Extended Theories of Gravity can be considered as a new paradigm to cure shortcomings of
General Relativity at infrared and ultraviolet scales. They are an approach that, by …

The essential singularity in Einstein's gravity can be avoidable if the preconditions of
Penrose's theorem can be bypassed, ie, if the strong energy condition is broken in the …

We drop the complexification procedure from the Newman-Janis algorithm and introduce
more physical arguments and symmetry properties, and we show how one can generate …

We give the general Kerr–de Sitter metric in arbitrary space–time dimension D≥ 4, with the
maximal number [(D− 1)/2] of independent rotation parameters. We obtain the metric in Kerr …

We present a rotating regular black hole whose inner horizon has zero surface gravity for
any value of the spin parameter and is, therefore, stable against mass inflation. Our metric is …

We study the shadow produced by a class of rotating black holes surrounded by plasma.
The metric for these black holes arises by applying the Newman-Janis algorithm to a family …

General relativity has been widely tested in weak gravitational fields but still stands largely
untested in the strong-field regime. According to the no-hair theorem, black holes in general …

All energy is gravitational energy. That is the consequence of the equivalence principle,
according to which gravity is the universal interaction. The physical charges of this …

A bstract We propose seven criteria to single out physically reasonable non-singular black-
hole models and adopt them to four different spherically symmetric models with a regular …

We show that the pseudotensors of Einstein, Tolman, Landau and Lifshitz, Papapetrou, and
Weinberg essentially coincide for any Kerr-Schild metric if calculations are carried out in …