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arXiv · 2508.09988

General Boosted Black Holes: A First Approximation

Rodrigo Maier
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Abstract

In this paper we obtain an approximate solution of Einstein field equations which describes a general boosted Kerr-Newman black hole relative to a Lorentz frame at future null infinity. The boosted black hole is obtained from a general twisting metric whose boost emerges from the BMS group. Employing a standard procedure we build the electromagnetic energy-momentum tensor with the Kerr boosted metric together with its timelike Killing vector as the electromagnetic potential. We demonstrate that our solution satisfies Einstein field equations up to a fourth-order expansion in $1/r$, indicating that the spacetime closely resembles a Kerr-Newman black hole whose boost points in a arbitrary direction. Spacetime structures of the general black hole -- namely the event horizon and ergosphere -- are examined in Bondi-Sachs coordinates. For a proper timelike observer we show that the electric field generated by the boosted black hole exhibits a purely radial behavior, whereas the magnetic field develops a complex structure characterized by two pronounced lobes oriented opposite to the boost direction.

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Rodrigo Maier. 2025-08-13. General Boosted Black Holes: A First Approximation. https://arxiv.org/abs/2508.09988

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