arXiv subjects

M A. M. Smith

Publications and source records attributed to M A. M. Smith.

2 recordsLinked to original sources

arXiv2024

High-energy interactions of charged black holes in full general relativity II: Near-extremal merger remnants and universality with the irreducible mass

In a previous paper, arXiv:2411.11960 [gr-qc], we initiated a study of high-energy interactions of charged binary black holes near the scattering threshold, focusing on zoom-whirl orbits. In this second paper in our series, we focus on merger remnant properties and energetics with new simulations of equal-mass, equal-charge, nonspinning binary black holes with variable impact parameter. We find near-extremal merger remnants with Kerr-Newman parameter reaching $Υ_f = 0.97$, and observe that the maximum $Υ_f$ increases monotonically with $λ$ for a fixed initial Lorentz factor. We find that binaries with larger $λ$ radiate less total energy despite having stronger electromagnetic emission. The maximum energy radiated by a binary in our study is $31\%$ of its gravitational mass. Increasing $λ$ has little effect on the maximum angular momentum radiated, which was $\approx 72\%$ of the spacetime total angular momentum for each $λ$ explored here. Lastly, we provide additional evidence for the universality with the irreducible mass that we discovered in arXiv:2411.11960 [gr-qc]. The black hole horizon areal radius determines a fundamental, gauge-invariant length scale governing BH interactions near the scattering threshold.

gr-qc↗

arXiv2024

High-energy interactions of charged black holes in full general relativity I: Zoom-whirl orbits and universality with the irreducible mass

We simulate high-energy scattering of equal-mass, nonspinning black holes endowed with like charges in full general relativity while varying the impact parameter $b$. We show that electrodynamics does not suppress zoom-whirl orbits for at least charge-to-mass ratios $λ= 0.1, 0.4, 0.6$. However, we find that as $λ$ increases, the immediate merger and scattering thresholds defining the zoom-whirl regime move to smaller impact parameter $b/M_{\rm ADM}$, with $M_{\rm ADM}$ designating the binary black hole gravitational mass. This demonstrates that charge leaves observable imprints in key properties at energy scales where charge has negligible influence in head-on collisions. Additionally, we find that these threshold impact parameters become universal, i.e., charge-independent, when we normalize $b$ by the sum of the initial BH irreducible masses in the binary ($b/M_{\rm irr}$). This is the first explicit demonstration that the irreducible mass, which is proportional to the black hole areal radius, defines a fundamental gauge-invariant length scale governing horizon scale scattering events in the strong-field, dynamical spacetime regime.

gr-qc↗