The dust content of damped Lyman [Alpha] systems in the Sloan Digital Sky Survey

The dust content of damped Lyman a systems (DLAs) is an important observable for understanding their origin and the neutral gas reservoirs of galaxies. While the average colour excess of DLAs, E(B - V), is known to be ... 15 millimagnitude (mmag), both detections and non-detections with ~2 mmag prec...

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Bibliographic Details
Published in:Monthly notices of the Royal Astronomical Society 2016-01, Vol.455 (1), p.1043
Main Authors: Murphy, Michael T, Bernet, Martin L
Format: Article
Language:English
Subjects:
Astronomy
Dust
Quasars
Red shift
Star & galaxy formation
Online Access:Get full text
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Summary:The dust content of damped Lyman a systems (DLAs) is an important observable for understanding their origin and the neutral gas reservoirs of galaxies. While the average colour excess of DLAs, E(B - V), is known to be ... 15 millimagnitude (mmag), both detections and non-detections with ~2 mmag precision have been reported. Here we find 3.2s statistical evidence for DLA dust-reddening of 774 Sloan Digital Sky Survey (SDSS) quasars by comparing their fitted spectral slopes to those of ~7000 control quasars. The corresponding E(B - V) is 3.0 ± 1.0 mmag, assuming a Small Magellanic Cloud (SMC) dust extinction law, and it correlates strongly (3.5s) with the metal content, characterized by the Si II ...1526 absorption-line equivalent width, providing additional confidence that the detection is due to dust in the DLAs. Evolution of E(B - V) over the redshift range 2.1 < z < 4.0 is limited to
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stv2420