742 citations · 1.6k across the 26 of their papers we have counts for
29 papers
Spectral instabilities in the time domain
Taillte May, Adrien Kuntz, Nicola Franchini +2
We investigate the effect of a spectral instability on the time domain waveform using a one-dimensional double Pöschl-Teller model. By analytically following successive scatterings…
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…
Quasinormal modes of rotating black holes beyond general relativity in the WKB approximation
Ruijing Tang, Nicola Franchini, Sebastian H. Völkel +1
Exploring gravitational theories beyond general relativity (GR) with black hole (BH) spectroscopy requires accurate and flexible methods for computing their quasinormal mode (QNM)…
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…
Hyperbolicity in scalar-Gauss-Bonnet gravity: a gauge invariant study for spherical evolution
Farid Thaalba, Nicola Franchini, Miguel Bezares +1
We study spherical evolution in scalar-Gauss-Bonnet gravity with additional Ricci coupling and use the gauge-invariant approach of Ref.~\cite{Reall:2021voz} to track well-posedness…
The dynamics of spherically symmetric black holes in scalar-Gauss-Bonnet gravity with a Ricci coupling
Farid Thaalba, Nicola Franchini, Miguel Bezares +1
We study the dynamics of spherically symmetric black holes in scalar Gauss-Bonnet gravity with an additional coupling between the scalar field and the Ricci scalar using non-linear…
Higher-derivative corrections to the Kerr quasinormal mode spectrum
Pablo A. Cano, Lodovico Capuano, Nicola Franchini +2
We provide the most complete analysis so far of quasinormal modes of rotating black holes in a general higher-derivative extension of Einstein's theory. By finding the corrections…
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…
Slow rotation black hole perturbation theory
Nicola Franchini
In this paper, we present a detailed analysis of first-order perturbations of the Kerr metric in the slow-rotation limit. We perform the calculation by perturbing the Schwarzschild…
Spherical collapse in scalar-Gauss-Bonnet gravity: taming ill-posedness with a Ricci coupling
Farid Thaalba, Miguel Bezares, Nicola Franchini +1
We study spherical collapse of a scalar cloud in scalar-Gauss-Bonnet gravity - a theory in which black holes can develop scalar hair if they are in a certain mass range. We show th…
Testing General Relativity with Black Hole Quasi-Normal Modes
Nicola Franchini, Sebastian H. Völkel
The purpose of this chapter is to provide an overview of the exciting field of black hole quasi-normal modes and its capabilities to test general relativity in the 21st century. Af…
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…
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…
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…
Fixing the dynamical evolution in scalar-Gauss-Bonnet gravity
Nicola Franchini, Miguel Bezares, Enrico Barausse +1
One of the major obstacles to testing alternative theories of gravity with gravitational-wave data from merging binaries of compact objects is the formulation of their field equati…
Extreme mass-ratio inspirals as probes of scalar fields: eccentric equatorial orbits around Kerr black holes
Susanna Barsanti, Nicola Franchini, Leonardo Gualtieri +2
We study binary systems in which a stellar mass compact object spirals into a massive black hole, known as extreme mass ratio inspirals, in scenarios with a new fundamental scalar…
Theory-agnostic Reconstruction of Potential and Couplings from Quasi-Normal Modes
Sebastian H. Völkel, Nicola Franchini, Enrico Barausse
In this work, we use a parametrized theory-agnostic approach that connects the observation of black hole quasi-normal modes with the underlying perturbation equations, with the goa…
Detecting fundamental fields with LISA observations of gravitational waves from extreme mass-ratio inspirals
Andrea Maselli, Nicola Franchini, Leonardo Gualtieri +3
The Laser Interferometer Space Antenna, LISA, will detect gravitational wave signals from Extreme Mass Ratio Inspirals, where a stellar mass compact object orbits a supermassive bl…
The relation between general relativity and a class of Hořava gravity theories
Nicola Franchini, Mario Herrero-Valea, Enrico Barausse
Violations of Lorentz (and specifically boost) invariance can make gravity renormalizable in the ultraviolet, as initially noted by Hořava, but are increasingly constrained in the…
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…
Spin-induced black hole spontaneous scalarization
Alexandru Dima, Enrico Barausse, Nicola Franchini +1
We study scalar fields in a black hole background and show that, when the scalar is suitably coupled to curvature, rapid rotation can induce a tachyonic instability. This instabili…
Detecting scalar fields with Extreme Mass Ratio Inspirals
Andrea Maselli, Nicola Franchini, Leonardo Gualtieri +1
We study Extreme Mass Ratio Inspirals (EMRIs), during which a small body spirals into a supermassive black hole, in gravity theories with additional scalar fields. We first argue t…
Spontaneous scalarization in generalised scalar-tensor theory
Nikolas Andreou, Nicola Franchini, Giulia Ventagli +1
Spontaneous scalarization is a mechanism that endows relativistic stars and black holes with a nontrivial configuration only when their spacetime curvature exceeds some threshold.…
Cosmology with subdominant Horndeski scalar field
Nicola Franchini, Thomas P. Sotiriou
We study the cosmological evolution of a scalar field in Horndeski gravity, assuming that the scalar field is subdominant with respect to the cosmic fluid. We first analyse the mos…