All-Moscow Seminar of Astrophysicists
(ASA)


annotation of talk
Dr. M.V. Barkov (Space Research Institute, University of Leeds)
The nature of very long GRBs


We present simple stellar collapse physical model which allow us estimate the time evolution of the most important physical parameters of Black Holes --- mass and specific angular momentum and disk formation time. Polytrope star and star with power low density distributions was investigated. The disk accretion play important role in acceleration of BH rotaion. The BH specific angular momentum can reach value more than $0.9$ for wide range of stellar envelop angular momentum. Then with out disk accretion in case of power low stellar envelop it limited by value $0.45$. For solid body star rotation disk formed after 20-150 sec after core collapse, but accretion rate is hight enought to hold strong magnetosphere of black hole to provide hypernovae and gamma ray burst explosion duration 100-1000 sec. That was shown by numerical modeling with realistic initial conditions.