TY - JOUR

T1 - Simulations of the early postbounce phase of core-collapse supernovae in three-dimensional space with full boltzmann neutrino transport

AU - Iwakami, Wakana

AU - Okawa, Hirotada

AU - Nagakura, Hiroki

AU - Harada, Akira

AU - Furusawa, Shun

AU - Sumiyoshi, Kosuke

AU - Matsufuru, Hideo

AU - Yamada, Shoichi

N1 - Funding Information:
This research used high-performance computing resources of the K-computer/the supercomputer Fugaku provided by RIKEN, the FX10 provided by Tokyo University, the FX100 provided by the Nagoya University, the Grand Chariot provided by Hokkaido University, and the Oakforest-PACS provided by JCAHPC through the HPCI System Research Project (Project ID: hp130025, 140211, 150225, 150262, 160071, 160211, 170031, 170230, 170304, 180111, 180179, 180239, 190100, 190160, 200102, 200124), SR16000 and XC40 at YITP of Kyoto University, NEC SX Aurora Tsubasa at KEK, Research Center for Nuclear Physics (RCNP) at Osaka University, and the XC50 and the general common-use computer system provided by CfCA in the National Astronomical Observatory of Japan (NAOJ). Large-scale storage of numerical data is supported by JLDG constructed over SINET4 of NII. This work is supported in part by Grants-in-Aid for Scientific Research (26104006, 15K05093, 19K03837, 20H01905) and Grant-in-Aid for Scientific Research on Innovative areas "Gravitational wave physics and astronomy: Genesis" (17H06357, 17H06365) and "Unraveling the History of the Universe and Matter Evolution with Underground Physics" (19H05802) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. This work was also partly supported by research programs at K-computer of the RIKEN R-CCS, HPCI Strategic Program of Japanese MEXT, Priority Issue on Post-K-computer (Elucidation of the Fundamental Laws and Evolution of the Universe), Joint Institute for Computational Fundamental Sciences (JICFus) and MEXT as "Program for Promoting Researches on the Supercomputer Fugaku" (Toward a unified view of the universe: from large scale structures to planets). A.H. is supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Research Activity Start-up (19K23435). S.F. is supported by JSPS KAKENHI (19K14723). S.Y. is supported by Institute for Advanced Theoretical and Experimental Physics, and Waseda University and the Waseda University Grant for Special Research Projects (project No. 2020-C273). K.S. acknowledges the Particle, Nuclear and Astro Physics Simulation Program (2019-002, 2020-004) at KEK.
Publisher Copyright:
© 2020 The American Astronomical Society. All rights reserved.

PY - 2020/11/10

Y1 - 2020/11/10

N2 - We report on the core-collapse supernova simulation we conducted for a 11.2M⊙ progenitor model in threedimensional space up to 20 ms after bounce, using a radiation-hydrodynamics code with full Boltzmann neutrino transport. We solve the six-dimensional Boltzmann equations for three neutrino species and the three-dimensional compressible Euler equations with Furusawa and Togashi's nuclear equation of state. We focus on the prompt convection at ∼10 ms after bounce and investigate how neutrinos are transported in the convective matter. We apply a new analysis based on the eigenvalues and eigenvectors of the Eddington tensor and make a comparison between the Boltzmann transport results and the M1 closure approximation in the transition regime between the optically thick and thin limits. We visualize the eigenvalues and eigenvectors using an ellipsoid, in which each principal axis is parallel to one of the eigenvectors and has a length proportional to the corresponding eigenvalue. This approach enables us to understand the difference between the Eddington tensor derived directly from the Boltzmann simulation and the one given by the M1 prescription from a new perspective. We find that the longest principal axis of the ellipsoid is almost always nearly parallel to the energy flux in the M1 closure approximation, whereas in the Boltzmann simulation it becomes perpendicular in some transition regions, where the mean free path is ∼0.1 times the radius. In three spatial dimensions, the convective motions make it difficult to predict where this happens and to possibly improve the closure relation there.

AB - We report on the core-collapse supernova simulation we conducted for a 11.2M⊙ progenitor model in threedimensional space up to 20 ms after bounce, using a radiation-hydrodynamics code with full Boltzmann neutrino transport. We solve the six-dimensional Boltzmann equations for three neutrino species and the three-dimensional compressible Euler equations with Furusawa and Togashi's nuclear equation of state. We focus on the prompt convection at ∼10 ms after bounce and investigate how neutrinos are transported in the convective matter. We apply a new analysis based on the eigenvalues and eigenvectors of the Eddington tensor and make a comparison between the Boltzmann transport results and the M1 closure approximation in the transition regime between the optically thick and thin limits. We visualize the eigenvalues and eigenvectors using an ellipsoid, in which each principal axis is parallel to one of the eigenvectors and has a length proportional to the corresponding eigenvalue. This approach enables us to understand the difference between the Eddington tensor derived directly from the Boltzmann simulation and the one given by the M1 prescription from a new perspective. We find that the longest principal axis of the ellipsoid is almost always nearly parallel to the energy flux in the M1 closure approximation, whereas in the Boltzmann simulation it becomes perpendicular in some transition regions, where the mean free path is ∼0.1 times the radius. In three spatial dimensions, the convective motions make it difficult to predict where this happens and to possibly improve the closure relation there.

UR - http://www.scopus.com/inward/record.url?scp=85096060949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85096060949&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/abb8cf

DO - 10.3847/1538-4357/abb8cf

M3 - Article

AN - SCOPUS:85096060949

SN - 0004-637X

VL - 903

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 82

ER -