A black hole window into p-wave dark matter annihilation

TL;DR

This paper proposes a new method to detect or constrain p-wave dark matter annihilation signals near supermassive black holes by analyzing gamma-ray emissions from the Galactic center, leveraging high-density spikes and velocity dispersion.

Contribution

It introduces a novel approach to measure p-wave dark matter annihilation cross sections using gamma-ray observations of black hole-induced density spikes, providing new constraints on dark matter models.

Findings

Fermi telescope is sensitive to thermal p-wave dark matter in the Galactic center.

Dark matter annihilation signals can appear as bright point sources without extended halo emission.

New limits on particle and astrophysical parameters of p-wave dark matter models are established.

Abstract

We present a new method to measure or constrain p-wave-suppressed cross sections for dark matter (DM) annihilations inside the steep density spikes induced by supermassive black holes. We demonstrate that the high DM densities, together with the increased velocity dispersion, within such spikes combine to make thermal p-wave annihilation cross-sections potentially visible in gamma-ray observations of the Galactic center (GC). The resulting DM signal is a bright central point source with emission originating from DM annihilations in the absence of a detectable spatially-extended signal from the halo. We define two simple reference theories of DM with a thermal p-wave annihilation cross-section and establish new limits on the combined particle and astrophysical parameter space of these models, demonstrating that Fermi is currently sensitive to thermal p-wave DM over a wide range of possible scenarios for the DM distribution in the GC.