Near-extremal black holes

Abstract

We present a new formulation of deriving Hawking temperature for near-extremal black holes using distributions. In this paper the nearextremal Reissner-Nordström and Kerr black holes are discussed. It is shown that the extremal solution as a limit of non-extremal metric is well-defined. The pure extremal case is also discussed separately.

Estimation of temperature of cosmological apparent horizons: a new approach

“…As was mentioned earlier, this formalism was introduced in [37,38] and applied to the stationary and dynamical black hole horizons including extremal ones. The present work is the first attempt to find horizon temperature in a cosmological scenario using this formalism.…”

“…This method of calculating temperature associated with a trapping horizon was previously been introduced in [37,38] in the case of a black hole. It was motivated by the work of Damour and Ruffini [39] and is found to work for different types of horizons just as well as the tunneling method.…”

Black holes in Einstein-Gauss-Bonnet gravity: dynamical and 4-dimensional novel stationary black hole

“…To determine the temperature of the outer horizon we shall adopt the formalism discussed in [21] for static spherically symmetric black holes. Considering a scalar field, we shall construct the modes of the Killing vector across the horizon.…”

“…The method we have employed to calculate temperature of the dynamical horizon has been used to calculate temperature for the stationary (both non-extremal and extremal) [21] as well as dynamical horizons [22,23]. For dynamical horizons in 4-dimensions the symmetry of the spacetime plays an important role.…”

“…We shall calculate the temperature of the trapping horizon in EGB gravity by considering radiation from the horizon in the form of positive frequency field modes of the Kodama vector. This method has previously been employed to calculate temperature of horizons in different 4-dimensional spacetimes [21][22][23]. The set up is essentially local and dynamical.…”