Gravitational wave detected on 09.14.2015 resulted from a merger of two black holes.
Gamma ray burst that could be related with GW150914 was observed by Fermi satellite.
Collapsing massive star and a black hole in a close binary could lead to the event.
GRB was powered by a weak neutrino flux produced in the remnant matter.
Low spin and kick velocity of the merged black hole are found in our simulations.