GRB-SN CONNECTION: CENTRAL ENGINE OF LONG GRBs AND EXPLOSIVE NUCLEOSYNTHESIS

I have developed two-dimensional general relativistic magnetohydrodynamic (GRMHD) code. I have performed numerical simulations of collapsars using these codes and realistic progenitor models. In the GRMHD simulation, it is shown that a jet is launched from the center of the progenitor. We also performed two-dimensional hydrodynamic simulations in the context of collapsar model to investigate the explosive nucleosynthesis happened there. It is found that the amount of (56)Ni is very sensitive to the energy deposition rate. This result means that the amount of synthesized (56)Ni can be little even if the total explosion energy is as large as 10(52) erg. Thus, some GRBs can associate with faint supernovae. Thus we consider it is quite natural to detect no underlying supernova in some X-ray afterglows.