Galaxy growth by merging in the nearby universe
  We measure the mass growth rate by merging for a wide range of galaxy types.
We present the small-scale (0.014 < r < 11 h70^{-1} Mpc) projected
cross-correlation functions w(rp) of galaxy subsamples from the spectroscopic
sample of the NYU VAGC (5 \times 10^5 galaxies of redshifts 0.03 < z < 0.15)
with galaxy subsamples from the SDSS imaging (4 \times 10^7 galaxies). We use
smooth fits to de-project the two-dimensional functions w(rp) to obtain smooth
three-dimensional real-space cross-correlation functions \xi(r) for each of
several spectroscopic subsamples with each of several imaging subsamples.
Because close pairs are expected to merge, the three-space functions and
dynamical evolution time estimates provide galaxy accretion rates. We find that
the accretion onto massive blue galaxies and onto red galaxies is dominated by
red companions, and that onto small-mass blue galaxies, red and blue galaxies
make comparable contributions. We integrate over all types of companions and
find that at fixed stellar mass, the total fractional accretion rates onto red
galaxies (\sim 1.5 h70 percent per Gyr) is greater than that onto blue galaxies
(\sim 0.5 h70 percent per Gyr). Although these rates are very low, they are
almost certainly over-estimates because we have assumed that all close pairs
merge as quickly as dynamical friction permits.
