Piercing of a boson star by a black hole
Abstract
New light fundamental fields are natural candidates for all or a fraction of dark matter. Selfgravitating structures of such fields might be common objects in the universe, and could comprise even galactic halos. These structures would interact gravitationally with black holes, a process of the utmost importance since it dictates their lifetime, the black hole motion, and possible gravitational radiation emission. Here, we study the dynamics of a black hole piercing through a much larger fully relativistic boson star, made of a complex minimally coupled massive scalar without selfinteractions. As the black hole pierces through the bosonic structure, it is slowed down by accretion and dynamical friction, giving rise to gravitationalwave emission. Since we are interested in studying the interaction with large and heavy scalar structures, we consider mass ratios up to q ∼10 and length ratios L ∼62 . Somewhat surprisingly, for all our simulations, the black hole accretes more than 95% of the boson star material, even if an initially small black hole collides with large velocity. This is a consequence of an extreme "tidal capture" process, which binds the black hole and the boson star together, for these mass ratios. We find evidence of a "gravitational atom" left behind as a product of the process.
 Publication:

Physical Review D
 Pub Date:
 August 2022
 DOI:
 10.1103/PhysRevD.106.044030
 arXiv:
 arXiv:2206.00021
 Bibcode:
 2022PhRvD.106d4030C
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  High Energy Astrophysical Phenomena;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 13 pages, 11 figures, 2 movies in ancillary files. revised to match the published version. Movies are also available on https://centra.tecnico.ulisboa.pt/network/grit/files/movies/