Transcript 高密度天体物理学 イントロダクション

Extraction of Rotation Energy
from a Black Hole
Kyoto University （YITP）
S. Nagataki
１８th July 2007, YITP
Gamma-Ray Bursts
～the most powerful explosion in the universe～
Image of GRB９７０２２８ by HST
Some GRBs are known to be
associated with hypernova explosions
whose explosion energy is 10^52 erg.
= 10 times larger than the explosion
energy of a supernova explosion.
= 10 times larger than the energy
emitted from the sun in its whole
life.
Feb 28ｔｈ １９９７
Mar 3ｒｄ １９９７
= 10^31 times larger than the atomic
bomb dropped on Hiroshima.
Explosion mechanism is still unknown.
Hypernova Explosion
Its spectrum is similar to that of
a core-collapse supernova (death of
a massive star).
Hypernova will be also associated with
death of a (very) massive star.
In a core-collapase supernova, a neutron
Star is formed at the center.
In a hypernova, a black hole is formed
At the center?
GRB030329 / SN2003dh
Extraction of Rotation Energy
from a Black Hole (BZ effect)?
I’m going to study
BZ effect numerically.
For any stationary system, we can
It’s an interesting
define conserved flux vector for energy.
project!
=
Axisymmetry
Rotation Energy of a central BH
Roger and Me 2005, Banff, Canada.
Const.
If an appropriate Tmunu is put around
a BH, energy can be extracted from
the BH.
Blandford and Znajek (1977)
Numerical simulation of Blandford-Znajek Process
Numerical results for energy
flux with various a.
a=0.95
T=200, c=G=M=1
Red:Numerical
Blue:Analytical
=
Monopole solution
For a << 1
Blandford and Znajek (1997)
Formation of a jet (GRB?) from a Kerr BH
Beta_min=100
a=0.938, with-magnetic field
N×N=150×150
T=1200
R
<
60
We are planning to include microphysics and
R <perform
300
more realistic simulations of GRBs in the near future. G=c=M=1
My Collaborators on GRBs
R. Blandford (KIPAC)
F. Iocco （KIPAC）
S. Pasquale （Fermi Lab）
K. Murase (Kyoto)
J. Aoi (Kyoto)
A. Mizuta (Chiba)
R. Takahashi (U. of Tokyo)
T. Kato (OSAKA)
K. Asano (NAOJ)
T. Yamasaki (CEA Saclay)
S. Mineshige (Kyoto)
H. Takami (U. of Tokyo)
T. Takiwaki (U. of Tokyo)
H. Yoshiguchi (U. of Tokyo)
S. Tsubaki (U. of Tokyo)
K. Kohri (Lancaster)
T. Shimizu (RIKEN)
S. Yamada (Waseda)
H. Takabe (Osaka)
M. Hashimoto (Kyusyu)
K. Sato (U. of Tokyo)
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