We study the shadows cast by different types of rotating regular black holes viz. Ay\'on-Beato-Garc\'ia {(ABG)}, Hayward, and Bardeen. These have in addition to total mass ($M$) rotation parameter ($a$), parameters as electric charge ($Q$), deviation ($g$), magnetic ($g_{*}$), respectively. Interestingly, size shadow is affected these parameter. found that radius each case decreases monotonically distortion increases when value increase. A comparison with standard Kerr also investigated....

The shadow of a rotating non-Kerr black hole has been studied, and it was shown that in addition to the specific angular momentum $a$, deformation parameter spacetime essentially deforms shape shadow. For given value spin presence $ϵ$ reduces enlarges its with respect one Kerr spacetime. Optical features terms rotation polarization vector along null congruences have studied. A comparison obtained theoretical results on angle observational data Faraday measurements provides upper limit for...

Based on the Newman-Janis algorithm, Ay\'on-Beato-Garc\'{\i}a spacetime metric [Phys. Rev. Lett. 80, 5056 (1998)] of regular spherically symmetric, static, and charged black hole has been converted into rotational form. It is shown that derived solution for rotating a critical value electric charge which two horizons merge one sufficiently decreases in presence nonvanishing rotation parameter $a$ hole.

A black hole casts a shadow as an optical appearance because of its strong gravitational field. We study the cast by five-dimensional Myers-Perry with equal rotation parameters. demonstrate that null geodesic equation can be integrated, which provides us opportunity to investigate hole. The is found dark zone covered deformed circle. Interestingly, shapes are more distorted and size decreases for larger spins. it turns out that, fixed values parameter, slightly smaller less than...

A large international effort is under way to assess the presence of a shadow in radio emission from compact source at centre our Galaxy, Sagittarius A$^*$ (Sgr A$^*$). If detected, this would provide first direct evidence existence black holes and that Sgr supermassive hole. In addition, shape could be used learn about extreme gravity near event horizon determine which theory better describes observations. The mathematical description has so far number simplifying assumptions are unlikely...

We have studied photon motion around axially symmetric rotating Kerr black holes in the presence of a plasma with radial power-law density. It is shown that plasma, observed shape and size shadow changes depending on (i) parameters, (ii) hole spin, (iii) inclination angle between observer plane axis rotation hole. In order to extract pure effect influence image, particular case Schwarzschild has also been investigated it sphere spherically left unchanged under influence; however, reduced due...

compact astrophysical objects such as black holes and wormholes, well testing gravity theories, are important issues in relativistic astrophysics. In this sense, theoretical observational studies of quasiperiodic oscillations (QPOs) observed (micro)quasars become helpful exploring their central object, which can be a hole or wormhole. the present work, we study throat properties traversable wormholes beyond Horndeski theory. Also, investigate circular motion test particles orbiting We...

We study the shadow of rotating black hole with quintessential energy (i) in vacuum, (ii) presence plasma radial power-law density. For vacuum case, field parameter significantly changes shape shadow. With increasing parameter, radius also increases. increase hole, causes decrease distortion shape: fast becomes too close to circle. assume distant observer be located near so-called static where gravitational attraction is just balanced by cosmic repulsion. The and size surrounded depends on...

Analytical solutions of Maxwell equations in background spacetime a black hole braneworld immersed an external uniform magnetic field have been found. The influence both and brane parameters on the effective potential radial motion charged test particle around slowly rotating has investigated by using Hamilton-Jacobi method. An exact analytical solution for dependence radius innermost stable circular orbits (ISCO) ${r}_{\mathrm{ISCO}}$ from parameter nonrotating isolated derived. It shown...

We construct regular rotating black hole and no-horizon spacetimes based on the recently introduced spherically symmetric generic related to electric or magnetic charge under nonlinear electrodynamics coupled general relativity that for special values of spacetime parameters reduce Bardeen Hayward spacetimes. show weak strong energy conditions are violated inside Cauchy horizons these holes. give boundary between determine ergosphere. introduce separated Carter equations geodesic motion in...

Can the observation of ``shadow'' allow us to distinguish a black hole from more exotic compact object? We study motion photons in class vacuum static axially symmetric space-times that is continuously linked Schwarzschild metric through value one parameter can be interpreted as measure deformation source. investigate lensing effect and shadow produced by source with aim comparing expected image hole. In context astrophysical holes, we found it may not possible an small However, increases,...

