Neutralino gamma-ray signals from accreting halo dark matter - art. no. 083515

There is mounting evidence that a self-consistent model for particle cold d ark matter has to take into consideration spatial inhomogeneities on sub-ga lactic scales seen, for instance, in high-resolution N-body simulations of structure formation. Also in more idealized, analytic models, there appear density enhancements in certain regions of the halo. We use the results fro m a recent N-body simulation of the Milky Way halo and investigate the gamm a-ray flux which would be produced when a specific dark matter candidate, t he neutralino, annihilates in regions of enhanced density. The clumpiness f ound on all scales in the simulation results in very strong gamma-ray signa ls which seem to already rule out some regions of the supersymmetric parame ter space, and would be further: probed by upcoming experiments, such as th e GLAST gamma-ray satellite. As an orthogonal model of structure formation, we also consider Sikivie's simple infall model of dark matter which predic ts that there should exist continuous regions of enhanced density, caustic rings, in the dark matter halo of the Milky Way. We find, however, that the gamma-ray signal from caustic rings is generally too small to be detectabl e.