Dynamical stability of hypermassive neutron stars against quasi-radial perturbations

Fuente: arXiv
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Hauptverfasser: Szewczyk, Paweł, Gondek-Rosińska, Dorota, Cerdá-Durán, Pablo
Format: Preprint
Veröffentlicht: 2025
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author Szewczyk, Paweł
Gondek-Rosińska, Dorota
Cerdá-Durán, Pablo
author_facet Szewczyk, Paweł
Gondek-Rosińska, Dorota
Cerdá-Durán, Pablo
contents The dynamical stability of differentially rotating neutron stars, including hypermassive neutron stars, is of paramount importance in understanding the fate of the post-merger remnant of binary neutron stars mergers and the formation of a black hole during core collapse supernovae. We study systematically the dynamical stability of differentially rotating neutron stars within a broad range of masses, rotation rates and degrees of differential rotation, modeled as polytropes with $Γ=2$. We pay particular attention to quasi-toroidal configurations that are outside the parameter space region explored in previous works. We estimate the limits of the region of stability against quasi-radial perturbations by performing an extensive set of numerical simulations. We find that some of the stability criteria proposed in the past are not sufficient nor necessary to determine stability if differential rotation is present and propose a new more general criterion. We show that there is a large parameter space that allows for quasi-toroidal configurations that will not collapse immediately to a black hole and that can sustain masses up to $\sim 2.5$ times the maximum mass of a non-rotating neutron star.
format Preprint
id arxiv_https___arxiv_org_abs_2507_05453
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamical stability of hypermassive neutron stars against quasi-radial perturbations
Szewczyk, Paweł
Gondek-Rosińska, Dorota
Cerdá-Durán, Pablo
High Energy Astrophysical Phenomena
The dynamical stability of differentially rotating neutron stars, including hypermassive neutron stars, is of paramount importance in understanding the fate of the post-merger remnant of binary neutron stars mergers and the formation of a black hole during core collapse supernovae. We study systematically the dynamical stability of differentially rotating neutron stars within a broad range of masses, rotation rates and degrees of differential rotation, modeled as polytropes with $Γ=2$. We pay particular attention to quasi-toroidal configurations that are outside the parameter space region explored in previous works. We estimate the limits of the region of stability against quasi-radial perturbations by performing an extensive set of numerical simulations. We find that some of the stability criteria proposed in the past are not sufficient nor necessary to determine stability if differential rotation is present and propose a new more general criterion. We show that there is a large parameter space that allows for quasi-toroidal configurations that will not collapse immediately to a black hole and that can sustain masses up to $\sim 2.5$ times the maximum mass of a non-rotating neutron star.
title Dynamical stability of hypermassive neutron stars against quasi-radial perturbations
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2507.05453