Related papers: A Comptonization Model for Phase Lag Variability i…
We present three spectra of Cygnus X-1 in the low/hard state from 3-1000 keV produced with RXTE and OSSE. We demonstrate that a pure thermal Comptonization model, with Compton reflection fits the data well, with coronal temperatures of…
Most of the spectra of neutron star low mass X-ray binaries (NS LMXBs), being them persistent or transient, are characterized by the presence of a strong thermal Comptonization bump, thought to originate in the transition layer (TL) between…
We have found relations between the temporal and spectral properties of radiation Comptonized in an extended atmosphere associated with compact accreting sources. We demonstrate that the fluctuation power spectrum density (PSD) imposes…
I review the temporal/spectral data of accreting black hole sources paying most attention to the properties of the temporal variability such as photon energy dependent auto- and cross-correlation functions, average shot profiles and…
We performed time lag analysis on the X-ray light curves of Centaurus A (Cen A) obtained by the Gas Slit Camera (GSC) aboard the Monitor of All-sky X-ray Image ({\it MAXI}) in three energy bands (2--4 keV, 4--10 keV, and 10--20 keV). We…
We analyse the radiation pressure instability of the standard, optically thisc disc and propose it as an explanation of the obseved variability of the superluminal microquasar GRS 1915+105. The quantitave agreement with the observed…
We study the vertical structure of the transition layer between an accretion disc and corona in the context of the existence of two-phase medium in thermally unstable regions. The disc is illuminated by hard X-ray radiation and satisfies…
Cygnus X-1 (Cyg X-1) exhibited a low hard state in 2022, observed by several missions. The IXPE reported that the polarization angle is aligned with the radio jet and gave a polarization degree approximately 4 times higher than the general…
We investigate thermal synchrotron radiation at semi-relativistic and relativistic temperatures. We find an analytic expression for the angle-averaged emission coefficient, and show that it is significantly more accurate that those derived…
Hard X-ray spectra of black hole binaries in the low/hard state are well modeled by thermal Comptonization of soft seed photons by a corona-type region with $kT$\thinspace$\sim 50${\thinspace}keV and optical depth around 1. Previous…
S5 0716+714 is a well-studied BL Lac object in the sky. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate the emission processes. To examine the possible…
In many astrophysical systems, mixing between cool and hot temperature gas/plasma through Kelvin-Helmholtz-instability-driven turbulence leads to the formation of an intermediate temperature phase with increased radiative losses that drive…
In this work, a thermal rectification ratio $\eta$ of 18.5% was observed in partially perforated graphene with the use of Molecular Dynamics (MD) simulations. In all cases studied here, heat preferentially flows from the porous to the…
We show that waves propagating in a transition disk can explain the short term temporal behavior of Cygnus X-1. In the transition disk model the spectrum is produced by saturated Comptonization within the inner region of the accretion disk…
We investigate the nature of the inner accretion disk in the neutron star source GX 5-1 by making a detailed study of time lags between X-rays of different energies. Using the cross-correlation analysis, we found anti-correlated hard and…
A BeppoSAX survey of bright Neutron Star (NS) systems in globular clusters, together with the results obtained on Galactic LMXRB, suggests that a two-component model is a reasonable description of the 0.1-200 keV spectra. At energies lower…
The thermal state of active galactic nucleus (AGN) coronae is commonly characterized by the electron temperature $kT_{\rm e}$, the Thomson optical depth $\tau$, and the geometry of the Comptonizing medium. We compile a literature sample of…
We develop a simple, time-dependent Comptonization model to probe the origins of spectral variability in accreting neutron star systems. In the model, soft ``seed photons'' are injected into a corona of hot electrons, where they are Compton…
This article characterizes phase transitions in temperature within a specific space of H\"older continuous potentials, distinguished by their regularity and asymptotic behavior at zero. We also characterize the phase transitions in…
We review major achievements in our understanding of multiphase coronal plasma, where cool-dense and hot-tenuous matter coexists, brought about by advances in modeling and theory, inspired by observations. We give an overview of models that…