Evolução de Buracos Negros Primordiais no Universo

Abstract

a lei de Stefan-Boltzmann válida pelo princípio da equivalência. 8 Ver capítulo 2 para uma discussão.

Realistic fluids as source for dynamically accreting black holes in a cosmological background

“…The off-diagonal term, together with the fact that G r r and G θ θ have to be equal, puts a stringent constraint on the choice of fluid. If a single perfect fluid is used as a source for this metric, the equality of the diagonal terms implies that the fluid has to be comoving [23]. This in turn implies that the off-diagonal term is zero, and therefore that ṁ has to vanish.…”

Horndeski theory meets the McVittie solution: A scalar field theory for accretion onto cosmological black holes

“…(a) McVittie metric (15) with constant mass In both examples, the expansion is given by Eq. (31). Note that, in this class of metrics, the null infinity I + is space-like.…”

“…A seminal step in this direction arXiv:1408.5538v1 [gr-qc] 24 Aug 2014 was taken when a generalized version of the McVittie metric was introduced with an arbitrary time-dependent mass [27], which generalized the Sultana-Dyer black hole [28] (in its turn obtained via a conformal transformation of the Schwarzschild metric), and was later applied to the problem of dark-energy accretion [29]. The specific form of the mass function could then in principle be obtained from the field equations, or from some hydrodynamic model for the source, which no longer could be taken to be a single perfect fluid [30] or a superposition of multiple perfect fluids [31], so a more general approach was needed. The needed step forward arrived when it was found that in the fluid interpretation the accretion (or evaporation) rate could be explained by the introduction of a heat-flow term associated to the presence of a temperature gradient via a Landau-Eckart model [32], as other viscous terms vanish due to the high degree of symmetry of the metric.…”

“…Figure 1: Examples of the causal structure of the McVittie and generalized McVittie metrics, depicting the apparent horizons and surfaces of constant time. A Schwarzschild-de Sitter extension is patched at the left of each diagram.In both examples, the expansion is given by Eq (31)…”