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Title

A galaxy as the source of a C IV absorption system close to the epoch of reionization

Author(s)

Gonzalo Diaz, C.;  Ryan-Weber, Emma V.;  Cooke, Jeff;  Pettini, Max;  Madau, Piero

Abstract

We find a bright (LUV= 2.5 L★z= 6) Lyα emitter (LAE) at redshift z= 5.719 at a projected distance of 79 physical kpc from a strong triply ionized carbon (C iv) absorption system at redshift z= 5.7238 previously reported in the spectrum of the zem= 6.309 quasi-stellar object SDSS J1030+0524. This is the highest redshift galaxy–absorber pair detected to-date, supporting the idea that galaxy-wide outflows were already in place at the end of the epoch of reionization. The proximity of this object makes it the most likely source of metals, consistent with models of outflows at lower redshift where significant observational evidence relates metal absorption systems with galaxies hosting outflows. In a typical outflow scenario, a wind of 200 km s−1, active since the Universe was only 0.6 Gyr old (z∼ 8.4), could eject metals out to 79 kpc at z= 5.719. Although the origin of metals in the intergalactic medium (IGM) is still under debate, our results are consistent with predictions from cosmological simulations which reproduce the evolution of the cosmic density of C iv from z∼ 6 to the present day based on outflow-driven enrichment of the IGM. We also report two more LAEs in this field, at z= 5.973 ± 0.002 and 5.676 ± 0.002, respectively the former confirming the original identification by Stiavelli et al. Our results suggest that the colour cut typically used to identify i-dropouts (i775& 8722;z850 > 1.3) misses a non-negligible fraction of blue galaxies with faint ultraviolet continuum at z≳ 5.7.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Monthly Notices of the Royal Astronomical Society, Vol. 418, no. 2 (Dec 2011), pp. 820-827

Publication year

2011

FOR Code(s)

0201 Astronomical and Space Sciences

Keyword(s)

C IV;  Distances;  Galaxies;  Redshifts;  Reionization;  Triply ionized carbon

Publisher

Wiley-Blackwell

ISSN

0035-8711

Publisher URL

http://dx.doi.org/10.1111/j.1365-2966.2011.19534.x

Copyright

Copyright © 2011 The Authors. Journal compilation copyright © 2011 Royal Astronomical Society. The accepted manuscript is reproduced in accordance with the copyright policy of the publisher. The definitive publication is available at www.interscience.wiley.com.

Research Projects

The intergalactic medium: from cosmic dawn to the local web, Australian Research Council grant number DP1095600

Full text

Peer reviewed