Reddening of ~35000 quasars from SDSS Virtual Observatory Resource

Authors
  1. Krawczyk C.M.
  2. Richards G.T.
  3. Gallagher S.C.
  4. Leighly K.M.
  5. Hewett P.C.,Ross N.P.
  6. Hall P.B.
  7. Published by
    CDS
Abstract

We explore the extinction/reddening of ~35000 uniformly selected quasars with 0<z{<=}5.3 in order to better understand their intrinsic optical/ultraviolet (UV) spectral energy distributions. Using rest-frame optical-UV photometry taken from the Sloan Digital Sky Survey's (SDSS) 7th data release, cross-matched to WISE in the mid-infrared, 2MASS and UKIDSS in the near-infrared, and GALEX in the UV, we isolate outliers in the color distribution and find them well described by an SMC-like reddening law. A hierarchical Bayesian model with a Markov Chain Monte Carlo sampling method was used to find distributions of power law indices and E(B-V) consistent with both the broad absorption line (BAL) and non-BAL samples. We find that, of the ugriz color-selected type 1 quasars in SDSS, 2.5% (13%) of the non-BAL (BAL) sample are consistent with E(B-V)>0.1 and 0.1% (1.3%) with E(B-V)>0.2. Simulations show both populations of quasars are intrinsically bluer than the mean composite, with a mean spectral index ({alpha}_{lambda}_) of -1.79 (-1.83). The emission and absorption-line properties of both samples reveal that quasars with intrinsically red continua have narrower Balmer lines and stronger high-ionization emission lines, the latter indicating a harder continuum in the extreme-UV and the former pointing to differences in black hole mass and/or orientation.

Keywords
  1. quasars
  2. interstellar-reddening
Bibliographic source Bibcode
2015AJ....149..203K
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/149/203
IVOA Identifier IVOID
ivo://CDS.VizieR/J/AJ/149/203
Document Object Identifer DOI
doi:10.26093/cds/vizier.51490203

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http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/149/203
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https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/149/203/table2?
http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/149/203/table2?

History

2015-06-22T12:11:21Z
Resource record created
2015-06-22T12:11:21Z
Created
2017-12-15T10:55:04Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr