Evolution of star formation in the UKIDSS Ultra Deep Survey Field - II. Star formation as a function of stellar mass between z = 1.46 and 0.63

Abstract

We present new results on the evolution of the cosmic star formation rate as a function of stellar mass in the Subaru/XMM-Newton Deep Survey-Ultra Deep Survey field. We make use of narrow-band-selected emission line galaxies in four redshift slices between z = 1.46 and 0.63, and compute stellar masses by fitting a series of templates to recreate each galaxy's star formation history. We determine mass-binned luminosity functions in each redshift slice, and derive the star formation rate density (ρSFR) as a function of mass using the [O III] or [O II] emission lines. We calculate dust extinction and metallicity as a function of stellar mass, and investigate the effect of these corrections on the shape of the overall ρSFR(M). We find that both these corrections are crucial for determining the shape of the ρSFR(M), and its evolution with redshift. The fully corrected ρSFR(M) is a relatively flat distribution, with the normalization moving towards lower values of ρSFR with increasing cosmic time/decreasing redshift, and requiring star formation to be truncated across all masses studied here. The peak of ρSFR(M) is found in the 1010.5 < M⊙ < 1011.0 mass bin at z = 1.46. In the lower redshift slices, the location of the peak is less certain; however, low-mass galaxies in the range 107.0 < M⊙ < 108.0 play an important part in the overall ρSFR(M) out to at least z ~ 1.2.