Proper motion of gamma-rays from microhalo sources

Abstract

I discuss the prospects of detecting the smallest dark matter bound structures present in the Milky Way by searching for the proper motion of $γ$-ray sources in the upcoming GLAST all sky map. I show that for dark matter particle candidates that couple to photons the detection of at least one $γ$-ray microhalo source with proper motion places a constraint on the couplings and mass of the dark matter particle. For SUSY dark matter, proper motion detection implies that the mass of the particle is less than 500 GeV and the kinetic decoupling temperature is in the range of [4-100] MeV.