HE 0450-2958 is interacting with a companion galaxy at 6.5 kpc distance and the whole system radiates in the infrared (IR) at the level of an ultraluminous infrared galaxy (ULIRG). A so far undetected host galaxy triggered the hypothesis of a mostly 'naked' black hole (BH) ejected from the companion by three-body interaction. We present new Hubble Space Telescope (HST)/NICMOS 1.6 {mu}m imaging data at 0.''1 resolution and VLT/VISIR 11.3 {mu}m images at 0.''35 resolution that are for the first time resolving the system in the near- and mid-infrared. We combine these data with existing optical HST and CO maps. (1) At 1.6 {mu}m we find an extension NE of the quasar nucleus that is likely a part of the host galaxy, though not its main body. If true, a combination with upper limits on a main body co-centered with the quasar brackets the host-galaxy luminosity to within a factor of {approx}4 and places HE 0450-2958 directly onto the M{sub BH} - M{sub bulge} relation for nearby galaxies. (2) A dust-free line of sight to the quasar suggests a low dust obscuration of the host galaxy, but the formal upper limit for star formation (SF) lies at 60 M{sub sun} yr{sup -1}. HE 0450-2958 is consistent with lying at the high-luminosity end of Narrow-Line Seyfert 1 Galaxies, and more exotic explanations like a 'naked quasar' are unlikely. (3) All 11.3 {mu}m radiation in the system is emitted by the quasar nucleus. It has warm ULIRG-strength IR emission powered by BH accretion and is radiating at super-Eddington rate, L/L{sub Edd} = 6.2{sup +3.8}{sub -1.8}, or 12 M{sub sun} yr{sup -1}. (4) The companion galaxy is covered in optically thick dust and is not a collisional ring galaxy. It emits in the far-infrared at ULIRG strength, powered by Arp220-like SF (strong starburst-like). An M82-like SED is ruled out. (5) With its BH accretion rate, HE 0450-2958 produces not enough new stars to maintain its position on the M{sub BH} - M{sub bulge} relation, and SF and BH accretion are spatially disjoint. This relation can either only be maintained averaging over a longer timescale ({approx}<500 Myr) and/or the bulge has to grow by redistribution of pre-existing stars. (6) Systems similar to HE 0450-2958 with spatially disjoint ULIRG-strength star formation and quasar activity might be common at high redshifts but at z < 0.43 we only find <4% (3/77) candidates for a similar configuration.

  3. Deep imaging of high redshift QSO fields below the Lyman limit. II - Number counts and colors of field galaxies

    NASA Technical Reports Server (NTRS)

    Steidel, Charles C.; Hamilton, Donald

    1993-01-01

    We present an analysis of the number counts and colors of faint galaxies to about 26.5 mag in the fields of two high Galactic latitude, very-high-redshift QSOs. We concentrate on the general properties of the field galaxies at faint magnitudes. In particular, we readdress the faint galaxy number counts and colors as a function of apparent magnitude and we reexamine the possible contribution of very-high-redshift galaxies to the faint samples. We find that the number counts to R = 26 are well fitted by the relation log N(m) = 0.31R + C. The G-band counts for the same galaxies are consistent with the same slope fainter than G about 23.5, but exhibit a much steeper slope at brighter magnitudes. At R = 25.5, the differential number counts have reached about 1.2 x 10 exp 5/sq deg; the same surface density of galaxies is reached at G = 26.5. We confirm the existence of a gradual 'blueing' trend of the field galaxies toward fainter apparent magnitude; however, the blueing trend appears to extend only as faint as G about 24, fainter than which both the (G-R) and (U sub n-G) colors appear to level off. The mean colors of faint galaxies are considerably redder than flat spectrum. There are essentially no objects to R = 26 which have spectral energy distributions which are bluer than flat spectrum. The potential contribution of very-high-redshift galaxies may have been underestimated in previous analyses; the current data are consistent with the same population of relatively luminous galaxies at z about 3 as exist at z about 0.7.

  4. Mapping Baryons in the Halo of NGC 1097

    NASA Astrophysics Data System (ADS)

    Bowen, David

    2012-10-01

    We propose observing 5 background QSOs whose sightlines pass through the halo of NGC 1097 at impact parameters of 53-183 kpc. NGC 1097 is a bright {-21.1} spiral galaxy that has the highest surface density of background, UV-bright QSOs in the nearby Universe. The galaxy hosts a low luminosity AGN at its core, surrounded by a ring of intense star-forming regions; there is also evidence from stellar tidal streams that the galaxy has recently cannibalized a number of dwarf galaxies, and a companion dwarf elliptical is still clearly merging with the outer disk. We aim to examine the physical conditions of gas that fills the halo of such an active galaxy. We will search primarily for Lya and SiIV absorption lines in the spectra of the background QSOs, as well as weak NV from hot gas. At the lowest impact parameters, we may also be able to find absorption lines from low ionization species. Our goals are to test whether the halo of NGC 1097 contains the same distribution of Lyman-alpha forest clouds seen at higher redshifts out to large distances from galaxies, and determine how the HI column density, covering fraction, and temperature of the gas decline with radius in a single galaxy halo. We will examine whether the velocities of the absorbers are consistent with those expected from gas co-rotating in the dark matter halo of the galaxy, or whether there exists a distribution of velocities that might indicate outflows from the galactic disk or from the central AGN, or, alternatively, from inflows from the IGM. Our map of Lya and SiIV around NGC 1097 will provide an important template for understanding the origin of higher redshift QSO absorption line systems.

  5. A compact, metal-rich, kpc-scale outflow in FBQS J0209-0438: detailed diagnostics from HST/COS extreme UV observations

    NASA Astrophysics Data System (ADS)

    Finn, Charles W.; Morris, Simon L.; Crighton, Neil H. M.; Hamann, Fred; Done, Chris; Theuns, Tom; Fumagalli, Michele; Tejos, Nicolas; Worseck, Gabor

    2014-06-01

    We present HST/COS observations of highly ionized absorption lines associated with a radio-loud quasar (QSO) at z = 1.1319. The absorption system has multiple velocity components, with an overall width of ≈600 km s-1, tracing gas that is largely outflowing from the QSO at velocities of a few 100 km s-1. There is an unprecedented range in ionization, with detections of H I, N III, N IV, N V, O IV, O IV*, O V, O VI, Ne VIII, Mg X, S V and Ar VIII. We estimate the total hydrogen number density from the column density ratio N(OIV*) / N(OIV) to be log(nH/cm-3)˜3. Combined with constraints on the ionization parameter in the O IV bearing gas from photoionization equilibrium models, we derive a distance to the absorbing complex of 2.3≲R≲6.0kpc from the centre of the QSO. A range in ionization parameter, covering ˜two orders of magnitude, suggest absorption path lengths in the range 10-4.5≲labs≲1pc. In addition, the absorbing gas only partially covers the background emission from the QSO continuum, which suggests clouds with transverse sizes ltrans≲10-2.5 pc. Widely differing absorption path lengths, combined with covering fractions less than unity across all ions pose a challenge to models involving simple cloud geometries in associated absorption systems. These issues may be mitigated by the presence of non-equilibrium effects, which can be important in small, dynamically unstable clouds, together with the possibility of multiple gas temperatures. The dynamics and expected lifetimes of the gas clouds suggest that they do not originate from close to the active galactic nuclei, but are instead formed close to their observed location. Their inferred distance, outflow velocities and gas densities are broadly consistent with scenarios involving gas entrainment or condensations in winds driven by either supernovae, or the supermassive black hole accretion disc. In the case of the latter, the present data most likely does not trace the bulk of the outflow by mass

  6. The Ionization and Metallicity of the Intervening O VI Absorber at z=0.1212 in the Spectrum of H1821+643

    NASA Astrophysics Data System (ADS)

    Tripp, Todd M.; Giroux, Mark L.; Stocke, John T.; Tumlinson, Jason; Oegerle, William R.

    2001-12-01

    We use high-resolution UV spectra of the radio-quiet quasar (QSO) H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE), to study the ionization and metallicity of an intervening O VI absorption line system at zabs=0.1212. This absorber has the following notable properties: (1) several galaxies are close to the sight line at the absorber redshift, including an actively star-forming galaxy at a projected distance of 144 h-175 kpc, (2) there is a complex cluster of H I Lyα absorption lines near the O VI redshift, including at least five components spread over a velocity range of ~700 km s-1, (3) the strongest Lyα line in the cluster appears to be composed of a mildly saturated component with a typical b-value blended with a remarkably broad component with b~85 km s-1, (4) the O VI absorption is not aligned with the strongest (saturated) H I absorption, but instead is well aligned with the very broad component, and (5) the only detected species (at the 4 σ level) are O VI and H I, despite coverage of strong transitions of abundant elements (e.g., C II, C III, and C IV). Based on these constraints, we find that the absorption line properties can be produced in collisionally ionized gas with 105.3<=T<=105.6 K and -1.8<=[O/H]<=-0.6. However, we find that photoionization is also viable if the path length l through the absorbing gas is long enough; simple photoionization models require 85<=l<=1900 kpc and -1.1<=[O/H]<=-0.3. We briefly discuss how observations of X-ray absorption lines due to O VII and O VIII could be used, in principle, to break the ionization mechanism degeneracy, and we conclude with some comments regarding the nature of O VI absorbers. Based on observations 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.

  7. The Ionization and Metallicity of the Intervening O VI Absorber at z=0.1212 in the Spectrum of H1821+643

    NASA Technical Reports Server (NTRS)

    Tripp, Todd M.; Giroux, Mark L.; Stocke, John T.; Tumlinson, Jason; Oegerle, William R.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We use high-resolution UV (ultraviolet) spectra of the radio-quiet QSO (quasi-stellar object) H1821+643 (z(sub em) = 0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer (FUSE), to study the ionization and metallicity of an intervening O VI absorption line system at z(sub abs) = 0.1212. This absorber has the following notable properties: (1) Several galaxies are close to the sight line at the absorber redshift, including an actively star-forming galaxy at a projected distance of 144 h(sub 75)(exp -1) kpc. (2) There is a complex cluster of H I Ly(alpha) absorption lines near the O VI redshift, including at least five components spread over a velocity range of approximately 700 km s(exp -1). (3) The strongest Ly(alpha) line in the cluster appears to be composed of a mildly saturated component with a typical b-value blended with a remarkably broad component with b approximately equals 85 km s(exp -1). (4) The O VI absorption is not aligned with the strongest (saturated) H I absorption, but instead is well-aligned with the very broad component. (5) The only detected species (at the 4(sigma) level) are O VI and H I despite coverage of strong transitions of abundant elements (e.g., C II, C III, and C IV). Based on these constraints, we find that the absorption line properties can be produced in collisionally ionized gas with 10(exp 5.3) is equal to or less than T is equal to or less than 10(exp 5.6) K and -1.8 is equal to or less than [O/H] is equal to or less than -0.6. However, we find that photoionization is also viable if the pathlength l through the absorbing gas is long enough; simple photoionization models require 85 is equal to or less than l is equal to or less than 1900 kpc and -1.1 is equal to or less than [O/H] is equal to or less than -0.3. We briefly discuss how observations of X-ray absorption lines due to O VII and O VIII could be used, in principle, to break the ionization mechanism

  8. The z = 0.8596 damped Ly-alpha absorbing galaxy toward PKS 0454+039

    NASA Technical Reports Server (NTRS)

    Steidel, Charles C.; Bowen, David V.; Blades, J. Chris; Dickenson, Mark

    1995-01-01

    We present Hubble Space Telescope (HST) and ground-based data on the Z(sub abs) = 0.8596 metal-line absorption system along the line of sight to PKS 0454+0356. The system is a moderate-redshift damped Ly-alpha system, with N(H I) = (5.7 +/- 0.3) x 10(exp 20)/sq cm as measured from the Faint Object Spectrograph (FOS) spectrum. We also present ground-based images which we use to identify the galaxy which most probably gives rise to the damped system; the most likely candidate is relatively underluminous by QSO absorber standards M(sub B) approximately -19.0 for A(sub 0) = 0.5 and H(sub 0) = 50 km/s/Mpc) and lies approximately 8.5/h kpc in projection from the QSO sight line. Ground-based measurements of Zn II, Cr II, and Fe II absorption lines from this system allow us to infer abundances of (Zn/H) = -1.1, (Cr/H) = -1.2, and (Fe/H) = -1.2 indicating overall metallicity similar to damped systems at z is greater than 2, and that the depletion of Cr and Fe onto dust grains may be even less important than in many of the high-redshift systems of comparable metallicity. Limits previously placed on the 21 cm optical depth in the z = 0.8596 system, together with our new N(H I) measurement, suggest a very high spin temperature for the H I, T(sub s) is greater than 580 K.

  9. BAL QSOs AND EXTREME UFOs: THE EDDINGTON CONNECTION

    SciTech Connect

    Zubovas, Kastytis; King, Andrew

    2013-05-20

    We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby active galactic nuclei (AGNs), and the slower and less ionized winds of broad absorption line (BAL) QSOs. The primary difference is the mass-loss rate in the wind, which is ultimately determined by the rate at which mass is fed toward the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to {approx}10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass-loss rates which are at most comparable to Eddington, giving fast, highly ionized winds. In contrast, BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass-loss rates are significantly super-Eddington, and so are slower and less ionized. This picture correctly predicts the velocities and ionization states of the observed winds, including the recently discovered one in SDSS J1106+1939. We suggest that luminous AGNs may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionization cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M-{sigma} relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

  10. BAL QSOs and Extreme UFOs: The Eddington Connection

    NASA Astrophysics Data System (ADS)

    Zubovas, Kastytis; King, Andrew

    2013-05-01

    We suggest a common physical origin connecting the fast, highly ionized winds (UFOs) seen in nearby active galactic nuclei (AGNs), and the slower and less ionized winds of broad absorption line (BAL) QSOs. The primary difference is the mass-loss rate in the wind, which is ultimately determined by the rate at which mass is fed toward the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to ~10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass-loss rates which are at most comparable to Eddington, giving fast, highly ionized winds. In contrast, BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass-loss rates are significantly super-Eddington, and so are slower and less ionized. This picture correctly predicts the velocities and ionization states of the observed winds, including the recently discovered one in SDSS J1106+1939. We suggest that luminous AGNs may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionization cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M-σ relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

  11. The Circumgalactic Medium of Submillimeter Galaxies. I. First Results from a Radio-identified Sample

    NASA Astrophysics Data System (ADS)

    Fu, Hai; Hennawi, J. F.; Prochaska, J. X.; Mutel, R.; Casey, C.; Cooray, A.; Kereš, D.; Zhang, Z.-Y.; Clements, D.; Isbell, J.; Lang, C.; McGinnis, D.; Michałowski, M. J.; Mooley, K.; Perley, D.; Stockton, A.; Thompson, D.

    2016-11-01

    We present the first results from an ongoing survey to characterize the circumgalactic medium (CGM) of massive high-redshift galaxies detected as submillimeter galaxies (SMGs). We constructed a parent sample of 163 SMG-QSO pairs with separations less than ˜36″ by cross-matching far-infrared-selected galaxies from Herschel with spectroscopically confirmed QSOs. The Herschel sources were selected to match the properties of the SMGs. We determined the sub-arcsecond positions of six Herschel sources with the Very Large Array and obtained secure redshift identification for three of those with near-infrared spectroscopy. The QSO sightlines probe transverse proper distances of 112, 157, and 198 kpc at foreground redshifts of 2.043, 2.515, and 2.184, respectively, which are comparable to the virial radius of the ˜1013 M ⊙ halos expected to host SMGs. High-quality absorption-line spectroscopy of the QSOs reveals systematically strong H i Lyα absorption around all three SMGs, with rest-frame equivalent widths of ˜2-3 Å. However, none of the three absorbers exhibit compelling evidence for optically thick H i gas or metal absorption, in contrast to the dominance of strong neutral absorbers in the CGM of luminous z ˜ 2 QSOs. The low covering factor of optically thick H i gas around SMGs tentatively indicates that SMGs may not have as prominent cool gas reservoirs in their halos as the coeval QSOs and that they may inhabit less massive halos than previously thought.

