The Bright Ages Survey. II. Evolution of Luminosity, Dust Extinction, and Star Formation fromz = 0.5 toz = 2.5

The Bright Ages Survey is a K -band-selected redshift survey over six separate fields with UBVRIzJHK imaging covering a total of 75.6 arcmin 2 and reaching K = 20-20.5. Two fields have deep HST imaging, while all are centered on possible overdensities in the z ~ 2 range. Here we report photometric redshifts and spectroscopy for this sample, which has been described in Paper I. We find 18 galaxies with spectroscopic redshifts of z > 1.5. The derived rest-frame R -band luminosity functions show strong evolution out to z = 2. The luminosity function at z = 2 shows more bright galaxies than at any other epoch, even the extrapolated z = 3 luminosity function from Shapley et al. However, the R -band integrated luminosity density remains roughly constant from to z = 0.5 to z = 2. Evolved galaxies (E, S0, Sa) show a decreasing contribution to the total R -band luminosity density with redshift. The dust extinction in our K -selected sample is moderately larger [median z = 2 E ( B - V ) = 0.30] than that found in Lyman break galaxies, although not enough to make a significant impact on the total light or star formation found at high redshift. We measure the extinction-corrected star formation rate density at z = 2, finding ρ SFR ( z = 1.5-2.5) = 0.093 M ☉ yr -1 Mpc -3 , consistent with a relatively flat instantaneous star formation rate from z = 1-4.