Satellite Kinematics III: Halo Masses of Central Galaxies in SDSS
  We use the kinematics of satellite galaxies that orbit around the central
galaxy in a dark matter halo to infer the scaling relations between halo mass
and central galaxy properties. Using galaxies from the Sloan Digital Sky
Survey, we investigate the halo mass-luminosity relation (MLR) and the halo
mass-stellar mass relation (MSR) of central galaxies. In particular, we focus
on the dependence of these scaling relations on the colour of the central
galaxy. We find that red central galaxies on average occupy more massive haloes
than blue central galaxies of the same luminosity. However, at fixed stellar
mass there is no appreciable difference in the average halo mass of red and
blue centrals, especially for M* $\lsim$ 10^{10.5} h^{-2} Msun. This indicates
that stellar mass is a better indicator of halo mass than luminosity.
Nevertheless, we find that the scatter in halo masses at fixed stellar mass is
non-negligible for both red and blue centrals. It increases as a function of
stellar mass for red centrals but shows a fairly constant behaviour for blue
centrals. We compare the scaling relations obtained in this paper with results
from other independent studies of satellite kinematics, with results from a
SDSS galaxy group catalog, from galaxy-galaxy weak lensing measurements, and
from subhalo abundance matching studies. Overall, these different techniques
yield MLRs and MSRs in fairly good agreement with each other (typically within
a factor of two), indicating that we are converging on an accurate and reliable
description of the galaxy-dark matter connection. We briefly discuss some of
the remaining discrepancies among the various methods.
