Accretion-regulated star formation in late-type galaxies
  We develop a four-phase galaxy evolution model in order to study the effect
of accretion of extra-galactic gas on the star formation rate (SFR) of a
galaxy. Pure self-regulated star formation of isolated galaxies is replaced by
an accretion-regulated star formation mode. The SFR settles into an equlibrium
determined entirely by the gas accretion rate on a Gyr time scale.
