Lopsided Satellite Distributions around Isolated Host Galaxies

Abstract

Abstract We summarize preliminary results from a new analysis of the spatial distributions of the satellites of isolated host galaxies. We identify 789 host-satellite systems in the NASA-Sloan Atlas, each with 5 or more satellites. Consistent with previous studies, we find that, on average, the satellites of red hosts are located preferentially close to their hosts’ major axes, while the satellites of blue hosts are distributed isotropically. The pairwise clustering of the satellites reveals a strong tendency for pairs of satellites to be located on the same side of their host, resulting in lopsided satellite distributions. The signal is most pronounced for the satellites of blue hosts, where we find ∼50% more satellite pairs on the same side of their host than on opposite sides. For red hosts, we find ∼6% more satellite pairs on the same side of their host than on opposite sides.