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arXiv · 1205.3945

Dynamical apparent horizons in inhomogeneous Brans-Dicke universes

Valerio Faraoni·Vincenzo Vitagliano·Thomas P. Sotiriou·Stefano Liberati
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Abstract

The presence and evolution of apparent horizons in a two-parameter family of spherically symmetric, time-dependent solutions of Brans-Dicke gravity are analyzed. These solutions were introduced to model space- and time-varying gravitational couplings and are supposed to represent central objects embedded in a spatially flat universe. We find that the solutions possess multiple evolving apparent horizons, both black hole horizons covering a central singularity and cosmological ones. It is not uncommon for two of these horizons to merge, leaving behind a naked singularity covered only by a cosmological horizon. Two characteristic limits are also explicitly worked out: the limit where the theory reduces to general relativity and the limit where the solutions become static. The physical relevance of this family of solutions is discussed.

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Valerio Faraoni, Vincenzo Vitagliano, Thomas P. Sotiriou, Stefano Liberati. 2012-09-26. Dynamical apparent horizons in inhomogeneous Brans-Dicke universes. https://doi.org/10.1103/physrevd.86.064040

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