The Application of Photometric Redshifts to the SDSS Early Data Release


Csabai I, Budavári T, Connolly AJ, Szalay AS, Győry Z, Benítez N, Annis J, Brinkmann J, Eisenstein D, Fukugita M, et al. The Application of Photometric Redshifts to the SDSS Early Data Release. The Astronomical Journal. 2003;125 :580-592.

Date Published:

February 1, 2003


The Early Data Release (EDR) from the Sloan Digital Sky Survey providesone of the largest multicolor photometric catalogs currently availableto the astronomical community. In this paper we present the firstapplication of photometric redshifts to the ~6 million extended sourcesin these data (with 1.8 million sources having r'<21). Utilizing arange of photometric redshift techniques, from empirical to template andhybrid techniques, we investigate the statistical and systematicuncertainties present in the redshift estimates for the EDR data. Forr'<21, we find that the redshift estimates provide realistic redshifthistograms with an rms uncertainty in the photometric redshift relationof 0.035 at r'<18 and rising to 0.1 at r'<21. We conclude bydescribing how these photometric redshifts and derived quantities, suchas spectral type, rest-frame colors, and absolute magnitudes, are storedin the SDSS database. We provide sample queries for searching onphotometric redshifts and list the current caveats and issues thatshould be understood before using these photometric redshifts instatistical analyses of the SDSS galaxies.