194 citations · 788 across the 27 of their papers we have counts for
27 papers
The Star Universe Model -- Another FLRW Patch
Mustapha Azreg-A\"ınou
The Black Hole Universe model has advanced in the literature. It assumes that the whole mass of the Universe remains inside the Schwarzschild radius of a black hole after being sub…
Chaotic imprints of dark matter in extreme mass-ratio inspirals
Mustapha Azreg-Aïnou, Mubasher Jamil, Emmanuel N. Saridakis
Extreme mass-ratio inspirals (EMRIs) are among the most powerful probes of strong-field gravity and of the environments surrounding supermassive compact objects. Motivated by the e…
Gravitational and kinematic redshifts of black holes in nonlinear electrodynamics
Marco A. A. de Paula, Mustapha Azreg-Aïnou
Spacetimes arising from nonlinear electrodynamics (NED) are a good laboratory for studying both the nature of regular black hole (RBH) solutions and the imprints of nonlinear elect…
Observational test of spacetimes with the S2 star in the Milky Way galactic center
Jian-Ming Yan, Tao Zhu, Mustapha Azreg-Aïnou +2
A novel class of vacuum metrics expressible in analytical form was recently found for pure gravity, based on a groundwork put forth by Buchdahl in 1962. These Buchda…
Observational tests of asymptotically flat spacetimes
Tao Zhu, Hoang Ky Nguyen, Mustapha Azreg-Aïnou +1
A novel class of Buchdahl-inspired metrics with closed-form expressions was recently obtained based on Buchdahl's seminal work on searching for static, spherically symmetric metric…
Joshi--Malafarina--Narayan singularity in weak magnetic field
Mustapha Azreg-Aïnou, Kauntey Acharya, Pankaj S. Joshi
The importance and significance of magnetic fields in the astrophysical scenario is well known. Many domains of astrophysical black hole physics such as polarized shadow image, hig…
Traversable Morris-Thorne-Buchdahl wormholes in quadratic gravity
Hoang Ky Nguyen, Mustapha Azreg-Aïnou
The special Buchdahl-inspired metric obtained in a recent paper [Phys. Rev. D 107, 104008 (2023)] describes asymptotically flat spacetimes in pure gravity. The me…
On the parameters of the spherically symmetric parametrized Rezzolla-Zhidenko spacetime through solar system tests, orbit of S2 star about Sgr A, and quasiperiodic oscillations
Sanjar Shaymatov, Bobomurat Ahmedov, Mariafelicia De Laurentis +4
In this paper, we find the higher order expansion parameters and of spherically symmetric parametrized Rezzolla--Zhidenko (PRZ) spacetime by using its functions of the radi…
Revisiting Weak Energy Condition and wormholes in Brans-Dicke gravity
Hoang Ky Nguyen, Mustapha Azreg-Aïnou
It is known that the formation of a wormhole typically involves a violation of the Weak Energy Condition (WEC), but the reverse is not necessarily true. In the context of Brans-Dic…
Constraints on Barrow entropy from M87* and S2 star observations
Kimet Jusufi, Mustapha Azreg-Aïnou, Mubasher Jamil +1
We use data from M87* central black hole shadow, as well as from the S2 star observations, in order to extract constraints on Barrow entropy. The latter is a modified entropy arisi…
Constraining Wormhole Geometries using the Orbit of S2 Star and the Event Horizon Telescope
Kimet Jusufi, Saurabh Kumar, Mustapha Azreg-Aïnou +3
In this paper we study the possibility of having a wormhole (WH) as a candidate for the Sgr A central object and test this idea by constraining their geometry using the mot…
Constraining the Generalized Uncertainty Principle Through Black Hole Shadow and Quasiperiodic Oscillations
Kimet Jusufi, Mustapha Azreg-Aïnou, Mubasher Jamil +1
In this paper we study the effect of the Generalized Uncertainty Principle (GUP) on the shadow of GUP-modified Kerr black hole and the correspondence between the shadow radius and…
Shadow and Quasinormal Modes of a Rotating Loop Quantum Black Hole
Cheng Liu, Tao Zhu, Qiang Wu +4
In this paper, we construct an effective rotating loop quantum black hole (LQBH) solution, starting from the spherical symmetric LQBH by applying the Newman-Janis algorithm modifie…
Epicyclic oscillations of charged particles in stationary solutions immersed in a magnetic field with application to the Kerr--Newman black hole
Mustapha Azreg-Aïnou
We consider a stationary metric immersed in a uniform magnetic field and determine general expressions for the epicyclic frequencies of charged particles. Applications to the Kerr-…
Strong Gravitational Lensing by a Charged Kiselev Black Hole
Mustapha Azreg-Aïnou, Sebastian Bahamonde, Mubasher Jamil
We study the gravitational lensing scenario where the lens is a spherically symmetric charged black hole (BH) surrounded by quintessence matter. The null geodesic equations in the…
Astrophysical flows near gravity black holes
Ayyesha K. Ahmed, Mustapha Azreg-Aïnou, Sebastian Bahamonde +2
In this paper, we study the accretion process for fluids flowing near a black hole in the context of teleparallel gravity. Specifically, by performing a dynamical analysis b…
Cyclic and heteroclinic flows near general static spherically symmetric black holes
Ayyesha K. Ahmed, Mustapha Azreg-Aïnou, Mir Faizal +1
We investigate the Michel-type accretion onto a static spherically symmetric black hole. Using a Hamiltonian dynamical approach, we show that the standard method employed for tackl…
Black hole thermodynamics: No inconsistency via the inclusion of the missing P-V terms
Mustapha Azreg-Aïnou
The early literature on black hole thermodynamics ignored the - term associated with the existence of a fundamental physical constant in the black hole solution. The inclusio…
Phantom black holes and critical phenomena
Mustapha Azreg-Aïnou, Glauber T. Marques, Manuel E. Rodrigues
We consider the two classes cosh and sinh of normal and phantom black holes of Einstein-Maxwell-dilaton theory. The thermodynamics of these holes is characterized by heat capacitie…
Geometrothermodynamics: Comments, critics, and supports
Mustapha Azreg-Aïnou
We write explicitly the Euler identity and the Gibbs-Duhem relation for thermodynamic potentials that are not homogeneous first-order functions of their natural extensive variables…
On `The conformal metric structure of Geometrothermodynamics': Generalizations
Mustapha Azreg-Aïnou
We show that the range of applicability of the change of representation formula derived in J. Math. Phys. \textbf{54}, 033513 (2013) [arXiv:1302.6928] is very narrow and extend it…
Thermodynamical, geometrical and Poincaré methods for charged black holes in presence of quintessence
Mustapha Azreg-Aïnou, Manuel E. Rodrigues
Properties pertaining to thermodynamical local stability of Reissner-Nordström black holes surrounded by quintessence as well as adiabatic invariance, adiabatic charging and a gene…
Rotation and twist regular modes for trapped ghosts
Mustapha Azreg-Aïnou
A parameter-independent notion of stationary slow motion is formulated then applied to the case of stationary rotation of massless trapped ghosts. The excitations correspond to a r…
All extremal instantons in Einstein-Maxwell-dilaton-axion theory
Mustapha Azreg-Aïnou, Gérard Clément, Dmitri V. Gal'tsov
We construct explicitly all extremal instanton solutions to supergravity truncated to one vector field (Einstein-Maxwell-dilaton-axion (EMDA) theory). These…