ANNIHILATION IN THE MILKY WAY: SIMULATED DISTRIBUTION OF DARK MATTER ON SMALL SCALES

We use a high-resolution simulation of a galaxy-sized dark matter halo, published simulated data as well as four cluster-sized haloes¹ to study the inner halo structure in a Lambda cold dark matter cosmology. We find that the circular velocity curves are substantially better described by SWTS^2,3 profiles than by NFW⁴ or Moore⁵ profiles. Our findings confirm that no asymptotic slope is reached and that the corresponding extrapolated density profiles reach a finite maximum density. We analyse the impact of our findings on the detectability of the gamma-ray signal from the central regions of the Milky Way (MW) and from dark matter substructures in its halo, if the dark matter in the Universe is made of weakly self-interacting particles which self-annihilate. We discuss detection strategies for current gamma-ray detectors. We in addition review recent work by other authors and comment on possible boosts due to effects of structure on very small scales.