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

Abstract

We find a bright (L_{UV}=2.5 L*_{z=6}) Lyman alpha emitter at redshift z=5.719 at a projected distance of 79 physical kpc from a strong triply ionized carbon (Civ) absorption system at redshift z=5.7238 previously reported in the spectrum of the z_{em} = 6.309 QSO 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, 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 Civ, from z ~ 6 to the present day based on outflow-driven enrichment of the IGM. We also report two more Lyman alpha emitters in this field, at z=5.973\pm 0.002 and z=5.676\pm 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 (i_{775}-z_{850}>1.3) misses a non-negligible fraction of blue galaxies with faint UV continuum at z \geq 5.7.

Accepted for publication in MNRAS, 9 pages, 3 figures, 1 table

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Cited by in corpus (13)

• Reionization and high-redshift galaxies: the view from quasar absorption lines
• Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT
• The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251
• The role of galaxies and AGN in reionizing the IGM - II: metal-tracing the faint sources of reionization at $5\lesssim z\lesssim 6$
• The primordial environment of supermassive black holes (II): deep Y and J band images around the z=6.3 quasar SDSS J1030+0524
• On inferring extinction laws in z~6 quasars as signatures of supernova dust
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• The Faint Host Galaxies of C IV Absorbers at z > 5
• Faint LAEs near z>4.7 CIV absorbers revealed by MUSE
• Probing the Metal Enrichment of the Intergalactic Medium at $z=5-6$ Using the Hubble Space Telescope
• Searching for [CII] Emission from the First Sample of $z\sim 6$ OI Absorption-Associated Galaxies with ALMA
• A census of H$\alpha$ emitters in the intergalactic medium of the NGC 2865 system
• The clustering of C IV and Si IV at the end of reionisation: A perspective from the E-XQR-30 survey