Primordial black hole formation from massless scalar isocurvature

作     者：Yoo, Chul-Moon Harada, Tomohiro Hirano, Shinichi Okawa, Hirotada Sasaki, Misao 

作者机构：Division of Particle and Astrophysical Science Graduate School of Science Nagoya University Nagoya464-8602 Japan Department of Physics Rikkyo University Toshima Tokyo171-8501 Japan  Waseda University Shinjuku Tokyo169-0051 Japan  University of Tokyo Kashiwa277-8583 Japan Center for Gravitational Physics Yukawa Institute for Theoretical Physics Kyoto University Kyoto606-8502 Japan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei10617 Taiwan 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2021年

核心收录：

主　　题：Expansion 

摘      要：We numerically study the primordial black hole (PBH) formation by an isocurvature perturbation of a massless scalar field on super Hubble scales in the radiation-dominated universe. As a first step we perform simulations of spherically symmetric configurations. For the initial condition, we employ the spatial gradient expansion and provide the general form of the growing mode solutions valid up through the second order in this expansion. The initial scalar field profile is assumed to be Gaussian with a characteristic comoving wavenumber k;∼ exp(−k2R2), where R is the radial coordinate. We find that a PBH is formed for a sufficiently large amplitude of the scalar field profile. Nevertheless, we find that the late time behavior of the gravitational collapse is dominated by the dynamics of the fluid but not by the scalar field, which is analogous to the PBH formation from an adiabatic perturbation in the radiation-dominated universe. © 2021, CC BY.