Dust-reddening and gravitational lensing of SDSS QSOs due to foreground damped Lyman-alpha systems

Abstract

We use Sloan Digital Sky Survey Data Release 2 QSO spectra to constrain the dust-reddening caused by intervening damped Lyman-alpha systems (DLAs). Comparing the spectral index distribution of a 70 sight-line DLA sample with that of a large control sample reveals no evidence for dust-reddening at z~3. Our limit on the shift in spectral index, |Delta(alpha)| < 0.19 (3-sigma), corresponds to a limit on the colour excess due to SMC-like dust-reddening, E(B-V) < 0.02 mag (3-sigma). This is inconsistent with the early studies of Fall, Pei and collaborators who used the small QSO and DLA samples available. Comparison of the DLA and control magnitude distributions also reveals >2-sigma evidence for an excess of bright and/or a deficit of faint QSOs with foreground DLAs. Higher equivalent width DLAs give a stronger signal. We interpret this as the signature of gravitational magnification due to the intervening DLAs.

arXiv comment6 pages, 6 figures (8 EPS files), 2 tables. Accepted by MNRAS Letters. v2: S/N threshold for fiducial DLA sample somewhat higher and so limits on dust-reddening slightly weaker. Now includes discussion of DLA incompleteness at low N(HI). Qualitative results and conclusions unchanged. Added table of QSOs and DLAs; complete table available at http://www.ast.cam.ac.uk/~mim/pub.html

References in corpus (17)

• Composite Quasar Spectra From the Sloan Digital Sky Survey
• The Second Data Release of the Sloan Digital Sky Survey
• Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample
• The First Data Release of the Sloan Digital Sky Survey
• Red and Reddened Quasars in the Sloan Digital Sky Survey
• The Age-Metallicity Relation of the Universe in Neutral Gas: The First 100 Damped Lya Systems
• The VLT-UVES survey for molecular hydrogen in high-redshift damped Lyman-alpha systems
• The UCSD HIRES/KeckI Damped Lya Abundance Database: II. The Implications
• The Sloan Digital Sky Survey Quasar Catalog II. First Data Release
• The CORALS Survey I: New Estimates of the Number Density and Gas Content of Damped Lyman Alpha Systems Free from Dust Bias
• Dust in High Redshift Galaxies
• A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Early Data Release
• The Reddest Quasars
• The SDSS Damped Lya Survey: Data Release 1
• Cosmological Evolution of Heavy Element and Molecular Hydrogen Abundances
• Investigating lensing by absorbers in the 2dF-Quasar survey
• The 2dF QSO Redshift Survey - VIII. Absorption systems in the 10k catalogue

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