2016/09/30 by Tomohiro Harada, Chul-Moon Yoo, Chul-moon Yoo +3 · 4 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Black hole (networking) #Cosmology #Cosmology and Gravitation Theories #Curvature #Density contrast #Horizon #Order (exchange) #Phase (matter) #Primordial black hole #Pulsars and Gravitational Waves Research #Universe #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.3847/1538-4357/833/1/61
12 pages, 1 figure, minor correction, accepted for publication in Astrophysical Journal
openalex created_date 2016/09/16 · arxiv created 2016/11/07 · openalex publication_date 2016/12/07 · arxiv updated 2018/01/25 · openalex updated_date 2026/08/06
ABSTRACT We investigate primordial black hole formation in the matter-dominated phase of the universe, where nonspherical effects in gravitational collapse play a crucial role. This is in contrast to the black hole formation in a radiation-dominated era. We apply the Zel’dovich approximation, Thorne’s hoop conjecture, and Doroshkevich’s probability distribution and subsequently derive the production probability of primordial black holes. The numerical result obtained is applicable even if the density fluctuation σ at horizon entry is of the order of unity. For , we find a semi-analytic formula , which is comparable to the Khlopov–Polnarev formula. We find that the production probability in the matter-dominated era is much larger than that in the radiation-dominated era for , while they are comparable with each other for . We also discuss how σ can be written in terms of primordial curvature perturbations.