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Free keywords:
General Relativity and Quantum Cosmology, gr-qc, Astrophysics, High Energy Astrophysical Phenomena, astro-ph.HE
Abstract:
Recently, two of us have argued that non-Kerr black holes in gravity theories
different from General Relativity may have a topologically non-trivial event
horizon. More precisely, the spatial topology of the horizon of non-rotating
and slow-rotating objects would be a 2-sphere, like in Kerr space-time, while
it would change above a critical value of the spin parameter. When the topology
of the horizon changes, the black hole central singularity shows up. The
accretion process from a thin disk can potentially overspin these black holes
and induce the topology transition, violating the Weak Cosmic Censorship
Conjecture. If the astrophysical black hole candidates are not the black holes
predicted by General Relativity, we might have the quite unique opportunity to
see their central region, where classical physics breaks down and quantum
gravity effects should appear. Even if the quantum gravity region turned out to
be extremely small, at the level of the Planck scale, the size of its apparent
image would be finite and potentially observable with future facilities.
