Phenomenological Extension for Tidal Charge Black Hole

A simple phenomenological extension of the black hole solution with tidal charge is proposed. Empirical data on the Sgr A* black hole is consistent with the suggested metric which serves as a generalization of the Reissner–Nordström one. Such a generalization includes the leading effects beyond general relativity; so, the discussed metric can explain wider range of gravitational effects. We discuss physical features of an object described by the proposed metric, namely, the size of its shadow and the innermost stable circular orbit radius.