Are Gamma-Ray Bursts in Star-Forming Regions?

摘要: The optical afterglow of the gamma-ray burst GRB 970508 (z=0.835) was a few hundred times more luminous than any supernova. Therefore, name "hypernova" is proposed for whole GRB/afterglow event. There tentative evidence that GRBs 970228, 970508, and 970828 were close to star-forming regions. If this case strengthened with future afterglows, then popular model in which are caused by merging neutron stars will have be abandoned, linking cataclysmic deaths massive favored. presence X-ray precursors, first detected Ginga, easier understand within framework "dirty" rather "clean" fireball. A very energetic explosion star likely create dirty fireball clean one. specific speculative example such an proposed: microquasar. Its geometrical structure similar "failed supernova" Woosley: inner core massive, rapidly rotating collapses into ~10 M☉ Kerr black hole ~5×1054 ergs rotational energy, while outer forms disk/torus. superstrong ~1015 G magnetic field needed make object operate as microquasar Blandford & Znajek model. Such events must vary rare, 104-105 less common ordinary supernovae, if they account observed GRBs.