Gamma-Ray Constraints on the First Stars from Annihilation of Light
  WIMPs
  We calculate the limits on the fraction of viable dark matter minihalos in
the early universe to host Population III.1 stars, surviving today as dark
matter spikes in our Milky Way halo. Motivated by potential hints of light dark
matter from the DAMA and CoGeNT direct dark matter searches, we consider
thermal relic WIMP dark matter with masses of 5, 10, and 20 GeV, and
annihilation to mu^+ mu^-, tau^+ tau^-, and q bar{q}. From this brief study we
conclude that, if dark matter is light, either the typical black hole size is
\lesssim 100 M_\odot (i.e. there is no significant Dark Star phase), and/or
dark matter annihilates primarily to mu^+ mu^- or other final states that
result in low gamma-ray luminosity, and/or that an extremely small fraction of
minihalos in the early universe that seem suitable to host the formation of the
first stars actually did.
