A deep search for metals near redshift 7: the line of sight towards ULAS J1120+0641

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Title: A deep search for metals near redshift 7: the line of sight towards ULAS J1120+0641
Author(s): Bosman, SEI
Becker, GD
Haehnelt, MG
Hewett, PC
McMahon, RG
Mortlock, DJ
Simpson, C
Venemans, BP
Item Type: Journal Article
Abstract: We present a search for metal absorption line systems at the highest redshifts to date using a deep (30 h) Very Large Telescope/X-Shooter spectrum of the z = 7.084 quasi-stellar object (QSO) ULAS J1120+0641. We detect seven intervening systems at z > 5.5, with the highest redshift system being a C iv absorber at z = 6.51. We find tentative evidence that the mass density of C iv remains flat or declines with redshift at z < 6, while the number density of C ii systems remains relatively flat over 5 < z < 7. These trends are broadly consistent with models of chemical enrichment by star formation-driven winds that include a softening of the ultraviolet background towards higher redshifts. We find a larger number of weak (Wrest < 0.3 Å) Mg ii systems over 5.9 < z < 7.0 than predicted by a power-law fit to the number density of stronger systems. This is consistent with trends in the number density of weak Mg ii systems at z ≲ 2.5, and suggests that the mechanisms that create these absorbers are already in place at z ∼ 7. Finally, we investigate the associated narrow Si iv, C iv and N v absorbers located near the QSO redshift, and find that at least one component shows evidence of partial covering of the continuum source.
Publication Date: 29-May-2017
Date of Acceptance: 24-May-2017
URI: http://hdl.handle.net/10044/1/57878
DOI: https://dx.doi.org/10.1093/mnras/stx1305
ISSN: 0035-8711
Publisher: Oxford University Press (OUP)
Start Page: 1919
End Page: 1934
Journal / Book Title: Monthly Notices of the Royal Astronomical Society
Volume: 470
Issue: 2
Copyright Statement: © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Sponsor/Funder: Science and Technology Facilities Council
Science and Technology Facilities Council (STFC)
Funder's Grant Number: ST-N000838
ST/N000838/1
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
intergalactic medium
quasars: absorption lines
quasars: individual: ULAS J1120+0641
dark ages, reionization, first stars
MG II ABSORPTION
SIMILAR-TO 6
INTERGALACTIC C-IV
LESS-THAN 6
CIRCUMGALACTIC MEDIUM
MASS DENSITY
COSMIC REIONIZATION
INFRARED-SPECTRA
SELF-SIMILARITY
GALACTIC HALOS
astro-ph.GA
astro-ph.GA
Science & Technology
Physical Sciences
Astronomy & Astrophysics
intergalactic medium
quasars: absorption lines
quasars: individual: ULAS J1120+0641
dark ages, reionization, first stars
MG II ABSORPTION
SIMILAR-TO 6
INTERGALACTIC C-IV
LESS-THAN 6
CIRCUMGALACTIC MEDIUM
MASS DENSITY
COSMIC REIONIZATION
INFRARED-SPECTRA
SELF-SIMILARITY
GALACTIC HALOS
0201 Astronomical And Space Sciences
Astronomy & Astrophysics
Publication Status: Published
Open Access location: https://arxiv.org/pdf/1705.08925.pdf
Appears in Collections:Physics
Astrophysics



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