Chemical abundances of the damped Lyman α systems in the XQ-100 survey

Journal
Date Issued
2016
Author(s)
Berg, T. A. M.
•
Ellison, S. L.
•
Sánchez-Ramírez, R.
•
Prochaska, J. X.
•
Lopez, S.
•
•
Becker, G.
•
Christensen, L.
•
•
Denney, K.
•
Worseck, G.
DOI
Abstract
The XQ-100 survey has provided high signal-noise spectra of 100 redshift 3-4.5 quasars with the X-Shooter spectrograph. The metal abundances for 13 elements in the 41 damped Ly α systems (DLAs) identified in the XQ-100 sample are presented, and an investigation into abundances of a variety of DLA classes is conducted. The XQ-100 DLA sample contains five DLAs within 5000 km s-1 of their host quasar (proximate DLAs; PDLAs) as well as three sightlines which contain two DLAs within 10 000 km s-1 of each other along the same line of sight (multiple DLAs; MDLAs). Combined with previous observations in the literature, we demonstrate that PDLAs with log N(H I) < 21.0 show lower [S/H] and [Fe/H] [relative to intervening systems with similar redshift and N(H I)], whilst higher [S/H] and [Si/H] are seen in PDLAs with log N(H I) > 21.0. These abundance discrepancies are independent of their line-of-sight velocity separation from the host quasar, and the velocity width of the metal lines (v90). Contrary to previous studies, MDLAs show no difference in [α/Fe] relative to single DLAs matched in metallicity and redshift. In addition, we present follow-up UVES data of J0034+1639, a sightline containing three DLAs, including a metal-poor DLA with [Fe/H] = -2.82 (the third lowest [Fe/H] in DLAs identified to date) at zabs = 4.25. Lastly we study the dust-corrected [Zn/Fe], emphasizing that near-IR coverage of X-Shooter provides unprecedented access to Mg II, Ca II and Ti II lines (at redshifts 3-4) to provide additional evidence for subsolar [Zn/Fe] ratio in DLAs.
Volume
463
Issue
3
Start page
3021
Uri
Url
Issn Identifier
0035-8711
Ads BibCode
2016MNRAS.463.3021B
Rights
open.access
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