Related papers: Thick accretion disk configurations in the Born-In…
We study the quasi-periodic oscillations from the accretion disk around the distorted Schwarzschild black hole in the framework of the resonant models. We confine ourselves to the case of a quadrupole distortion which can be caused for…
Recent numerical cosmological radiation-magnetohydrodynamic-thermochemical-star formation simulations have resolved the formation of quasar accretion disks with Eddington or super-Eddington accretion rates onto supermassive black holes…
We use a ray-tracing technique to compute the observed spectrum of a thin accretion disk around a Kerr black hole. We include all relativistic effects such as frame-dragging, Doppler boost, gravitational redshift, and bending of light by…
Along the last ten years, a general relativistic method has been developed to generate analytical expressions for the black hole (BH) parameters in terms of observables, namely the frequency shift of photons emitted by orbiting test…
We study stable circular orbits (SCO) around static spherically symmetric configuration of General Relativity with a non-linear scalar field (SF). The configurations are described by solutions of the Einstein-SF equations with monomial SF…
We construct a general relativistic model for the accretion flow of a rotating finite cloud of non-interacting particles infalling onto a Schwarzschild black hole. The streamlines start at a spherical shell, where boundary conditions are…
This study investigates the visual characteristics of a rotating black hole (BH) within the fabric of $4$D Einstein-Gauss-Bonnet gravity illuminated with two illumination models, such as a celestial light sphere and a thin accretion disk.…
In this paper we investigate charged static black holes in 4D for generalized teleparallel models of gravity, based on torsion as the geometric object for describing gravity according to the equivalence principle. As a motivated idea, we…
We show that viscous, transonic accretion disks which start with sub-Keplerian angular momentum at the outer boundary reproduce the features of the so-called thick, thin, slim and other accretion disk models depending upon the accretion…
We analyze gravitational lensing and their cast images from thin-disks in shadow observations of a family of spherically symmetric black hole solutions previously derived within the framework of Loop Quantum Gravity. Such black holes depend…
The tidal Love numbers of self-gravitating compact objects describe their response to external tidal perturbations, such as those from a companion in a binary system, offering valuable insights into their internal structure. For static…
With the advent of gravitational wave astronomy and first pictures of the "shadow" of the central black hole of our milky way, theoretical analyses of black holes (and compact objects mimicking them sufficiently closely) have become more…
We reexamine the hypothesis that the optical/UV/soft X-ray continuum of Active Galactic Nuclei is thermal emission from an accretion disk. Previous studies have shown that fitting the spectra with the standard, optically thick and…
We present a numerical method for spatially 1.5-dimensional and time-dependent studies of accretion disks around black holes, that is originated from a combination of the standard pseudo-spectral method and the adaptive domain decomposition…
In this thesis, I study hydrodynamical models of slim accretion disks --- advective, optically thick disks which generalize the standard models of radiatively efficient thin disks to all accretion rates. I start with a general introduction…
Contrary to some recent claims the `no torque inner boundary condition' as applied at the marginally stable orbit is correct for geometrically thin disks accreting into black holes.
We study the observational properties of a class of exact solutions of Einstein's field equations describing stationary, axially symmetric, rigidly rotating dust (i.e. non interacting particles). We ask the question whether such solutions…
The accretion-ejection activities of black holes play a vital role in shaping the Universe. Bright and recurrent black hole X-ray binaries are ideal objects for studying accretion physics across a wide range of accretion rates, providing…
We show that, in principle, a slowly evolving gravitationally collapsing perfect fluid cloud can asymptotically settle to a static spherically symmetric equilibrium configuration with a naked singularity at the center. We consider one such…
We discuss how disk models may limit the scope of identifying astrophysical black holes. We show that the standard Keplerian thin disk model, the thick disk model, slim disks, ADAFs etc. are fundamentally limited. We present the most…