2006/10/16 by David Merritt, Stefan Harfst, Gianfranco Bertone · 1 citation
Physics and Astronomy · #Accretion (finance) #Astrophysics #Cold dark matter #Cosmology and Gravitation Theories #Dark Matter and Cosmic Phenomena #Dark matter #Dark matter halo #Galaxies: Formation, Evolution, Phenomena #Galaxy #Halo #Milky Way #Physics #Stars #Supermassive black hole #astro-ph #hep-ph
paper · pdf · doi:10.1103/physrevd.75.043517
published as Phys.Rev. D75 (2007) 043517 · 11 pages, uses revtex4
arxiv created 2006/10/16 · openalex publication_date 2007/02/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We show that the presence of a \ensuremathρ\ensuremath∼r^\ensuremath-3/2 dark matter overdensity can be robustly predicted at the center of any galaxy old enough to have grown a power-law density cusp in the stars via the Bahcall-Wolf mechanism. Using both Fokker-Planck and direct N-body integrations, we demonstrate collisional generation of these dark matter ``crests'' (collisionally regenerated structures) even in the extreme case that the density of both stars and dark matter were previously lowered by slingshot ejection from a binary supermassive black hole. The time scale for collisional growth of the crest is approximately the two-body relaxation time as defined by the stars, which is \ensuremath\lesssim10 Gyr at the centers of stellar spheroids with luminosities L\ensuremath\lesssim109.5L_\ensuremath\bigodot, including the bulge of the Milky Way. The presence of crests can robustly be predicted in such galaxies, unlike the steeper enhancements, called ``spikes,'' produced by the adiabatic growth of black holes. We discuss special cases where the prospects for detecting dark matter annihilations from the centers of galaxy halos are significantly affected by the formation of crests.