Anisotropies in the gamma-ray sky from millisecond pulsars
  Pulsars emerge in the Fermi era as a sizable population of gamma-ray sources.
Millisecond pulsars (MSPs) constitute an older subpopulation whose sky
distribution extends to high Galactic latitudes, and it has been suggested that
unresolved members of this class may contribute a significant fraction of the
measured large-scale isotropic gamma-ray background (IGRB). We investigate the
possible energy-dependent contribution of unresolved MSPs to the anisotropy of
the Fermi-measured IGRB. For observationally-motivated MSP population models,
we show that the preliminary Fermi anisotropy measurement places an interesting
constraint on the abundance of MSPs in the Galaxy and the typical MSP flux,
about an order of magnitude stronger than constraints on this population
derived from the intensity of the IGRB alone. We also examine the possibility
of a MSP component in the IGRB mimicking a dark matter signal in
anisotropy-based searches, and conclude that the energy dependence of an
anisotropy signature would distinguish MSPs from all but very light dark matter
candidates.
