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From the 1 of 7 linked papers with an AI index.

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7 papers

gr-qc2026

Parametrized beyond-Teukolsky framework in the time domain

Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas +1

The authors develop a time‑domain implementation of the parametrized beyond‑Teukolsky framework to study how modifications to General Relativity affect black‑hole perturbations, an…

astro-ph.HE2026

Magnetorotational instabilities in solids: Application to neutron-star crusts

Arthur G. Suvorov, Thomas Celora, Kostas D. Kokkotas

The magnetorotational instability can generate strong, turbulent substructure within magnetized shear flows. The efficacy of the mechanism as a function of microphysical aspects of…

gr-qc2026

Confronting eikonal and post-Kerr methods with numerical evolution of scalar field perturbations in spacetimes beyond Kerr

Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas +2

The accurate computation of quasinormal modes from rotating black holes beyond general relativity is crucial for testing fundamental physics with gravitational waves. In this study…

gr-qc2026

Parameter estimation of gravitational wave echoes from exotic compact objects

Andrea Maselli, Sebastian H. Völkel, Kostas D. Kokkotas

Relativistic ultracompact objects without an event horizon may be able to form in nature and merge as binary systems, mimicking the coalescence of ordinary black holes. The postmer…

astro-ph.HE2026

Modeling X-ray reflection spectra from returning radiation: application to 4U 163047

Kostas Kourmpetis, Shafqat Riaz, Honghui Liu +6

Returning radiation is thought to play a key role in disk illumination of black hole X-ray binaries in the high-soft state, yet it has not been fully incorporated into XSPEC reflec…

gr-qc2025

Perturbing the vortex: quasinormal and quasibound spectra of rotating acoustic geometries

H. S. Vieira, Kyriakos Destounis, Kostas D. Kokkotas

Strong-field gravity simulators are laboratory experiments that can investigate a wide range of both classical and quantum phenomena occurring in nature. In this work, we introduce…