  Indirect detection is the search for the particle nature of dark matter with
astrophysical probes. Manifestly, it exists right at the intersection of
particle physics and astrophysics, and the discovery potential for dark matter
can be greatly extended using insights from both disciplines. This thesis
provides an exploration of this philosophy. On the one hand, I will show how
astrophysical observations of dark matter, through its gravitational
interaction, can be exploited to determine the most promising locations on the
sky to observe a particle dark matter signal. On the other, I demonstrate that
refined theoretical calculations of the expected dark matter interactions can
be used disentangle signals from astrophysical backgrounds. Both of these
approaches will be discussed in the context of general searches, but also
applied to the case of an excess of photons observed at the center of the Milky
Way. This galactic center excess represents both the challenges and joys of
indirect detection. Initially thought to be a signal of annihilating dark
matter at the center of our own galaxy, it now appears more likely to be
associated with a population of millisecond pulsars. Yet these pulsars were
completely unanticipated, and highlight that indirect detection can lead to
many new insights about the universe, hopefully one day including the particle
nature of dark matter.
