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The High AV Quasar Survey: A z = 2.027 metal-rich damped Lyman-α absorber towards a red quasar at z = 3.21

Abstract : It is important to understand the selection effects behind the quasar samples to fully exploit the potential of quasars as probes of cosmic chemical evolution and the internal gas dynamics of galaxies; in particular, it is vital to understand whether the selection criteria exclude foreground galaxies with certain properties, most importantly a high dust content. Here we present spectroscopic follow-up from the 10.4 m GTC telescope of a dust-reddened quasar, eHAQ0111+0641, from the extended High AV Quasar (HAQ) survey. We find that the z = 3.21 quasar has a foreground damped Lyman-α absorber (DLA) at z = 2.027 along the line of sight. The DLA has very strong metal lines due to a moderately high metallicity with an inferred lower limit of 25% of the solar metallicity, but a very large gas column density along the line of sight in its host galaxy. This discovery is further evidence that there is a dust bias affecting the census of metals, caused by the combined effect of dust obscuration and reddening, in existing samples of z > 2 DLAs. The case of eHAQ0111+0641 illustrates that dust bias is not only caused by dust obscuration, but also dust reddening.

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Contributor : Nathalie POTHIER Connect in order to contact the contributor
Submitted on : Monday, August 8, 2022 - 2:26:51 PM
Last modification on : Tuesday, August 9, 2022 - 3:45:02 AM


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J. P. U. Fynbo, J. -K. Krogager, K. E. Heintz, S. Geier, P. Møller, et al.. The High AV Quasar Survey: A z = 2.027 metal-rich damped Lyman-α absorber towards a red quasar at z = 3.21. Astronomy & Astrophysics, 2017, 606, ⟨10.1051/0004-6361/201730726⟩. ⟨insu-03747444⟩



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