  We propose that the nature of indirect signals of dark matter (DM) can depend
on the Galactic environment they originate from. We demonstrate this
possibility in models where DM annihilates into light mediators whose branching
fractions depend on a long range force sourced by ordinary matter. In
particular, electromagnetic signals of DM may only arise near the centers of
galaxies where the ordinary matter densities, and hence astrophysical
background levels, are high. We briefly discuss how our model could explain the
Galactic Center gamma ray excess, without leaving much of a trace in
baryon-poor environments, like dwarf spheroidal galaxies. Similar spatial
dependence of indirect signals can also apply to models featuring metastable DM
decay into light mediators.
