The Satellite Population Around Luminous Red Galaxies in the Legacy Surveys

Luminous Red Galaxies, or LRGs, were originally selected in the Sloan Digital Sky Survey asgood tracers of large scale structure. Subsequent investigations showed them to be among themost massive galaxies in the Universe and dominated by uniformly old stellar populations.Despite being dominated by old stars, however, they have grown in stellar mass since z=1,implying that they grow predominantly via accretion of mostly passive satellites. This picturehas not yet been tested because of the lack of deep imaging data sets that both covers a largeenough area of the sky to contain substantial numbers of LRGs and also is deep enough todetect faint satellites. I will present our initial characterization the satellite galaxy population ofLRGs out to z=0.65. To accomplish I use the Legacy Surveys, which are comprised of grzimaging to 2-2.5 mag deeper than SDSS, over a larger footprint, and with better image quality.Specifically, I will present our first measurement of the number of satellite galaxies aroundLRGs and how this number depends on LRG properties.