Searching for velocity-dependent dark matter annihilation signals from extragalactic halos

We consider gamma-ray signals of dark matter annihilation in extragalactic halos the case where annihilates from a $p$-wave or $d$-wave state. In these scenarios, are enhanced relative to other targets, such as Galactic Center dwarf spheroidal galaxies, because typical speed is larger halos. perform mock data analysis gamma rays produced by detected Sloan Digital Sky Survey. include model for uncorrelated galactic and ray backgrounds, well simple backgrounds due astrophysical processes survey. find that, models which still allowed searches, searches with current Fermi exposure can produce evidence annihilation, though it difficult distinguish scenarios. With factor $10\times$ exposure, though, discrimination velocity-dependence possible.