232 citations · 734 across the 30 of their papers we have counts for
30 papers
Black holes in alternative theories of gravity
Jose Luis Blázquez-Salcedo, Fech Scen Khoo, Burkhard Kleihaus +1
Black holes, with their strong gravitational fields, provide an important testing ground for theories of gravity beyond General Relativity. Among the many proposed alternatives, co…
Nonradial perturbations of static charged wormholes
Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo +2
We investigate the nonradial quasinormal-mode spectrum of static charged Ellis--Bronnikov wormholes in Einstein--Maxwell theory minimally coupled to a phantom scalar field. The bac…
Hierarchy of Angular Instabilities in Scalarized Black Holes
Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo +2
We investigate the stability of scalarized black holes in Einstein-scalar-Gauss-Bonnet-Ricci theory along their fundamental branches. We show that initially stable solutions first…
Radial perturbations of charged wormholes
Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo +2
Ellis-Bronnikov wormholes suffer from an unstable radial mode. Here we investigate the evolution of the unstable mode(s) for charged wormholes. We show that the instability remains…
Quadrupole perturbations of slowly spinning Ellis-Bronnikov wormholes
Bahareh Azad, Jose Luis Blázquez-Salcedo, Fech Scen Khoo +2
We study the axial and polar perturbations of slowly rotating Ellis-Bronnikov wormholes in General Relativity, applying a perturbative double expansion. In particular, we derive th…
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…
Scalar Quasinormal Modes of Rotating Regular Black Holes
Fech Scen Khoo
Quasinormal modes are characteristic signatures of compact objects. Here we consider rotating regular black holes, representing rotating generalizations of the Simpson and Visser m…
Quasinormal mode spectrum of rotating black holes in Einstein-Gauss-Bonnet-dilaton theory
Jose Luis Blázquez-Salcedo, Fech Scen Khoo, Burkhard Kleihaus +1
Quasinormal modes are excited during the ringdown phase of black holes after merger. Determination of quasinormal modes of rapidly rotating black holes in alternative theories of g…
Quasinormal modes of rotating black holes in shift-symmetric Einstein-scalar-Gauss-Bonnet theory
Fech Scen Khoo, Jose Luis Blázquez-Salcedo, Burkhard Kleihaus +1
We employ a recently developed spectral method to obtain the spectrum of quasinormal modes of rapidly rotating black holes in alternative theories of gravity and apply it to the bl…
Quasinormal modes of rapidly rotating Einstein-Gauss-Bonnet-dilaton black holes
Jose Luis Blázquez-Salcedo, Fech Scen Khoo, Burkhard Kleihaus +1
Quasinormal modes of rapidly rotating black holes are crucial in understanding the ringdown phase after a merger. While for Kerr black holes these modes have been known for a long…
Radial perturbations of Ellis-Bronnikov wormholes in slow rotation up to second order
Bahareh Azad, Jose Luis Blázquez-Salcedo, Fech Scen Khoo +1
We consider slowly rotating Ellis-Bronnikov wormholes and investigate their radial perturbations (), expanding up to second order in rotation. We present the detailed…
Quasinormal modes of rapidly rotating Ellis-Bronnikov wormholes
Fech Scen Khoo, Bahareh Azad, Jose Luis Blázquez-Salcedo +4
We present for the first time a study of the quasinormal modes of rapidly rotating Ellis-Bronnikov wormholes in General Relativity. We compute the spectrum of the wormholes using a…
Quasinormal modes of Kerr black holes using a spectral decomposition of the metric perturbations
Jose Luis Blázquez-Salcedo, Fech Scen Khoo, Jutta Kunz +1
We report a new method to calculate the quasinormal modes of rotating black holes, using a spectral decomposition to solve the partial differential equations that result from intro…
NASA Science Mission Directorate Knowledge Graph Discovery
Roelien C. Timmer, Fech Scen Khoo, Megan Mark +4
The size of the National Aeronautics and Space Administration (NASA) Science Mission Directorate (SMD) is growing exponentially, allowing researchers to make discoveries. However,…
Are slowly rotating Ellis-Bronnikov wormholes stable?
Bahareh Azad, Jose Luis Blázquez-Salcedo, Fech Scen Khoo +1
We investigate the radial perturbations of Ellis-Bronnikov wormholes () in a slowly rotating background expanded up to second order in rotation. We find indications t…
Quasinormal modes of slowly rotating Kerr-Newman black holes using the double series method
Jose Luis Blázquez-Salcedo, Fech Scen Khoo
We calculate the spectrum of quasinormal modes of slowly rotating Kerr-Newman black holes. Using a perturbative double expansion method, second order in rotation and first order in…
-modes of neutron stars in a massless scalar-tensor theory
Jose Luis Blázquez-Salcedo, Luis Manuel González-Romero, Fech Scen Khoo +2
Scalar-tensor theories allow for a rich spectrum of quasinormal modes of neutron stars. The presence of the scalar field allows for polar monopole and dipole radiation, as well as…
Universal relations for quasinormal modes of neutron stars in gravity
J. L. Blázquez-Salcedo, L. M. González-Romero, F. S. Khoo +2
We construct quasinormal modes for neutron stars in gravity in the Einstein frame, considering scalar masses in the sub-neV range. In particular, we investigate the fundament…
BRST symmetry of doubled membrane sigma-models
Athanasios Chatzistavrakidis, Clay J. Grewcoe, Larisa Jonke +2
Courant sigma-models encode the geometric and non-geometric fluxes of compactified closed string theory as generalized Wess-Zumino terms and exhibit their relation to Courant algeb…
The Algebroid Structure of Double Field Theory
Athanasios Chatzistavrakidis, Larisa Jonke, Fech Scen Khoo +1
By doubling the target space of a canonical Courant algebroid and subsequently projecting down to a specific subbundle, we identify the data of double field theory (DFT) and hence…
Quasinormal modes of compact objects in alternative theories of gravity
Jose Luis Blázquez-Salcedo, Zahra Altaha Motahar, Daniela D. Doneva +5
We address quasinormal modes of compact objects in several alternative theories of gravity. In particular, we focus on black holes and neutron stars with scalar hair. We consider b…
Double Field Theory and Membrane Sigma-Models
Athanasios Chatzistavrakidis, Larisa Jonke, Fech Scen Khoo +1
We investigate geometric aspects of double field theory (DFT) and its formulation as a doubled membrane sigma-model. Starting from the standard Courant algebroid over the phase spa…
Quasinormal modes of Einstein-Gauss-Bonnet-dilaton black holes
Jose Luis Blázquez-Salcedo, Fech Scen Khoo, Jutta Kunz
We study quasinormal modes of static Einstein-Gauss-Bonnet-dilaton black holes. Both axial and polar perturbations are considered and studied from to . We emphasize the…
Tensor Galileons and Gravity
Athanasios Chatzistavrakidis, Fech Scen Khoo, Diederik Roest +1
The particular structure of Galileon interactions allows for higher-derivative terms while retaining second order field equations for scalar fields and Abelian -forms. In this w…