Evolution of the DM distribution function in the density spikes around PBHs

Abstract

At the cosmological stage of radiation dominance, dark matter density spikes should form around primordial black holes. In the case when dark matter particles are able to annihilate, the density in the central regions of the spikes decreases due to the elimination of particles, which gives an upper bound on the central density. In this paper, the modification of the central density profile is investigated, taking into account the distribution of the particle orbits. The orbits in spike around a primordial black hole are very elongated, almost radial, and the angular momentum distribution has an exponential form. For such an initial distribution function, it is obtained that a cusp with the exponent $\approx -0.7$ is formed in the central region, instead of an annihilation plateau. The presence of the cusp provides some correction to the rate of dark matter annihilation around primordial black holes.

7 pages, 3 figures, some misprints have been corrected

References in corpus (14)

• Primordial Black Hole Scenario for the Gravitational-Wave Event GW150914
• Primordial Black Holes as Dark Matter: Recent Developments
• The Formation of Primary Galactic Nuclei during Phase Transitions in the Early Universe
• WIMPs and stellar-mass primordial black holes are incompatible
• Primordial Black Holes as Dark Matter: Almost All or Almost Nothing
• Dark Matter Density Spikes around Primordial Black Holes
• Black Holes and WIMPs: All or Nothing or Something Else
• Novel Constraints on Mixed Dark-Matter Scenarios of Primordial Black Holes and WIMPs
• Dark matter annihilation near a black hole: plateau vs. weak cusp
• Impact of Primordial Ultracompact Minihaloes on the Intergalactic Medium and First Structure Formation
• On mass distribution of coalescing black holes
• Primordial Black Hole as a Source of the Boost Factor
• Black Hole in a Radiation-Dominated Universe
• Dark matter around primordial black hole at the radiation-dominated stage

Cited by in corpus (3)

• Constraining the impact of standard model phase transitions on primordial black holes
• Universal Density and Velocity Distributions of Dark Matter around Massive Black Holes
• Beyond general relativity: gravitational waves in non-minimally coupled theories