1 Nuclear physics and neutrino transfer in supernovae and compact objects K. ‘Sumi’yoshi - Neutrino transfer: Solver of 6D Boltzmann equation - Equation of state: Composition of dense matter Numazu College of Technology Japan NPCSM2016@YITP, Kyoto, 2016/11/15 Crab nebula hubblesite.org Nuclei and neutrinos Numazu near Mt. Fuji Wikipedia (trimmed) n
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Nuclear physics and neutrino transferin supernovae and compact objects
K. ‘Sumi’yoshi
- Neutrino transfer: Solver of 6D Boltzmann equation- Equation of state: Composition of dense matter
Numazu College of TechnologyJapan
NPCSM2016@YITP, Kyoto, 2016/11/15
Crab nebula
hubblesite.org
Nuclei and neutrinos
Numazu near Mt. FujiWikipedia (trimmed)
n
~10 km
Core-collapse SNe: collapse, bounce and explosion
1000 km
Fe core Collapse n-trapping
e-capture
Core Bounce
νν ν
ν
Shockwaveνν
ν
ν
Explosion
NS
ν
ν
10 km
proto-
Neutron star
Supernova neutrinos
Massive star ~20Msun
difficult part!!
2
~6000 km
~50 km
1051 erg
1053 ergscattering
in 1 second
n
r > r0
Proto-NS
Explosions mechanism in 2D & 3D
- Convection, SASI, rotation, magnetic etc
3
neutrino-heating with hydro instabilities
n-heating
n
n
shockwave
Marek et al, ApJ (2009) Suwa et al. (2010) PASJ
Enough time for n-heating
Deformation of shock Convection
* Sloweraccretion
* Longer Falling time
Roberts ApJ (2016)
1D
3D
2D
100 km
Takiwaki (2015)
Shock radius
time
• Numerical simulations of core-collapse supernovae
• Equation of state• Neutrino reactions
at 105-1015 g/cm3, ~1011 K
• Hydrodynamics• Neutrino transfer• General Relativity
4
Nuclear Physics Astrophysics
Supercomputing technology
Huge supercomputing power is necessary
• Main trigger, 2D vs 3D, low explosion energy?• Evaluation of neutrino-heating• Dependence on nuclear physics
http://www.aics.riken.jp
Remaining issues of explosion mechanism
• To clarify the problem we need full simulations
K-Computer, Japan
5
Neutrino transfer in 2D/3D supernovae
From approximate to exactneutrino-radiation hydrodynamics
Nagakura et al., ApJS (2014, 2016)Sumiyoshi et al., ApJS (2012, 2015)
Neutrino heating mechanism for revival of shockHeating by neutrino absorption ne + n → e- + p,
ne + p → e+ + n
nn n
~100km
Proto-NS
heating
Shock
Fe core surface
n-heating
Delayed explosion
Eν−heat ~ 2×1051 ΔM0.1Msolar
$
%&
'
()
Δt0.1s$
%&
'
()erg
Transfer of energy from n
Shock position
time [s]
100ms after bounce
Neutrino energy/fluxfrom trapped neutrinos
Janka A&A (1996)
n
pTrapped neutrinos
“Legendary simulation” in 1980’s
Bethe & Wilson ApJ (1985)Liebendörfer et al. (2000)
Shock position
time [s]
No explosion by modern 1D simulations
6
Reaction/scatteringDiffusion
High T/r Shock wave
Free-streamingn n
nn
n
n
n-transfer to determine n-heating
• From diffusion to free-streaming– Intermediate regime is important
• Approximations used so far- 2D/3D: Diffusion, Ray-by-Ray method
(1D spherical: 1st principle calculations)
• Comparison with Ray-by-ray- Local ν-heating ~20% difference
n nn
Ray-by-ray method
Sumiyoshi & Yamada, ApJS (2012)
€
fν (r,θ,φ; εν ,θν ,φν ; t)
Sumiyoshi et al. ApJS (2015)
Time evolution+Advection=Collision
€
1c∂fν∂t
+ n ⋅ ∇ fν =
1cδfνδt
'
( )
*
+ ,
collision
Boltzmann eq. • Collision Term is tough- Energy, angle dependent- Stiff, non-linear- Frame dependent→ Huge computation
Background fix 8
Neutrino-transfer in 3D space: fixed profile
150 msec after bounceRshock~250-400km
From Takiwaki et al. ApJ (2012)
entropy density Ye
entropy
9
11.2Msun, 3D
Fix hydro. variables, solve time evolution by 6D Boltzmann eq.- Evaluate stationary state of the neutrino distributions in 6D- Study neutrino transfer in 3D, heating rates, angle moments
3D supernova core at 150ms
Sumiyoshi et al. ApJS (2015)
6D BoltzmannRay-by-ray: radial only
• Ray-by-ray- Only radial transfer- Anisotropy enhanced