A Blind Test of Photometric Redshift Prediction

Results of a blind test of photometric redshift predictions against spectroscopic galaxy redshifts obtained in the Hubble Deep Field with the Keck Telescope are presented. The best photometric redshift schemes predict spectroscopic redshifts with a redshift accuracy of Deltaz < 0.1 for more than 68% of sources and with Deltaz < 0.3 for 100%, when single-feature spectroscopic redshifts are removed from consideration. This test shows that photometric redshift schemes work well, at least when the photometric data are of high quality and when the sources are at moderate redshifts. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555 at the W. M. Keck Observatory, which is operated jointly by the California Institute of Technology and the University of California; and at Kitt Peak National Observatory, which is operated by AURA, Inc., under cooperative agreement with the National Science Foundation.