Flaring of tidally compressed dark-matter clumps

Abstract

We explore the physics and observational consequences of tidal compression events (TCEs) of dark-matter clumps (DMCs) by supermassive black holes (SMBHs). Our analytic calculations show that a DMC approaching a SMBH much closer than the tidal radius undergoes significant compression along the axis perpendicular to the orbital plane, shortly after pericenter passage. For DMCs composed of self-annihilating dark-matter particles, we find that the boosted DMC density and velocity dispersion lead to a flaring of the annihilation rate, most pronounced for a velocity- dependent annihilation cross section. If the end products of the annihilation are photons, this results in a gamma-ray flare, detectable (and possibly already detected) by the Fermi telescope for a range of model parameters. If the end products of dark-matter annihilation are relativistic electrons and positrons and the local magnetic field is large enough, TCEs of DMCs can lead to flares of synchrotron radiation. Finally, TCEs of DMCs lead to a burst of gravitational waves, in addition to the ones radiated by the orbital motion alone, and with a different frequency spectrum. These transient phenomena provide interesting new avenues to explore the properties of dark matter.

11 pages, 6 figures; Minor changes; Version as published in PRD

References in corpus (10)

• A Continuum of H- to He-Rich Tidal Disruption Candidates With a Preference for E+A Galaxies
• Multi-wavelength signals of dark matter annihilations at the Galactic center
• Remnants of dark matter clumps
• Small-scale clumps of dark matter
• A strong magnetic field in the jet base of a supermassive black hole
• On mini-halo encounters with stars
• Galactic Center Excess in Gamma Rays from Annihilation of Self-Interacting Dark Matter
• Superdense cosmological dark matter clumps
• Dark matter annihilation radiation in hydrodynamic simulations of Milky Way haloes
• Gravitational wave searches with Advanced LIGO and Advanced Virgo

Cited by in corpus (7)

• The Black Hole Mass Function from Gravitational Wave Measurements
• Determining the progenitors of merging black-hole binaries
• Tidal deformability of boson stars and dark matter clumps
• Dark Matter Signatures of Supermassive Black Hole Binaries
• Neutron star mass in dark matter clumps
• Fast radio burst repeaters produced via Kozai-Lidov feeding of neutron stars in binary systems
• Signatures of Compact Halos of Sterile-Neutrino Dark Matter