http://arxiv.org/abs/1706.01843
We investigate rotationally supported dwarf irregular (dIrr) galaxies as new targets for dark matter (DM) indirect search with gamma-ray telescopes. As a difference with pressure-supported objects, their dynamic provides to well constrain the DM distribution in the halo. We calculate the astrophysical factor for a sample of 36 dIrr galaxies. The range of values turns out to be competitive with the astrophysical factor of well known dwarf spheroidal galaxies. The existence of the star forming region in dIrrs constitutes an extra background, that is instead negligible in dwarf spheroidal galaxies. On the one hand, such unresolved gamma-ray emission may represent a component of the diffuse isotropic gamma-ray background. On the other, we show that it may be masked or neglected with the intent of DM search in the extended halo. The detection of an extended DM component would constitute a smoking gun for DM particle annihilation eventually. We individuate IC10 and WLM as the best candidates in our sample of galaxies. We get the first constraints for DM annihilation cross-section with the current and next generation of gamma-ray telescopes.
V. Gammaldi, E. Karukes and P. Salucci
Wed, 7 Jun 17
15/52
Comments: 30 pages, 11 figures, to be submitted to JCAP