Mapping dark matter in the gamma-ray sky with galaxy catalogs
  Cross-correlating gamma-ray maps with locations of galaxies in the
low-redshift Universe vastly increases sensitivity to signatures of
annihilation of dark matter particles. Low-redshift galaxies are ideal targets,
as the largest contribution to anisotropy in the gamma-ray sky from
annihilation comes from $z\lesssim 0.1$, where we expect minimal contributions
from astrophysical sources such as blazars. Cross-correlating the five-year
data of Fermi-LAT with the redshift catalog of the 2MASS survey can detect
gamma rays from annihilation if dark matter has the canonical annihilation
cross section and its mass is smaller than $\sim$100 GeV.
