Version 1
: Received: 10 October 2024 / Approved: 10 October 2024 / Online: 11 October 2024 (08:21:07 CEST)
How to cite:
Pradhan, S.; Gabler, M.; Gaztanaga, E. Cold Collapse and Bounce of a FLRW Cloud. Preprints2024, 2024100839. https://doi.org/10.20944/preprints202410.0839.v1
Pradhan, S.; Gabler, M.; Gaztanaga, E. Cold Collapse and Bounce of a FLRW Cloud. Preprints 2024, 2024100839. https://doi.org/10.20944/preprints202410.0839.v1
Pradhan, S.; Gabler, M.; Gaztanaga, E. Cold Collapse and Bounce of a FLRW Cloud. Preprints2024, 2024100839. https://doi.org/10.20944/preprints202410.0839.v1
APA Style
Pradhan, S., Gabler, M., & Gaztanaga, E. (2024). Cold Collapse and Bounce of a FLRW Cloud. Preprints. https://doi.org/10.20944/preprints202410.0839.v1
Chicago/Turabian Style
Pradhan, S., Michael Gabler and Enrique Gaztanaga. 2024 "Cold Collapse and Bounce of a FLRW Cloud" Preprints. https://doi.org/10.20944/preprints202410.0839.v1
Abstract
We study the collapse of spherical cold clouds beyond black hole (BH) formation to investigate the possibility of a bounce in the in-falling matter when a critical density or pressure is reached. As a first step, we analyze the pressureless collapse in general relativity (GR), where an analytic solution exists, and demonstrate that an equivalent Newtonian solution can be derived. Such equivalence also holds for spherically symmetric perfect fluids with uniform density and non-vanishing pressure. We numerically investigate the Newtonian collapse of such clouds with masses of $5$, $20$, and $1000$ M$_\odot$ obeying a polytropic equation of state (EoS). By choosing EoS parameters inspired by typical neutron star conditions, we observe bounces at and above nuclear saturation density. Assuming approximate uniformity, we explore the equivalent GR behaviour of the matter during the bounce. Our findings are: i) A GR bounce occurs around the ground state of the matter, characterized by $P = -\rho$. ii) The GR solution significantly differs from the Newtonian result due to the presence of curvature ($k \neq 0$). iii) Both the curvature and the ground state are crucial factors in allowing a GR bounce to occur.
Keywords
cosmology; theory; inflation; early Universe; dark energy; black hole physics; hydrodynamics
Subject
Physical Sciences, Astronomy and Astrophysics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