  12. Resolving the Structure of Ionized Helium in the Intergalactic Medium with the Far Ultraviolet Spectroscopic Explorer. 2.3

    NASA Technical Reports Server (NTRS)

    Kriss, G. A.; Shull, J. M.; Oegerle, W.; Zheng, W.; Davidsen, A. F.; Songaila, A.; Tumlinson, J.; Cowie, L. L.; Dehavreng, J.-M.; Friedman, S. D.

    2001-01-01

    The neutral hydrogen and the ionized helium absorption in the spectra of high-redshift quasi-stellar objects (QSOs) are unique probes of structure in the universe at epochs intermediate between the earliest density fluctuations seen in the cosmic background radiation and the distribution of galaxies visible today. We present Far-Ultraviolet Spectroscopic Explorer (FUSE) observations of the line of sight to the QSO HE2347-4342 in the 1000-1187 angstrom band at a resolving power of 15,000. Above redshift z = 2.7, the IGM is largely opaque in He II Ly-alpha (304 angstroms). At lower redshifts, the optical depth gradually decreases to a mean value tau = 1 at z = 2.4. We resolve the He II Ly-alpha absorption as a discrete forest of absorption lines in the z = 2.3 - 2.7 redshift range. Approximately 50% of these spectral features have H I counterparts with column densities N(sub HI) > 10(exp 12.3)/sq cm visible in a Keck spectrum. These account for most of the observed opacity in He II Ly-alpha. The remainder have N(sub HI) < 10(exp 12.3)/sq cm, below the threshold for current observations. A short extrapolation of the power-law distribution of H I column densities to lower values can account for these new absorbers. The He II to H I column density ratio eta averages approximately 80, consistent with photoionization of the IGM by a hard ionizing spectrum resulting from the integrated light of quasars at high redshift, but there is considerable scatter. Values of eta > 100 in many locations indicate that there may be localized contributions from starbursts or heavily filtered QSO radiation.

  13. On the covering fraction variability in an EUV mini-BAL outflow from PG 1206+459

    NASA Astrophysics Data System (ADS)

    Muzahid, S.; Srianand, R.; Charlton, J.; Eracleous, M.

    2016-04-01

    We report on the first detection of extreme-ultraviolet (EUV) absorption variability in the Ne VIII λλ770, 780 mini-broad absorption line (mini-BAL) in the spectrum of the quasar (QSO) PG 1206+459. The observed equivalent width (EW) of the Ne VIII doublet shows a ˜4σ variation over a time-scale of 2.8 months in the QSO's rest frame. Both members of the Ne VIII doublet exhibit non-black saturation, indicating partial coverage of the continuum source. An increase in the Ne VIII covering fraction from fc = 0.59 ± 0.05 to 0.72 ± 0.03 is observed over the same period. The Ne VIII profiles are too highly saturated to be susceptible to changes in the ionization state of the absorbing gas. In fact, we do not observe any significant variation in the EW and/or column density after correcting the spectra for partial coverage. We, thus, propose transverse motions of the absorbing gas as the cause of the observed variability. Using a simple model of a transiting cloud we estimate a transverse speed of ˜1800 km s-1. For Keplerian motion, this corresponds to a distance between the absorber and the central engine of ˜1.3 pc, which places the absorber just outside the broad-line region. We further estimate a density of ˜5 × 106 cm-3 and a kinetic luminosity of ˜1043-1044 erg s-1. Such large kinetic powers suggest that outflows detected via EUV lines are potentially major contributors to active galactic nuclei feedback.

  14. A Deep Survey of Low-Redshift Absorbers and Their Connections with Galaxies: Probing the Roles of Dwarfs, Satellites, and Large-Scale Environment

    NASA Astrophysics Data System (ADS)

    Burchett, Joseph

    2014-10-01

    In the not-too-distant past, the study of galaxy evolution neglected the vast interface between the stars in a galaxy and intergalactic space except for the dynamical effects of dark matter. Thanks to QSO absorption line spectroscopy and the Cosmic Origins Spectrograph {COS}, the circumgalactic medium {CGM} has come into sharp focus as a rich ecosystem playing a vital role in the evolution of the host galaxy. However, attributing the gas detected in absorption with host dwarf galaxies detected in optical surveys around the sightline becomes very difficult very quickly with increasing redshift. In addition, both targeted UV spectroscopy and ground-based galaxy surveys are resource intensive, which complicates compiling large, statistically robust samples of very-low-redshift absorber/galaxy pairs. We propose a CGM study of unprecedented statistical power by exploiting the vast number of sightlines in the HST/COS archive located within the Sloan Digital Sky Survey {SDSS} footprint to compile an estimated sample of 586 absorbers at z<0.015. This very-low-redshift criterion enables spectroscopic completeness down to L<0.01 L* galaxies in publicly available optical imaging and spectroscopy.Our survey is uniquely poised to address the following questions: {1} What is the role of dwarf galaxies that would be undetectable at higher redshift in giving rise to the gas detected in QSO spectroscopy? {2} How does galaxy environment and large-scale structure affect the CGM and what are the implications for environmental quenching of star formation? {3} How efficiently do feedback mechanisms expel metal-enriched gas to great distances into the galaxy halo and into the IGM?

  15. THE NATURE OF A GALAXY ALONG THE SIGHT LINE TO PKS 0454+039

    SciTech Connect

    Takamiya, Marianne; Chun, Mark; Kulkarni, Varsha P.; Gharanfoli, Soheila

    2012-10-01

    We report on the properties of a faint blue galaxy (G1) along the line of sight to the QSO PKS 0454+039 from spectroscopic and imaging data. We measured emission lines of H{alpha}, [S II] {lambda}{lambda}6716, 6732, and [N II] {lambda}6584 in the spectrum of G1 obtained with the Gemini/GMOS instrument. The spectroscopic redshift of G1 is z = 0.0715 {+-} 0.0002. From the extinction-corrected H{alpha} flux, we determine a modest star formation rate of SFR = 0.07 M{sub Sun} yr{sup -1} and a specific SFR of log (sSFR) -8.4. Using three different abundance indicators, we determine a nebular abundance 12 + log (O/H) ranging from 7.6 to 8.2. Based on the velocity dispersion inferred from the emission line widths and the observed surface brightness profile, we estimate the virial mass of G1 to be M{sub vir} {approx} 6.7 Multiplication-Sign 10{sup 9} M{sub Sun} with an effective radius of 2.0 kpc. We estimate the stellar mass of G1 using spectral energy distribution fitting to be M{sub *} Almost-Equal-To 1.2 Multiplication-Sign 10{sup 7} M{sub Sun} and an r'-luminosity of L{sub r'} = 1.5x10{sup 8} L{sub Sun }. Overall, G1 is a faint, low-mass, low-metallicity Im/H II galaxy. We also report on the line flux limits of another source (G3) which is the most likely candidate for the absorber system at z = 0.8596. From the spectrum of the QSO itself, we report a previously undetected Mg II {lambda}{lambda}2796, 2803 absorption line system at z = 1.245.

  16. Metal-enriched, subkiloparsec gas clumps in the circumgalactic medium of a faint z = 2.5 galaxy

    NASA Astrophysics Data System (ADS)

    Crighton, Neil H. M.; Hennawi, Joseph F.; Simcoe, Robert A.; Cooksey, Kathy L.; Murphy, Michael T.; Fumagalli, Michele; Prochaska, J. Xavier; Shanks, Tom

    2015-01-01

    We report the serendipitous detection of a 0.2 L*, Lyα emitting galaxy at redshift 2.5 at an impact parameter of 50 kpc from a bright background QSO sightline. A high-resolution spectrum of the QSO reveals a partial Lyman-limit absorption system ({N}_H I=10^{16.94± 0.10} cm-2) with many associated metal absorption lines at the same redshift as the foreground galaxy. Using photoionization models that carefully treat measurement errors and marginalize over uncertainties in the shape and normalization of the ionizing radiation spectrum, we derive the total hydrogen column density {N}_H=10^{19.4± 0.3} cm^{-2}, and show that all the absorbing clouds are metal enriched, with Z = 0.1-0.6 Z⊙. These metallicities and the system's large velocity width (436 km s- 1) suggest the gas is produced by an outflowing wind. Using an expanding shell model we estimate a mass outflow rate of ˜5 M⊙ yr-1. Our photoionization model yields extremely small sizes (<100-500 pc) for the absorbing clouds, which we argue is typical of high column density absorbers in the circumgalactic medium (CGM). Given these small sizes and extreme kinematics, it is unclear how the clumps survive in the CGM without being destroyed by hydrodynamic instabilities. The small cloud sizes imply that even state-of-the-art cosmological simulations require more than a 1000-fold improvement in mass resolution to resolve the hydrodynamics relevant for cool gas in the CGM.

  17. Galaxies with Strong Nitrogen Lines

    NASA Astrophysics Data System (ADS)

    Bergmann, T. S.; Pastoriza, M. G.

    1987-05-01

    ABSTRACT. From a qualitative spectroscopic survey of southern galaxies made by Pastoriza, a group with different morphological types whose nuclear region showed particular strong emission [N II]A6548-6584 lines when compared to Hn, was selected in order to investigate why [N II] is so strong. This work presents the results of a first analysis of the spectra of some of the galaxies above obtained with the 1-m telescope plus 2DFRUTTI detector of the Cerro Tololo Inter-American Observatory. The spectra are all very similar showing strong stellar continuum and absorption lines, and all the emission spectra show [0111] >[OII], [NIl] > H . None of the spectra show H in emission. Using the relative intensities of the H and K Call lines (Talent 1982, PLtb. A.S.P., 94,36), the obtained integrated spectra for all the observed galaxies is later than GO, which means that the H absorption lines should not be strong. From the relative intensities of the emission lines, we conclude that these galaxies cannot be classified as Starburst or LINERS. They are similar to Seyfert 2 (Osterbrock 1986, Act#va QSO4, preprint), but the FWHM of the lines is less than 300 km s . Also Ol X6300 is not clearly seen, and the absorption spectrum is strong relative to the emission spectrum. The preliminary conclusion is an activity similar but milder than that present in Seyfert 2 galaxies, as sug gested by Rose and Searle (1982, Ap. 5., 253, 556) and Rose and Cecil (1983, Ap. 5., 266, 531) for the nucleus of M51, maybe affected by an anomalous nitrogen abundance. K o : GALAXIES-ACTIVE - SPECTROSCOPY

  18. Tracing the outflow of a z = 0.334 FeLoBAL: New constraints from low-ionization absorbers in FBQS J1151+3822

    SciTech Connect

    Lucy, Adrian B.; Leighly, Karen M.; Terndrup, Donald M.; Dietrich, Matthias; Gallagher, Sarah C.

    2014-03-01

    We show for the first time that FBQS J1151+3822 is an iron low-ionization broad absorption line quasar (FeLoBAL QSO), the second-brightest and second-closest known example of this class. He I* and Fe II together act as an effective analytical tool, allowing us to obtain useful kinematic constraints from photoionization models of the outflow without needing to assume any particular acceleration model. The main outflow's log ionization parameter is –1.5, the log hydrogen density (cm{sup –3}) 5.5-8, the log hydrogen column density (cm{sup –2}) 21.7-21.9, the absorption radius 7.2-127 pc, and the kinetic luminosity is 0.16%-4.5% of the bolometric luminosity. We obtain line-of-sight covering fractions of ∼0.25 for strong Fe II, ∼0.5 for He I*, and ∼0.6 for Mg II. Narrower and shallower absorption lines from weaker Fe II and Mn II with an outflow velocity of ∼3400 km s{sup –1} have appeared between 2005 and 2011, suggesting that dense cores may have condensed inside the main outflow. Consideration of the literature might suggest that the FBQS J1151+3822 outflow is a member of a rare and distinct subclass of FeLoBALs with high densities and correspondingly small absorption radii. We find, however, that such outflows are not necessarily a distinct subclass, and that their apparent rarity could be a symptom of selection bias in studies using density-sensitive lines.

  19. The Number Density of 0.6 < z < 1.7 Mg II Systems from CORALS: Observational Biases at Intermediate Redshift

    NASA Astrophysics Data System (ADS)

    Ellison, Sara L.; Churchill, Chris W.; Rix, Samantha A.; Pettini, Max

    2004-11-01

    The goal of the Complete Optical and Radio Absorption Line System (CORALS) survey is to quantify the potential impact on QSO absorber statistics from dust in intervening galaxies. Dust may introduce a selection bias in surveys that are based on magnitude-limited QSO samples, leading to an underestimate of absorber number density, n(z). Here we present the results of the second phase of the CORALS survey, which extends our previous work on z>1.8 damped Lyα systems (DLAs) to search for strong metal line systems (candidate DLAs) in the range 0.60.3 Å in our sample of 75 radio-selected quasars. The total redshift path covered by the survey is Δz=35.2, 58.2, and 63.8 for EW(MgIIλ2796)>0.3, 0.6, and 1.0 Å thresholds, respectively (5 σ). Our principal and most robust result is that the n(z) value of low-redshift Mg II systems determined for the CORALS survey is in excellent agreement with that of optically selected, magnitude-limited QSO samples. We use empirically determined Mg II equivalent width statistics to estimate the likely number of DLAs in this sample. The statistically inferred number density of DLAs, n(z)=0.16+0.08-0.06, is consistent with other low-redshift samples, although the large 1 σ error bars permit up to a factor of 2.5 more DLAs in CORALS. However, confirmation of the DLA candidates, precise evaluation of their n(z) values, and measurement of their H I column densities awaits UV observations with the Hubble Space Telescope. Finally, we report an excess of intermediate-redshift Mg II systems observed toward bright QSOs, which could be due to a lensing amplification bias. However, there is also evidence that this excess could simply be due to more sensitive EW detection limits toward brighter QSOs. We also emphasize that absorber statistics determined from magnitude-limited surveys reach a steady value if the completeness limit is significantly fainter

  20. Hubble space telescope/cosmic origins spectrograph observations of the quasar Q0302–003: Probing the He II reionization epoch and QSO proximity effects

    SciTech Connect

    Syphers, David; Shull, J. Michael

    2014-03-20

    Q0302–003 (z = 3.2860 ± 0.0005) was the first quasar discovered that showed a He II Gunn-Peterson trough, a sign of incomplete helium reionization at z ≳ 2.9. We present its Hubble Space Telescope/Cosmic Origins Spectrograph far-UV medium-resolution spectrum, which resolves many spectral features for the first time, allowing study of the quasar itself, the intergalactic medium, and quasar proximity effects. Q0302–003 has a harder intrinsic extreme-UV spectral index than previously claimed, as determined from both a direct fit to the spectrum (yielding α{sub ν} ≈ –0.8) and the helium-to-hydrogen ion ratio in the quasar's line-of-sight proximity zone. Intergalactic absorption along this sightline shows that the helium Gunn-Peterson trough is largely black in the range 2.87 < z < 3.20, apart from ionization due to local sources, indicating that helium reionization has not completed at these redshifts. However, we tentatively report a detection of nonzero flux in the high-redshift trough when looking at low-density regions, but zero flux in higher-density regions. This constrains the He II fraction to be about 1% in the low-density intergalactic medium (IGM) and possibly a factor of a few higher in the IGM as a whole, suggesting helium reionization has progressed substantially by z ∼ 3.1. The Gunn-Peterson trough recovers to a He II Lyα forest at z < 2.87. We confirm a transmission feature due to the ionization zone around a z = 3.05 quasar just off the sightline, and resolve the feature for the first time. We discover a similar such feature possibly caused by a luminous z = 3.23 quasar further from the sightline, which suggests that this quasar has been luminous for >34 Myr.

