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arXiv · 2509.07061

Spinning Black Holes in Modified Gravity via Spectral Methods

Kelvin Ka-Ho Lam·Adrian Ka-Wai Chung·Nicolás Yunes
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Abstract

Rapidly-rotating black-hole spacetimes outside general relativity are key to many tests of Einstein's theory. We here develop an efficient spectral method to represent such spacetimes analytically, in closed-form, and to high accuracy, in a large class of effective-field-theory extensions of general relativity. We exemplify this method by constructing, for the first time, closed-form and analytic representations of spinning black holes in scalar-Gauss-Bonnet, dynamical Chern-Simons, and axidilaton gravity to an accuracy better than $10^{-8}$ for all dimensionless spins below 0.99.

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Kelvin Ka-Ho Lam, Adrian Ka-Wai Chung, Nicolás Yunes. 2025-09-08. Spinning Black Holes in Modified Gravity via Spectral Methods. https://arxiv.org/abs/2509.07061

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