Gamma rays and microwave observations of the Galactic Center and surrounding
areas indicate the presence of anomalous emission, whose origin remains
ambiguous. The possibility of dark matter (DM) annihilation explaining both
signals through prompt emission at gamma-rays and secondary emission at
microwave frequencies from interactions of high-energy electrons produced in
annihilation with the Galactic magnetic fields has attracted much interest in
recent years. We investigate the DM interpretation of the Galactic Center
gamma-ray excess by searching for the associated synchrotron in the WMAP-Planck
data. Considering various magnetic field and cosmic-ray propagation models, we
predict the synchrotron emission due to DM annihilation in our Galaxy, and
compare it with the WMAP-Planck data at 23-70GHz. In addition to standard
microwave foregrounds, we separately model the microwave counterpart to the
Fermi Bubbles and the signal due to DM, and use component separation techniques
to extract the signal associated with each template from the total emission. We
confirm the presence of the Haze at the level of 7% of the total sky intensity
at 23GHz in our chosen region of interest, with a harder spectrum I∼ν−0.8 than the synchrotron from regular cosmic-ray electrons. The data do
not show a strong preference towards fitting the Haze by either the Bubbles or
DM emission only. Inclusion of both components provides a better fit with a DM
contribution to the Haze emission of 20% at 23GHz, however, due to significant
uncertainties in foreground modeling, we do not consider this a clear detection
of a DM signal. We set robust upper limits on the annihilation cross section by
ignoring foregrounds, and also report best-fit DM annihilation parameters
obtained from a complete template analysis. We conclude that the WMAP-Planck
data are consistent with a DM interpretation of the gamma-ray excess.Comment: 34 pages, 9 figure
