The galaxy cross-correlation function as a probe of the spatial distribution of galactic satellites

¹ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: jchen@astro.uni-bonn.de
² Kavli Institute for Cosmological Physics, Dept. of Astronomy & Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA

Received: 3 December 2007
Accepted: 8 December 2008

Abstract

The spatial distribution of satellite galaxies around host galaxies can illuminate the relationship between satellites and dark matter subhalos and aid in developing and testing galaxy formation models. Previous efforts to constrain the distribution attempted to eliminate interlopers from the measured projected number density of satellites and found that the distribution is generally consistent with the expected dark matter halo profile of the parent hosts, with a best-fit power-law slope of ≈-1.7 between projected separations of ~ kpc and  Mpc. Here, I use the projected cross-correlation of bright and faint galaxies to analyze contributions from satellites and interlopers together, using a halo occupation distribution (HOD) analytic model for galaxy clustering. This approach is tested on mock catalogs constructed from simulations. I find that analysis of Sloan Digital Sky Survey (SDSS) data gives results generally consistent with interloper subtraction methods between the projected separations of  kpc and  Mpc, although the errors on the parameters that constrain the radial profile are large, and larger samples of data are required.