The Influence of Uniform Magnetic Fields on Strong Field Gravitational Lensing by Kerr Black Holes

Abstract

We investigate strong gravitational lensing using magnetized Kerr black holes (MKBHs), which are accurate Kerr-Bertotti-Robinson solutions for Kerr black holes in a uniform magnetic field with additional magnetic field strength $B$ apart from mass $M$ and spin $a$. Unlike previous magnetized spacetimes, the MKBH geometry is Petrov type D, devoid of conical singularities, allowing photons to reach asymptotic infinity and making the concept astrophysically feasible. We use the strong deflection limit formalism to calculate the photon sphere radius, critical impact parameter, deflection angle, and lensing observables including the image position ${\theta }_{\infty }$, angular separation $s$ and relative magnification $r_{\text{mag}}$, as well as their relationships with the parameters $a$ and $B$. Our results reveal that the relativistic image's photon sphere and angular size increase with $B$, whereas lensing observables deviate significantly from the Kerr scenario. For M87*, with $a=0.9$, the angular position of relativistic images increases from $10.8\mu$as (Kerr) to $12.02\mu$as, and the time delay between the first two images increases from $158.5$ h to $176$ h at $B=0.4$. Similarly, for Sgr A*, the image position increases from $14.4\mu$as to $16\mu$as, with time delays enhanced by approximately $0.7$ minutes. The relative magnification $r_{\text{mag}}$ grows with $B$ and deviates by $0.53$ from Kerr black holes at $B=0.4$. Our findings highlight strong gravitational lensing as a powerful tool to probe the presence of magnetic fields around astrophysical black holes, and in particular, we demonstrate that the MKBH spacetime enables constraints on the parameters $a$ and $B$.

arXiv comment17 pages, 7 figures, 5 tables, Matched with the published version

References in corpus (57)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• Weak Gravitational Lensing
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• Revisiting the Scaling Relations of Black Hole Masses and Host Galaxy Properties
• Schwarzschild black hole lensing
• Gravitational lensing in the strong field limit
• First M87 Event Horizon Telescope Results. VIII. Magnetic Field Structure near The Event Horizon
• First Sagittarius A* Event Horizon Telescope Results. VI: Testing the Black Hole Metric
• The geometry of photon surfaces
• An Update on Monitoring Stellar Orbits in the Galactic Center
• Probing the Universe with Weak Lensing
• Strong field limit of black hole gravitational lensing
• Shadow of rotating regular black holes
• Gravitational Lensing by Black Holes
• Spacetime perspective of Schwarzschild lensing
• On the exact gravitational lens equation in spherically symmetric and static spacetimes
• Rotating black holes in $4D$ Einstein-Gauss-Bonnet gravity and its shadow
• Gravitational deflection of light and shadow cast by rotating Kalb-Ramond black holes
• Quasi-Equatorial Gravitational Lensing by Spinning Black Holes in the Strong Field Limit
• Parameter estimation of hairy Kerr black holes from its shadow and constraints from M87*
• Gravitational lensing by black holes in the $4D$ Einstein-Gauss-Bonnet gravity
• Strong field gravitational lensing in the deformed Hǒrava-Lifshitz black hole
• Analytic Kerr black hole lensing for equatorial observers in the strong deflection limit
• Shadow cast and deflection of light by charged rotating regular black holes
• Weak Lensing Probes of Modified Gravity
• Deflection angle in the strong deflection limit in a general asymptotically flat, static, spherically symmetric spacetime
• Kerr black hole lensing for generic observers in the strong deflection limit
• A comparison of approximate gravitational lens equations and a proposal for an improved new one
• Gravitational Lensing in presence of Plasma: Strong Lens Systems, Black Hole Lensing and Shadow
• Time Delay in Black Hole Gravitational Lensing as a Distance Estimator
• Strong deflection limit of black hole gravitational lensing with arbitrary source distances
• Gravitational lensing by Einstein-Born-Infeld black holes
• Gravitational lensing by charged black hole in regularized $4D$ Einstein-Gauss-Bonnet gravity
• Strong gravitational lensing and shadow constraint from M87* of slowly rotating Kerr-like black hole
• Constraining a modified gravity theory in strong gravitational lensing and black hole shadow observations
• Cosmological constant corrections to the photon sphere and black hole shadow radii
• Shadows and lensing of black holes immersed in strong magnetic fields
• Parameters estimation and strong gravitational lensing of nonsingular Kerr-Sen black holes
• Strong gravitational lensing by Kerr and Kerr-Newman black holes
• Strong gravitational lensing in a squashed Kaluza-Klein black hole spacetime
• Strong field gravitational lensing by hairy Kerr black holes
• Testing strong gravitational lensing effects by supermassive compact objects with regular spacetimes
• Strong gravitational lensing in a noncommutative black-hole spacetime
• Rotating Black Holes in Horndeski Gravity: Thermodynamic and Gravitational Lensing
• Particle motion and gravitational lensing in the metric of a dilaton black hole in a de Sitter universe
• Strong gravitational lensing in a squashed Kaluza-Klein Gödel black hole
• Particle motion around magnetized black holes: Preston-Poisson space-time
• Magnetized black hole as a gravitational lens
• Strong gravitational lensing for black hole with scalar charge in massive gravity
• Probing spacetime noncommutative constant via charged astrophysical black hole lensing
• Effects of Homogeneous Plasma on Strong Gravitational Lensing of Kerr Black Holes
• Microscopic Entropy of the Magnetised Extremal Reissner-Nordstrom Black Hole
• Black hole tidal charge constrained by strong gravitational lensing
• The impact of gravitational lensing in the reconstruction of stellar orbits around Sgr A*
• Strong Gravitational Lensing Effects of the Rotating Short-Haired Black Hole and Constraints from EHT Observations

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