How neutral is the intergalactic medium surrounding the redshift z = 7.085 quasar ULAS J1120+0641?
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Published version
Author(s)
Type
Journal Article
Abstract
The quasar ULAS J1120+0641 at redshift z = 7.085 has a highly ionized near zone which is smaller than those around quasars of similar luminosity at z ≃ 6. The spectrum also exhibits evidence for a damping wing extending redward of the systemic Lyα redshift. We use radiative transfer simulations in a cosmological context to investigate the implications for the ionization state of the inhomogeneous intergalactic medium (IGM) surrounding this quasar. Our simulations show that the transmission profile is consistent with an IGM in the vicinity of the quasar with a volume averaged H I fraction of ? and that ULAS J1120+0641 has been bright for 10^6-10^7 yr. The observed spectrum is also consistent with smaller IGM neutral fractions, ?, if a damped Lyα system in an otherwise highly ionized IGM lies within 5 proper Mpc of the quasar. This is, however, predicted to occur in only ˜5 per cent of our simulated sightlines for a bright phase of 10^6-10^7 yr. Unless ULAS J1120+0641 grows during a previous optically obscured phase, the low age inferred for the quasar adds to the theoretical challenge of forming a 2 × 10^9 Msun black hole at this high redshift.
Date Issued
2011-09-01
Date Acceptance
2011-06-23
Citation
Monthly Notices of the Royal Astronomical Society, 2011, 416 (1), pp.70-74
ISSN
0035-8711
Publisher
Oxford University Press (OUP)
Start Page
70
End Page
74
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
416
Issue
1
Copyright Statement
© 2011 The Authors.
Sponsor
Science and Technology Facilities Council (STFC)
Grant Number
ST/G001901/1
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
dark ages, reionization, first stars
intergalactic medium
quasars: absorption lines
astro-ph.CO
astro-ph.CO
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
Publication Status
Published
Date Publish Online
2011-09-01