Evolution of the Rate and Mode of Star Formation in Galaxies since z=0.7
  We present the star formation rate (SFR) and starburst fraction (SBF) for a
sample of field galaxies from the ICBS intermediate-redshift cluster survey. We
use [O II] and Spitzer 24 micron fluxes to measure SFRs, and 24 micron fluxes
and H-delta absorption to measure of SBFs, for both our sample and a
present-epoch field sample from the Sloan Digital Sky Survey (SDSS) and Spitzer
Wide-area Infrared Extragalactic (SWIRE) survey. We find a precipitous decline
in the SFR since z=1, in agreement with other studies, as well as a
corresponding rapid decline in the fraction of galaxies undergoing
long-duration moderate-amplitude starbursts. We suggest that the change in both
the rate and mode of star formation could result from the strong decrease since
z=1 of gas available for star formation.
