| Irfu-12-59
|
|---|
| Prospects for a Dark Matter annihilation signal towards the
Sagittarius dwarf galaxy with ground based Cherenkov telescopes |
| A. Viana, M.C. Medina, J. Pe˜narrubia, P. Brun, J.F. Glicenstein, K. Kosack,
E. Moulin, M. Naumann-Godo, B. Peyaud |
| Dwarf galaxies are widely believed to be among the best targets for indirect
dark matter searches using high-energy gamma rays; and indeed gamma-ray
emission from these objects has long been a subject of detailed study for groundbased
atmospheric Cherenkov telescopes. Here, we update current exclusion
limits obtained on the closest dwarf, the Sagittarius dwarf galaxy, in light of recent
realistic dark matter halo models. The constraints on the velocity-weighted
annihilation cross section of the dark matter particle are of a few 10−23 cm3s−1
in the TeV energy range for a 50 h exposure. The limits are extrapolated to the
sensitivities of future Cherenkov Telescope Arrays. For 200 h of observation time,
the sensitivity at 95% C.L. reaches 10−25 cm3s−1. Possible astrophysical backgrounds
from gamma-ray sources dissembled in Sagittarius dwarf are studied. It
is shown that with long-enough observation times, gamma-ray background from
millisecond pulsars in a globular cluster contained withinSagittarius dwarf may
limit the sensitivity to dark matter annihilations. |
