Spectroscopic identification of a galaxy at a probable redshift of z = 6.68

• Published in: Nature (London) 1999-04, Vol.398 (6728), p.586-588
• Main Authors: Chen, Hsiao-Wen, Lanzetta, Kenneth M, Pascarelle, Sebastian
• Format: Article
• Language: English
• Subjects: Astronomy; Cosmology; Earth, ocean, space; Exact sciences and technology; Humanities and Social Sciences; Instrumentation; letter; multidisciplinary; Protogalaxies; primordial galaxies; Quasars. Active or peculiar galaxies, objects, and systems; Science; Science (multidisciplinary); Stars & galaxies; Stellar systems. Galactic and extragalactic objects and systems. The universe; Universe
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/19251

The detection and identification of distant galaxies is an important goal of observational cosmology, as such galaxies are seen at a time when the Universe was very young. The development of new techniques and instrumentation permits the search for ever-fainter galaxies, and so aids attempts to determine when the first stars and galaxies formed. Here we report the identification of a galaxy at a probable redshift of 6.68, the most distant object yet detected. The galaxy's spectrum is characterized by an abrupt discontinuity at a wavelength λ 9,300 Å, which we interpret as arising from the absorption of light at shorter wavelengths by hydrogen gas along the line of sight (the Lyman-α decrement), and by an emission line at λ 9,334 Å, which we interpret as the Lyman-α line at a redshift of 6.68. The galaxy is relatively bright: the ultraviolet luminosity density contributed by this one galaxy is almost ten times the value measured at z = 3.