2016MNRAS.457.1399R

We present the results of a 135-arcmin² search for high-redshift galaxies lensed by 29 clusters from the MAssive Cluster and extended MAssive Cluster Surveys. We use relatively shallow images obtained with the Hubble Space Telescope in four passbands, namely, F606W, F814W, F110W, and F140W. We identify 130 F814W dropouts as candidates for galaxies at z >= 6. In order to fit the available broad-band photometry to galaxy spectral energy distribution (SED) templates, we develop a prior for the level of dust extinction at various redshifts. We also investigate the systematic biases incurred by the use of SED-fit software. The fits we obtain yield an estimate of 20 Lyman-break galaxies with photometric redshifts from z ∼ 7 to 9. In addition, our survey has identified over 100 candidates with a significant probability of being lower redshift (z ∼ 2) interlopers. We conclude that even as few as four broad-band filters - when combined with fitting the SEDs - are capable of isolating promising objects. Such surveys thus allow one both to probe the bright end (M₁₅₀₀ <= -19) of the high-redshift ultraviolet luminosity function and to identify candidate massive evolved galaxies at lower redshifts.