Related papers: Luminosity of accretion disks in compact objects w…
The accretion disk is formed by particles moving in closed orbits around a compact object, whose physical properties and the electromagnetic radiation characteristics are determined by the space-time geometry around the compact object. In…
This review covers the main aspects of black hole accretion disk theory. We begin with the view that one of the main goals of the theory is to better understand the nature of black holes themselves. In this light we discuss how accretion…
Gravitational lensing of a light source by a black hole leads to appearance of higher-order images produced by photons that loop around the black hole before reaching the observer. Higher-order images were widely investigated numerically…
The extreme conditions found near black holes and neutron stars provide a unique opportunity for testing physical theories. Observations of both types of compact objects can be used to probe regions of strong gravity, allowing for tests of…
The silhouette of a black hole having a critical curve (an unstable bound photon orbit) when illuminated by an optically thin accretion disk whose emission is confined to the equatorial plane shows a distinctive central brightness…
We consider the observational properties of a static black hole space-time immersed in a dark matter envelope. We thus investigate how the modifications to geometry, induced by the presence of dark matter affect the luminosity of the black…
We describe the most general nature of accretion and wind flows around a compact object and emphasize on the properties which are special to black hole accretion. The angular momentum distribution in the most general solution is far from…
This paper investigates the shadow images of rotating charged black holes in Kalb-Ramond (KR) gravity, using an accretion disk that is both optically and geometrically thin and located on the equatorial plane as the light source model. The…
In astrophysics, the process of a massive body acquiring matter is referred to as accretion. The extraction of gravitational energy occurs as a result of the infall. Since it converts gravitational energy into radiation, accretion onto dark…
The geometry of black hole spacetimes can be probed with exquisite precision in the gravitational-wave window, and possibly also in the optical regime. We study the accretion of bright spots -- objects which emit strongly in the optical or…
We investigate the epicyclic motion of charged test particles and the associated quasi-periodic oscillations (QPOs) around a weakly magnetized black hole surrounded by quintessence within the framework of Einstein-ModMax theory. We analyze…
A relativistic model of geometrically thin and optically thick accretion disks is worked out for a class of magnetically charged black holes, which are solutions to the Einstein-Maxwell-dilaton theory with a dilaton-coupled Euler-Heisenberg…
In the dark energy star picture a compact object is transparent at radio and optical frequencies, and acts as a defocusing lens. Thus the object itself appears as a luminous disk whose surface brightness reflects the surface brightness of…
This paper investigates photon motion in black hole of Einstein-Maxwell-dilaton theory, exploring black hole shadows and observational characteristics under various accretion models. We first give the relation of the event horizon, photon…
The Event Horizon Telescope (EHT) imaging of the supermassive black holes at the centers of Messier 87 galaxy and the Milky Way galaxy marks a significant step in observing the photon rings and central brightness depression that define the…
We demonstrate the investigation of thin accretion disc surrounding the Einstein- Euler-Heisenberg-Anti-de Sitter black hole. Additionally, we analyze the black hole event horizons and compute their effective potential and equations of…
Relativistic reflection features in the X-ray spectra of black hole binaries and AGNs are thought to be produced through illumination of a cold accretion disk by a hot corona. In this work, we assume that the corona has the shape of an…
We report the development of a new tool to determine the origin of quasi-periodic oscillations (QPOs) in accretion disk systems. The technique uses the source energy spectrum and the energy dependence of the QPO fractional amplitude to…
Numerical general relativistic radiative magnetohydrodynamic simulations of accretion disks around a stellar mass black hole with a luminosity above 0.5 of the Eddington value reveal their stratified, elevated vertical structure. We refer…
This paper investigates the dynamical behavior of steady spherical accretion onto a static, magnetically charged black hole embedded in a perfect fluid dark matter (PFDM) background. Using the shadow observations of M87* from the Event…