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Discovery of the most metal-poor damped Lyman-α system

Cooke, Ryan J.; Pettini, Max; Steidel, Charles C.

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Authors

Max Pettini

Charles C. Steidel



Abstract

We report the discovery and analysis of the most metal-poor damped Lyman α (DLA) system currently known, based on observations made with the Keck HIRES spectrograph. The metal paucity of this system has only permitted the determination of three element abundances: [C/H] = −3.43 ± 0.06, [O/H] = −3.05 ± 0.05 and [Si/H] = −3.21 ± 0.05, as well as an upper limit on the abundance of iron: [Fe/H] ≤ −2.81. This DLA is among the most carbon-poor environment currently known with detectable metals. By comparing the abundance pattern of this DLA to detailed models of metal-free nucleosynthesis, we find that the chemistry of the gas is consistent with the yields of a 20.5 M⊙ metal-free star that ended its life as a core-collapse supernova; the abundances we measure are inconsistent with the yields of pair-instability supernovae. Such a tight constraint on the mass of the progenitor Population III star is afforded by the well-determined C/O ratio, which we show depends almost monotonically on the progenitor mass when the kinetic energy of the supernova explosion is Eexp ≳ 1.5 × 1051 erg. We find that the DLA presented here has just crossed the critical ‘transition discriminant’ threshold, rendering the DLA gas now suitable for low mass star formation. We also discuss the chemistry of this system in the context of recent models that suggest some of the most metal-poor DLAs are the precursors of the ‘first galaxies’, and are the antecedents of the ultrafaint dwarf galaxies.

Citation

Cooke, R. J., Pettini, M., & Steidel, C. C. (2017). Discovery of the most metal-poor damped Lyman-α system. Monthly Notices of the Royal Astronomical Society, 467(1), 802-811. https://doi.org/10.1093/mnras/stx037

Journal Article Type Article
Acceptance Date Jan 5, 2017
Online Publication Date Jan 9, 2017
Publication Date May 11, 2017
Deposit Date May 25, 2017
Publicly Available Date Mar 28, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 467
Issue 1
Pages 802-811
DOI https://doi.org/10.1093/mnras/stx037
Related Public URLs https://arxiv.org/abs/1701.03103

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Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.





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