89 citations · 774 across the 55 of their papers we have counts for
6 papers · 1 filter
Gravitational-wave Echoes Beyond the Hubble Time from Quantum Black Holes
Che-Yu Chen, Naritaka Oshita, Yuki Yokokura
We investigate gravitational-wave echoes in a horizonless compact object model, a non-perturbative solution of the semi-classical Einstein equation that reproduces the entropy-area…
Theoretical Aspects of Direct Waves in Kerr Black Holes: Pole-Splitting Method for Ringdown Analysis
Nao Nakamoto, Naritaka Oshita, Hiroki Takeda
We formulate the theoretical aspects of direct waves (DWs) in the case of extreme-mass merger. A DW is a source-driven waveform characterized by a complex frequency , wh…
Excitation factors and exceptional points of Kerr-de Sitter quasinormal modes
Dario Rossi, Naritaka Oshita, Leonardo Gualtieri +1
We compute the excitation factors of Kerr-de Sitter black hole quasinormal modes using two different techniques: a Heun function representation and an expansion of the solution in…
Excitation region of Kerr black hole quasinormal modes from Stokes geometry
Naritaka Oshita
We investigate the excitation region of black hole quasinormal modes (QNMs) from both analytical and numerical perspectives. On the analytical side, we propose that the QNM excitat…
Detectability of avoided crossings in black hole ringdowns
Hayato Imafuku, Naritaka Oshita, Hiroki Takeda
Quasinormal modes (QNMs) of black holes can exhibit avoided crossings (ACs), in which specific QNM frequencies approach each other while their amplitudes are enhanced and acquire n…
Exceptional Lines and Excitation of (Nearly) Double-Pole Quasinormal Modes: A Semi-Analytic Study in the Nariai Black Hole
Nao Nakamoto, Naritaka Oshita
We show that quasinormal modes (QNMs) of a massive scalar field in Kerr-de Sitter and Myers-Perry black holes exhibit an exceptional line (EL), which is a continuous set of excepti…