  1. PROPERTIES OF QSO METAL-LINE ABSORPTION SYSTEMS AT HIGH REDSHIFTS: NATURE AND EVOLUTION OF THE ABSORBERS AND NEW EVIDENCE ON ESCAPE OF IONIZING RADIATION FROM GALAXIES

    SciTech Connect

    Boksenberg, Alec; Sargent, Wallace L. W.

    2015-05-15

    Using Voigt-profile-fitting procedures on Keck High Resolution Spectrograph spectra of nine QSOs, we identify 1099 C IV absorber components clumped in 201 systems outside the Lyman forest over 1.6 ≲ z ≲ 4.4. With associated Si IV, C II, Si II  and N V where available, we investigate the bulk statistical and ionization properties of the components and systems and find no significant change in redshift for C IV and Si IV while C II, Si II  and N V change substantially. The C IV components exhibit strong clustering, but no clustering is detected for systems on scales from 150 km s{sup –1} out to 50,000 km s{sup –1}. We conclude that the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios, we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find that the generally accepted means of radiative escape by transparent channels from the internal star-forming sites is spectrally not viable for our stronger absorbers. We develop an active scenario based on runaway stars with resulting changes in the efflux of radiation that naturally enable the needed spectral convergence, and in turn provide empirical indicators of morphological evolution in the associated galaxies. Together with a coexisting population of relatively compact galaxies indicated by the weaker absorbers in our sample, the collective escape of radiation is sufficient to maintain the intergalactic medium ionized over the full range 1.9 < z ≲ 4.4.

  2. Hubble Space Telescope faint object spectrograph Quasar Absorption System Snapshot Survey (AbSnap). 1: Astrometric optical positions and finding charts of 269 bright QSO

    NASA Technical Reports Server (NTRS)

    Bowen, David V.; Osmer, Samantha J.; Blades, J. Chris; Tytler, David; Cottrell, Lance; Fan, Xiao-Ming; Lanzetta, Kenneth M.

    1994-01-01

    We present finding charts and optical positions accurate to less than 1 arcsec for 269 bright (V less than or = 18.5) Quasi-Stellar Objects (QSOs). These objects were selected as candidates for the Hubble Space Telescope (HST) Quasar Absorption System Snapshot Survey (AbSnap), a program designed to use the Faint Object Spectrograph (FOS) to obtain short exposure ultraviolet (UV) spectra of bright QSOs. Many quasars were included because of their proximity to bright, low redshift galaxies and positions of these QSOs are measured accurately for the first time. Data were obtained using the digitized sky survey produced by the Space Telescope Science Institute's Guide Stars Selection System Astrometric Support Program.

  3. Exploring the thermal state of the low-density intergalactic medium at z = 3 with an ultrahigh signal-to-noise QSO spectrum

    NASA Astrophysics Data System (ADS)

    Rorai, A.; Becker, G. D.; Haehnelt, M. G.; Carswell, R. F.; Bolton, J. S.; Cristiani, S.; D'Odorico, V.; Cupani, G.; Barai, P.; Calura, F.; Kim, T.-S.; Pomante, E.; Tescari, E.; Viel, M.

    2017-04-01

    At low densities, the standard ionization history of the intergalactic medium (IGM) predicts a decreasing temperature of the IGM with decreasing density once hydrogen (and helium) reionization is complete. Heating the high-redshift, low-density IGM above the temperature expected from photoheating is difficult, and previous claims of high/rising temperatures in low-density regions of the Universe based on the probability density function (PDF) of the opacity in Ly α forest data at 2 < z < 4 have been met with considerable scepticism, particularly since they appear to be in tension with other constraints on the temperature-density relation (TDR). We utilize here an ultrahigh signal-to-noise spectrum of the Quasi-stellar object HE0940-1050 and a novel technique to study the low opacity part of the PDF. We show that there is indeed evidence (at 90 per cent confidence level) that a significant volume fraction of the underdense regions at z ∼ 3 has temperatures as high or higher than those at densities comparable to the mean and above. We further demonstrate that this conclusion is nevertheless consistent with measurements of a slope of the TDR in overdense regions that imply a decreasing temperature with decreasing density, as expected if photoheating of ionized hydrogen is the dominant heating process. We briefly discuss implications of our findings for the need to invoke either spatial temperature fluctuations, as expected during helium reionization, or additional processes that heat a significant volume fraction of the low-density IGM.

  4. VizieR Online Data Catalog: 3XMM-DR4 QSO candidates at 3

    NASA Astrophysics Data System (ADS)

    Khorunzhev, G. A.; Burenin, R. A.; Mescheryakov, A. V.; Sazonov, S. Yu.

    2016-03-01

    The catalog of X-ray selected (3XMM-DR4) quasar candidates with photometric redshifts 2.753 quasars from 3XMM-DR4 that have not been selected by our algorithm. (2 data files).

  5. Properties of QSO Metal-line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies

    NASA Astrophysics Data System (ADS)

    Boksenberg, Alec; Sargent, Wallace L. W.

    2015-05-01

    Using Voigt-profile-fitting procedures on Keck High Resolution Spectrograph spectra of nine QSOs, we identify 1099 C IV absorber components clumped in 201 systems outside the Lyman forest over 1.6 <~ z <~ 4.4. With associated Si IV, C II, Si II and N V where available, we investigate the bulk statistical and ionization properties of the components and systems and find no significant change in redshift for C IV and Si IV while C II, Si II and N V change substantially. The C IV components exhibit strong clustering, but no clustering is detected for systems on scales from 150 km s-1 out to 50,000 km s-1. We conclude that the clustering is due entirely to the peculiar velocities of gas present in the circumgalactic media of galaxies. Using specific combinations of ionic ratios, we compare our observations with model ionization predictions for absorbers exposed to the metagalactic ionizing radiation background augmented by proximity radiation from their associated galaxies and find that the generally accepted means of radiative escape by transparent channels from the internal star-forming sites is spectrally not viable for our stronger absorbers. We develop an active scenario based on runaway stars with resulting changes in the efflux of radiation that naturally enable the needed spectral convergence, and in turn provide empirical indicators of morphological evolution in the associated galaxies. Together with a coexisting population of relatively compact galaxies indicated by the weaker absorbers in our sample, the collective escape of radiation is sufficient to maintain the intergalactic medium ionized over the full range 1.9 < z <~ 4.4. 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.

  6. Exploring the dust content of Sloan Digital Sky Survey Data Release %7 damped Lyman α systems at 2.15 ≤ z ≤ 5.2

    NASA Astrophysics Data System (ADS)

    Khare, Pushpa; vanden Berk, Daniel; York, Donald G.; Lundgren, Britt; Kulkarni, Varsha P.

    2012-01-01

    We have studied a sample of 1084 intervening absorption systems with 2.15 ≤zab≤ 5.2, having ? in the spectra of quasi-stellar objects (QSOs) in Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7), with the aim of understanding the nature and abundance of the dust and the chemical abundances in the damped Lyman α (DLA) absorbers. Composite spectra were constructed for the full sample and several subsamples, chosen on the basis of absorber and QSO properties. Average extinction curves were obtained for the samples by comparing their geometric mean composite spectra with those of two samples of QSOs, matching in zem and i magnitude with the DLA sample, one sample without any absorbers along their lines of sight and the other without any DLAs along their lines of sight irrespective of the presence of other absorption systems. We also derived relative extinction curves of several pairs of subsamples. While the average reddening in the DLA sample is small, we find definite evidence for the presence of dust in subsamples based on absorber properties, in particular the strength of metal absorption lines. DLAs along lines of sight to QSOs which are not colour selected are found to be more dusty compared to those along the lines of sight to the more numerous colour-selected QSOs. From these studies and from the strengths of absorption lines in the composite spectra, we conclude that ≤10 per cent of the DLAs in SDSS DR7 cause significant reddening, have stronger absorption lines and have higher abundances as compared to the rest of the sample. The rest of the sample shows little reddening. While, due to the dominant colour selection method used to target QSOs in the SDSS DR7, this fraction of 10 per cent likely represents a lower limit for the global fraction of dusty DLAs at high z, it is also possible that the dust grain sizes at high redshifts are larger, giving rise to a flat extinction curve over the observed range of wavelengths.

  7. A MULTIPHASE ABSORBER CONTAINING O VI AND BROAD H I DIRECTLY TRACING 10{sup 6} K PLASMA AT LOW REDSHIFT TOWARD HE 0153-4520

    SciTech Connect

    Savage, B. D.; Narayanan, A.; Wakker, B. P.; Lehner, N.

    2011-04-10

    Observations of the QSO HE 0153-4520 (z{sub em} = 0.450) with the Cosmic Origins Spectrograph (COS) from 1134 to 1796 A with a resolution of {approx}17 km s{sup -1} and a signal-to-noise ratio per resolution element of 20-40 are used to study a multiphase partial Lyman limit system (LLS) at z = 0.22601 tracing both cool and hot gas. Far-Ultraviolet Spectroscopic Explorer observations of the Lyman limit break yield log N(H I) = 16.61 (0.12, -0.17). The observed UV absorption lines of H I {lambda}{lambda}1216 to 926, C III, C II, N III, N II, Si III, and Si II imply the existence of cool photoionized gas in the LLS with log U = -2.8 {+-} 0.1 and log N(H) = 19.35 {+-} 0.18, log n{sub H} = -2.9 {+-} 0.2, log T = 4.27 {+-} 0.02, log (P/k) = 1.75 {+-} 0.17, and log L (kpc) = 0.70 {+-} 0.25. The abundances are [X/H] = -0.8 (+0.3, -0.2) for N, Si, and C, but the result is sensitive to the assumed shape of the ionizing background radiation field. The multiphase system has strong O VI and associated broad Ly{alpha} absorption (BLA) with log N(O VI) = 14.21 {+-} 0.02, b(O VI) = 37 {+-} 1 km s{sup -1}, log N(H I) = 13.70 (+0.05, -0.08), b(H I) = 140 (+14, -16) km s{sup -1} and b(H I)/b(O VI) = 3.9 {+-} 0.4. The O VI does not arise in the cool photoionized gas of the LLS. The O VI and BLA imply the direct detection of thermally broadened absorption by hot gas with log T = 6.07 (+0.09, -0.12), [O/H] = -0.28 (+0.09, -0.08), and log N(H) = 20.41 (+0.13, -0.17). The absorber probably occurs in the circumgalactic environment (halo) of a foreground galaxy. The very high sensitivity of UV absorption line spectroscopy to O VI and thermally broadened H I Ly{alpha} now permits the direct detection of hot gas with log T > 6, a determination of the abundance of O/H, and log N(H) in low-redshift intergalactic medium absorption line systems.

  8. Predicting the Quasar Photometric Reshift with the Sloan Digital Sky Survey Filter System

    NASA Astrophysics Data System (ADS)

    Laubacher, Emily M.; York, Donald G.

    1999-10-01

    Photometric data were obtained for a set of known quasars (QSOs) in five bands with the Sloan Digital Sky Survey (SDSS) filter system for the purpose of testing the ability of the SDSS system to accurately predict the photometric redshift of QSOs. The initial plot of the SDSS photometric redshift versus the measured redshift shows a good relationship, but a lot of scatter. A literature search was conducted on a selected sampling of 49 QSOs, 26 with redshift z <= 0.5 and 23 with 0.5 < z < 2.6, to confirm their accurate identifications as QSOs with their advertised redshifts. This search revealed 10 rejected QSOs which were not QSOs but rather Seyfert galaxies or Narrow Line Objects. Additionally, 11 QSOs were either Broad Absorption Line Systems or had spectra that were in some way incomplete, and therefore, their QSO identification could not be confirmed. The revised plot, with the rejected and unconfirmed QSOs removed, gives an excellent straight line with very little scatter. Although these results are preliminary and for only a small sampling of QSOs, they show that further study of the relationship is warranted and that eventually the SDSS method may be used to accurately predict the photometric redshift of QSOs.

  9. The WSRT virgo filament survey

    NASA Astrophysics Data System (ADS)

    Popping, A.; Braun, R.

    2007-02-01

    In the last few years, the realization has emerged that the universal baryons are almost equally distributed by mass in three components: (1) galactic concentrations, (2) a warm-hot intergalactic medium (WHIM) and (3) a diffuse intergalactic medium. These three components are predicted by hydrodynamical simulations and are probed by QSO absorption lines. To observe the WHIM in neutral hydrogen, observations are needed which are deeper than log( NHI) = 18. The WHIM should appear as a Cosmic Web, underlying the galaxies with higher column densities. We have used the WSRT to simulate a filled aperture by observing at very high hour angles, to reach very high column density sensitivity. To achieve even higher image fidelity, an accurate model of the WSRT primary beam was developed. This will be used in the joint deconvolution of the observations. To get a good overview of the distribution and kinematics of the Cosmic Web, a deep survey of 1500 square degrees of sky was undertaken, containing the galaxy filament extending between the Local Group and the Virgo Cluster. The auto-correlation data have been reduced and has an RMS of Δ NHI = 4.2 × 10 16 cm -2 over 20 km s -1. Several sources have been tentatively detected, which were previously unknown, as well as an indication for diffuse intergalactic filaments.

  10. An HST study of galactic inerstellar zinc and chromium

    NASA Technical Reports Server (NTRS)

    Roth, Katherine C.; Blades, J. Chris

    1995-01-01

    We present a survey of interstellar Zn II and Cr II absorption extracted from the Hubble Space Telescope Goddard High Resolution Spectrograph (HST GHRS) data archive. We find clear evidence for an enhanced depletion of Zn from the gas phase with increasing fractional abundance of molecular hydrogen f(H2). Our lower limit to the Galactic interstellar metallicity is approximately 65% of the solar value as determined by the measured Zn abundances in the lowest f(H2) sightlines, (N(Zn)/N(H(sup 0)(sub tot)) = -0.19 +/- 0.04. The correspondingly high depletion of Cr with respect to solar (N(Cr/N(H(sup 0)(sub tot)) = -1.44 +/- 0.26 indicates that there are significant amounts of dust present in these lines of sight. The Galactic abundances of Zn and Cr in the ISM provide a fundamental reference point which is used to understand the metal enrichment and dust formation history of damped Lyman alpha QSO absorption-line systems, normally believed to arise from intervening precursors to modern disk galaxies. Although the spread in Zn abundances is large for both the local ISM and in damped Lyman alpha systems, we still find a substantial difference (factor of 4-10) in metallicity between the two sets. This survey and future observations of more distant objects which probe the full extent of the Milky Way halo provide a more complete picture of the enrichment and depletion characteristics of present-day galaxies.

