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arXiv · 1808.06692

Isolated black holes without $\mathbb{Z}_2$ isometry

Pedro V. P. Cunha·Carlos A. R. Herdeiro·Eugen Radu
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Abstract

A mechanism to construct asymptotically flat, isolated, stationary black hole (BH) spacetimes with no $\mathbb{Z}_2$ (No$\mathbb{Z}$) isometry is described. In particular, the horizon geometry of such No$\mathbb{Z}$ BHs does not have the usual north-south (reflection) symmetry. We discuss two explicit families of models wherein No$\mathbb{Z}$ BHs arise. In one of these families, we exhibit the intrinsic horizon geometry of an illustrative example by isometrically embedding it in Euclidean 3-space, resulting in an "egg-like" shaped horizon. This asymmetry leaves an imprint in the No$\mathbb{Z}$ BH phenomenology, for instance in its lensing of light; but it needs not be manifest in the BH shadow, which in some cases can be analytically shown to retain a $\mathbb{Z}_2$ symmetry. Light absorption and scattering due to an isotropic source surrounding a No$\mathbb{Z}$ BH endows it with a non-zero momentum, producing an asymmetry triggered BH rocket effect.

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Pedro V. P. Cunha, Carlos A. R. Herdeiro, Eugen Radu. 2018-11-21. Isolated black holes without $\mathbb{Z}_2$ isometry. https://doi.org/10.1103/physrevd.98.104060

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