Photometric Redshifts Of Starburst Galaxies

Abstract

Although starburst galaxies have relatively flat spectral energy distributions, their strong optical emission lines and near-UV continua make it very feasible to estimate their redshifts photometrically. In this work, I describe a photometric technique that simultaneously (1) identifies galaxies by star formation rate and (2) measures their redshifts with an accuracy of sigma_z = 0.05 for objects at z < 1. (An extension of the technique is potentially feasible, with the use of near-infrared colors, to 1.6 < z < 2.5.) Applying this technique to a deep multicolor field survey reveals a large excess population of strongly star-forming galaxies at z > 0.3 compared with z < 0.3. Followup with spectroscopy and near-infrared photometry confirms their presence, and suggests that some of them may be in the midst of their initial burst of star formation.