Emergence of Microphysical Bulk Viscosity in Binary Neutron Star Postmerger Dynamics
In: The Astrophysical Journal Letters, Jg. 967 (2024), Heft 1, S. L14
Online
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Zugriff:
In nuclear matter in isolated neutron stars, the flavor content (e.g., proton fraction) is subject to weak interactions, establishing flavor ( β -)equilibrium. However, there can be deviations from this equilibrium during the merger of two neutron stars. We study the resulting out-of-equilibrium dynamics during the collision by incorporating direct and modified Urca processes (in the neutrino-transparent regime) into general-relativistic hydrodynamics simulations with a simplified neutrino transport scheme. We demonstrate how weak-interaction-driven bulk viscosity in postmerger simulations can emerge and assess the bulk viscous dynamics of the resulting flow. We further place limits on the impact of the postmerger gravitational-wave strain. Our results show that weak-interaction-driven bulk viscosity can potentially lead to a phase shift of the postmerger gravitational-wave spectrum, although the effect is currently on the same level as the numerical errors of our simulation.
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Emergence of Microphysical Bulk Viscosity in Binary Neutron Star Postmerger Dynamics
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Autor/in / Beteiligte Person: | Most, Elias R. ; Haber, Alexander ; Harris, Steven P. ; Zhang, Ziyuan ; Alford, Mark G. ; Noronha, Jorge |
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Zeitschrift: | The Astrophysical Journal Letters, Jg. 967 (2024), Heft 1, S. L14 |
Veröffentlichung: | IOP Publishing, 2024 |
Medientyp: | academicJournal |
ISSN: | 2041-8213 (print) ; 2041-8205 (print) |
DOI: | 10.3847/2041-8213/ad454f |
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