Letters to Nature

Nature 398, 586-588 (15 April 1999) | doi:10.1038/19251; Received 24 August 1998; Accepted 26 January 1999

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

Hsiao-Wen Chen1, Kenneth M. Lanzetta1 & Sebastian Pascarelle1

  1. Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800, USA

Correspondence to: Hsiao-Wen Chen1 Correspondence should be addressed to H.-W.C.
(e-mail: Email: hchen@sbastr.ess.sunysb.edu).

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 lambdaapproximately 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-alpha decrement), and by an emission line at lambdaapproximately 9,334 Å, which we interpret as the Lyman-alpha 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.