SMuK 2023 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 9: Gravitational Waves and Astrophysics I

GR 9.5: Vortrag

Mittwoch, 22. März 2023, 17:20–17:40, ZEU/0260

Binary neutron star merger simulations with neutrino transport and turbulent viscosity: impact of different schemes and grid resolution — •Francesco Zappa — Friedrich-Schiller-Universität Jena, Theoretisch-Physikalisches Institut, Jena, Germany

We present a systematic numerical relativity study of the impact of different treatment of microphysics and grid resolution in binary neutron star mergers.

We find that viscosity helps to stabilise the remnant against gravitational collapse but grid resolution has a larger impact than microphysics on the remnant's stability. The gravitational wave (GW) energy correlates with the maximum remnant density, that can be thus inferred from GW observations.

Simulations employing the M1 transport schemes show the emergence of a neutrino trapped gas that locally decreases the temperature a few percent when compared to the other simulation series. This out-of-equilibrium effect does not alter the GW emission at the typical resolutions considered for mergers.

Different microphysics treatments impact mass, geometry and composition of the remnant's disc and ejecta. Ejecta composition influences the nucleosynthesis yields, that are robust only if both neutrino emission and absorption are simulated. Synthetic kilonova light curves can be reliably predicted only including the various ejecta components.

We conclude that advanced microphysics in combination with resolutions higher than current standards appear essential for robust long-term evolutions and astrophysical predictions.