A near horizon extreme binary black hole geometry

Jacob Ciafre,Maria J Rodriguez

doi:10.1140/epjc/s10052-019-7188-3

Jacob Ciafre, Maria J Rodriguez

Open Access

https://doi.org/10.1140/epjc/s10052-019-7188-3

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Abstract

A new solution of four-dimensional vacuum General Relativity is presented. It describes the near horizon region of the extreme (maximally spinning) binary black hole system with two identical extreme Kerr black holes held in equilibrium by a massless strut. This is the first example of a non-supersymmetric, near horizon extreme binary black hole geometry of two uncharged black holes. The black holes are co-rotating, their relative distance is fixed, and the solution is uniquely specified by the mass. Asymptotically, the geometry corresponds to the near horizon extreme Kerr (NHEK) black hole. The binary extreme system has finite entropy.

Highlights

Stationary BBHs solutions of Einstein’s equations of General Relativity in vacuum with two-(neutral)Kerr black holes are known analytically
The geometry corresponds to the near horizon extreme Kerr (NHEK) black hole
The solution of extremal co-rotating identical BBHs [28] from which we derive the new near-horizon geometry of extreme BBHs, takes a simpler representation in Weyl coordinates

Summary

Near-horizon extreme black hole binary geometry

The solution of extremal co-rotating identical BBHs [28] (that for completeness we review in Appendix A) from which we derive the new near-horizon geometry of extreme BBHs, takes a simpler representation in Weyl coordinates. As a result of this process, we find the near-horizon extreme black hole binary NHEK2 geometry in Weyl coordinates (1) This is defined by the equations f. For a fixed value of the total mass, it is expected that other finite near-horizon extremal BBHs with localized conical singularities (or equivalently non-smooth horizons) exist. These may include extremal BBHs containing two black holes with non-identical masses or with spins that are not aligned. Another intriguing aspects related to the uniqueness includes the classifications of near horizon geometries

Discussion

A Extreme co-rotating binary black hole review and