Hunting
for Dark Matter in the Gamma-ray Sky
Mariangela Lisanti
Princeton Astrophysics
The
annihilation of dark matter can lead to observable signatures
in high-energy gamma rays across the Milky Way sky. I
will review
the
current status of such dark matter searches with data
from the Fermi Large Area Telescope. The centers of galaxies,
dense in dark matter,
provide the best targets to search for annihilation
signatures. I will begin with the center of our own
Galaxy,
where an observed gamma-ray excess had been interpreted as a
signal of dark matter. Using a novel data
analysis
method, however, we showed that the excess is more consistent
with a population of unresolved
astrophysical
sources, such as millisecond pulsars. These new sources
may be fossil remnants from Galactic bulge formation,
possibly
providing a window into the formation history of the Milky
Way.
Then, I will discuss searches in galaxies outside our own,
including the Milky Way dwarfs as well as
thousands
of other galaxies outside the Local Group. We have built a
catalog of the most promising dark matter
targets
out to redshifts of ~0.03. Using this catalog, we have
obtained the best sensitivity on extragalactic
dark
matter annihilation to date, with results complementing
existing dwarf studies. This catalog is
widely
applicable to annihilation or decay signatures into neutral
cosmic-rays, regardless of wavelength,
messenger,
or instrument.