A Metal-poor Damped Lyα System at Redshift 6.4
Abstract We identify a strong Ly α damping wing profile in the spectrum of the quasar P183+05 at z = 6.4386. Given the detection of several narrow metal absorption lines at z = 6.40392, the most likely explanation for the absorption profile is that it is due to a damped Ly α system. However, in or...
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Published in | The Astrophysical journal Vol. 885; no. 1; p. 59 |
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Main Authors | , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Philadelphia
IOP Publishing
01.11.2019
|
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
We identify a strong Ly
α
damping wing profile in the spectrum of the quasar P183+05 at
z
= 6.4386. Given the detection of several narrow metal absorption lines at
z
= 6.40392, the most likely explanation for the absorption profile is that it is due to a damped Ly
α
system. However, in order to match the data a contribution of an intergalactic medium 5%–38% neutral or additional weaker absorbers near the quasar is also required. The absorption system presented here is the most distant damped Ly
α
system currently known. We estimate an H
i
column density of 10
20.68±0.25
cm
−2
, metallicity [O/H] = −2.92 ± 0.32, and relative chemical abundances of a system consistent with a low-mass galaxy during the first Gyr of the universe. This object is among the most metal-poor damped Ly
α
systems known and, even though it is observed only ∼850 Myr after the big bang, its relative abundances do not show signatures of chemical enrichment by Population III stars. |
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ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/ab4129 |