High energy particles with negative and positive energies in the vicinity of black holes

It is shown that the energy in the centre of mass frame of two colliding particles in free fall at any point of the ergosphere of the rotating black hole can grow without limit for fixed energy values of particles on infinity. The effect takes place for large negative values of the angular momentum of one of the particles. It occurs that the geodesics with negative energy in equatorial plane of rotating black holes cannot originate or terminate inside the ergosphere. Their length is always finite and this leads to conclusion that they must originate and terminate inside the gravitational radius of the ergosphere. The energy in the centre of mass frame of one particle falling into the gravitational radius and the other arriving from the area inside it is growing without limit on the horizon.Comment: 12 pages, no figures. arXiv admin note: substantial text overlap with arXiv:1301.0698, arXiv:1304.736

On the energy of particle collisions in the ergosphere of the rotating black holes

It is shown that the energy in the centre of mass frame of colliding particles in free fall at any point of the ergosphere of the rotating black hole can grow without limit for fixed energy values on infinity. The effect takes place for large negative values of the angular momentum of one of the particles.Comment: 4 pages, 1 figur

Black holes and particles with zero or negative energy

We study properties of particles with zero or negative energy and a nonzero orbital angular momentum in the ergosphere of a rotating black hole. We show that the sign of the particle energy is uniquely determined by the angular velocity of its rotation in the ergosphere. We give a simple proof of the fact that extreme black holes cannot exist. We investigate the question of the possibility of an unlimited energy increase in the center-of-mass system of two colliding particles, one or both of which have negative or zero energy.Comment: 13 pages, 7 figure

Back reaction of the gravitational radiation on the metric of spacetime

The problem of back reaction of the gravitational radiation of the two merging black holes on the metric of the spacetime is investigated. It is shown for some models that large energy density of the gravitational waves close to the merger can lead to the disappearance of the visible accretion disc of the merged pair of black holes.Comment: 9 pages, no figures. New version matches the published version, includes adding references and corrections mainly in section