Related papers: Predicting Stellar-Mass Black Hole X-ray Spectra f…
In the absence of direct kinematic measurements, the mass of an accreting black hole is sometimes inferred from the X-ray spectral parameters of its accretion disk; specifically, from the temperature and normalization of a disk-blackbody…
We use the public code ebhlight to carry out 3D radiative general relativistic magnetohydrodynamics (GRMHD) simulations of accretion onto the supermassive black hole in M87. The simulations self-consistently evolve a frequency-dependent…
The role of radiation in general relativistic magnetohydrodynamic (GRMHD) accretion simulations is discussed through axisymmetric simulations of the evolution of an initial torus seeded with a weak magnetic field. The paper compares and…
We present a ``cyclic zoom'' method to capture the dynamics of accretion flows onto black holes across a vast range of spatial and temporal scales in general relativistic magnetohydrodynamic (GRMHD) simulations. In this method, we…
We present the results of a calculation of the thermal spectrum from a 2D, moving mesh, high-accuracy, viscous hydrodynamical simulation of an accreting supermassive black hole binary. We include viscous heating, shock heating, and…
(Abridged) We investigate non-spherical behavior of gas accreting onto a central supermassive black hole performing simulations using the SPH code GADGET-3 including radiative cooling and heating by the central X-ray source. As found in…
We present new calculations of X-ray polarization from accreting black holes (BHs), using a Monte-Carlo ray-tracing code in full general relativity. In our model, an optically thick disk in the BH equatorial plane produces thermal seed…
Stellar-mass black holes in x-ray binary systems are powered by mass transfer from a companion star. The accreted gas forms an accretion disk around the black hole and emits x-ray radiation in two distinct modes: hard and soft state. The…
In this thesis a computational tool for modelling spectral features of X-ray sources in a strong gravitational field is developed. Six transfer functions, the gravitational and Doppler shift, lensing, emission angle, relative time delay,…
The structure of the accretion flow onto supermassive black holes (SMBH) is not well understood. Standard disc models match to zeroth order in predicting substantial energy dissipation within optically-thick material producing a…
We present the first three-dimensional, fully general-relativistic magnetohydrodynamic (3D GRMHD) simulation of a black hole (BH) formed from the collapsed core of a massive star. The ability to self-consistently capture the birth of a…
We propose a novel theoretical model to describe a physical identity of the soft X-ray excess, ubiquitously detected in many Seyfert galaxies, by considering a steady-state, axisymmetric plasma accretion within the innermost stable circular…
Continuum and reflection spectral models have each been widely employed in measuring the spins of accreting black holes. However, the two approaches have not been implemented together in a photon-conserving, self-consistent framework. We…
The supermassive black hole in the center of the Milky Way, Sgr A*, displays a nearly flat radio spectrum that is typical for jets in active galactic nuclei. Indeed, time-dependent magnetized models of radiatively inefficient accretion…
Accretion is a universal astrophysical process that plays a key role in cosmic history, from the epoch of reionization to galaxy and stellar formation and evolution. Accreting stellar-mass black holes in X-ray binaries are one of the best…
With the goal of providing more accurate and realistic estimates of the secular behavior of the mass accretion and drag rates in the "common-envelope" scenario encountered when a black hole or a neutron star moves in the stellar envelope of…
A variety of current models for gamma-ray bursts (GRBs) suggest a common engine - a black hole of several solar masses accreting matter from a disk at a rate 0.01 to 10 solar masses per second. Using a numerical model for relativistic disk…
The interplay between supermassive black holes (SMBHs) and their environments is believed to command an essential role in galaxy evolution. The majority of these SMBHs are in the radiative inefficient accretion phase where this interplay…
We study spectra produced by weakly accreting black hole (BH) systems using the semi-analytic advection dominated accretion flow (ADAF) model and the general-relativistic magentohydrodynamic (GRMHD) simulation. We find significant…
It is now well established that changes in the X-ray spectral state of black hole low-mass X-ray binaries are correlated with changes in the radio properties of those systems. Assuming radio power is a proxy for jet power, we can say that…