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The slimming effect of advection on black-hole accretion flows
(EDP Sciences, 2016)
We study energy flows in geometrically thick accretion discs, both optically thick and thin, using general relativistic, three-dimensional simulations of black hole accretion flows. We find that for non-rotating black holes ...
Three-dimensional general relativistic radiation magnetohydrodynamical simulation of super-Eddington accretion, using a new code HARMRAD with M1 closure
(Oxford University Press (OUP), 2014)
Black hole (BH) accretion flows and jets are dynamic hot relativistic magnetized plasma flows whose radiative opacity can significantly affect flow structure and behavior. We describe a numerical scheme, tests, and an ...
HERO - A 3D general relativistic radiative post-processor for accretion discs around black holes
(Oxford University Press (OUP), 2015)
HERO (Hybrid Evaluator for Radiative Objects) is a 3D general relativistic radiative transfer code which has been tailored to the problem of analyzing radiation from simulations of relativistic accretion discs around black ...
Simulations of ultrarelativistic magnetodynamic jets from gamma-ray burst engines
(Oxford University Press (OUP), 2008)
Long-duration gamma-ray bursts (GRBs) require an engine capable of driving a jet of plasma to ultrarelativistic bulk Lorentz factors of up to several hundred and into narrow opening angles of a few degrees. We use global ...
Numerical simulations of super-critical black hole accretion flows in general relativity
(Oxford University Press (OUP), 2014)
A new general relativistic radiation magnetohydrodynamical code KORAL is described, which employs the M1 scheme to close the radiation moment equations. The code has been successfully verified against a number of tests. ...
Measuring Black Hole Spin by the Continuum-Fitting Method: Effect of Deviations from the Novikov-Thorne Disc Model
(Oxford University Press (OUP), 2011)
The X-ray spectra of accretion discs of eight stellar mass black holes have been analysed to date using the thermal continuum-fitting method, and the spectral fits have been used to estimate the spin parameters of the black ...
Efficiency of Magnetic to Kinetic Energy Conversion in a Monopole Magnetosphere
(IOP Publishing, 2009)
Unconfined relativistic outflows from rotating, magnetized compact objects are often well modeled by assuming that the field geometry is approximately a split-monopole at large radii. Earlier work has indicated that such ...
Photon-conserving Comptonization in simulations of accretion discs around black holes
(Oxford University Press (OUP), 2015)
We introduce a new method for treating Comptonization in computational fluid dynamics. By construction, this method conserves the number of photons. Whereas the traditional “blackbody Comptonization” approach assumes that ...
Efficient generation of jets from magnetically arrested accretion on a rapidly spinning black hole
(Oxford University Press (OUP), 2011)
We describe global, 3D, time‐dependent, non‐radiative, general‐relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transport a large amount of magnetic flux to the ...
Powerful radiative jets in supercritical accretion discs around non-spinning black holes
(Oxford University Press (OUP), 2015)
We describe a set of simulations of super-critical accretion onto a non-rotating supermassive BH. The accretion flow is radiation pressure dominated and takes the form of a geometrically thick disk with twin low-density ...