Gravity waves from extreme-mass-ratio plunges into Kerr black holes

We semi-analytically investigate the scalar self-force experienced in the final stages of extreme mass ratio inspirals of non-spinning scalar particles into supermassive nearly extremal Kerr black holes. We exploit the near-horizon conformal symmetry to find the self-force for general corotating equatorial geodesics. The angular component of the selfforce is shown to be universal at leading order in the high spin limit. We verify that the energy and angular momentum losses of the scalar particle match with the asymptotic fluxes of scalar radiation. In particular, we relate the previously described persistent oscillations in the asymptotic energy and angular momentum fluxes with the local selfforce. Such oscillations arise from travelling waves that prevent the near-horizon and the asymptotic region to fully decouple in the extremal limit. Conformal invariance is therefore reduced to discrete scale invariance with associated logarithmic periodicity.

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“…with R 0 = e κt 0κ . This exactly matches (4.18) of[55]. • γ → Plunging * (e)Bl mω = 2(2κ) −1 B circ √…”

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confidence: 81%

Scalar self-force for high spin black holes

et al. 2020

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“…The equivalence classes of equatorial critical and supercritical prograde timelike geodesics under the action of SL(2, R) × U (1)× ↑↓ symmetry were derived in [16] following earlier work [36][37][38]40]. In this section, we will perform the decomposition of arbitrary geodesics into equivalence classes under the action of SL(2, R) × U (1)× ↑↓ × × .…”

Section: Conformal Mappings Between Radial Classesmentioning

confidence: 99%

Near-horizon geodesics of high spin black holes

Compère

Druart

2020

Phys. Rev. D

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We provide an exhaustive and illustrated classification of timelike and null geodesics in the near-horizon region of near-extremal Kerr black holes. The classification of polar motion extends to Kerr black holes of arbitrary spin. The classification of radial motion leads to a simple parametrization of the separatrix between bound and unbound motion. Furthermore, we prove that each timelike or null geodesic is related via conformal transformations and discrete symmetries to spherical orbits and we provide the explicit mappings. We detail the high spin behavior of both the innermost stable and the innermost bound spherical orbits.

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“…Following the discussion in [54], we define κ ≡ √ 1 − a 2 and the following coordinate system 10) which is a simple transformation from the BL coordinates in Kerr. Here r + ≡ M (1 + κ) is the radius of the outer horizon.…”

Section: The Nhek Spacetime and The Ffe Equationsmentioning

confidence: 99%

Towards an understanding of the force-free magnetosphere of rapidly spinning black holes

2014

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The ability of a plasma surrounding spinning black holes to extract rotational energy and power energetic emissions has been recognized as a key astrophysical phenomenon. Important insights into the nature of this process are obtained through the analysis of the interplay between a force-free magnetosphere and the black hole. This task involves solving a complicated system of equations, often requiring complex numerical simulations. Recent analytical attempts at tackling this problem have exploited the fact that the near horizon region of extreme Kerr (NHEK) is endowed with an enhanced symmetry group. We continue in this direction and show that for some conformally selfsimilar solutions, the NHEK force-free equations reduce to a single non-linear ordinary differential equation which is difficult to solve with straightforward integration. We here introduce a new approach specifically tailored to this problem and describe how one can obtain physically meaningful solutions.

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Gravity waves from extreme-mass-ratio plunges into Kerr black holes

Cited by 62 publications

References 27 publications

Scalar self-force for high spin black holes

Scalar self-force for high spin black holes

Near-horizon geodesics of high spin black holes

Towards an understanding of the force-free magnetosphere of rapidly spinning black holes

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