Color dependence in the spatial distribution of satellite galaxies

Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: jchen@astro.uni-bonn.de

Received: 7 November 2007
Accepted: 31 March 2008

Abstract

Aims. We explore the color dependence of the radial profile of satellite galaxies around isolated parent galaxies.

Methods. Samples of potential satellites selected from large galaxy redshift surveys are significantly contaminated by interlopers – objects not bound to the parent galaxy. We use the Sloan Digital Sky Survey to estimate the interloper fraction in samples of candidate satellite galaxies.

Results. We show that samples of red and blue satellites have different interloper populations: a larger fraction of blue galaxies are likely to be interlopers compared to red galaxies. Both with and without interloper subtraction, the radial profile of blue satellites is significantly shallower than that of red satellites. In addition, while red and blue primaries have different interloper fractions, the slope of the corrected radial profiles are consistent after interloper correction. We discuss the implications of these results for galaxy formation models.