Gamma Rays from Top-Mediated Dark Matter Annihilations
  Lines in the energy spectrum of gamma rays are a fascinating experimental
signal, which are often considered "smoking gun" evidence of dark matter
annihilation. The current generation of gamma ray observatories are currently
closing in on parameter space of great interest in the context of dark matter
which is a thermal relic. We consider theories in which the dark matter's
primary connection to the Standard Model is via the top quark, realizing strong
gamma ray lines consistent with a thermal relic through the forbidden channel
mechanism proposed in the Higgs in Space Model. We consider realistic
UV-completions of the Higgs in Space and related theories, and show that a rich
structure of observable gamma ray lines is consistent with a thermal relic as
well as constraints from dark matter searches and the LHC. Particular attention
is paid to the one loop contributions to the continuum gamma rays, which can
easily swamp the line signals in some cases, and have been largely overlooked
in previous literature.
