A statistical test of emission from unresolved point sources
  We describe a simple test of the spatial uniformity of an ensemble of
discrete events. Given an estimate for the point source luminosity function and
an instrumental point spread function (PSF), a robust upper bound on the
fractional point source contribution to a diffuse signal can be found. We
verify with Monte Carlo tests that the statistic has advantages over the
two-point correlation function for this purpose, and derive analytic estimates
of the statistic's mean and variance as a function of the point source
contribution. As a case study, we apply this statistic to recent gamma-ray data
from the Fermi Large Area Telescope (LAT), and demonstrate that at energies
above 10 GeV, the contribution of unresolved point sources to the diffuse
emission is small in the region relevant for study of the WMAP Haze.
