Extraction of Rotation Energy from a Black Hole

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Extraction of Rotation Energy from a Black Hole

• Kyoto University (YITP)
• S. Nagataki

18th July 2007, YITP
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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
1052 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. 1031 times larger than
the atomic bomb dropped on Hiroshima.
Feb 28th 1997 Mar 3rd 1997
Explosion mechanism is still unknown.
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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
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Extraction of Rotation Energy from a Black Hole
(BZ effect)?
For any stationary system, we can define
conserved flux vector for energy.
Im going to study BZ effect numerically.
Its an interesting project!

Axisymmetry
Const.
Rotation Energy of a central BH
If an appropriate Tmunu is put around a BH,
energy can be extracted from the BH.
Blandford and Znajek (1977)
Roger and Me 2005, Banff, Canada.
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Numerical simulation of Blandford-Znajek Process
Numerical results for energy flux with various a.
T200, cGM1
RedNumerical BlueAnalytical
a0.95

For a ltlt 1 Blandford and Znajek (1997)
Monopole solution
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Formation of a jet (GRB?) from a Kerr BH
Beta_min100
NN150150
a0.938, with-magnetic field
T1200
R lt 60
We are planning to include microphysics and
perform more realistic simulations of GRBs in the
near future.
R lt 300
GcM1
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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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(H.19-H.22) ??????????????????? ? ?? ????