2004/07/19 by Daniel Stern, S. A. Yost, Sarah A. Yost +7 · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.1086/426423
published as Astrophys.J. 619 (2005) 12-18 · 16 pages, 4 figures; submitted to the Astrophysical Journal
arxiv created 2004/07/19 · openalex publication_date 2005/01/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We report the discovery of a Lyα-emitting galaxy at redshift z = 6.545 serendipitously identified in the course of spectroscopic follow-up of hard X-ray sources on behalf of the Serendipitous Extragalactic X-Ray Source Identification (SEXSI) survey. The line flux of the galaxy, 2.1 × 10 -17 ergs cm -2 s -1 , is similar to line fluxes probed by narrowband imaging surveys; the 5.2 arcmin 2 surveyed implies a surface density of z ≈ 6.5 Lyα emitters somewhat higher than that inferred from narrowband surveys. This source marks the sixth Lyα-emitting galaxy identified at z ≈ 6.5, a redshift putatively beyond the epoch of reionization when the damping wings of the neutral hydrogen of the intergalactic medium is capable of severely attenuating Lyα emission. By comparing the Lyα luminosity functions at z ≈ 5.7 and z ≈ 6.5, we infer that the intergalactic medium may remain largely reionized from the local universe out to z ≈ 6.5.