Optimal observing strategies for velocity-suppressed dark matter annihilation

Abstract

Numerous particle models for the cosmological dark matter feature a pair-annihilation rate that scales with powers of the relative velocity between the annihilating particles. As a result, the annihilation rate in the central regions of a dark matter halo can be significantly lower than at the halo's periphery for particular ambient gravitational potentials. While this might be offset by an increasing dark matter pair number density in the inner halo, it raises the question: what angular region for dark matter models with velocity-suppressed annihilation rates optimizes signal-to-noise? Here, we consider simplified background models for galactic and extragalactic targets and demonstrate that the optimal observing strategy varies greatly case-by-case. Generally, a bright central source warrants an annular region of interest, while a flatter background warrants as large as possible an angular region, possibly including the central regions.

9 pages, 7 figures. Comments welcome

References in corpus (6)

• Searching for Dark Matter Annihilation in Recently Discovered Milky Way Satellites with Fermi-LAT
• Effect of Black Holes in Local Dwarf Spheroidal Galaxies on Gamma-Ray Constraints on Dark Matter Annihilation
• Search for $\gamma$-ray emission from dark matter particle interactions from Andromeda and Triangulum Galaxies with the Fermi Large Area Telescope
• Search for gamma-ray emission from $p$-wave dark matter annihilation in the Galactic Center
• TASI Lectures on Indirect Detection of Dark Matter
• Relativistic dark matter at the Galactic center

Cited by in corpus (1)

• Velocity-dependent annihilation radiation from dark matter subhalos in cosmological simulations