Bulk viscous damping of density oscillations in neutron star mergers

  • In this paper, we discuss the damping of density oscillations in dense nuclear matter in the temperature range relevant to neutron star mergers. This damping is due to bulk viscosity arising from the weak interaction “Urca” processes of neutron decay and electron capture. The nuclear matter is modelled in the relativistic density functional approach. The bulk viscosity reaches a resonant maximum close to the neutrino trapping temperature, then drops rapidly as temperature rises into the range where neutrinos are trapped in neutron stars. We investigate the bulk viscous dissipation timescales in a post-merger object and identify regimes where these timescales are as short as the characteristic timescale ∼10 ms, and, therefore, might affect the evolution of the post-merger object. Our analysis indicates that bulk viscous damping would be important at not too high temperatures of the order of a few MeV and densities up to a few times saturation density.

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Author:Mark Alford, Arus Harutyunyan, Armen SedrakianORCiDGND
Parent Title (German):Particles
Place of publication:Basel
Document Type:Article
Date of Publication (online):2020/06/19
Date of first Publication:2020/06/19
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2020/09/14
Tag:Urca processes; bulk viscosity; density oscillations; dissipation; neutrino-trapping; neutron star mergers
Page Number:18
First Page:500
Last Page:517
Institutes:Wissenschaftliche Zentren und koordinierte Programme / Frankfurt Institute for Advanced Studies (FIAS)
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - Namensnennung 4.0