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

The detection and identification of distant galaxies is an important goal o f observational cosmology, as such galaxies are seen at a time when the Uni verse was very young The development of new techniques and instrumentation permits the search for ever-fainter galaxies, and so aids attempts to deter mine when the first stars and galaxies formed. Here we report the identific ation of a galaxy at a probable redshift of 6.68, the most distant object y et detected. The galaxy's spectrum is characterized by an abrupt discontinu ity at a wavelength lambda approximate to 9,300 Angstrom, which we interpre t as arising from the absorption of light at shorter wavelengths by hydroge n gas along the Line of sight (the Lyman-alpha decrement), and by an emissi on line at lambda approximate to 9,334 Angstrom, which we interpret as the Lyman-alpha line at a redshift of 6.68, The galaxy is relatively bright: th e ultraviolet luminosity density contributed by this one galaxy is almost t en times the value measured at z = 3.