Implications of a Temperature-dependent Initial Mass Function. III. Mass Growth and Quiescence

Abstract

The stellar initial mass function (IMF) is predicted to depend upon the temperature of gas in star-forming molecular clouds. The introduction of an additional parameter, T IMF, into photometric template fitting suggests most galaxies obey an IMF top heavier than the Galactic IMF. The implications of the revised fit on mass function, quiescence, and turnoff are discussed. At all redshifts, the highest-mass galaxies become quiescent first with the turnoff mass decreasing toward the present. The synchronous turnoff mass across galaxies suggests quiescence is driven by universal mechanisms rather than by stochastic or environmental processes.