The extended High A(V) Quasar Survey: Searching for dusty absorbers toward mid-infrared selected quasars

Abstract

We present the results of a new spectroscopic survey for dusty intervening absorption systems, particularly damped Ly$\alpha$ absorbers (DLAs), towards reddened quasars. The candidate quasars are selected from mid-infrared photometry from the Wide-field Infrared Survey Explorer combined with optical and near-infrared photometry. Out of 1073 candidates, we secure low-resolution spectra for 108 using the Nordic Optical Telescope on La Palma, Spain. Based on the spectra, we are able to classify 100 of the 108 targets as quasars. A large fraction (50 %) is observed to have broad absorption lines (BALs). Moreover, we find 6 quasars with strange breaks in their spectra, which are not consistent with regular dust reddening. Using template fitting we infer the amount of reddening along each line of sight ranging from A(V)$\approx$0.1 mag to 1.2 mag (assuming an SMC extinction curve). In four cases, the reddening is consistent with dust exhibiting the 2175Å feature caused by an intervening absorber, and for two of these, a MgII absorption system is observed at the best-fit absorption redshift. In the rest of the cases, the reddening is most likely intrinsic to the quasar. We observe no evidence for dusty DLAs in this survey. However, the large fraction of BAL quasars hampers the detection of absorption systems. Out of the 50 non-BAL quasars only 28 have sufficiently high redshift to detect Ly$\alpha$ in absorption.

45 pages containing a large set of 100 figures and 2 long tables. Accepted for publication in ApJS

References in corpus (29)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• On the (Non)Evolution of HI Disks over Cosmic Time
• Optical spectroscopy and X-ray detections of a sample of quasars and AGN selected in the mid-infrared from two Spitzer wide-area surveys
• Chandra and Spitzer unveil heavily obscured quasars in the SWIRE/Chandra Survey
• The FIRST-2MASS Red Quasar Survey
• An X-shooter composite of bright 1 < z < 2 quasars from UV to infrared
• The WISE Blazar-Like Radio-Loud Sources: An All-Sky Catalog Of Candidate Gamma-Ray Blazars
• Luminous K-band Selected Quasars from UKIDSS
• The UCSD Radio-Selected Quasar Survey for Damped Lyman alpha System
• Mining for Dust in Type 1 Quasars
• Radio Sources Toward Galaxy Clusters at 30 GHz
• A survey of polarization in the JVAS/CLASS flat-spectrum radio source surveys: I. The data and catalogue production
• Physical conditions in the neutral interstellar medium at z=2.43 toward Q2348-011
• The color excess of quasars with intervening DLA systems- Analysis of the SDSS data release five
• Optical/near-infrared selection of red QSOs: Evidence for steep extinction curves towards galactic centers?
• VLT/UVES observations of extremely strong intervening damped Lyman-alpha systems: Molecular hydrogen and excited carbon, oxygen and silicon at log N(HI)=22.4
• A quasar reddened by a sub-parsec sized, metal-rich and dusty cloud in a damped Lyman-alpha absorber at z=2.13
• Extinction curve template for intrinsically reddened quasars
• Dust Biasing of Damped Lyman Alpha Systems: a Bayesian Analysis
• Probing the Physical Conditions of Atomic Gas at High Redshift
• The elusive HI-> H2 transition in high-z damped Lyman-alpha systems
• The High A(V) Quasar Survey: Reddened quasi-stellar objects selected from optical/near-infrared photometry - II
• Near Infrared Photometric properties of 130,000 Quasars: An SDSS-UKIDSS matched catalog
• A Spectroscopic Survey of WISE-selected Obscured Quasars with the Southern African Large Telescope
• A Metal-Strong and Dust-Rich Damped \lya Absorption System toward the Quasar SDSS J115705.52+615521.7
• The dust content of damped Lyman-alpha systems in the Sloan Digital Sky Survey
• A study of purely astrometric selection of extragalactic point sources with Gaia
• Broad-band spectral energy distribution of 3000 Angstroem break quasars from the Sloan Digital Sky Survey
• Serendipitous discovery of a projected pair of QSOs separated by 4.5 arcsec on the sky

Cited by in corpus (22)

• The Cosmic Baryon and Metal Cycles
• Evolution of the dust-to-metals ratio in high-redshift galaxies probed by GRB-DLAs
• The cosmic evolution of dust-corrected metallicity in the neutral gas
• Molecular gas and star formation in an absorption-selected galaxy: Hitting the bull's eye at z = 2.46
• The Physical Properties of Low Redshift FeLoBAL Quasars. I. Spectral Synthesis Analysis of the BAL Outflows using $SimBAL$
• 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
• Stellar masses, metallicity gradients and suppressed star formation revealed in a new sample of absorption selected galaxies
• Dust depletion of of metals from local to distant galaxies II: Cosmic dust-to-metal ratio and dust composition
• The nature of damped HI absorbers probed by cosmological simulations: satellite accretion and outflows
• Cold gas in the early Universe. Survey for neutral atomic-carbon in GRB host galaxies at 1 < z < 6 from optical afterglow spectroscopy
• Unidentified quasars among stationary objects from Gaia DR2
• A quasar hiding behind two dusty absorbers. Quantifying the selection bias of metal-rich, damped Lyman-alpha absorption systems
• Steep extinction towards GRB 140506A reconciled from host galaxy observations: Evidence that steep reddening laws are local
• The high A_V Quasar Survey: A z=2.027 metal-rich damped Lyman-alpha absorber towards a red quasar at z=3.21
• Quasar 2175 Å dust absorbers I: metallicity, depletion pattern, and kinematics
• MALS-NOT: Identifying Radio-Bright Quasars for the MeerKAT Absorption Line Survey
• Solving the conundrum of intervening strong MgII absorbers towards GRBs and quasars
• Gaia-assisted selection of a quasar reddened by dust in an extremely-strong Damped Lyman-α Absorber at z=2.226
• Damped Lyman-$\alpha$ absorbers and atomic hydrogen in galaxies: the view of the GAEA model
• The galaxy counterpart and environment of the dusty Damped Lyman-alpha Absorber at z=2.226 towards Q1218+0832
• Gaia-assisted discovery of a detached low-ionisation BAL quasar with very large ejection velocities
• On the Dusty Proximate Damped Lyman-α System toward Q2310-3358 at z = 2.40