1. Extraction of Rotation Energy from a Black Hole Kyoto University （ YITP ） S. Nagataki １８ th July 2007, YITP

2. Gamma-Ray Bursts ～ the most powerful explosion in the universe ～ Image of GRB ９７０２２８ by HST Feb 28 ｔｈ １９９７ Mar 3 ｒｄ １９９７ 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. = 10^31 times larger than the atomic bomb dropped on Hiroshima. Explosion mechanism is still unknown.

3. Hypernova Explosion GRB030329 / SN2003dh 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?

4. Extraction of Rotation Energy from a Black Hole (BZ effect)? Rotation Energy of a central BH = Const. For any stationary system, we can define conserved flux vector for energy. Blandford and Znajek (1977)Roger and Me 2005, Banff, Canada. I’m going to study BZ effect numerically. It’s an interesting project! If an appropriate Tmunu is put around a BH, energy can be extracted from the BH. Axisymmetry

5. Numerical simulation of Blandford-Znajek Process For a << 1 Blandford and Znajek (1997) = a=0.95 Monopole solution T=200, c=G=M=1 Red:Numerical Blue:Analytical Numerical results for energy flux with various a.

6. Formation of a jet (GRB?) from a Kerr BH a=0.938, with-magnetic field N×N=150×150 T=1200 R < 60 R < 300 G=c=M=1 Beta_min=100 We are planning to include microphysics and perform more realistic simulations of GRBs in the near future.

7. 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) 科学研究費 若手 B （ H.19 － H.21 ） 「ガンマ線バーストに於けるハドロン加速及び高エネルギー放射」 代表 長瀧 重博 科学研究費 基盤 S （ H.19 － H.23 ） 「超新星の爆発機構とガンマ線バースト源エンジンの統一的解明」 代表 佐藤 勝彦 科学研究費 特定領域 （ H.19 － H.22 ） 「ガンマ線バーストで読み解く太古の宇宙 」 代表 河合誠之