2021/11/30 by Viktor Stasenko, Viktor D. Stasenko, А. А. Кириллов +3
Physics and Astronomy · #Astronomy #Astrophysics #Binary black hole #Cluster (spacecraft) #Cosmology and Gravitation Theories #Gamma-ray bursts and supernovae #Gravitation #Gravitational collapse #Gravitational wave #Mass distribution #Physics #Power law #Primordial black hole #Pulsars and Gravitational Waves Research #Redshift #Statistics #astro-ph.CO
paper · pdf · doi:10.3390/universe8010041
published as Universe 2022, 8(1), 41
openalex publication_date 2022/01/11 · arxiv created 2022/01/18 · arxiv updated 2022/01/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The PBH clusters can be sources of gravitational waves, and the merger rate depends on the spatial distribution of PBHs in the cluster which changes over time. It is well known that gravitational collisional systems experience the core collapse that leads to significant increase of the central density and shrinking of the core. After core collapse, the cluster expands almost self-similarly (i.e., density profile extends in size without changing its shape). These dynamic processes affect the merger rate of PBHs. In this paper, the dynamics of the PBH cluster is considered using the Fokker–Planck equation. We calculate the merger rate of PBHs on cosmic time scales and show that its time dependence has a unique signature. Namely, it grows by about an order of magnitude at the moment of core collapse which depends on the characteristics of the cluster, and then decreases according to the dependence R∝t−1.48. It was obtained for monochromatic and power-law PBH mass distributions with some fixed parameters. Obtained results can be used to test the model of the PBH clusters via observation of gravitational waves at high redshift.