280 citations · 2.4k across the 47 of their papers we have counts for
15 papers · 1 filter
Photon-Return and Polar-Focusing Crossovers near Extremal Kerr
Valentina Gonzalez-Moya, Ali Ovgun, Joel Saavedra
How precisely must a photon's impact parameter be tuned for it to complete windings around a nearly extremal Kerr black hole before escaping, and how does the same near extrema…
Acceleration radiation, quasinormal modes and quasi-bound states in generic rotating regular black holes
Uktamjon Uktamov, Ali Övgün, Reggie C. Pantig +1
We study horizon-brightened acceleration radiation for a neutral scalar field in separable Kerr-like rotating metrics with nonlinear-electrodynamic mass profiles. The principal bra…
Tidal Response Beyond the Background Geometry in Einstein-Euler-Heisenberg Black Holes
Ramon Becar, P. A. Gonzalez, Ali Ovgun +2
We determine the quadrupolar logarithmic tidal response of electrically charged Einstein-Euler-Heisenberg black holes from the coupled static odd-parity gravitational and electroma…
Effective Matter Conversion in Gravitational Collapse and the Dynamical Formation of Regular Black Holes
Emmanuele Battista, Ali Ovgun, Vitalii Vertogradov
We study inverse source reconstruction in generalized Vaidya spacetimes. A prescribed density fixes the mass and tangential pressure, while a two-sector decomposition determines a…
Josephson interferometry in an Oppenheimer--Snyder-like scale-dependent black-hole spacetime
Ali Ovgun, Reggie C. Pantig, G. Lambiase
We develop a covariant framework for Josephson transport, superconducting interference, and shunt noise in the scale-dependent exterior generated by an Oppenheimer--Snyder-like col…
Optical-area minimum method for static spherical black hole shadows
Vitalii Vertogradov, Nikko John Leo S. Lobos, Ali Ovgun +1
We formulate a global optical-area method for shadows of static, spherically symmetric black holes. For the metric \(ds^{2}=-A(r)dt^{2}+B(r)dr^{2}+C(r)dΩ^{2}\), spherical sections…
Two-scale magnetically charged regular black holes from nonlinear electrodynamics and a T-duality-inspired zero-point length
Ali Ovgun, Reggie C. Pantig, Joel Saavedra
We construct a two-scale, static, spherically symmetric regular black hole in Einstein gravity sourced by magnetic nonlinear electrodynamics (NED). The zero-point length reg…
Spinning particle dynamics, epicyclic frequencies, and transient QPO signatures in Schwarzschild spacetime
Uktamjon Uktamov, Ali Övgün, Reggie C. Pantig +1
We study the motion of spinning test particles in Schwarzschild spacetime within the Mathisson--Papapetrou--Dixon pole--dipole approximation, imposing the Tulczyjew--Dixon spin sup…
Scattering, Hawking Radiation and Neutrino Energy Deposition in Euler-Heisenberg Black Holes Surrounded by Perfect Fluid Dark Matter
Ramon Becar, P. A. Gonzalez, Ali Ovgun +2
We study the dynamical and scattering properties for the Euler-Heisenberg BH surrounded by perfect fluid dark matter. The geometry contains a compact non-linear electrodynamic corr…
Near extremal RN-AdS control of holographic Josephson transport
Ali Övgün, Reggie C. Pantig
We formulate a holographic weak-link construction in which Josephson transport is controlled by the charge sector of a Reissner--Nordstrom-AdS black brane. The model is an Einstein…
Energy extraction from NED-deformed rotating black holes via the Comisso-Asenjo reconnection process
Marco Figliolia, Gaetano Lambiase, Ali Övgün +1
We study rotating black holes in general relativity coupled to nonlinear electrodynamics (NED), focusing on an axisymmetric solution with deformation parameter . On the spherica…
Reference-renormalized curvature-primitive Gauss-Bonnet formalism for finite-distance weak gravitational lensing in static spherical spacetimes
Reggie C. Pantig, Ali Övgün
We develop a reference-renormalized (photon-sphere-free) normalization scheme for Gauss-Bonnet gravitational lensing at finite distance in static, spherically symmetric spacetimes.…
Breaking Parameter Degeneracies in a Magnetically Charged Black Hole Embedded in a Hernquist Dark-Matter Halo: A Multi-Observable Analysis
Ali Ovgun, Reggie C. Pantig, Joel Saavedra
We study the degeneracy of intrinsic and environmental parameters for BH observables in a static spacetime sourced by a nonlinear magnetic monopole immersed in a Hernquist dark-mat…
Optical and orbital characterization of spherically symmetric static black holes of self-gravitating new nonlinear electrodynamics model
İlim İrfan Çimdiker, Ali Övgün, Yosef Verbin
Horizon scale imaging and precision lensing have turned black holes into quantitative laboratories for strong gravity and for non standard electromagnetic physics. We study the opt…
Finite Distance Corrections to Vacuum Birefringence in Strong Gravitational and Electromagnetic Fields
Ali Övgün, Reggie C. Pantig
We study polarization dependent photon propagation in static, spherically symmetric spacetimes permeated by strong magnetic fields, with the aim of quantifying how finite emission…