Published May 2, 2023
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Emergence of microphysical viscosity in binary neutron star post-merger dynamics
Abstract
In nuclear matter in neutron stars the flavor content (e.g., proton fraction) is subject to weak interactions, establishing flavor (β-)equilibrium. During the merger of two neutron stars there can be deviations from this equilibrium. By incorporating Urca processes into general-relativistic hydrodynamics simulations, we study the resulting out-of-equilibrium dynamics during the collision. We provide the first direct evidence that microphysical transport effects at late times reach a hydrodynamic regime with a nonzero bulk viscosity, making neutron star collisions intrinsically viscous. Finally, we identify signatures of this process in the post-merger gravitational wave emission.
Additional Information
ERM thanks F. Foucart, J. Noronha-Hostler, A. Pandya, F. Pretorius and C. Raithel for insightful discussions related to this work. ERM gratefully acknowledges support from a joint fellowship at the Princeton Center for Theoretical Science, the Princeton Gravity Initiative and the Institute for Advanced Study. ERM acknowledges support for compute time allocations on the NSF Frontera supercomputer under grants AST21006. This work used the Extreme Science and Engineering Discovery Environment (XSEDE) [144] through Expanse at SDSC and Bridges-2 at PSC through allocations PHY210053 and PHY210074. The simulations were also in part performed on computational resources managed and supported by Princeton Research Computing, a consortium of groups including the Princeton Institute for Computational Science and Engineering (PICSciE) and the Office of Information Technology's High Performance Computing Center and Visualization Laboratory at Princeton University. ERM also acknowledges the use of high-performance computing at the Institute for Advanced Study. MGA, AH, and ZZ are partly supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award No. #DE-FG02-05ER41375. SPH is supported by the U. S. Department of Energy grant DE-FG02-00ER41132 as well as the National Science Foundation grant No. PHY-1430152 (JINA Center for the Evolution of the Elements). JN is partially supported by the U.S. Department of Energy, Office of Science, Office for Nuclear Physics under Award No. DE-SC0021301.Attached Files
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Additional details
- Eprint ID
- 121201
- Resolver ID
- CaltechAUTHORS:20230501-296892000.14
- Princeton University
- Institute for Advanced Study
- AST-21006
- NSF
- PHY-210053
- NSF
- PHY-210074
- NSF
- DE-FG02-00ER41132
- Department of Energy (DOE)
- PHY-1430152
- NSF
- DE-SC0021301
- Department of Energy (DOE)
- Created
-
2023-05-02Created from EPrint's datestamp field
- Updated
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2023-05-02Created from EPrint's last_modified field