Galaxy and Mass Assembly (GAMA): Small-scale anisotropic galaxy
  clustering and the pairwise velocity dispersion of galaxies
  The galaxy pairwise velocity dispersion (PVD) can provide important tests of
non-standard gravity and galaxy formation models. We describe measurements of
the PVD of galaxies in the Galaxy and Mass Assembly (GAMA) survey as a function
of projected separation and galaxy luminosity. Due to the faint magnitude limit
($r < 19.8$) and highly-complete spectroscopic sampling of the GAMA survey, we
are able to reliably measure the PVD to smaller scales ($r_\bot = 0.01$ Mpc/h)
than previous work. The measured PVD at projected separations $r_\bot <~ 1$
Mpc/h increases near-monotonically with increasing luminosity from $\sigma
\approx 200$ km/s at $M_r = -17$ mag to $\sigma \approx 600$ km/s at $M_r
\approx -22$ mag. Analysis of the Gonzalez-Perez (2014) GALFORM semi-analytic
model yields no such trend of PVD with luminosity: the model over-predicts the
PVD for faint galaxies. This is most likely a result of the model placing too
many low-luminosity galaxies in massive halos.
