Letters to Nature

Nature 408, 560-562 (30 November 2000) | doi:10.1038/35046027; Received 5 July 2000; Accepted 3 October 2000

Evidence against a redshift z > 6 for the galaxy STIS123627+621755

Daniel Stern1, Peter Eisenhardt1, Hyron Spinrad2, Steve Dawson2, Wil van Breugel3, Arjun Dey4, Wim de Vries3 & S. A. Stanford3,5

  1. Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 169-327, Pasadena, California 91109, USA
  2. Department of Astronomy, University of California at Berkeley, Berkeley, California 94720, USA
  3. Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, L-413, Livermore, California 94550, USA
  4. KPNO/NOAO, 850 N. Cherry Avenue, PO Box 26732, Tucson, Arizona 85726, USA
  5. Physics Department, University of California at Davis, Davis, California 95616, USA

Correspondence to: Daniel Stern1 Correspondence and requests for materials should be addressed to D.S. (e-mail: Email: stern@zwolfkinder.jpl.nasa.gov).

The identification of galaxies at extreme distances provides the most direct information about the earliest phases of galaxy formation. But at redshifts z > 5 even the most luminous galaxies appear faint; the interpretation of low signal-to-noise ratio data is difficult and misidentifications do occur. Here we report optical and near-infrared observations of the source STIS123627+621755, which was previously suggested to be at a redshift of 6.68 (ref. 1). At that redshift, and with the reported1 spectral energy distribution, the galaxy should be essentially invisible at wavelengths less than 9,300Å, because the intervening intergalactic medium absorbs almost all light energetic enough to ionize neutral hydrogen—that is, with wavelengths less than the redshifted Lyman limit of λ = (1 + z) × 912Å. At near-infrared wavelengths, however, the galaxy should be relatively bright. Here we report a detection of the galaxy at 6,700Å and a non-detection at a wavelength of 1.2µm, contrary to expectations for z 6.68. The data conservatively require that STIS123627+621755 has a redshift z < 6.