  11. HST STIS Observations of PG 0946+301: The Highest Quality UV Spectrum of a BALQSO

    NASA Astrophysics Data System (ADS)

    Arav, Nahum; de Kool, Martijn; Korista, Kirk T.; Crenshaw, D. Michael; van Breugel, Wil; Brotherton, Michael; Green, Richard F.; Pettini, Max; Wills, Bev; de Vries, Wim; Becker, Bob; Brandt, W. N.; Green, Paul; Junkkarinen, Vesa T.; Koratkar, Anuradha; Laor, Ari; Laurent-Muehleisen, Sally A.; Mathur, Smita; Murray, Norman

    2001-11-01

    We describe deep (40 orbits) Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph observations of the broad absorption line (BAL) quasi-stellar object (QSO) PG 0946+301 and make them available to the community. These observations are the major part of a multiwavelength campaign on this object aimed at determining the ionization equilibrium and abundances (IEAs) in BALQSOs. We present simple template fits to the entire data set, which yield firm identifications for more than two dozen BALs from 18 ions and give lower limits for the ionic column densities. We find that the outflow's metallicity is consistent with being solar, while the abundance ratio of phosphorus to other metals is at least 10 times solar. These findings are based on diagnostics that are not sensitive to saturation and partial covering effects in the BALs, which considerably weakened previous claims for enhanced metallicity. Ample evidence for these effects is seen in the spectrum. We also discuss several options for extracting tighter IEA constraints in future analyses and present the significant temporal changes that are detected between these spectra and those taken by the HST Faint Object Spectrograph in 1992.

  12. Discovery of a Damped Lyα Absorber at z = 3.3 along a Galaxy Sight-line in the SSA22 Field

    NASA Astrophysics Data System (ADS)

    Mawatari, K.; Inoue, A. K.; Kousai, K.; Hayashino, T.; Cooke, R.; Prochaska, J. X.; Yamada, T.; Matsuda, Y.

    2016-02-01

    Using galaxies as background light sources to map the Lyα absorption lines is a novel approach to study Damped Lyα Absorbers (DLAs). We report the discovery of an intervening z = 3.335 ± 0.007 DLA along a galaxy sight-line identified among 80 Lyman Break Galaxy (LBG) spectra obtained with our Very Large Telescope/Visible Multi-Object Spectrograph survey in the SSA22 field. The measured DLA neutral hydrogen (H i) column density is log(NH i/cm-2) = 21.68 ± 0.17. The DLA covering fraction over the extended background LBG is >70% (2σ), yielding a conservative constraint on the DLA area of ≳1 kpc2. Our search for a counterpart galaxy hosting this DLA concludes that there is no counterpart galaxy with star formation rate larger than a few M⊙ yr-1, ruling out an unobscured violent star formation in the DLA gas cloud. We also rule out the possibility that the host galaxy of the DLA is a passive galaxy with M* ≳ 5 × 1010M⊙ or a heavily dust-obscured galaxy with E(B - V) ≳ 2. The DLA may coincide with a large-scale overdensity of the spectroscopic LBGs. The occurrence rate of the DLA is compatible with that of DLAs found in QSO sight-lines.

  13. Implications of an updated ultraviolet background for the ionization mechanisms of intervening Ne VIII absorbers

    NASA Astrophysics Data System (ADS)

    Hussain, Tanvir; Khaire, Vikram; Srianand, Raghunathan; Muzahid, Sowgat; Pathak, Amit

    2017-04-01

    Ne VIII absorbers seen in QSO spectra are useful tracers of warm ionized gas, when collisional ionization is the dominant ionization process. While photoionization by the ultraviolet background (UVB) is a viable option, it tends to predict large line-of-sight thickness for the absorbing gas. Here, we study the implications of the recently updated UVB at low z to understand the ionization mechanisms of intervening Ne VIII absorbers. With the updated UVB, one typically needs higher density and metallicity to reproduce the observed ionic column densities under photoionization. Both reduce the inferred line-of-sight thicknesses of the absorbers. We find a critical density of ≥5 × 10-5 cm-3 above which the observed N({Ne VIII})/N({O VI}) can be reproduced by pure collisional processes. If the gas is of near solar metallicity (as measured for the low ions) then the cooling time-scales will be small (<108 yrs). Therefore, a continuous injection of heat is required in order to enhance the detectability of the collisionally ionized gas. Using photoionization models we find that in almost all Ne VIII systems the inferred low ion metallicity is near solar or supersolar. If we assume the Ne VIII phase to have similar metallicities then photoionization can reproduce the observed N({Ne VIII})/N({O VI}) without the line-of-sight thickness being unreasonably large and avoids cooling issues related to the collisional ionization at these metallicities. However, the indication of broad Lyα absorption in a couple of systems, if true, suggests that the Ne VIII phase is distinct from the low ion phase having much lower metallicity.

  14. EVIDENCE FOR COLD ACCRETION: PRIMITIVE GAS FLOWING ONTO A GALAXY AT z {approx} 0.274

    SciTech Connect

    Ribaudo, Joseph; Lehner, Nicolas; Christopher Howk, J.; Werk, Jessica K.; Xavier Prochaska, J.; Tumlinson, Jason

    2011-12-20

    We present UV and optical observations from the Cosmic Origins Spectrograph on the Hubble Space Telescope and Keck of a z = 0.27395 Lyman limit system (LLS) seen in absorption against the QSO PG1630+377. We detect H I absorption with log N(H I) = 17.06 {+-} 0.05 as well as Mg II, C III, Si III, and O VI in this system. The column densities are readily explained if this is a multi-phase system, with the intermediate and low ions arising in a very low metallicity ([Mg/H] = -1.71 {+-} 0.06) photoionized gas. We identify via Keck spectroscopy and Large Binocular Telescope imaging a 0.3 L{sub *} star-forming galaxy projected 37 kpc from the QSO at nearly identical redshift (z = 0.27406 and {Delta}v = -26 km s{sup -1}) with near solar metallicity ([O/H] = -0.20 {+-} 0.15). The presence of very low metallicity gas in the proximity of a near-solar metallicity, sub-L{sub *} galaxy strongly suggests that the LLS probes gas infalling onto the galaxy. A search of the literature reveals that such low-metallicity LLSs are not uncommon. We found that 50% (4/8) of the well-studied z {approx}< 1 LLSs have metallicities similar to the present system and show sub-L{sub *} galaxies with {rho} < 100 kpc in those fields where redshifts have been surveyed. We argue that the properties of these primitive LLSs and their host galaxies are consistent with those of cold mode accretion streams seen in galaxy simulations.

  15. The Chandra Multi-wavelength Project: Optical Spectroscopy and the Broadband Spectral Energy Distributions of X-Ray-selected AGNs

    NASA Astrophysics Data System (ADS)

    Trichas, Markos; Green, Paul J.; Silverman, John D.; Aldcroft, Tom; Barkhouse, Wayne; Cameron, Robert A.; Constantin, Anca; Ellison, Sara L.; Foltz, Craig; Haggard, Daryl; Jannuzi, Buell T.; Kim, Dong-Woo; Marshall, Herman L.; Mossman, Amy; Pérez, Laura M.; Romero-Colmenero, Encarni; Ruiz, Angel; Smith, Malcolm G.; Smith, Paul S.; Torres, Guillermo; Wik, Daniel R.; Wilkes, Belinda J.; Wolfgang, Angie

    2012-06-01

    From optical spectroscopy of X-ray sources observed as part of the Chandra Multi-wavelength Project (ChaMP), we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow-up using the FLWO/1.5 m, SAAO/1.9 m, WIYN 3.5 m, CTIO/4 m, KPNO/4 m, Magellan/6.5 m, MMT/6.5 m, and Gemini/8 m telescopes, and from archival Sloan Digital Sky Survey (SDSS) spectroscopy. We classify the optical counterparts as 50% broad-line active galactic nuclei (AGNs), 16% emission line galaxies, 14% absorption line galaxies, and 20% stars. We detect QSOs out to z ~ 5.5 and galaxies out to z ~ 3. We have compiled extensive photometry, including X-ray (ChaMP), ultraviolet (GALEX), optical (SDSS and ChaMP-NOAO/MOSAIC follow-up), near-infrared (UKIDSS, Two Micron All Sky Survey, and ChaMP-CTIO/ISPI follow-up), mid-infrared (WISE), and radio (FIRST and NVSS) bands. Together with our spectroscopic information, this enables us to derive detailed spectral energy distributions (SEDs) for our extragalactic sources. We fit a variety of template SEDs to determine bolometric luminosities, and to constrain AGNs and starburst components where both are present. While ~58% of X-ray Seyferts (1042 erg s-1 < L 2 - 10 keV <1044 erg s-1) require a starburst event (>5% starburst contribution to bolometric luminosity) to fit observed photometry only 26% of the X-ray QSO (L 2 - 10 keV >1044 erg s-1) population appear to have some kind of star formation contribution. This is significantly lower than for the Seyferts, especially if we take into account torus contamination at z > 1 where the majority of our X-ray QSOs lie. In addition, we observe a rapid drop of the percentage of starburst contribution as X-ray luminosity increases. This is consistent with the quenching of star formation by powerful QSOs, as predicted by the merger model, or with a time lag between the peak of star formation and QSO activity. We have tested the hypothesis that there should be a

  16. Intervening O vi Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir.

    PubMed

    Tripp; Savage; Jenkins

    2000-05-01

    Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at approximately 7 km s-1 resolution, reveals four definite O vi absorption-line systems and one probable O vi absorber at 0.15QSO. In the case of the strong O vi system at zabs=0.22497, multiple components are detected in Si iii and O vi as well as H i Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O vi absorber is detected at zabs=0.22637, i.e., offset by approximately 340 km s-1 from the zabs=0.22497 system. Lyalpha absorption is detected at zabs=0.22613, but no Lyalpha absorption is significantly detected at 0.22637. Other weak O vi absorbers at zabs=0.24531 and 0.26659 and the probable O vi system at 0.21326 have widely diverse O vi/H i column density ratios with N(O vi)/N(H i) ranging from

  17. Intergalactic Medium Emission Observations with the Cosmic Web Imager. II. Discovery of Extended, Kinematically Linked Emission around SSA22 Lyα Blob 2

    NASA Astrophysics Data System (ADS)

    Martin, D. Christopher; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.; Matsuda, Yuichi

    2014-05-01

    The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Lyα blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Lyα emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Lyα emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 × 1011 M ⊙, and the dark halo mass is at least 2 × 1012 M ⊙. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas have significant and

  18. Intergalactic medium emission observations with the cosmic web imager. II. Discovery of extended, kinematically linked emission around SSA22 Lyα BLOB 2

    SciTech Connect

    Christopher Martin, D.; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.; Matsuda, Yuichi

    2014-05-10

    The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Lyα blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Lyα emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Lyα emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 × 10{sup 11} M {sub ☉}, and the dark halo mass is at least 2 × 10{sup 12} M {sub ☉}. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas

  19. Precision Measures of the Primordial Abundance of Deuterium

    NASA Astrophysics Data System (ADS)

    Cooke, Ryan J.; Pettini, Max; Jorgenson, Regina A.; Murphy, Michael T.; Steidel, Charles C.

    2014-01-01

    We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = -2.88) damped Lyα system at z abs = 3.06726 toward the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyα transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias) and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H)p = (2.53 ± 0.04) × 10-5, corresponding to a universal baryon density 100 Ωb, 0 h 2 = 2.202 ± 0.046 for the standard model of big bang nucleosynthesis (BBN). By combining our measure of (D/H)p with observations of the cosmic microwave background (CMB), we derive the effective number of light fermion species, N eff = 3.28 ± 0.28. We therefore rule out the existence of an additional (sterile) neutrino (i.e., N eff = 4.046) at 99.3% confidence (2.7σ), provided that the values of N eff and of the baryon-to-photon ratio (η10) did not change between BBN and recombination. We also place a strong bound on the neutrino degeneracy parameter, independent of the 4He primordial mass fraction, Y P: ξD = +0.05 ± 0.13 based only on the CMB+(D/H)p observations. Combining this value of ξD with the current best literature measure of Y P, we find a 2σ upper bound on the neutrino degeneracy parameter, |ξ| <= +0.062. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (VLT program IDs: 68.B-0115(A), 70.A-0425(C), 078.A-0185(A), 085.A-0109(A)), and at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of

  20. Precision measures of the primordial abundance of deuterium

    SciTech Connect

    Cooke, Ryan J.; Jorgenson, Regina A.; Murphy, Michael T.; Steidel, Charles C.

    2014-01-20

    We report the discovery of deuterium absorption in the very metal-poor ([Fe/H] = –2.88) damped Lyα system at z {sub abs} = 3.06726 toward the QSO SDSS J1358+6522. On the basis of 13 resolved D I absorption lines and the damping wings of the H I Lyα transition, we have obtained a new, precise measure of the primordial abundance of deuterium. Furthermore, to bolster the present statistics of precision D/H measures, we have reanalyzed all of the known deuterium absorption-line systems that satisfy a set of strict criteria. We have adopted a blind analysis strategy (to remove human bias) and developed a software package that is specifically designed for precision D/H abundance measurements. For this reanalyzed sample of systems, we obtain a weighted mean of (D/H){sub p} = (2.53 ± 0.04) × 10{sup –5}, corresponding to a universal baryon density 100 Ω{sub b,} {sub 0} h {sup 2} = 2.202 ± 0.046 for the standard model of big bang nucleosynthesis (BBN). By combining our measure of (D/H){sub p} with observations of the cosmic microwave background (CMB), we derive the effective number of light fermion species, N {sub eff} = 3.28 ± 0.28. We therefore rule out the existence of an additional (sterile) neutrino (i.e., N {sub eff} = 4.046) at 99.3% confidence (2.7σ), provided that the values of N {sub eff} and of the baryon-to-photon ratio (η{sub 10}) did not change between BBN and recombination. We also place a strong bound on the neutrino degeneracy parameter, independent of the {sup 4}He primordial mass fraction, Y {sub P}: ξ{sub D} = +0.05 ± 0.13 based only on the CMB+(D/H){sub p} observations. Combining this value of ξ{sub D} with the current best literature measure of Y {sub P}, we find a 2σ upper bound on the neutrino degeneracy parameter, |ξ| ≤ +0.062.

  1. GRBs Redshift Distribution Shape Properties as Confirmation of their Progenitors Population Non-uniformity

    NASA Astrophysics Data System (ADS)

    Arkhangelskaja, I. V.

    In the supposition of sources population uniformity the GRBs redshift distribution shape could similar ones for other objects with demonstrated or theoretically required uniform space allocation. The shape of redshift distribution for uniform sources set in our Metagalaxy defined by properties of space and cosmological parameters. Supernovae of Ia type were considered as populations with real uniform distributions on redshift because of it were used for definition of Ω and Λ or our Metagalaxy. Therefore, the GRB sources redshift distribution analysis allows us to investigate the uniformity of this population. The results of redshifts distribution investigation for GRB with defined duration from Swift/BAT registered subset (308 events) are discussed. The analysis of Swift/BAT GRBs subset duration distribution allows to conclude the difference of boundary between short and long events from value of 2 s obtained from CGRO/BATSE bursts catalogue. Durations of 1 s and 0.6 s more likely correspond to this separator point for Swift/BAT GRBs subset duration distributions without and with correction on redshift. Two long GRBs with known redshift subsets were analysed: one contains the events registered from the beginning of Swift/BAT operation up to the end of autumn, 2014 (273 bursts) and other was similar but up to the end of August, 2015 (284 events). The shapes of these distributions sufficiently differ from ones for SN Ia supernovae. Also the sufficient deficit of GRB with z˜2 was found during both subsets analysis. Moreover, this feature existence retain in the same redshift region even if the bursts with sources redshift defined using one of the methods (for example, afterglow absorption lines studying) included in the analysable subset. Such deficit was not observed in QSO redshift distribution and thereof it couldn't explained as apparatus effects caused by some difficulties to measure z because of the lack of strong emission or absorption lines covered by

  2. On orthogonality preserving quadratic stochastic operators

    SciTech Connect

    Mukhamedov, Farrukh; Taha, Muhammad Hafizuddin Mohd

    2015-05-15

    A quadratic stochastic operator (in short QSO) is usually used to present the time evolution of differing species in biology. Some quadratic stochastic operators have been studied by Lotka and Volterra. In the present paper, we first give a simple characterization of Volterra QSO in terms of absolutely continuity of discrete measures. Further, we introduce a notion of orthogonal preserving QSO, and describe such kind of operators defined on two dimensional simplex. It turns out that orthogonal preserving QSOs are permutations of Volterra QSO. The associativity of genetic algebras generated by orthogonal preserving QSO is studied too.

