MATCHING THE EVOLUTION OF THE STELLAR MASS FUNCTION USING LOG-NORMAL STAR FORMATION HISTORIES

We show that a model consisting of individual, log-normal star formation histories for a volume-limited sample of z approximate to 0 galaxies reproduces the evolution of the total and quiescent stellar mass functions at z less than or similar to 2.5 and stellar massesM(*) >= 10(10) M-circle dot. This model has previously been shown to reproduce the star formation rate/stellar mass relation (SFR-M-*) over the same interval, is fully consistent with the observed evolution of the cosmic SFR density at z <= 8, and entails no explicit "quenching" prescription. We interpret these results/features in the context of other models demonstrating a similar ability to reproduce the evolution of (1) the cosmic SFR density, (2) the total/quiescent stellar mass functions, and (3) the SFR-M-* relation, proposing that the key difference between modeling approaches is the extent to which they stress/address diversity in the (star-forming) galaxy population. Finally, we suggest that observations revealing the timescale associated with dispersion in SFR(M-*) will help establish which models are the most relevant to galaxy evolution.