Numerical modeling of core-collapse supernovae and compact objects

Simulations Crab nebula K. Sumiyoshi

Numazu College of Technology, Japan hubblesite.org Y. Suwa (2010)

• Challenges to clarify supernova explosions • Multi-physics at extreme conditions in 3D to understand birth places of neutron stars

IAU Sympo on NS & pulsars, 2012. 8. 20. 1� SN1054 Supernovae are fascinating� Crab nebula – Bright displays by explosions • Recorded in old Chinese literatures

– Supernova neutrinos from SN1987A 客星 “Guest Star” From Gravitation by Misner, Thorn, Wheeler • Neutrinos in supernova mechanism Prof. Koshiba

– Birth places of neutron stars and black holes • Mass, rotations, distributions SN1987A Prof. Koshiba

Neutrinos play important roles! Kamiokande

Mann "Shadow of a Star" ν

http://www-sk.icrr.u-tokyo.ac.jp/ http://nobelprize.org/ Nobel prizes in 2002 2� time Massive stars to neutron stars� ~107 years

• Fe core of ~20Msun stellar evolution

~1 second • Collapse, bounce & explosion difficult part!! Supernova simulations

ν • Proto-neutron star cooling ~20 seconds – neutrino bursts neutron star models • Neutron star cooling ~103 years – X, γ-rays

http://chandra.harvard.edu/photo/ Mann "Shadow of a Star" 3� Challenges in supernova physics�

• Difficult to reproduce explosions in simulations

Major problems • Exotic conditions • Counteracting ~1% effects • Multi-dimensions�

• Need large scale simulations in supercomputers

4� Gravitational collapse, bounce and explosion Massive star Fe core Collapse ν ν-trapping high density

e-capture ν ν ν

1000 km ν Supernova neutrinos ν Core Bounce Explosion ν nuclear force difficult part!!

ν proto- NS ν ν Shockwave 10 km Neutron star 5� Exotic conditions: challenges in nuclear physics� • Equation of state (EOS) in supernova core 14 3 - Dense more than nuclei: ρ > ρ0=3x10 g/cm 56 - Neutron-rich: Yp < Z/A=0.46 for Fe - Very Hot: T > 1011 K (~10 MeV)

• Neutrino reactions in hot-dense matter

- Energy, angle dependent ex. - e + p ↔ νe + n - All targets (n, p, nuclei, leptons) νi + Fe ↔ νi + Fe Emission, absorption, scattering & pairs - + e + e ↔ νi + νi • Necessary inputs for numerical simulations

6� Issues on equation of state (EOS)�

Nuclear mass, radius R • Data table of EOS n Rp – Nuclear theory Rn R for wide range of (ρ, T, Y ) p e Na isotopes • 2 major EOS sets Neutron star mass, radius – LS-EOS, Shen-EOS 3 • New: Hempel, G. Shen 2 Shen-EOS 1 LS-EOS 0 14 15 16 10 10 10 3 central mass density [g/cm ] http://user.numazu-ct.ac.jp/~sumi/eos Shen-EOS table 7� 1% effects: energy budget for explosion

• Iron core to neutron star (Mcore~1.4Msolar) 3 – RFe~10 km → RNS~10 km • Gravitational energy released 2 2 ⎛ GM GM ⎞ 53 ΔEGrav = −⎜ − ⎟ ~ 10 erg ⎝ RFe RNS ⎠ 51 • Explosion energy: Eexp ~ 10 erg 53 € • Neutrino carries away: Eν ~ 10 erg

• Only ~1% is used for the explosion • Neutrino-matter interaction is essential

8� Initial shockwave stalls on the way Energy is used during the propagation Shock 200 wave Shock position [km] 150

Fe core 100

After 50 Core bounce Sumiyoshi et al. (2005) 0 0.0 0.1 0.2 time0.3 [s]

Initial shock energy Energy loss due to Fe dissociation 2 ⎛ ⎞ GMinner 51 51 Mouter E shock ~ = several ×10 erg E loss ~ −1.6 ×10 ⎜ ⎟erg Rinner ⎝ 0.1Msolar ⎠

9

€ € Neutrino heating mechanism for revival of shock - Heating by neutrino absorption νe + n → e + p, Fe core ν + p → e+ + n surface e Transfer of energy from ν Shock ⎛ ΔM ⎞⎛ Δt ⎞ ~200km 51 Eν −heat ~ 2.2 ×10 ⎜ ⎟⎜ ⎟erg ⎝ 0.1Msolar ⎠⎝ 0.1s⎠ heating Shock position Delayed explosion� ν ν ν € Proto-NS ν- 100ms after bounce heating

Depends on neutrino energy/flux time [s]

Bethe & Wilson ApJ (1985) 10� SN1987A Multi-dimensions: new findings� - Convection, SASI, rotation, magnetic etc - Observations ν-heating and/or hydro instability Wang (2002)

ν

ν Proto- NS shockwave ν-heating�

To obtain enough ν-heating

Suwa et al. (2010) PASJ 11� Challenges toward 3D simulations Liebendoerfer (2001) Neutrino-radiation hydrodynamics

• 1D: No explosion found Marek (2009) – first principle calculations • 2D: Cases of explosions – State-of-the-art, but approximate neutrinos Several mechanisms, discussions not settled Iwakami (2008)

• 3D: Explore new instabilities – Major challenges of supernova simulations

3D Neutrino transfer is 6D problems (Sumiyoshi-Yamada, 2012 ApJS) 12� 3D simulation of supernovae from a massive star Explosions obtained, but still not conclusive Need high resolutions, accurate ν-transfer • Simulations running at K-computer, 10Peta-flops

@ Kobe, Japan

Takiwaki et al. (2012) ApJ 13� Assuming explosion, neutron star modeling� ν-bursts from proto-NS pulsar kicks and rotations

ν-average energy Proto- NS

LS-EOS velocity ~ 300 km/s Shen-EOS

time time cooling of proto-NS postbounce 3D hydro Suzuki et al. (2004) Janka (2012) 14� Supernovae: Multi-physics from fm to km� Extreme conditions, ~1% effects, multi-dimensions Microphysics Macrophysics • Equation of state • Hydrodynamics • Neutrino reactions • Neutrino transfer • Nuclear data • Stellar models

>10 km=103 m ~ fm=10-15 m • Numerical simulations of core-collapse supernovae • Supercomputing technology • Challenges continue to answer the birth of pulsars 2D: cases of explosions 3D: current challenges 15� 3D supernova project in collaboration with • Supernova research • Supercomputing – S. Yamada – H. Matsufuru – H. Nagakura – A. Imakura – H. Suzuki – T. Sakurai • RMF-EOS table • Numerical simulations – H. Shen – K. Kotake – K. Oyamatsu – T. Takiwaki – H. Toki – K. Nakazato • Extension of EOS table • Neutrino reactions – S. Furusawa – T. Sato – A. Ohnishi – S. Nasu – C. Ishizuka – S. Nakamura Supercomputing resources at KEK, RCNP, YITP, UT Support from: HPCI Strategic Program Field 5 - Grant-in-Aid for Scientific Research on Innovative Areas (20105004, 20105005) - Grant-in-Aid for Scientific Research (22540296, 24244036) 16