  3. The Lyman Continuum Escape Fraction of the Cosmic Horseshoe: A Test of Indirect Estimates

    NASA Astrophysics Data System (ADS)

    Vasei, Kaveh; Siana, Brian; Shapley, Alice E.; Quider, Anna M.; Alavi, Anahita; Rafelski, Marc; Steidel, Charles C.; Pettini, Max; Lewis, Geraint F.

    2016-11-01

    High-redshift star-forming galaxies are likely responsible for the reionization of the universe, yet direct detection of their escaping ionizing (Lyman continuum [LyC]) photons has proven to be extremely challenging. In this study, we search for escaping LyC of the Cosmic Horseshoe, a gravitationally lensed, star-forming galaxy at z = 2.38 with a large magnification of ∼24. Transmission at wavelengths of low-ionization interstellar absorption lines in the rest-frame ultraviolet suggests a patchy, partially transparent interstellar medium. This makes it an ideal candidate for direct detection of the LyC. We obtained a 10-orbit Hubble near-UV image using the Wide Field Camera 3 (WFC3)/UVIS F275W filter that probes wavelengths just below the Lyman limit at the redshift of the Horseshoe in an attempt to detect escaping LyC radiation. After fully accounting for the uncertainties in the opacity of the intergalactic medium (IGM) and accounting for the charge transfer inefficiency in the WFC3 CCDs, we find a 3σ upper limit for the relative escape fraction of {f}{esc,{rel}}\\lt 0.08. This value is a factor of five lower than the value (0.4) predicted by the 40% transmission in the low-ion absorption lines. Though possible, it is unlikely that the nondetection is due to a high-opacity line of sight through the IGM (\\lt 20% chance). We discuss several possible causes for the discrepancy between the escape fraction and the covering fraction and consider the implications for future attempts at both direct LyC detection and indirect estimates of the escape fraction.

  4. Krypton

    NASA Astrophysics Data System (ADS)

    Cardelli, J. A.; Meyer, D. M.

    1995-05-01

    From the chemical composition of Galactic interstellar dust to the metallicity of QSO absorption line systems, solar system (photospheric and/or meteoritic) elemental abundances have served as the standard against which such measures have been compared and interpreted. However, recent analysis of the interstellar abundance of oxygen (Meyer et al. 1994), particularly in low density sight lines, has suggested that solar abundances may not be generally representative of the true (average) cosmic abundance. Specifically, the ISM abundance measures of oxygen suggest that the solar system might be over abundant in O by as much as a factor 2. Similar results are also suggested from analyses of the Fe-peak element zinc (Roth & Blades 1995; Sembach et al. 1995). However, a major difficulty in these analyses is that fact that both elements show some level of depletion onto dust grains which makes definitive interpretation difficult. To avoid this potential pitfall, we have obtained interstellar abundance data of the chemically inert noble gas element krypton toward six stars in three distinct Galactic directions. Since krypton is not expected to deplete onto dust (Kr I is the dominant form in the ISM and so is characterized by a filled outer shell, 4p(6) ) its interstellar abundance should reflect the true cosmic abundance. For all six sight lines, which probe moderate to very low density gas, we find that the ISM abundance of krypton is constant and roughly a factor 2 below that inferred for the solar system. This result strongly supports the conclusions derived from the study of oxygen and zinc and suggests that elemental abundances in the solar system may be (generically?) too high by perhaps as much as a factor 2. These results are also generally consistent with elemental abundances (C, N, and O) observed in early B-type stars (Gies & Lambert 1992).

  5. Towards the statistical detection of the warm-hot intergalactic medium in intercluster filaments of the cosmic web

    NASA Astrophysics Data System (ADS)

    Tejos, Nicolas; Prochaska, J. Xavier; Crighton, Neil H. M.; Morris, Simon L.; Werk, Jessica K.; Theuns, Tom; Padilla, Nelson; Bielby, Rich M.; Finn, Charles W.

    2016-01-01

    Modern analyses of structure formation predict a universe tangled in a `cosmic web' of dark matter and diffuse baryons. These theories further predict that at low z, a significant fraction of the baryons will be shock-heated to T ˜ 105-107 K yielding a warm-hot intergalactic medium (WHIM), but whose actual existence has eluded a firm observational confirmation. We present a novel experiment to detect the WHIM, by targeting the putative filaments connecting galaxy clusters. We use HST/COS to observe a remarkable quasi-stellar object (QSO) sightline that passes within Δd = 3 Mpc from the seven intercluster axes connecting seven independent cluster pairs at redshifts 0.1 ≤ z ≤ 0.5. We find tentative excesses of total H I, narrow H I (NLA; Doppler parameters b < 50 km s-1), broad H I (BLA; b ≥ 50 km s-1) and O VI absorption lines within rest-frame velocities of Δv ≲ 1000 km s-1 from the cluster-pairs redshifts, corresponding to ˜2, ˜1.7, ˜6 and ˜4 times their field expectations, respectively. Although the excess of O VI likely comes from gas close to individual galaxies, we conclude that most of the excesses of NLAs and BLAs are truly intergalactic. We find the covering fractions, fc, of BLAs close to cluster pairs are ˜4-7 times higher than the random expectation (at the ˜2σ c.l.), whereas the fc of NLAs and O VI are not significantly enhanced. We argue that a larger relative excess of BLAs compared to those of NLAs close to cluster pairs may be a signature of the WHIM in intercluster filaments. By extending this analysis to tens of sightlines, our experiment offers a promising route to detect the WHIM.

  6. THE INTERPRETATION OF ROTATION MEASURES IN THE PRESENCE OF INHOMOGENEOUS FOREGROUND SCREENS

    SciTech Connect

    Bernet, M. L.; Miniati, F.; Lilly, S. J. E-mail: simon.lilly@phys.ethz.ch

    2012-12-20

    We analyze the redshift evolution of the rotation measure (RM) in the Taylor et al. data set, based on NVSS radio data at 21 cm, and compare with results from our previous work based on RMs determined at lower wavelengths, e.g., 6 cm. We find that, in spite of the same analysis, Taylor et al.'s data set produces neither an increase of the RM dispersion with redshift nor the correlation of RM strength with Mg II absorption lines that we found previously. We develop a simple model to understand this discrepancy. The model assumes that the Faraday rotators, namely the QSO's host galaxy and the intervening Mg II host galaxies along the line of sight, contain partially inhomogeneous RM screens. We find that this leads to an increasing depolarization toward longer wavelengths and to wavelength-dependent RM values. In particular, due to cosmological redshift, observations at fixed wavelength of sources at different redshift are affected differently by depolarization and are sensitive to different Faraday active components. For example, at 21 cm the polarized signal is averaged out by inhomogeneous Faraday screens and the measured RM mostly reflects the Milky Way contributions for low-redshift QSOs whereas polarization is relatively unaffected for high-redshift QSOs. Similar effects are produced by intervening galaxies acting as inhomogeneous screens. Finally, we assess the performance of RM synthesis on our synthetic models and conclude that the study of magnetic fields in galaxies as a function of cosmic time will benefit considerably from the application of such a technique, provided there is sufficient instrumental bandwidth. For this purpose, high-frequency channels appear preferable but not strictly necessary.

  7. Are There Intrinsically X-Ray Quiet Quasars

    NASA Technical Reports Server (NTRS)

    Gallagher, S. C.; Brandt, W. N.; Laor, A.; Elvis, Martin; Mathur, S.; Wills, Beverly J.; Iyomoto, N.; White, Nicholas (Technical Monitor)

    2000-01-01

    Recent ROSAT studies have identified a significant population of Active Galactic Nuclei (AGN) that are notably faint in soft X-rays relative to their optical fluxes. Are these AGN intrinsically X-ray weak or are they just highly absorbed? Brandt, Laor & Wills have systematically examined the optical and UV spectral properties of a well-defined sample of these soft X-ray weak (SXW) AGN drawn from the Boroson & Green sample of all the Palomar Green AGN 00 with z < 0.5. We present ASCA observations of three of these SXW AGN: PG 1011-040, PG 1535+547 (Mrk 486), and PG 2112+059. In general, our ASCA observations support the intrinsic absorption scenario for explaining soft X-ray weakness; both PG 1535+547 and PG 2112+059 show significant column densities (NH is approximately 10(exp 22) - 10(exp 23)/sq cm) of absorbing gas. Interestingly, PG 1011-040 shows no spectral evidence for X-ray absorption. The weak X-ray emission may result from very strong absorption of a partially covered source, or this AGN may be intrinsically X-ray weak. PG 2112+059 is a Broad Absorption Line (BAL) QSO, and we find it to have the highest X-ray flux known of this class. It shows a typical power-law X-ray continuum above 3 keV; this is the first direct evidence that BAL QSOs indeed have normal X-ray continua underlying their intrinsic absorption. Finally, marked variability between the ROSAT and ASCA observations of PG 1535+547 and PG 2112+059 suggests that the soft X-ray weak designation may be transient, and multi-epoch 0.1-10.0 KeV X-ray observations are required to constrain variability of the absorber and continuum.

  8. High S/N Observations of Low-Ionization Gas Through the Galactic Halo

    NASA Astrophysics Data System (ADS)

    Meyer, D. M.; Roth, K. C.; Savage, B. D.; Lu, L.

    1993-12-01

    Optical absorption-line studies of extragalactic objects can now provide a sensitive probe of low-ionization gas over the full extent of the Galactic halo. Such work is particularly pertinent to a better understanding of the distances, metallicities, and sky coverage of the high-velocity clouds (HVCs) primarily observed in H I 21 cm emission. We have recently obtained high S/N, high resolution (20 km s(-1) ) KPNO 4-m echelle observations of the Ca II absorption toward the QSO 1821+643, the Seyfert galaxy Mkn 231, and SN 1993J in the galaxy M81. We detect a weak (W_lambda ~30 m Angstroms) Ca II component at an LSR velocity of -140 km s(-1) toward 1821+643 that corresponds to the Outer Arm H I HVC Complex. In the case of Mkn 231, we find no evidence of high-velocity Ca II absorption despite the location of this sightline near H I HVC Complex C. Our Ca II observations toward SN 1993J are especially exceptional in quality (S/N~500) and reveal absorption due to the Galactic halo, the disk of M81, and intergalactic material in the M81 group. Although the M81 disk gas dominates the absorption in the velocity region encompassing HVC Complex C, we do find a high-velocity component at +228 km s(-1) in Ca II that has also been seen in Mg II absorption with HST (Bowen et al. 1994, Ap. J. (Letters), in press). Our echelle spectra of SN 1993J also reveal detections of other interstellar atoms and molecules such as Ti II, Ca I, and CH(+) \\@. The Ti II measurement is particularly interesting in that it represents the first detection of Ti II toward an extragalactic object and indicates a Ti II scale height of about 1200 pc which is somewhat less than expected from observations of Ti II toward halo stars.

  9. Quasar Unification Via Disk Winds: From Phenomenology to Physics

    NASA Astrophysics Data System (ADS)

    Knigge, C.

    2015-09-01

    I will give an overview of a collaborative project aimed at testing the viability of QSO unification via accretion disk winds. In this scenario, most of the characteristic spectral features of QSOs are formed in these outflows. More specifically, broad absorption lines (BALs) are produced for sight lines within the outflow, while broad emission lines (BELs) are observed for other viewing angles. In order to test these ideas, we use a state-of- the-art Monte Carlo radiative transfer and photoionization code to predict emergent spectra for a wide range of viewing angles and quasar properties (black hole mass, accretion rate, X-ray luminosity, etc). It turns out to be relatively straightforward to produce BALs, but harder to obtain sufficiently strong BELs. We also find that it is easy to overionize the wind with realistic X-ray luminosities. In addition, we are using our code to test and improve hydrodynamic disk wind models for quasars. So far, we have been able to demonstrate that the treatment of ionization in existing hydrodynamic models of line-driven disk winds is too simplistic to yield realistic results: the modelled outflows would be strongly overionized and hence would not feel the line-driving forces that are asssumed to produce them. We have therefore embarked on an effort to model line-driven disk winds self-consistently by linking a hydrodynamics code with our ionization and radiative transfer code. Finally, we can also predict the reverberation signatures produced by disk winds, which can be directly compared to the results of the latest reverberation mapping campaigns.

  10. DISCOVERY OF A DAMPED Lyα ABSORBER AT z = 3.3 ALONG A GALAXY SIGHT-LINE IN THE SSA22 FIELD

    SciTech Connect

    Mawatari, K.; Inoue, A. K.; Kousai, K.; Hayashino, T.; Cooke, R.; Prochaska, J. X.; Matsuda, Y.

    2016-02-01

    Using galaxies as background light sources to map the Lyα absorption lines is a novel approach to study Damped Lyα Absorbers (DLAs). We report the discovery of an intervening z = 3.335 ± 0.007 DLA along a galaxy sight-line identified among 80 Lyman Break Galaxy (LBG) spectra obtained with our Very Large Telescope/Visible Multi-Object Spectrograph survey in the SSA22 field. The measured DLA neutral hydrogen (H i) column density is log(N{sub H} {sub i}/cm{sup −2}) = 21.68 ± 0.17. The DLA covering fraction over the extended background LBG is >70% (2σ), yielding a conservative constraint on the DLA area of ≳1 kpc{sup 2}. Our search for a counterpart galaxy hosting this DLA concludes that there is no counterpart galaxy with star formation rate larger than a few M{sub ⊙} yr{sup −1}, ruling out an unobscured violent star formation in the DLA gas cloud. We also rule out the possibility that the host galaxy of the DLA is a passive galaxy with M{sub *} ≳ 5 × 10{sup 10}M{sub ⊙} or a heavily dust-obscured galaxy with E(B − V) ≳ 2. The DLA may coincide with a large-scale overdensity of the spectroscopic LBGs. The occurrence rate of the DLA is compatible with that of DLAs found in QSO sight-lines.

  11. Variability of QSOs with variable regions in broad absorption troughs from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    He, Zhi-Cheng; Bian, Wei-Hao; Ge, Xue; Jiang, Xiao-Lei

    2015-12-01

    The variability of broad absorption lines (BALs) is investigated for a sample of 188 BAL quasars (QSOs) (z > 1.7) with at least two epoch observations from the Sloan Digital Sky Survey Data Release 7, covering a time-scale of about 0.001-3 yr in the rest frame. Considering only the longest time-scale between epochs for each QSO, 73 variable regions in the C IV BAL troughs are detected for 43 BAL QSOs. The proportion of BAL QSOs showing variable regions increases with longer time-interval than about 1 yr in the rest frame. The velocity width of variable regions is narrow compared to the BAL-trough outflow velocity. For 43 BAL QSOs with variable regions, it is found that there is a medium strong correlation between the variation of the continuum luminosity at 1500 Å and the variation of the spectral index. With respect to the total 188 QSOs, a larger proportion of BAL QSOs with variable regions appears bluer during their brighter phases, which implies that the origin of BAL variable regions is related to the central accretion process. For 43 BAL QSOs with variable regions, it is possible that there is a negative medium strong correlation between the absolute variation of the equivalent width and the Mg II-based black hole mass, and a medium strong correlation between the maximum outflow velocity of variable regions and the Eddington ratio. These results imply a connection between the BAL-trough variation and the central accretion process.

