prof. dr hab. Edward Malec, UJ

Gravitation and accretion of matter.

The energy efficiency in accretion processes onto black holes might exceed tenfold (and even more) the efficiency of thermonuclear fusion. Thus it is not suprising that brightest objects in the Universe are powered by accretion of matter onto black holes. The physical description of such systems must refer to Einstei equations with selfgravity of infalling fluids included, and in the first step (selfconsistent) equilibria solutions have to be found. I shall report recent results, obtained in Krakow, on finding stationary configurations that describe rotating fluid disks around spinless or spinning black holes. One of important ingredients is the discovery of new rotation laws; they include, in particular, generalization of the familiar Keplerian rotation. Interestingly, the general-relativistic Keplerian rotation seems to fit to the description of a phase of evolution of the black hole and a torus, that are produced in the coalescence of two neutron stars, and that might be associated with the recent detection (GW170817) of gravitational waves and gamma rays bursts.