  We investigate the relationship between Low Mass X-ray Binaries (LMXBs) and
globular clusters (GCs) using UKIRT observations of M31 and existing Chandra,
XMM-Newton, and ROSAT catalogues. By fitting King models to these data we have
estimated the structural parameters and stellar collision rates of 239 of its
GCs. We show a highly significant trend between the presence of a LMXB and the
stellar collision rate of a cluster. The stellar collision rate is found to be
a stronger predictor of which clusters will host LMXBs than the host cluster
mass. We argue that our results show that the stellar collision rate of the
clusters is the fundamental parameter related to the production LMXBs. This is
consistent with the formation of LMXBs through dynamical interactions with
little direct dependence on the neutron star retention fraction or cluster
mass.

Astrophysics