Abstract
The growth of a black hole surrounded by dark matter can lead to a significant enhance-ment of the dark matter density close to the hole. We investigate this effect, focusing on thephenomenologically interesting case where the black hole is supermassive and is embedded in a galactic dark matter halo, although the formalism developed does not depend on that fact.Due to the enhanced gravitational potential, the dark matter will tend to cluster around theblack hole. The precise details of this clustering will, in general, depend on the formationprocess of the black hole. However, if the black hole grows slowly with respect to the orbitaltimescales of the local galactic potential, the density cusp only depends on the black hole’smass and spin, as well as on the local distribution of orbits.The density cusp generated by the growing black hole is called an adiabatic spike. Inthe context of dark matter density cusps, these spikes were first investigated by Gondoloand Silk (1999), using a phase space analysis. General relativistic effects originating fromthe black hole’s mass were calculated by Sadeghian, Ferrer, and Will (2013), revealing anenhancement of the density in the spike. Our work extends this calculation to include theeffects of spin. We find a further enhancement to the spike that is strongly dependent on theblack hole’s spin parameter, meaning that it cannot be ignored for rapidly spinning blackholes. We estimate its impact in local annihilation rates for two particular physical processes:particle dark matter annihilation in the s-channel, and the merger rate of binaries composedof primordial black holes in the local universe. We also present a derivation of the two-bodycollision rate per four-volume in terms of the phase space distribution that can be used inany coordinate system.
Committee Chair
Francesc Ferrer
Committee Members
Claude W. Bernard, Renato Feres, Henric Krawczynski, Michael C. Ogilvie,
Degree
Doctor of Philosophy (PhD)
Author's Department
Physics
Document Type
Dissertation
Date of Award
Summer 8-15-2019
Language
English (en)
DOI
https://doi.org/10.7936/205a-j912
Recommended Citation
Medeiros Da Rosa, Augusto, "Adiabatic Dark Matter Density Cusps Around Supermassive Black Holes and Dark Matter Detection" (2019). Arts & Sciences Theses and Dissertations. 1928.
The definitive version is available at https://doi.org/10.7936/205a-j912
Comments
Permanent URL: https://doi.org/10.7936/205a-j912