Publication Date:
2015-02-14
Description:
The flow of baryons to and from a galaxy, which is fundamental for galaxy formation and evolution, can be studied with galaxy-metal absorption system pairs. Our search for galaxies around C iv absorption systems at z ~ 5.7 showed an excess of photometric Lyman α emitter (LAE) candidates in the fields J1030+0524 and J1137+3549. Here, we present spectroscopic follow-up of 33 LAEs in both fields. In the first field, three out of the five LAEs within 10 h –1 projected comoving Mpc from the C iv system are within ±500 km s –1 from the absorption at $z_{{\rm C\,{\small iv}}}=5.7242\pm 0.0001$ . The closest candidate (LAE 103027+052419) is robustly confirmed at $212.8^{+14}_{-0.4}\;h^{-1}$ physical kpc from the C iv system. In the second field, the LAE sample is selected at a lower redshift ( z ~ 0.04) than the C iv absorption system as a result of the filter transmission and, thus, do not trace its environment. The observed properties of LAE 103027+052419 indicate that it is near the high-mass end of the LAE distribution, probably having a large H i column density and large-scale outflows. Therefore, our results suggest that the C iv system is likely produced by a star-forming galaxy which has been injecting metals into the intergalactic medium since z 〉 6. Thus, the C iv system is either produced by LAE 103027+052419, implying that outflows can enrich larger volumes at z 〉 6 than at z ~ 3.5, or an undetected dwarf galaxy. In either case, C iv systems like this one trace the ionized intergalactic medium at the end of cosmic hydrogen reionization and may trace the sources of the ionizing flux density.
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
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