We study scalar, electromagnetic, and gravitational test fields in the Hayward, Bardeen, Ay\'on-Beato-Garc\'{\i}a regular black hole spacetimes demonstrate that are stable all of these spacetimes. Using sixth order WKB approximation linear ``axial'' perturbative scheme, we determine dependence quasinormal mode (QNM) frequencies on characteristic parameters spacetime charge holes. give also grey body factors, namely, transmission reflection coefficients scattered waves. show damping modes is...

We study physical processes around a rotating black hole in pure Gauss–Bonnet (GB) gravity. In GB gravity, the gravitational potential has slower fall-off as compared to corresponding Einstein same dimension. It is therefore expected that energetics of would be weaker, and our analysis bears out efficiency energy extraction by Penroseprocess increased 25.8 % particle acceleration 55.28 %; optical shadow decreased. These are principle distinguishing observable features hole.

In this Letter, we wish to point out that the distinguishing feature of Magnetic Penrose process (MPP) is its super high efficiency exceeding $100\%$ (which was established in mid 1980s for discrete particle accretion) extraction rotational energy a rotating black hole electromagnetically magnetic field milli Gauss order. Another similar process, which also driven by electromagnetic field, Blandford-Znajek mechanism (BZ), could be envisaged as limit MPP it requires threshold order $10^4$G....

Production and acceleration mechanisms of ultra-high-energy cosmic rays (UHECRs) energy $>10^{20}$eV, clearly beyond the GZK-cutoff limit remain unclear that points to exotic nature phenomena. Recent observations extragalactic neutrino may indicate source UHECRs being an supermassive black hole (SMBH). We demonstrate ultra-efficient extraction from rotating SMBH driven by magnetic Penrose process (MPP) could indeed foot bill. envision ionization neutral particles, such as neutron beta-decay,...

The electromagnetic (EM) perturbations of the black hole solutions in general relativity coupled to nonlinear electrodynamics (NED) are studied for both electrically and magnetically charged holes, assuming that EM do not alter spacetime geometry. It is shown effective potentials holes related test perturbative NED fields metric governing photon motion, contrary potential linear electrodynamic (Maxwell) field metric. Consequently, corresponding quasinormal (QN) frequencies differ as well. As...

In this paper, we study optical properties in terms of weak and strong (retrolensing) gravitational lensing around a black hole on the brane. The is described by Reissener-Nordstr\"om metric, where electric charge replaced Weyl tidal which acts consonance with mass. It is, therefore, expected that effects would be enhanced charge, what verify. We also shadow braneworld plasma show increases size shadow. finally consider energy emission from thermal radiation increased due to charge.

We study the dynamics of (i) neutral test particles, (ii) magnetically charged and (iii) magnetic dipole around a regular Bardeen black hole surrounded by perfect fluid dark matter (PFDM). It has been shown how charge parameter surrounding PFDM can influence innermost stable circular orbit (ISCO) radius particle. have found that ISCO is strongly affected as consequence combined effect matter. The $g$ mimic rotation up to $a/M\ensuremath{\approx}0.9$. observed for disappears at values...

Abstract The detailed study of horizon structure and the shadow cast by a Kerr-like black hole (BH) is performed. trajectory light rays forming BH found using solutions geodesic equation for motion effective potential photon around different values deviation parameter l in spcetime metric. It observed that with an increase size decreased. Additional, we have consider effect plasma on influence BH, observable radius oblateness are explored more details.

The Bardeen black hole holds historical significance as the first model of a regular hole. Recently, there have been proposed interpretations spacetime quantum corrections to Schwarzschild solution. Our study focuses on investigating quasinormal modes and Hawking radiation We observed that previous studies for suffer from inaccuracies cannot be neglected. Therefore, we propose accurate calculations scalar, electromagnetic, neutrino fields in spacetime. Additionally, computed gray-body...

This study explores the effect of charge on a special astronomical object known as gravastar, which is viewed an alternative to black hole. Based conjecture put out by Mazur and Mottola in general relativity, primarily focuses consequences $f(Q)$ gravity. The internal domain, intermediate shell, external domain are three separate sections that make up gravastar. Using particular gravity model includes conformal Killing vectors analyze these areas, we discover inner shows repulsive force...