77 citations · 652 across the 29 of their papers we have counts for
30 papers
Leviathan: a very massive, extended sub-millimetre galaxy spectroscopically confirmed at
William M. Baker, Francesco Valentino, Jens Hjorth +5
We present Leviathan, a sub-millimetre galaxy (SMG) spectroscopically confirmed at with JWST/NIRSpec. Modelling 31 bands of photometry from the rest-frame ultraviolet to…
Constraining the geometry of rotating black holes with eikonal QNMs
Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas
Quasinormal modes of black holes provide a central avenue for confronting general relativity with gravitational-wave observations from the ringdown stage of compact binary coalesce…
Optimal frequency scales for probing black-hole geometries
Saulo Albuquerque, Sebastian H. Völkel
Can gravitational waves probe the near-horizon geometry of black holes, and if yes, which frequency scale is optimal? Although shorter wavelengths usually resolve smaller scales, w…
Constraining deviations from the Teukolsky equation with GW250114
Sebastian H. Völkel, Nicola Franchini
The recent gravitational-wave detection GW250114 by the LIGO-Virgo-KAGRA (LVK) Collaboration provides unprecedented precision for testing general relativity (GR) through black hole…
Parametrized beyond-Teukolsky framework in the time domain
Ciro De Simone, Sebastian H. Völkel, Kostas D. Kokkotas +1
Modifications to General Relativity can significantly alter the perturbative response of black holes, leaving imprints on quasinormal-mode spectra, waveform amplitudes and phases,…
Bound States of the Schwarzschild Black Hole
Sebastian H. Völkel
Understanding the physical significance and spectral stability of black hole quasinormal modes is fundamental to high-precision spectroscopy with future gravitational wave detector…
Black hole spectroscopy: from theory to experiment
Emanuele Berti, Vitor Cardoso, Gregorio Carullo +65
The "ringdown" radiation emitted by oscillating black holes has great scientific potential. By carefully predicting the frequencies and amplitudes of black hole quasinormal modes a…
Ringdown spectroscopy of phenomenologically modified black holes
Spyros Thomopoulos, Sebastian H. Völkel, Harald P. Pfeiffer
The characteristic oscillations of black holes, as described by their quasinormal mode (QNM) spectrum, play a fundamental role in testing general relativity with gravitational wave…
Parametrized quasi-normal mode framework for modified Teukolsky equations
Pablo A. Cano, Lodovico Capuano, Nicola Franchini +2
Modifications to general relativity lead to effects in the spectrum of quasi-normal modes of black holes. In this paper, we develop a parametrized formalism to describe deviations…
Inverse problem of analog gravity systems II: Rotation and energy-dependent boundary conditions
Saulo Albuquerque, Sebastian H. Völkel, Kostas D. Kokkotas +1
In this work, we study the inverse problem of analog gravity systems which admit rotation and energy-dependent boundary conditions. By extending two recent results, we provide a re…
Inverse problem in energy-dependent potentials using semiclassical methods
Saulo Albuquerque, Sebastian H. Völkel, Kostas D. Kokkotas
Wave equations with energy-dependent potentials appear in many areas of physics, ranging from nuclear physics to black hole perturbation theory. In this work, we use the semi-class…
Inverse problem of analog gravity systems
Saulo Albuquerque, Sebastian H. Völkel, Kostas D. Kokkotas +1
Analog gravity models of black holes and exotic compact objects provide a unique opportunity to study key properties of such systems in controlled laboratory environments. In contr…
Rapidly rotating neutron stars: Universal relations and EOS inference
Christian J. Krüger, Sebastian H. Völkel
We provide accurate universal relations that allow to estimate the moment of inertia and the ratio of kinetic to gravitational binding energy of uniformly rotating neutro…
Quasi-normal modes of non-separable perturbation equations: the scalar non-Kerr case
Rajes Ghosh, Nicola Franchini, Sebastian H. Völkel +1
Scalar, vector and tensor perturbations on the Kerr spacetime are governed by equations that can be solved by separation of variables, but the same is not true in generic stationar…
Role of black hole quasinormal mode overtones for ringdown analysis
Peter James Nee, Sebastian H. Völkel, Harald P. Pfeiffer
Extracting quasinormal modes from compact binary mergers to perform black hole spectroscopy is one of the fundamental pillars in current and future strong-gravity tests. Among the…
A parametrized quasi-normal mode framework for non-Schwarzschild metrics
Nicola Franchini, Sebastian H. Völkel
In this work we comment in more detail on what happens to the parametrized framework first presented by Cardoso et al. when there are departures from the Schwarzschild background m…
Quasi-Normal Modes from Bound States: The Numerical Approach
Sebastian H. Völkel
It is known that the spectrum of quasi-normal modes of potential barriers is related to the spectrum of bound states of the corresponding potential wells. This property has been wi…
Constraining modifications of black hole perturbation potentials near the light ring with quasinormal modes
Sebastian H. Völkel, Nicola Franchini, Enrico Barausse +1
In modified theories of gravity, the potentials appearing in the Schrödinger-like equations that describe perturbations of non-rotating black holes are also modified. In this paper…
Constraining the Nuclear Equation of State from Rotating Neutron Stars
Sebastian H. Völkel, Christian J. Krüger
We demonstrate how observables of slowly rotating neutron stars can be used to constrain the nuclear equation of state. By building a Bayesian framework we demonstrate how combinin…
On Black Hole Area Quantization and Echoes
Andrew Coates, Sebastian H. Völkel, Kostas D. Kokkotas
In this work we argue that black hole area quantization of Bekenstein and Mukhanov should not give rise to measurable effects in terms of so-called gravitational wave echoes during…
Fast Rotating Neutron Stars: Oscillations and Instabilities
Christian J. Krüger, Kostas D. Kokkotas, Praveen Manoharan +1
In this review article, we present the main results from our most recent research concerning the oscillations of fast rotating neutron stars. We derive a set of time evolution equa…
Separating Astrophysics and Geometry in Black Hole Images
Guillermo Lara, Sebastian H. Völkel, Enrico Barausse
The observation of the shadow of the supermassive black hole M87 by the Event Horizon Telescope (EHT) is sensitive to the spacetime geometry near the circular photon orbit an…
Bayesian Inverse Problem of Rotating Neutron Stars
Sebastian H. Völkel, Christian J. Krüger, Kostas D. Kokkotas
In this work we provide a framework that connects the co-rotating and counter rotating -mode frequencies of rotating neutron stars with their stellar structure. The accurate com…
EHT tests of the strong-field regime of General Relativity
Sebastian H. Völkel, Enrico Barausse, Nicola Franchini +1
Following up on a recent analysis by Psaltis et al. [Phys. Rev. Lett. 125, 141104 (2020)], we show that the observed shadow size of M87 can be used to unambiguously and robustl…