  12. PG 0946+301: the Rosetta Stone of BALQSOs?

    SciTech Connect

    Arav, N., LLNL

    1998-06-01

    We describe the motivation and features of a multiwavelength spectroscopic campaign on broad absorption line (BAL) QSO PG 0946+301. The main goal of this project is to determine the ionization equilibrium and abundances (IEA) in BAL outflows. Previous studies of IEA in BALQSOs were based on the assumption that the BALs are not saturated so that the column densities inferred from the apparent optical depths are realistic. This critical assumption is at odds with several recent observations and with analysis of existing data which indicate that the absorption troughs are heavily saturated even when they are not black. In addition, X-ray observations, which are important for constraining the ionizing continuum, were not available for those objects that had UV spectral data. Quantifying the level of saturation in the BALs necessitates UV spectroscopy with much higher S/N and broader-spectral coverage than currently exist. After taking into account the capabilities of available observatories, our best hope for a substantial improvement in understanding the IEA in BALQSOs is to concentrate considerable observational resources on the most promising object. Our studies of available HST and ground-based spectra show that PG 0946+301 is by far the best candidate for such a program. This BALQSO is at least five times brighter, shortward of 1000 {Angstrom}, rest frame, than any other object, and due to its low redshift it has an especially sparse Ly{alpha} forest. At the same time PG 0946+301 is a typical BALQSO and therefore its IEA should be representative. To this effect we are developing a multiwavelength spectroscopic campaign (UV, FUV, X-ray and optical) on BALQSO PG 0946+301. We discuss the goals and feasibility of each observational component: HST, FUSE, ASCA and ground-based.

  13. THE PROPERTIES OF TWO LOW-REDSHIFT O VI ABSORBERS AND THEIR ASSOCIATED GALAXIES TOWARD 3C 263 ,

    SciTech Connect

    Savage, B. D.; Kim, T.-S.; Wakker, B. P.; Keeney, B.; Stocke, J.; Syphers, D.; Narayanan, A.

    2012-07-01

    Ultraviolet observations of the QSO 3C 263 (z{sub em} = 0.652) with Cosmic Origins Spectrograph and FUSE reveal O VI absorption systems at z = 0.06342 and 0.14072. WIYN multi-object spectrograph observations provide information about the galaxies associated with the absorbers. The multi-phase system at z = 0.06342 traces cool photoionized gas and warm collisionally ionized gas associated with an L {approx} 0.31 L* compact spiral emission line galaxy with an impact parameter of 63 kpc. The cool photoionized gas in the absorber is well modeled, with log U {approx} -2.6, log N(H) {approx} 17.8, log n(H) {approx} -3.3 and [Si/H] = -0.14 {+-} 0.23. The collisionally ionized gas containing C IV and O VI probably arises in cooling shock-heated transition temperature gas with log T {approx} 5.5. The absorber is likely tracing circumgalactic gas enriched by gas ejected from the spiral emission line galaxy. The simple system at z = 0.14072 only contains O VI and broad and narrow H I. The O VI with b = 33.4 {+-} 11.9 km s{sup -1} is likely associated with the broad H I {lambda}1215 absorption, with b = 86.7 {+-} 15.4 km s{sup -1}. The difference in Doppler parameters implies the detection of a very large column of warm gas with log T = 5.61(+0.16, -0.25), log N(H) = 19.54(+0.26, -0.44), and [O/H] = -1.48 (+0.46, -0.26). This absorber is possibly associated with a 1.6 L* absorption line galaxy with an impact parameter of 617 kpc, although an origin in warm filament gas or in the halo of a fainter galaxy is more likely.

  14. Radiative transfer in a clumpy universe: The colors of high-redshift galaxies

    NASA Technical Reports Server (NTRS)

    Madau, Piero

    1995-01-01

    We assess the effects of the stochastic attenuation produced by intervening QSO absorption systems on the broadband colors of galaxies at cosmological distances. We compute the H I opacity of a clumpy universe as a function of redshift, including scattering in resonant lines, such as Lyman alpha, Lyman beta, Lyman gamma, and higher order members, and Lyman-continuum absorption. Both the numerous, optically thin Lyman-alpha forest clouds and the rarer, optically thick Lyman limit systems are found to contribute to the obscuration of background sources. We study the mean properties of primeval galaxies at high redshift in four broad optical passbands, U(sub n), B, G, and R. Even if young galaxies radiated a significant amount of ionizing photons, the attenuation due to the accumulated photoelectric opacity along the path is so severe that sources beyond z approximately 3 will drop out of the U(sub n) image together. We also show that the observed B-R color of distant galaxies can be much redder than expected from a stellar population. At z approximately 3.5, the blanketing by discrete absorption lines in the Lyman series is so effective that background galaxies appear, on average, 1 mag fainter in B. By z approximately 4, the observed B magnitude increment due to intergalactic absorption exceeds 2 mag. By modeling the intrinsic UV spectral energy distribution of star-forming galaxies with a stellar population synthesis code, we show that the (B-R)(sub AB) approximately 0 criterion for identifying 'flat-spectrum,' metal-producing galaxies is biased against objects at z greater than 3. The continuum blanketing from the Lyman series produces a characteristic staircase profile in the transmitted power. We suggest that this cosmic Lyman decrement might be used as a tool to identify high-z galaxies.

  15. The Structure and Kinematics of the Circumgalactic Medium from Far-ultraviolet Spectra of z ~= 2-3 Galaxies

    NASA Astrophysics Data System (ADS)

    Steidel, Charles C.; Erb, Dawn K.; Shapley, Alice E.; Pettini, Max; Reddy, Naveen; Bogosavljević, Milan; Rudie, Gwen C.; Rakic, Olivera

    2010-07-01

    We present new results on the kinematics and spatial distribution of metal-enriched gas within ~125 kpc of star-forming ("Lyman break") galaxies at redshifts 2 <~ z <~ 3. In particular, we focus on constraints provided by the rest-frame far-ultraviolet (far-UV) spectra of faint galaxies, and demonstrate how galaxy spectra can be used to obtain key spatial and spectral information more efficiently than possible with QSO sightlines. Using a sample of 89 galaxies with langzrang = 2.3 ± 0.3 and with both rest-frame far-UV and Hα spectra, we re-calibrate the measurement of accurate galaxy systemic redshifts using only survey-quality rest-UV spectra. We use the velocity-calibrated sample to investigate the kinematics of the galaxy-scale outflows via the strong interstellar (IS) absorption lines and Lyα emission (when present), as well as their dependence on other physical properties of the galaxies. We construct a sample of 512 close (1''-15'') angular pairs of z ~ 2-3 galaxies with redshift differences indicating a lack of physical association. Sightlines to the background galaxies provide new information on the spatial distribution of circumgalactic gas surrounding the foreground galaxies. The close pairs sample galactocentric impact parameters 3-125 kpc (physical) at langzrang = 2.2, providing for the first time a robust map of cool gas as a function of galactocentric distance for a well-characterized population of galaxies. We propose a simple model of circumgalactic gas that simultaneously matches the kinematics, depth, and profile shape of IS absorption and Lyα emission lines, as well as the observed variation of absorption line strength (H I and several metallic species) versus galactocentric impact parameter. Within the model, cool gas is distributed symmetrically around every galaxy, accelerating radially outward with v out(r) increasing with r (i.e., the highest velocities are located at the largest galactocentric distances r). The inferred radial

  16. ESO Astronomers Detect a Galaxy at the Edge of the Universe

    NASA Astrophysics Data System (ADS)

    1995-09-01

    of the 18th magnitude quasar QSO 1202-07 with the EMMI Multi-Mode instrument at the ESO NTT telescope. At the redshift of z = 4.70, this quasar is one of the most distant, known objects. The astronomers noted a strong absorption line in the spectrum at a wavelength near 6545 A, indicating the existence of a massive cloud of neutral hydrogen in the line of sight towards the quasar. The quasar light shines through the cloud and from the measured wavelength, a cloud redshift of z = 4.38 can be deduced. This corresponds to a ``look-back time'' of ~ 90 percent of the age of the Universe. At smaller redshifts, such strong absorption-line systems (known as ``damped Lyman-alpha systems'') have been shown to be associated with visible galaxies in which are located the hydrogen clouds that cause the absorption lines in the quasar spectra. It is therefore reasonable to surmise that the absorption line seen at redshift z = 4.38 in the spectrum of QSO 1202-07 also arises in an intervening galaxy, situated at a distance that corresponds to this redshift. This is further supported by the detection in the near-infrared region (7000 - 9000 A) of the QSO spectrum, and at the same redshift as that of the cloud, of several absorption lines of other elements in various ionization stages, for instance neutral oxygen (O I), single-ionized carbon, silicon and aluminium (C II, Si II, Al II), as well as triple-ionized carbon and silicon (C IV, Si IV). This observation proves decisively that the hydrogen cloud, even though it is located at a very large distance and is therefore observed at a time when the Universe was only about 10 percent as old as now, has already been enriched by heavier elements. The observed elements cannot date from the Big Bang (only the lightest elements were synthesized then) and they were obviously produced by nuclear reactions in the interior of massive stars. These stars, in turn, must have been born and already arrived at the end of their evolution (thereby

  17. Discovery of an apparent companion galaxy to Q1548 + 0917 with z = 2.758

    NASA Technical Reports Server (NTRS)

    Steidel, Charles C.; Dickinson, Mark; Sargent, Wallace L. W.

    1991-01-01

    The discovery of a resolved companion to the QSO Q1548 + 0917 (redshift 2.749) is reported. The possible nature of the companion, designated C1548 + 0917, is discussed, and new spectroscopic observations of the prototypical case of a Lyman alpha emitting companion to a high-redshift QSO, PKS 1614 + 0508 A, are presented for comparison. C1548 + 0917 appears to be the first case of a radio-quiet continuum object discovered in the vicinity of what must be considered a radio-quiet QSO at high redshift. Evidence is also found for extended Lyman alpha emission associated with the QSO itself.

  18. An Arabidopsis quiescin-sulfhydryl oxidase regulates cation homeostasis at the root symplast–xylem interface

    PubMed Central

    Alejandro, Santiago; Rodríguez, Pedro L; Bellés, Jose M; Yenush, Lynne; García-Sanchez, María J; Fernández, José A; Serrano, Ramón

    2007-01-01

    A genetic screen of Arabidopsis ‘activation-tagging' mutant collection based on tolerance to norspermidine resulted in a dominant mutant (par1-1D) with increased expression of the QSO2 gene (At1g15020), encoding a member of the quiescin-sulfhydryl oxidase (QSO) family. The par1-1D mutant and transgenic plants overexpressing QSO2 cDNA grow better than wild-type Arabidopsis in media with toxic cations (polyamines, Li+ and Na+) or reduced K+ concentrations. This correlates with a decrease in the accumulation of toxic cations and an increase in the accumulation of K+ in xylem sap and shoots. Conversely, three independent loss-of-function mutants of QSO2 exhibit phenotypes opposite to those of par1-1D. QSO2 is mostly expressed in roots and is upregulated by K+ starvation. A QSO2∷GFP fusion ectopically expressed in leaf epidermis localized at the cell wall. The recombinant QSO2 protein, produced in yeast in secreted form, exhibits disulfhydryl oxidase activity. A plausible mechanism of QSO2 action consists on the activation of root systems loading K+ into xylem, but different from the SKOR channel, which is not required for QSO2 action. These results uncover QSOs as novel regulators of ion homeostasis. PMID:17568770

  19. OVI absorbers in SDSS spectra

    NASA Astrophysics Data System (ADS)

    Frank, Stephan

    We conducted a systematic search for signatures of the Intergalactic Medium (IGM) in Quasar spectra of the Sloan Digital Sky Survey (SDSS) Data Release 3 (DR3), focusing on finding intervening absorbers via detection of their O VI doublet. We present a search algorithm, and criteria for distinguishing candidates from spurious Lyman a forest lines. In addition, we compare our findings with simulations of the Lyman a forest in order to estimate the detectability of O VI doublets over various redshift intervals. We obtain a sample of 1866 O VI doublet candidates with rest-frame equivalent width >= 0.05 λ in 855 AGN spectra (out of 3702 objects with redshifts in the range accessible for O VI detection). This sample is subdivided into 3 groups according to the likelihood of being real and the potential for follow-up observation of the candidate. The group with the cleanest and most secure candidates is comprised of 145 candidates. 69 of these reside at a velocity separation >= 5000 km/s from the QSO, and can therefore be classified tentatively as intervening absorbers. Most of these absorbers have not been picked up by earlier, automated QSO absorption line detection algorithms. This sample increases the number of known O VI absorbers at redshifts beyond z abs >= 2.7 substantially. We propose to obtain observations of some of the candidates with the best signatures for O VI doublets with high signal-to-noise and high resolution in order to better constrain the physical state of the absorbers. We then focused on a subsample of 387 AGN sightlines with an average S/N >= 5: 0, allowing for the detection of absorbers above a rest-frame equivalent width limit of W r >= 0:19 ? A for the O VI 1032 λ component. Accounting for random interlopers mimicking an O VI doublet, we derive for the first time a secure lower limit for the redshift number density DN/Dz for redshifts z abs >= 2:8. With extensive Monte Carlo simulations we quantify the losses of absorbers due to blending

  20. Dark Galaxies and Lost Baryons (IAU S244)

    NASA Astrophysics Data System (ADS)

    Davies, Jonathan I.; Disney, Michael J.

    2008-05-01

    Preface; Conference prelims; The HI that barked in the night M. J. Disney; The detection of dark galaxies in blind HI surveys J. I. Davies; Red haloes of galaxies - reservoirs of baryonic dark matter? E. Zackrisson, N. Bergvall, C. Flynn, G. Ostlin, G. Micheva and B. Baldwell; Constraints on dark and visible mass in galaxies from strong gravitational lensing S. Dye and S. Warren; Lost baryons at low redshift S. Mathur, F. Nicastro and R. Williams; Observed properties of dark matter on small spatial scales R. Wyse and G. Gilmore; The mass distribution in spiral galaxies P. Salucci; Connecting lost baryons and dark galaxies via QSO absorption lines T. Tripp; ALFALFA: HI cosmology in the local universe R. Giovanelli; The ALFALFA search for (almost) dark galaxies across the HI mass function M. Haynes; HI clouds detected towards Virgo with the Arecibo Legacy Fast ALFA Survey B. Kent; Cosmic variance in the HI mass function S. Schneider; The Arecibo Galaxy Environments Survey - potential for finding dark galaxies and results so far R. Minchin et al.; Free-floating HI clouds in the M81 group E. Brinks, F. Walter and E. Skillman; Where are the stars in dark galaxies J. Rosenberg, J. Salzer and J. Cannon; The halo by halo missing baryon problem S. McGaugh; The local void is really empty R. Tully; Voids in the local volume: a limit on appearance of a galaxy in a dark matter halo A. Tikhonov and A. Klypin; Dim baryons in the cosmic web C. Impey; A census of baryons in galaxy clusters and groups A. Gonzalez, D. Zaritsky and A. Zabludo; Statistical properties of the intercluster light from SDSS image stacking S. Zibetti; QSO strong gravitational lensing and the detection of dark halos A. Maccio; Strong gravitational lensing: bright galaxies and lost dark-matter L. Koopmans; Mapping the distribution of luminous and dark matter in strong lensing galaxies I. Ferreras, P. Saha, L. Williams and S. Burles; Tidal debris posing as dark galaxies P. Duc, F. Bournaud and E. Brinks

  1. Intervening O VI Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir

    NASA Astrophysics Data System (ADS)

    Tripp, Todd M.; Savage, Blair D.; Jenkins, Edward B.

