General relativistic moving-mesh hydrodynamic simulations with arepo and applications to neutron star mergers

• Verfasst von: Lioutas, Georgios [VerfasserIn]
• Verfasst von: Bauswein, Andreas [VerfasserIn]
• Verfasst von: Soultanis, Theodoros [VerfasserIn]
• Verfasst von: Pakmor, Rüdiger [VerfasserIn]
• Verfasst von: Springel, Volker [VerfasserIn]
• Verfasst von: Röpke, Friedrich [VerfasserIn]
• Titel: General relativistic moving-mesh hydrodynamic simulations with arepo and applications to neutron star mergers
• Verf.angabe: Georgios Lioutas, Andreas Bauswein, Theodoros Soultanis, Rüdiger Pakmor, Volker Springel, Friedrich K Röpke
• E-Jahr: 2024
• Jahr: February 2024
• Umfang: 24 S.
• Illustrationen: Diagramme
• Fussnoten: Online veröffentlicht: 10. Januar 2024 ; Gesehen am 17.09.2024
• Titel Quelle: Enthalten in: Royal Astronomical SocietyMonthly notices of the Royal Astronomical Society
• Ort Quelle: Oxford : Oxford Univ. Press, 1827
• Jahr Quelle: 2024
• Band/Heft Quelle: 528(2024), 2 vom: Feb., Seite 1906-1929
• ISSN Quelle: 1365-2966
• DOI: doi:10.1093/mnras/stae057
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1902739191

Abstract

We implement general relativistic hydrodynamics in the moving-mesh code arepo. We also couple a solver for the Einstein field equations employing the conformal flatness approximation. The implementation is validated by evolving isolated static neutron stars using a fixed metric or a dynamical space-time. In both tests, the frequencies of the radial oscillation mode match those of independent calculations. We run the first moving-mesh simulation of a neutron star merger. The simulation includes a scheme to adaptively refine or derefine cells and thereby adjusting the local resolution dynamically. The general dynamics are in agreement with independent smoothed particle hydrodynamics and static-mesh simulations of neutron star mergers. Coarsely comparing, we find that dynamical features like the post-merger double-core structure or the quasi-radial oscillation mode persist on longer time scales, possibly reflecting a low numerical diffusivity of our method. Similarly, the post-merger gravitational wave emission shows the same features as observed in simulations with other codes. In particular, the main frequency of the post-merger phase is found to be in good agreement with independent results for the same binary system, while, in comparison, the amplitude of the post-merger gravitational wave signal falls off slower, i.e. the post-merger oscillations are less damped. The successful implementation of general relativistic hydrodynamics in the moving-mesh arepo code, including a dynamical space-time evolution, provides a fundamentally new tool to simulate general relativistic problems in astrophysics.