Fermi Gamma-ray Space Telescope

Search for Gamma-ray Emission from Dark Matter Annihilation in the Small Magellanic Cloud with the Fermi Large Area Telescope

R. Caputo
the Fermi-LAT Collaboration, A. M. Brooks, M. R. Buckley

Abstract:

The Small Magellanic Cloud (SMC) is the second-largest satellite galaxy of the Milky Way and is only 60 kpc from Earth. As a nearby, massive dense object with relatively low astrophysical backgrounds, it is a natural target for dark matter searches with gamma rays. The SMC was first detected in gamma rays by the Fermi Large Area Telescope (Fermi-LAT) Collaboration in 2010. Since the initial analysis, we have updated models of the gamma-ray emission using six years of Pass 8 data which provides a deeper and more detailed view of this region. In this work, we incorporate these new models and search for gamma-ray signals of dark matter annihilation in the SMC. In addition, we use a combination of N-body simulations and direct measurements of the rotation curve to set robust lower limits on the density of dark matter as a function of distance from the center of the SMC. In the absence of a dark matter signal, and based on the lower limits, we then find a conservative upper bound on the dark matter annihilation cross section that is competitive with limits for any other individual target.