  We consider the indirect detection of dark matter that is captured in the Sun
and subsequently annihilates to long lived dark mediators. If these mediators
escape the Sun before decaying, they can produce striking gamma ray signals,
either via the decay of the mediators directly to photons, or via
bremsstrahlung and hadronization of the mediator decay products. Using recent
measurements from the HAWC Observatory, we determine model-independent limits
on heavy dark matter that are orders of magnitude more powerful than direct
detection experiments, for both spin-dependent and spin-independent scattering.
We also consider a well-motivated model in which fermionic dark matter
annihilates to dark photons. For such a realistic scenario, the strength of the
solar gamma ray constraints are reduced, compared to the idealistic case, due
to the fact that the dark matter capture cross section and mediator lifetime
are related. Nonetheless, solar gamma ray constraints enable us to exclude a
previously unconstrained region of dark photon parameter space.
