Gas accretion from minor mergers in local spiral galaxies
  In this paper we quantify the gas accretion rate from minor mergers onto
star-forming galaxies in the Local Universe using HI observations of 148 nearby
spiral galaxies (WHISP sample). We developed a dedicated code that iteratively
analyses HI data-cubes, finds dwarf gas-rich satellites around larger galaxies
and estimates an upper limit to the gas accretion rate. We found that 22% of
the galaxies have at least one detected dwarf companion. We made the very
stringent assumption that all satellites are going to merge in the shortest
possible time transferring all their gas to the main galaxies. This leads to an
estimate of the maximum gas accretion rate of 0.28 solar masses per year, about
five times lower than the average SFR of the sample. Given the assumptions, our
accretion rate is clearly an overestimate. Our result strongly suggests that
minor mergers do not play a significant role in the total gas accretion budget
in local galaxies.