    2000-05-01

    Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at ~7 km s-1 resolution, reveals four definite O VI absorption-line systems and one probable O VI absorber at 0.15QSO. In the case of the strong O VI system at zabs=0.22497, multiple components are detected in Si III and O VI as well as H I Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O VI absorber is detected at zabs=0.22637, i.e., offset by ~340 km s-1 from the zabs=0.22497 system. Lyα absorption is detected at zabs=0.22613, but no Lyα absorption is significantly detected at 0.22637. Other weak O VI absorbers at zabs=0.24531 and 0.26659 and the probable O VI system at 0.21326 have widely diverse O VI/H I column density ratios with N(O VI)/N(H I) ranging from <=0.14+/-0.03 to 5.2+/-1.2. The number density of O VI absorbers with rest equivalent width greater than 30 mÅ in the H1821+643 spectrum is remarkably high, dN/dz~48, which implies with a high (90%) confidence that it is greater than 17 in the low-redshift intergalactic medium. We conservatively estimate that the cosmological mass density of the O VI systems is Ωb(OVI)>~0.0008 h-175. With an assumed metallicity of 1/10 solar and a conservative assumption that the fraction of oxygen in the O VI ionization stage is 0.2, we obtain Ωb(OVI)>~0.004 h-175. This is comparable to the combined cosmological mass density of stars and cool gas in galaxies and X-ray-emitting gas in galaxy clusters at low redshift. Based on observations 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

  2. The Intergalactic and Circumgalactic Medium surrounding Star-Forming Galaxies at Redshifts 2 < z < 3

    NASA Astrophysics Data System (ADS)

    Rudie, Gwen C.

    We present measurements of the spatial distribution, kinematics, and physical properties of gas in the circumgalactic medium (CGM) of 2.0 < z < 2.8 UV color-selected galaxies as well as within the 2 < z < 3 intergalactic medium (IGM). These measurements are derived from Voigt profile decomposition of the full Lyalpha and Lybeta forest in 15 high-resolution, high signal-to-noise ratio QSO spectra resulting in a catalog of ˜ 6000 H I absorbers. Chapter 2 of this thesis focuses on H I surrounding high-z star-forming galaxies drawn from the Keck Baryonic Structure Survey (KBSS). The KBSS is a unique spectroscopic survey of the distant universe designed to explore the details of the connection between galaxies and intergalactic baryons within the same survey volumes. The KBSS combines high-quality background QSO spectroscopy with large densely-sampled galaxy redshift surveys to probe the CGM at scales of ˜ 50 kpc to a few Mpc. Based on these data, Chapter 2 presents the first quantitative measurements of the distribution, column density, kinematics, and absorber line widths of neutral hydrogen surrounding high-z star-forming galaxies. Chapter 3 focuses on the thermal properties of the diffuse IGM. This analysis relies on measurements of the ˜ 6000 absorber line widths to constrain the thermal and turbulent velocities of absorbing "clouds." A positive correlation between the column density of H I and the minimum line width is recovered and implies a temperature-density relation within the low-density IGM for which higher-density regions are hotter, as is predicted by simple theoretical arguments. Chapter 4 presents new measurements of the opacity of the IGM and CGM to hydrogen-ionizing photons. The chapter begins with a revised measurement of the H I column density distribution based on this new absorption line catalog that, due to the inclusion of high-order Lyman lines, provides the first statistically robust measurement of the frequency of absorbers with H I column

  3. The Properties of Two Low-redshift O VI Absorbers and Their Associated Galaxies toward 3c 263

    NASA Astrophysics Data System (ADS)

    Savage, B. D.; Kim, T.-S.; Keeney, B.; Narayanan, A.; Stocke, J.; Syphers, D.; Wakker, B. P.

    2012-07-01

    Ultraviolet observations of the QSO 3C 263 (z em = 0.652) with Cosmic Origins Spectrograph and FUSE reveal O VI absorption systems at z = 0.06342 and 0.14072. WIYN multi-object spectrograph observations provide information about the galaxies associated with the absorbers. The multi-phase system at z = 0.06342 traces cool photoionized gas and warm collisionally ionized gas associated with an L ~ 0.31 L* compact spiral emission line galaxy with an impact parameter of 63 kpc. The cool photoionized gas in the absorber is well modeled, with log U ~ -2.6, log N(H) ~ 17.8, log n(H) ~ -3.3 and [Si/H] = -0.14 ± 0.23. The collisionally ionized gas containing C IV and O VI probably arises in cooling shock-heated transition temperature gas with log T ~ 5.5. The absorber is likely tracing circumgalactic gas enriched by gas ejected from the spiral emission line galaxy. The simple system at z = 0.14072 only contains O VI and broad and narrow H I. The O VI with b = 33.4 ± 11.9 km s-1 is likely associated with the broad H I λ1215 absorption, with b = 86.7 ± 15.4 km s-1. The difference in Doppler parameters implies the detection of a very large column of warm gas with log T = 5.61(+0.16, -0.25), log N(H) = 19.54(+0.26, -0.44), and [O/H] = -1.48 (+0.46, -0.26). This absorber is possibly associated with a 1.6 L* absorption line galaxy with an impact parameter of 617 kpc, although an origin in warm filament gas or in the halo of a fainter galaxy is more likely. Based on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555, the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555, and the NASA-CNES/ESA Far Ultraviolet Spectroscopic Explorer mission operated by Johns Hopkins University, supported by NASA contract NAS 05-32985. Based on observations obtained with the WIYN Observatory which is jointly operated by the

  4. Evidence of bimodal physical properties of intervening, optically thin C III absorbers at z ˜ 2.5

    NASA Astrophysics Data System (ADS)

    Kim, T.-S.; Carswell, R. F.; Ranquist, D.

    2016-03-01

    We present the Voigt profile analysis of 132 intervening C IV+C III components associated with optically thin H I absorbers at 2.1 < z < 3.4 in the 19 high-quality UVES/VLT and HIRES/Keck QSO spectra. For log N_{C I} in [11.7, 14.1], N_{C III} ∝ N_{C IV}^{1.42± 0.11} and < N_{C III}/N_{C {IV} > = 1.0± 0.3 with a negligible redshift evolution. For 54 C IV components tied (aligned) with H I at log N_{H I} in [12.2, 16.0] and log N_{C IV} in [11.8, 13.8], the gas temperature Tb estimated from absorption line widths is well approximated to a Gaussian peaking at log Tb ˜ 4.4 ± 0.3 for log Tb ∈ [3.5, 5.5], with a negligible non-thermal contribution. For 32 of 54 tied H I+C IV pairs, also tied with C III at log N_{C {III} in [11.7, 13.8], we ran both photoionization equilibrium (PIE) and non-PIE (using a fixed temperature Tb) CLOUDY models for the Haardt-Madau QSOs+galaxies 2012 UV background. We find evidence of bimodality in observed and derived physical properties. High-metallicity branch absorbers have a carbon abundance [C/H]temp ≥ -1.0, a line-of-sight length Ltemp ≤ 20 kpc and a total (neutral and ionized) hydrogen volume density log nH,temp ∈ [-4.5, -3.3] and log Tb ∈ [3.9, 4.5]. Low-metallicity branch absorbers have [C/H]temp ≤ -1.0, Ltemp ∈ [20, 480] kpc and log nH,temp ∈ [-5.2, -4.3] and log Tb ˜ 4.5. High-metallicity branch absorbers seem to be originated from extended discs, inner haloes or outflowing gas of intervening galaxies, while low-metallicity absorbers are produced by galactic haloes or the surrounding intergalactic medium filament.

  5. A Hot Gaseous Galaxy Halo Candidate with Mg X Absorption

    NASA Astrophysics Data System (ADS)

    Qu, Zhijie; Bregman, Joel N.

    2016-12-01

    The hot gas in galaxy halos may account for a significant fraction of missing baryons in galaxies, and some of these gases can be traced by high ionization absorption systems in QSO UV spectra. Using high S/N Hubble Space Telescope/Cosmic Origins Spectrograph spectra, we discovered a high ionization state system at z = 1.1912 in the sightline toward LBQS 1435-0134, and two-component absorption lines are matched for Mg x, Ne viii, Ne vi, O vi, Ne v, O v, Ne iv, O iv, N iv, O iii, and H i. Mg x, detected for the first time (5.8σ), is a particularly direct tracer of hot galactic halos, as its peak ion fraction occurs near 106.1 K, about the temperature of a virialized hot galaxy halo of mass ˜ 0.5{M}* . With Mg x and Ne viii, a photoionization model cannot reproduce the observed column densities with path lengths of galaxy halos. For collisional ionization models, one or two-temperature models do not produce acceptable fits, but a three-temperature model or a power-law model can produce the observed results. In the power-law model, {dN}/{dT}={10}4.4+/- 2.2-[Z/X]{T}1.55+/- 0.41 with temperatures in the range of {10}4.39+/- 0.13 {{K}}\\lt T\\lt {10}6.04+/- 0.05 {{K}}, the total hydrogen column density is 8.2× {10}19(0.3 {Z}⊙ /Z) {{cm}}-2 and the positive power-law index indicates most of the mass is at the high temperature end. We suggest that this absorption system is a hot volume-filled galaxy halo rather than interaction layers between the hot halo and cool clouds. The temperature dependence of the column density is likely due to the local mixture of multiple phase gases.

  6. TESTING THE POSSIBLE INTRINSIC ORIGIN OF THE EXCESS VERY STRONG Mg II ABSORBERS ALONG GAMMA-RAY BURST LINES-OF-SIGHT

    SciTech Connect

    Cucchiara, A.; Jones, T.; Charlton, J. C.; Fox, D. B.; Einsig, D.; Narayanan, A. E-mail: tjones@astro.psu.edu E-mail: charlton@astro.psu.edu E-mail: anand@astro.wisc.edu

    2009-05-20

    The startling discovery by Prochter et al. that the frequency of very strong (W{sub r} (2796)>1 A) Mg II absorbers along gamma-ray burst (GRB) lines of sight ([dN/dz]{sub GRB} = 0.90) is more than three times the frequency along quasar lines of sight ([dN/dz]{sub QSO} = 0.24), over similar redshift ranges, has yet to be understood. In particular, explanations appealing to dust antibias in quasar samples, partial covering of the quasar sources, and gravitational-lensing amplification of the GRBs have all been carefully examined and found wanting. We therefore reconsider the possibility that the excess of very strong Mg II absorbers toward GRBs is intrinsic either to the GRBs themselves or to their immediate environment, and associated with bulk outflows with velocities as large as v {sub max} {approx} 0.3c. In order to examine this hypothesis, we accumulate a sample of 27 W{sub r} (2796)>1 A absorption systems found toward 81 quasars, and compare their properties to those of 8 W{sub r} (2796) > 1 A absorption systems found toward six GRBs; all systems have been observed at high spectral resolution (R = 45, 000) using the Ultraviolet and Visual Echelle Spectrograph on the Very Large Telescope. We make multiple comparisons of the absorber properties across the two populations, testing for differences in metallicity, ionization state, abundance patterns, dust abundance, kinematics, and phase structure. We find no significant differences between the two absorber populations using any of these metrics, implying that, if the excess of absorbers along GRB lines of sight are indeed intrinsic, they must be produced by a process which has strong similarities to the processes yielding strong Mg II systems associated with intervening galaxies. Although this may seem a priori unlikely, given the high outflow velocities required for any intrinsic model, we note that the same conclusion was reached, recently, with respect to the narrow absorption line systems seen in some quasars.

  7. Joint Lyman α emitters - quasars reionization constraints

    NASA Astrophysics Data System (ADS)

    Baek, S.; Ferrara, A.; Semelin, B.

    2012-06-01

    We present a novel method to investigate c reionization, using joint spectral information on high-redshift Lyman α emitters (LAEs) and quasi-stellar objects (QSOs). Although LAEs have been proposed as reionization probes, their use is hampered by the fact their Lyα line is damped not only by intergalactic H I but also internally by dust. Our method allows us to overcome such degeneracy. First, we carefully calibrate a reionization simulation with QSO absorption line experiments. Then we identify LAEs (? and equivalent width >20 Å) in two simulation boxes at z= 5.7 and 6.6 and we build synthetic images/spectra of a prototypical LAE. The surface brightness maps show the presence of a scattering halo extending up to 150 kpc from the galaxye. For each LAE we then select a small box of (10 h-1 Mpc)3 around it and derive the optical depth τ along three viewing axes. At redshift 5.7, we find that the Lyα transmissivity ?, almost independent of the halo mass. This constancy arises from the conspiracy of two effects: (i) the intrinsic Lyα line width and (ii) the infall peculiar velocity. At higher redshift, z= 6.6, where ? the transmissivity is instead largely set by the local H I abundance and ? consequently increases with halo mass, Mh, from 0.15 to 0.3. Although outflows are present, they are efficiently pressure confined by infall in a small region around the LAE; hence they only marginally affect transmissivity. Finally, we cast line of sight originating from background QSOs passing through foreground LAEs at different impact parameters, and compute the quasar transmissivity (?). At small impact parameters, d < 1 cMpc, a positive correlation between ? and Mh is found at z= 5.7, which tends to become less pronounced (i.e. flatter) at larger distances. Quantitatively, a roughly 10× increase (from 5 × 10-3 to 6 × 10-2) of ? is observed in the range log Mh= (10.4-11.6). This correlation becomes even stronger at z= 6.6. By cross-correlating ? and ?, we can obtain a

  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. Reionization in a cold dark matter universe: The feedback of galaxy formation on the intergalactic medium

    NASA Technical Reports Server (NTRS)

    Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

    1994-01-01

    ) cannot account for the baryon content of the universe at z approximately 3 observed in quasar absorption line gas unless Omega (sub B) significantly exceeds the maximum value allowed by big bang nucleocynthesis. (5) For a CDM model with bias parameter within the allowed range of (lower) values, the lower limit to Omega(sub B) imposed by big bang nucleosynthesis (Omega(sub B) h(sup 2) greater than or equal to 0.01) combines with our results to yield the minimum IGM density for the CDM fodel. For CDM with b = 1 (Cosmic Background Explorer (COBE) normalization), we find Omega(sub IGM)(sup min) (z approximately 4) approx. equal 0.02-0.03, and Omega(sub IGM)(sup min)(z approximately 0) approx. equal 0.005-0.03, depending upon the nature of the sources of IGM reionization. (6) In general, we find that self-consistent reionization of the IGM by the collapsed baryon fraction has a strong effect on the rate of collapse. (7) As a further example, we show that the feedback effect on the IGM of energy release by the collapsed baryon fraction may explain the slow evolution of the observed comoving QSO number density between z = 5 and z = 2, followed by the sharp decline after z = 2.

  10. The Abundance of Interstellar Fluorine

    NASA Technical Reports Server (NTRS)

    Lauroesch, James T.

