1
|
Kiuchi K, Fujibayashi S, Hayashi K, Kyutoku K, Sekiguchi Y, Shibata M. Self-Consistent Picture of the Mass Ejection from a One Second Long Binary Neutron Star Merger Leaving a Short-Lived Remnant in a General-Relativistic Neutrino-Radiation Magnetohydrodynamic Simulation. PHYSICAL REVIEW LETTERS 2023; 131:011401. [PMID: 37478426 DOI: 10.1103/physrevlett.131.011401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 05/22/2023] [Accepted: 06/02/2023] [Indexed: 07/23/2023]
Abstract
We perform a general-relativistic neutrino-radiation magnetohydrodynamic simulation of a one second-long binary neutron star merger on the Japanese supercomputer Fugaku using about 85 million CPU hours with 20 736 CPUs. We consider an asymmetric binary neutron star merger with masses of 1.2M_{⊙} and 1.5M_{⊙} and a "soft" equation of state SFHo. It results in a short-lived remnant with the lifetime of ≈0.017 s, and subsequent massive torus formation with the mass of ≈0.05M_{⊙} after the remnant collapses to a black hole. For the first time, we find that after the dynamical mass ejection, which drives the fast tail and mildly relativistic components, the postmerger mass ejection from the massive torus takes place due to the magnetorotational instability-driven turbulent viscosity in a single simulation and the two ejecta components are seen in the distributions of the electron fraction and velocity with distinct features.
Collapse
Affiliation(s)
- Kenta Kiuchi
- Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg, Potsdam-Golm 14476, Germany
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Sho Fujibayashi
- Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg, Potsdam-Golm 14476, Germany
| | - Kota Hayashi
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Koutarou Kyutoku
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Interdisciplinary Theoretical and Mathematical Science Program (iTHEMS), RIKEN, Wako, Saitama 351-0198, Japan
| | - Yuichiro Sekiguchi
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
- Department of Physics, Toho University, Funabashi, Chiba 274-8510, Japan
| | - Masaru Shibata
- Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg, Potsdam-Golm 14476, Germany
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
| |
Collapse
|
2
|
Fujimoto Y, Fukushima K, Hotokezaka K, Kyutoku K. Gravitational Wave Signal for Quark Matter with Realistic Phase Transition. PHYSICAL REVIEW LETTERS 2023; 130:091404. [PMID: 36930907 DOI: 10.1103/physrevlett.130.091404] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 12/21/2022] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
The cores of neutron stars (NSs) near the maximum mass can realize a transitional change to quark matter (QM). Gravitational waves from binary NS mergers are expected to convey information about the equation of state (EOS) sensitive to the QM transition. Here, we present the first results of gravitational wave simulation with the realistic EOS that is consistent with ab initio approaches of χEFT and pQCD and is assumed to go through smooth crossover. We compare them to results obtained with another EOS with a first-order hadron-quark phase transition. Our results suggest that early collapse to a black hole in the post-merger stage after NS merger robustly signifies softening of the EOS associated with the QM onset in the crossover scenario. The nature of the hadron-quark phase transition can be further constrained by the condition that electromagnetic counterparts should be energized by the material left outside the remnant black hole.
Collapse
Affiliation(s)
- Yuki Fujimoto
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
- Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195, USA
| | - Kenji Fukushima
- Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kenta Hotokezaka
- Research Center for the Early Universe (RESCEU), The University of Tokyo, Tokyo 113-0033, Japan
| | - Koutarou Kyutoku
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan
- Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS), RIKEN, Saitama 351-0198, Japan
| |
Collapse
|
3
|
Foucart F. Neutrino transport in general relativistic neutron star merger simulations. LIVING REVIEWS IN COMPUTATIONAL ASTROPHYSICS 2023; 9:1. [PMID: 36852009 PMCID: PMC9950247 DOI: 10.1007/s41115-023-00016-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Numerical simulations of neutron star-neutron star and neutron star-black hole binaries play an important role in our ability to model gravitational-wave and electromagnetic signals powered by these systems. These simulations have to take into account a wide range of physical processes including general relativity, magnetohydrodynamics, and neutrino radiation transport. The latter is particularly important in order to understand the properties of the matter ejected by many mergers, the optical/infrared signals powered by nuclear reactions in the ejecta, and the contribution of that ejecta to astrophysical nucleosynthesis. However, accurate evolutions of the neutrino transport equations that include all relevant physical processes remain beyond our current reach. In this review, I will discuss the current state of neutrino modeling in general relativistic simulations of neutron star mergers and of their post-merger remnants. I will focus on the three main types of algorithms used in simulations so far: leakage, moments, and Monte-Carlo scheme. I will review the advantages and limitations of each scheme, as well as the various neutrino-matter interactions that should be included in simulations. We will see that the quality of the treatment of neutrinos in merger simulations has greatly increased over the last decade, but also that many potentially important interactions remain difficult to take into account in simulations (pair annihilation, oscillations, inelastic scattering).
Collapse
Affiliation(s)
- Francois Foucart
- Department of Physics and Astronomy, University of New Hampshire, 9 Library Way, Durham, NH 03824 USA
| |
Collapse
|