Gravitational Collapse of Rotating Massive Stars

Rotational Core-Collapse
in
Neutrino Leakage Scheme
東大理,早稲田理工
固武慶、山田章一、佐藤勝彦
Introduction
コアの回転により、非球対称なneutrino放射
が実現すれば、爆発する。
（Shimizu et al. ‘94)
ＰｒｏｔｏＮＳ
Oblate
Neutrino
Sphere
回転コラプス＋二次元neutrino輸送が必要
Neutrino Leakage Scheme
で neutrino sphere の物理的状況を調べる。
序章
1. Very Short Overview of Standard Supernova Physics
2. Why do we pay attention to rotation ?
3. Expected effects of Rotation on Dynamics
4. Known and Unknown things
Standard Supernova Scenarios.
Explosion Mechanism of Collapse-Driven Supernovae
Prompt Explosion
Delayed Explosion
Fe core
Shock wave
Stalled shock
PNS
DIFFICULT
LIKELY
Why do we pay attention to
rotation?
It’s because rotation is supported
By
Observation : Ring like CSM is reported
in SN 1987A
: Speckle image of envelope
&
Theory (maybe)
: No explosion by 1 dim simulation with G.R
and Boltzmann transfer (Liebendeorfer 00)
: multi-dimensional effect may be essential by Burrows (02)
(Our competitor: MPA(Janka ..), Oakridge(Messer), Swesty)
Expected effects of Rotation on Dynamics
Spherical Collapse
Rotational collapse
Rotation and Neutrino heating should be essential for successful
Explosion.
Unknown and Known thing
Rotation
NOT good for prompt explosion,
Because centrifugal force reduces
The gravitational energy.
Yamada and Sato (’94)
Good for delayed Explosion
IF
Anisotropic neutrino radiation
is obtained. (Shimizu et al.)
Set up for this Study
• Numerical Scheme
• Input Physics
: Electron capture
: Neutrino Leakage Scheme
Numerical Scheme for Hydro
•Hydro: (ROBUST) ZEUS Code (Stone and Norman ,92)
• ＥＯＳ: Shen et al. 98
• Self Gravity:
MICCG Method
ZEUS can reproduce numerical tests (Sod test etc..)
Input Microphysics のまとめ
電子捕獲
Ｐ
（１）
e
（１）自由陽子への捕獲
（２）原子核の中の陽子への捕獲
核
Ｐ
（２）
Ｐ
＋プラス
Neutrino の漏れ出し
Neutrino Leakage Scheme
(NLS)
Epstein (’78)
Van Riper et al. (’81)
電子捕獲の計算法(Epstein & Pethick, ’82)
Fermi Golden Rule
Electron capture on Free proton
Q value :
Transition rate:
Fermi Integral :
Electron Capture on Nuclei
As a result,
Concept of NLS.
Free escaping region
Diffusion region
Details of NLS
The opacity source of neutrino.
Neutrino - Nuclei Coherent scattering
Neutrino – Nucleons scattering
Neutrino absorption by Neutron
Escaping Time:
Numerical Results
0. Initial condition
1. Adiabatic and Spherical Collapse
2. Adiabatic and Rotational Collapse
3. Spherical Collapse in NLS
4. Rotational Collapse in NLS
5. The expected neutrino sphere
6. The waveform of Gravitational wave
Initial Condition
まずは、
For Spherical Collapse (回転なし）
Presupernova model by W & W (’95)
コア質量： 1.32 M_solar
コア半径：1200 km
初期条件
For Rotational Collapse
微分回転を仮定
M & M (‘89)
Heger et al. (‘01)
Standard model
Rapid model
Adiabatic and Spherical Collapse
Time evolution of the shock wave.
爆発する
Explosion energy =
Adiabatic and Rotational
Collapse
Bounce 時の諸物理量の比較
遠心力のなせる業
やはり、回転はprompt explosion
には良くない
Yamada et al. (94)
Shock Stalls!
Spherical Collapse in NLS
Shock Stalls.
Time Evolution of Shock Wave
Time evolution of Lepton.
Rotational Collapse in NLS
Standard model
SHOCK STALLS
Rapid model
The Expected Neutrino Sphere
(1)
Spherical Collapse
Rotational Collapse (Standard)
Z (cm)
R (cm)
The Expected Neutrino Sphere (2)
Rotational Collapse (standard)
Rotational Collapse (Rapid)
Neutrino Sphere の比較
We estimate the neutrino Luminosity as follows,
回転コラプス＋ Anisotropic neutrino heating scenario
を支持する結果を得た。
The Waveform of GW
The amplitude of GW as follows [Moenchmeyer et al . ’91]
The wave form
In standard model
Within Sensitivity?
（もっと、系統的に
調べる必要があるが）
一例（standardに
ついては）
YES
Summary
We simulated the rotational core-collapse in
Neutrino Leakage Scheme.
The anisotropic neutrino radiation,
which Shimizu et al. 94 assumed, is confirmed
by the Neutrino Leakage scheme.
The qualitative features induced by rotation do not change
with other works by employing the EOS (Shen et al. ’98)
[ Mueller et al. (‘80), Hillebrandt and Mueller (’81), Moenchmeyer et
al. (91), Yamada and Sato (94,95),Heger et al. (01), Demmelmeiner et al.
(02)]
高さ(時間）
展望
2 dim neutrino radiation transport
D1，厳冬、今の計算をまとめた後、愈々、登山開始。
D1, 初秋、山田、佐藤さんとの議論の中で、ZEUS を
使うことなる。
D1，酷暑、試行錯誤を繰り返す。
M2, 正月過ぎ、修論発表、清水さんhydro + Shen +Leakage
M2, 盛夏計算start

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