    2005-01-01

    The primary objective of this program was to obtain FUSE observations of the interstellar absorption lines of F I at 951 and 954 Angstroms to derive the abundance of fluorine toward the star HD 164816. The nucleosynthetic source(s) of fluorine are still a matter of debate - the present day abundance of fluorine can potentially constrain models for pulsationally driven dredge-up in asymptotic giant branch stars. An accurate measure for the depletion behavior of fluorine will determine whether it may be detectable in QSO absorption line systems - an unambiguous detection of fluorine at suitably high redshifts would provide the best evidence to date for the neutrino process in massive stars. Furthermore, due to its extreme reactivity, measurement of the gas-phase interstellar fluorine abundance is important for models of grain chemistry. Despite the importance of measuring the interstellar fluorine abundance, at the time of our proposal only one previous detection has been made due to the low relative abundance of fluorine, the lack of lines outside the far-UV, and the blending of the available F I transitions with lines of Hz. The star HD 164816 is associated with the Lagoon nebula (M8), and at a distance of approximately 1.5 kpc probes both distant and local gas. Beginning April 8th, 2004 FUSE FP-Split observations of the star HD 164816 were obtained for this program. This data became available in the FUSE data archive May 21, 2004, and these observations were then downloaded and we began our analysis. Our analysis procedure has involved (1) fitting stellar models to the FUSE spectra, (2) using the multiple lines of Hz and N I at other wavelengths in the FUSE bandpass to derive column densities for the lines of H2 and N I which are blended with the F I features at 951 and 954 angstroms (3) the measurement of the column densities of F I and the species O I and C1 I which are important species for the dis-entangling of dust and nucleosynthetic effects. As discussed in

  11. Baryon cycling in the low-redshift circumgalactic medium: a comparison of simulations to the COS-Halos survey

    NASA Astrophysics Data System (ADS)

    Ford, Amanda Brady; Werk, Jessica K.; Davé, Romeel; Tumlinson, Jason; Bordoloi, Rongmon; Katz, Neal; Kollmeier, Juna A.; Oppenheimer, Benjamin D.; Peeples, Molly S.; Prochaska, Jason X.; Weinberg, David H.

    2016-06-01

    We analyse the low-redshift (z ≈ 0.2) circumgalactic medium (CGM) by comparing absorption-line data from the COS-Halos survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different prescriptions for galactic outflows, namely hybrid energy/momentum driven wind (ezw), and constant winds (cw). We compare equivalent widths, covering factors, ion ratios, and kinematics. Both wind models show generally ≲ 1σ agreement with these observations for H I and certain low-ionization metal lines, but poorer agreement with higher ionization metal lines including Si III and O VI that are well observed by COS-Halos. This suggests that both models predict too much cool, metal-enriched gas and not enough hot gas, and / or that metals are not sufficiently mixed. This may reflect our model assumption of ejecting outflows as cool and unmixing gas. Our ezw simulation includes a heuristic prescription to quench massive galaxies by superheating interstellar medium gas. This produces low-ionization absorption broadly consistent with observations, but substantial O VI absorption inconsistent with data, suggesting that gas around quenched galaxies in the real Universe does not cool. At impact parameters of ≲ 50 kpc, recycling winds dominate the absorption of low ions and even H I, while O VI generally arises from metals ejected ≳ 1 Gyr ago. The similarity between the wind models is surprising, since they differ substantially in the amount and phase distribution of halo gas. We show that this similarity owes mainly to our comparison at fixed stellar (not halo) mass, suggesting that CGM properties are more closely tied to galaxy's stellar (versus halo) mass.

  12. Lick optical spectra of quasar HS 1946+7658 at 10 kilometers per second resolution Lyman-alpha forest and metal absorption systems

    NASA Technical Reports Server (NTRS)

    Fan, Xiao-Ming; Tytler, David

    1994-01-01

    We present optical spectra of the most luminous known quasi stellar object (QSO) HS 1946+7658 (z(sub em) = 3.051). Our spectra have both full wavelength coverage, 3240-10570 A, and in selected regions, either high signal-to-noise ratio, SNR approximately equals 40-100, or unusually high approximately 10 km/sec resolution, and in parts of the Ly alpha forest and to the red of Ly alpha emission they are among the best published. We find 113 Ly alpha systems and six metal-line systems, three of which are new. The metal systems at z(sub abs) = 2.844 and 3.050 have complex velocity structure with four and three prominent components, respectively. We find that the system at z(sub abs) = 2.844 is a damped Ly alpha absorption (DLA) system, with a neutral hydrogen column density of log N(H I) = 20.2 +/- 0.4, and it is the cause of the Lyman limit break at lambda approximately equals 3520 A. We believe that most of the H I column density in this system is in z(sub abs) = 2.8443 component which shows the strongest low-ionization absorption lines. The metal abundance in the gas phase of the system is (M/H) approximately equals -2.6 +/- 0.3, with a best estimate of (M/H) = -2.8, with ionizaion parameter log gamma = -2.75, from a photoionization model. The ratios of the logarithmic abundances of C, O, Al, and Si are all within a factor of 2 of solar, which is important for two reasons. First, we believe that the gas abundances which we measure are close to the total abundances, because the ratio of aluminum to other elements is near cosmic, and Al is a refractory element which depletes very readily like chromium, in the interstellar medium. Second, we do not see the enhancement of O with respect to C of (O/C) approximately equals 0.5-0.9 reported in three partial Lyman limit systems by Reimers et al. (1992) and Vogel & Reimers (1993); we measure (O/C) = -0.06 for observed ions and (O/C) approximately equals 0.2 after ionization corrections, which is consistent with solar

  13. Successful "First Light" for VLT High-Resolution Spectrograph

    NASA Astrophysics Data System (ADS)

    1999-10-01

    ago during the Hamburg-ESO Quasar Survey , by means of photographic plates taken with the 1-m ESO Schmidt Telescope at La Silla, the other ESO astronomical site in Chile. ESO PR Photo 37d/99 ESO PR Photo 37d/99 [Preview - JPEG: 400 x 309 pix - 92k] [Normal - JPEG: 800x 618 pix - 311k] [High-Res - JPEG: 3000 x 2316 pix - 5.0M] ESO PR Photo 37e/99 ESO PR Photo 37e/99 [Preview - JPEG: 400 x 310 pix - 43k] [Normal - JPEG: 800 x 619 pix - 100k] [High-Res - JPEG: 3003 x 2324 pix - 436k] Caption to ESO PR Photo 37d/99 : This UVES echelle spectrum QSO HE2217-2818 (U-magnitude = 16.5) is recorded in different orders (the individual horizontal lines) and altogether covers the wavelength interval between 330 - 450 nm (from the bottom to the top). It illustrates the excellent capability of UVES to work in the UV-band on even faint targets. Simultaneously with this observation, UVES also recorded the adjacent spectral region 465 - 660 nm in its other channel. The broad Lyman-alpha emission from ionized hydrogen associated with the powerful energy source of the QSO is seen in the upper half of the spectrum at wavelength 413 nm. At shorter wavelengths, the dark regions in the spectrum are Lyman-alpha absorption lines from intervening, neutral hydrogen gas located along the line-of-sight at different redshifts (the so-called Lyman-alpha forest ) in the redshift interval z = 1.7 - 2.4. Note that since this exposure was done with the nearly Full Moon above the horizon, an underlying, faint absorption-line spectrum of reflected sunlight is also visible. Caption to ESO PR Photo 37e/99 : A tracing of one spectral order, corresponding to one horizontal line in the echelle spectrum displayed in PR Photo 37d/99 . It shows part of the Lyman-alpha forest in the ultraviolet spectrum of the southern quasar QSO HE2217-2818 . The absorption lines are caused by intervening, neutral hydrogen gas located at different distances along the line-of-sight towards this quasar. How to obtain ESO Press

  14. Chemical detection with hyperspectral lidar using dual frequency combs.

    PubMed

    Boudreau, Sylvain; Levasseur, Simon; Perilla, Carlos; Roy, Simon; Genest, Jérôme

    2013-03-25

    High-resolution spectral lidar measurements using dual frequency combs as a source is presented. The technique enables the range-resolved measurement of fine spectral features, such as gas absorption lines, provided that a suitable scatterer is present in the scene. Measurements of HCN absorption lines at 20 meters are presented, with a water droplet cloud and a diffusely reflective surface as scatterers.

  15. Infrared laboratory studies of synthetic planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Williams, D.

    1973-01-01

    Previous research dealing with telluric gases is briefly reviewed. Current research concerning absorption-line broadening, and particulate constituents of planetary atmospheres are discussed. Two articles are included: optical constants of liquid ammonia in the infrared, and broadening of infrared absorption lines at reduced temperatures for nitrous oxide.

  16. ON PROBING THE PROPERTIES OF QSOs THROUGH THEIR PROXIMITY EFFECTS ON THE INTERGALACTIC MEDIUM

    SciTech Connect

    Lu Youjun; Yu Qingjuan E-mail: yuqj@pku.edu.cn

    2011-07-20

    The proximity effect (PE) of QSOs is believed to be useful in constraining the QSO lifetime. Observations of the PE so far, however, give apparently contradictory results-some are consistent with a long QSO lifetime ({approx}> a few 10{sup 7} yr), but others appear to be only consistent with a short QSO lifetime ({approx}< 10{sup 6} yr). In this paper, we show that this apparent contradiction may be solved by simultaneously taking into account both the effect due to the density enhancement in the QSO near zones and that due to the obscuration of the tori associated with the QSOs, using a large number of Monte Carlo generated synthetic Ly{alpha} forest spectra. We demonstrate that the QSO properties and environment can be constrained simultaneously by the transverse PE (TPE) and the line-of-sight PE of bright type 1 QSOs together. The current available measurements on the PEs of type 1 QSOs suggest that (1) the density is significantly enhanced in the vicinity of the QSOs; (2) the QSO lifetime is consistent with being as large as a few 10{sup 7} yr, and a substantially shorter lifetime (e.g., {approx}< 10{sup 6} yr) is not required; and (3) the half opening angle of the tori associated with QSOs is {approx}60{sup 0}, consistent with some other independent estimates. Our simulations also show that the TPE of type 2 QSOs can be significantly different from that of type 1 QSOs, which may be useful to put further constraints on the QSO properties and the QSO environment.

  17. Understanding the Relations between QSOs and Their Host Galaxies from Combined HST Imaging and VLT Spectroscopy

    NASA Astrophysics Data System (ADS)

    Letawe, Y.; Magain, P.; Letawe, G.; Courbin, F.; Hutsemékers, D.

    2008-06-01

    The host galaxies of six nearby QSOs are studied on the basis of high-resolution HST optical images and spatially resolved VLT slit spectra. The gas ionization and velocity are mapped as a function of the distance to the central QSO. In the majority of the cases, the QSO significantly contributes to the gas ionization in its whole host galaxy, and sometimes even outside. Reflection or scattering of the QSO Hα line from remote regions of the galaxy is detected in several instances. The line shifts show that, in all cases, the matter responsible for the light reflection moves away from the QSO, likely accelerated by its radiation pressure. The two faintest QSOs reside in spirals, with some signs of a past gravitational perturbation. One of the intermediate-luminosity QSOs resides in a massive elliptical containing gas ionized (and probably pushed away) by the QSO radiation. The other medium-power object is found in a spiral galaxy displaying complex velocity structure, with the central QSO moving with respect to the bulge, probably as a result of a galactic collision. The two most powerful objects are involved in violent gravitational interactions, and one of them has no detected host. These results suggest that (1) large-scale phenomena, such as galactic collisions, are closely related to the triggering and the feeding of the QSO and (2) once ignited, the QSO has significant influence on its large-scale neighborhood (often the whole host and sometimes further away). Based on observations made with the Nasa/ESA Hubble Space Telescope (Cycle 13 proposal 10238), and with ANTU/UT1 at ESO-Paranal observatory in Chile [programs 65.P-0361(A) and 66.B-0139(A)].

  18. A multicolor optical survey of QSOs to B of about 21. 8 in the Hercules field

    SciTech Connect

    Zhan, Yin; Koo, D.C.; Kron, R.G.; Toronto Univ.; Lick Observatory, Santa Cruz, CA; Yerkes Observatory, Williams Bay, WI )

    1989-07-01

    Using catalogs generated from automatic photometry of faint images on fine-grained 4-m photographic plates, a UBV multicolor survey of QSOs over an area of about 0.285 square degree in Hercular has been completed. Thirty QSO candidates brighter than B of about 21.8 were selected with stellar-like images and UBV colors uncommon for Galactic stars. The counts of QSO candidates from this study are consistent with those from other surveys. 23 refs.

  19. Primordial nucleosynthesis and neutrino physics

    NASA Astrophysics Data System (ADS)

    Smith, Christel Johanna

    We study primordial nucleosynthesis abundance yields for assumed ranges of cosmological lepton numbers, sterile neutrino mass-squared differences and active-sterile vacuum mixing angles. We fix the baryon-to-photon ratio at the value derived from the cosmic microwave background (CMB) data and then calculate the deviation of the 2 H, 4 He, and 7 Li abundance yields from those expected in the zero lepton number(s), no-new-neutrino-physics case. We conclude that high precision (< 5% error) measurements of the primordial 2 H abundance from, e.g., QSO absorption line observations coupled with high precision (< 1% error) baryon density measurements from the CMB could have the power to either: (1) reveal or rule out the existence of a light sterile neutrino if the sign of the cosmological lepton number is known; or (2) place strong constraints on lepton numbers, sterile neutrino mixing properties and resonance sweep physics. Similar conclusions would hold if the primordial 4 He abundance could be determined to better than 10%. We have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these distributions to the thermodynamics, the expansion rate and scale factor-time/temperature relationship, as well as to all relevant weak, electromagnetic, and strong nuclear reaction processes in the early universe. With this approach, we can treat any scenario in which neutrino or antineutrino spectral distortion might arise. These scenarios might include, for example, decaying particles, active-sterile neutrino oscillations, and active-active neutrino oscillations in the presence of significant lepton numbers. Our calculations allow lepton numbers and sterile neutrinos to be constrained with observationally-determined primordial helium and deuterium abundances. We have modified a standard BBN code to perform these

  20. Microlensing of Sub-parsec Massive Binary Black Holes in Lensed QSOs: Light Curves and Size-Wavelength Relation

    NASA Astrophysics Data System (ADS)

    Yan, Chang-Shuo; Lu, Youjun; Yu, Qingjuan; Mao, Shude; Wambsganss, Joachim

    2014-04-01

    Sub-parsec binary massive black holes (BBHs) have long been thought to exist in many QSOs but remain observationally elusive. In this paper, we propose a novel method to probe sub-parsec BBHs through microlensing of lensed QSOs. If a QSO hosts a sub-parsec BBH in its center, it is expected that the BBH is surrounded by a circumbinary disk, each component of the BBH is surrounded by a small accretion disk, and a gap is opened by the secondary component in between the circumbinary disk and the two small disks. Assuming such a BBH structure, we generate mock microlensing light curves for some QSO systems that host BBHs with typical physical parameters. We show that microlensing light curves of a BBH QSO system at the infrared-optical-UV bands can be significantly different from those of corresponding QSO system with a single massive black hole (MBH), mainly because of the existence of the gap and the rotation of the BBH (and its associated small disks) around the center of mass. We estimate the half-light radii of the emission region at different wavelengths from mock light curves and find that the obtained half-light radius versus wavelength relations of BBH QSO systems can be much flatter than those of single MBH QSO systems at a wavelength range determined by the BBH parameters, such as the total mass, mass ratio, separation, accretion rates, etc. The difference is primarily due to the existence of the gap. Such unique features on the light curves and half-light radius-wavelength relations of BBH QSO systems can be used to select and probe sub-parsec BBHs in a large number of lensed QSOs to be discovered by current and future surveys, including the Panoramic Survey Telescope and Rapid Response System, the Large Synoptic Survey telescope, and Euclid.