相关论文: Power-law Tails from Dynamical Comptonization in C…

The quasi-steady structure of super-critical accretion flows around a black hole is studied based on the two-dimensional radiation-hydrodynamical (2D-RHD) simulations. The super-critical flow is composed of two parts: the disk region and…

The curvature perturbations produced during an early era of inflation are known to have quasi-Gaussian distribution functions close to their maximum, where they are well constrained by measurements of the cosmic microwave background…

The aim of this work is to investigate in a physical and quantitative way the spectral evolution of bright Neutron Star Low-Mass X-ray Binaries (NS LMXBs), with special regard to the transient hard X-ray tails. We analyzed INTEGRAL data for…

We investigate the effects of dynamical Comptonization on the emergent radiation spectrum produced by near critical accretion onto a neutron star. The flow dynamics and the transfer of radiation are self--consistently solved in the case of…

We perform two-dimensional particle-in-cell simulations of reconnection in magnetically dominated electron-positron plasmas subject to strong Compton cooling. We vary the magnetization $\sigma\gg1$, defined as the ratio of magnetic tension…

We analyze the time dependence of fluid variables in general relativistic, magnetohydrodynamic simulations of accretion flows onto a black hole with dimensionless spin parameter a/M=0.9. We consider both the case where the angular momentum…

We study polarization from scattering of light on a cloud in radial motion along the symmetry axis of an accretion disk. Radiation drag from the disk and gravitational attraction of the central black hole are taken into account, as well as…

Power-law probability distributions are widely used to model extreme statistical events in complex systems, with applications to a vast array of natural phenomena ranging from earthquakes to stock market crashes to pandemics. We show that…

We study the spectral properties of a low angular momentum flow as a function of the shock strength, compression ratio, accretion rate and flow geometry. In the absence of a satisfactory description of magnetic fields inside the advective…

Matter accreting onto black holes may develop shocks due to the centrifugal barrier. A part of inflowing matter in the post-shock flow is deflected along the axis in the form of jets. Post-shock flow which behaves like a Compton cloud has…

By performing two-dimensional axisymmetric general relativistic radiation magnetohydrodynamics simulations with spin parameter $a^*$ varying from -0.9 to 0.9, we investigate the dependence on the black hole spin of the energy flow from…

We present a survey of how the spectral features of black hole X-ray binary systems depend on spin, accretion rate, viewing angle, and Fe abundance when predicted on the basis of first principles physical calculations. The power law…

We perform two-dimensional hydrodynamical simulations of slowly rotating accretion flows in the region of $ 0.01-7\, \mathrm{pc} $ around a supermassive black holes with $ M_\mathrm{BH} = 10^{8} M_{\odot} $. The accretion flow is irradiated…

We compute the effects of thermal Comptonization of soft photons emitted from a Kep- lerian disk around a black hole by the post-shock region of a sub-Keplerian flow, known as the CENtrifugal pressure dominated BOundary Layer (CENBOL). We…

All prior work on measuring the spins of stellar-mass black holes via the X-ray continuum-fitting method has relied on the use of weakly-Comptonized spectra obtained in the thermal dominant state. Using a self-consistent Comptonization…

Waves propagating in a curved spacetime develop tails. In particular, it is well established that the late-time dynamics of gravitational collapse is dominated by a power-law decaying tail of the form $Mt^{-(2l+3)}$, where $M$ is the…

We present the detailed global structure of black hole accretion flows and outflows through newly performed two-dimensional radiation-magnetohydrodynamic simulations. By starting from a torus threaded with weak toroidal magnetic fields and…

General properties of advection-dominated accretion flows are discussed. Special emphasis is given to the optically thin branch of solutions, which has very high ion and electron temperatures and is thermally stable. This solution branch…

For small values of the dimensionless viscosity parameter, namely $\alpha\lesssim 0.1$, the dynamics of non-radiating accretion flows is dominated by convection; convection strongly suppresses the accretion of matter onto the central object…

Nonlinear tails in black hole perturbations, arising from second-order effects, present a distinct departure from the well-known Price tail of linear theory. We present an analytical derivation of the power law indices and amplitudes for…