IMPROVING PHOTOMETRIC REDSHIFTS USING GALEX OBSERVATIONS FOR THE SDSS STRIPE 82 AND THE NEXT GENERATION OF SZ CLUSTER SURVEYS

Four large-area Sunyaev-Zeldovich (SZ) experiments – APEX-SZ, SPT, ACT, and Planck – promise to detect clusters of galaxies through the distortion of Cosmic Microwave Background photons by hot (> 10 6 K) cluster gas (the SZ effect) over thousands of square degrees. A large observational follow-up effort to obtain redshifts for these SZ-detected clusters is under way. Given the large area covered by these surveys, most of the redshifts will be obtained via the photometric redshift (photo-z) technique. Here we demonstrate, in an application using �3000 SDSS stripe 82 galaxies with r < 20, how the addition of GALEX photometry (FUV , NUV ) greatly improves the photometric redshifts of galaxies obtained with optical griz or ugriz photometry. In the case where large spectroscopic training sets are