The Spatial Distribution of Satellite Galaxies Selected from Redshift
  Space
  We investigate the spatial distribution of satellite galaxies using a mock
redshift survey of the first Millennium Run simulation. The satellites were
identified using common redshift space criteria and the sample therefore
includes a large percentage of interlopers. The satellite locations are
well-fitted by a combination of a Navarro, Frenk & White(NFW) density profile
and a power law. At fixed stellar mass, the NFW scale parameter, r_s, for the
satellite distribution of red hosts exceeds r_s for the satellite distribution
of blue hosts. In both cases the dependence of r_s on host stellar mass is
well-fitted by a power law. For the satellites of red hosts, r_s^{red} \propto
(M_\ast / M_\sun)^{0.71 \pm 0.05} while for the satellites of blue hosts,
r_s^{blue} \propto (M_\ast / M_\sun)^{0.48 \pm 0.07}$. For hosts with stellar
masses greater than 4.0E+10 M_sun, the satellite distribution around blue hosts
is more concentrated than is the satellite distribution around red hosts. The
spatial distribution of the satellites of red hosts traces that of the hosts'
halos; however, the spatial distribution of the satellites of blue hosts is
more concentrated than that of the hosts' halos by a factor of ~2. Our
methodology is general and applies to any analysis of satellites in a mock
redshift survey. However, our conclusions necessarily depend upon the
semi-analytic galaxy formation model that was adopted, and different galaxy
formation models may yield different results.
