THE RISE OF MASSIVE RED GALAXIES: THE COLOR-MAGNITUDE AND COLOR-STELLAR MASS DIAGRAMS FOR zphot ≤ 2 FROM THE MULTIWAVELENGTH SURVEY BY YALE-CHILE

We present the color-magnitude and color-stellar mass diagrams for galaxies with z(phot) <= 2, based on a K-(AB) < 22 catalog of the 1/2 x 1/2 square degrees. Extended Chandra Deep Field South from the MUltiwavelength Survey by Yale-Chile. Our main sample of 7840 galaxies contains 1297 M-* > 10(11)M circle dot galaxies in the range 0.2 < z(phot) < 1.8. We show empirically that this catalog is approximately complete for M-* > 10(11) M circle dot galaxies for z(phot) < 1.8. For this mass-limited sample, we show that the locus of the red sequence color-stellar mass relation evolves as Delta(u- r) alpha (-0.44 +/- 0.02) z(phot) for z(phot) less than or similar to 1.2. For z(phot) greater than or similar to 1.3, however, we are no longer able to reliably distinguish red and blue subpopulations from the observed color distribution; we show that this would require much deeper near-infrared data. At 1.5 < z(phot) < 1.8, the comoving number density of M-* > 10(11)M circle dot galaxies is approximate to 50% of the local value, with a red fraction of approximate to 33%. Making a parametric fit to the observed evolution, we find n(tot)(z) alpha (1 + z(phot))(-0.52 +/- 0.12(+/- 0.20)). We find stronger evolution in the red fraction: f(red)(z) alpha (1 + z(phot))(-1.17 +/- 0.18(+/- 0.21)). Through a series of sensitivity analyses, we show that the most important sources of systematic error are (1) systematic differences in the analysis of the z approximate to 0 and z >> 0 samples; (2) systematic effects associated with details of the photometric redshift calculation; and (3) uncertainties in the photometric calibration. With this in mind, we show that our results based on photometric redshifts are consistent with a completely independent analysis which does not require redshift information for individual galaxies. Our results suggest that, at most, 1/5 of local red sequence galaxies with M-* > 10(11) M circle dot were already in place at z similar to 2.