Searching for Dust Reddening in SDSS Spectra with Damped Lyman $\alpha${} Systems

Abstract

We searched for evidence of reddening of background SDSS QSO spectra due to dust in intervening DLA systems. We utilise the Data Releases 5 and 7 to arrive at sample sizes of 475 (DR5) and 676 (DR7) absorbers, based on two different published lists of SDSS DLAs. Both samples span roughly the redshift range of 2.2 < z_abs < 5.2, with a mean of z~3.0, and the majority of the DLAs (75%) below z=3.3. We construct geometric mean spectra in the absorber restframes ranging from 1240 to ~2800 A, and composite spectra of samples matching the 'DLA' QSOs in i band magnitude and emission redshift z_em, but without absorption lines. By comparing the slopes of these composite spectra with their matched counterparts, we find no sign of reddening in the ensemble of the absorbers from these samples. Owing to both the unprecedently large sizes of the DLA samples themselves and the non-DLA SDSS QSO sample, from which we can draw our matching spectra, we can place very tight limits for this non-detection (<E(B-V)> =-0.0013+-0.0025 (DR5) and <E(B-V)> =-0.0017+-0.0022 (DR7). Interestingly, when applying our technique to the samples of York et. al. (2006), vandenBerk et al. (2008) (intervening and intrinsic MgII absorbers) and the smaller DLA-subsample and pool of comparison QSOs of Vladilo et al. (2008), we do recover their results, i.e. detect the same amount of reddening as these authors do. Furthermore, we have tested whether subsamples of our large sample in categories involving the absorbers (HI column densities, presence or absence of accompanying metal absorption, absorber redshift) or the background quasars (emission redshift, brightness) do reveal dust extinction, but found no trends. These results are at odds with both detections of dust reddening from previous studies, and also with expectations from observations of high-redshift galaxies. (abridged)

16 pages, 12 figures, accepted for publication in MNRAS

References in corpus (11)

• A Catalog of Broad Absorption Line Quasars in Sloan Digital Sky Survey Data Release 5
• On the (Non)Evolution of HI Disks over Cosmic Time
• Evolution of the cosmological mass density of neutral gas from Sloan Digital Sky Survey II - Data Release 7
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Searching for Low Surface-brightness Galaxies in the Hubble Ultra Deep Field: Implications for the Star Formation Efficiency in Neutral Gas at z ~ 3
• Lensing, reddening and extinction effects of MgII absorbers from z=0.4 to z=2
• The UCSD Radio-Selected Quasar Survey for Damped Lyman alpha System
• The color excess of quasars with intervening DLA systems- Analysis of the SDSS data release five
• Dust Biasing of Damped Lyman Alpha Systems: a Bayesian Analysis
• Average Properties of a Large Sample of z_abs ~ z_em associated Mg II Absorption Line Systems
• 9.7 micrometer Silicate Absorption in a Damped Lyman-alpha Absorber at z=0.52

Cited by in corpus (24)

• The Cosmic Baryon and Metal Cycles
• The Fundamental Plane of Damped Lyman Alpha Systems
• Discovery of a compact gas-rich DLA galaxy at z = 2.2: evidences for a starburst-driven outflow
• The ESO UVES Advanced Data Products Quasar Sample - VI. Sub-Damped Lyman-$\alpha$ Metallicity Measurements and the Circum-Galactic Medium
• The Magellan Uniform Survey of Damped Lyman alpha Systems I: Cosmic Metallicity Evolution
• Star formation history, dust attenuation and extragalactic background light
• The large area KX quasar catalogue: I. Analysis of the photometric redshift selection and the complete quasar catalogue
• Optical/near-infrared selection of red QSOs: Evidence for steep extinction curves towards galactic centers?
• Star Formation from DLA Gas in the Outskirts of Lyman Break Galaxies at z~3
• Exploring the dust content of SDSS DR7 damped Lyman alpha systems at 2.15$\le z_{ab}<$5.2
• The Magellan Uniform Survey of Damped Lyman alpha Systems II: Paucity of Strong Molecular Hydrogen Absorption
• The Star Formation Rate Efficiency of Neutral Atomic-dominated Hydrogen Gas in the Outskirts of Star Forming Galaxies from z~1 to z~3
• The effect of dust bias on the census of neutral gas and metals in the high-redshift Universe due to SDSS-II quasar colour selection
• The extended High A(V) Quasar Survey: Searching for dusty absorbers toward mid-infrared selected quasars
• The dust content of damped Lyman-alpha systems in the Sloan Digital Sky Survey
• A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - V. Neutral and Ionised Phase Metallicities
• On the Origin of the High Column Density Turnover in the HI Column Density Distribution
• Using 21-cm absorption surveys to measure the average HI spin temperature in distant galaxies
• Metallicities and dust content of proximate damped Lyman alpha systems in the Sloan Digital Sky Survey
• A quasar hiding behind two dusty absorbers. Quantifying the selection bias of metal-rich, damped Lyman-alpha absorption systems
• The Ly$\alpha$ emission from high-$z$ galaxies hosting strong Damped Ly$\alpha$ systems
• MALS SALT-NOT survey of MIR-selected powerful radio-bright AGN at 0<z<3.5
• The nature of Damped Lyman-α and MgII absorbers explored with their dust contents
• Constraining stellar properties of intervening damped Lyα and MgII absorbing galaxies toward GRB 050730