Related papers: Thermal Comptonization and Disk Thermal Reprocessi…
We develop a Monte-Carlo code to compute the Compton scattered X-ray flux arising from a hot inner flow which undergoes Lense-Thirring precession. The hot flow intercepts seed photons from an outer truncated thin disk. A fraction of the…
We present a new analysis of the soft and medium energy X-ray spectrum of the Seyfert 1 galaxy NGC 3516 taken with the Reflection Grating Spectrometer (RGS) and European Photon Imaging Camera (EPIC) on board the XMM-Newton observatory. We…
We present a detailed study of the observable effects of photoionization and Comptonization of line and continuum radiation from a cold accretion disk with a thin, warm, photoionized transition layer in the framework of self-consistent…
We build a simple model of the optical/UV emission from irradiation of the outer disc by the inner disc and coronal emission in black hole binaries. We apply this to the broadband Swift data from the outburst of the black hole binary XTE…
Attempts were made to construct a unified description of the spectra of ULX (Ultra Luminous X-ray source) objects, including their Power-Law (PL) state and Disk-like state. Among spectral models proposed to explain either state, the present…
We present results from the major coordinated X-ray observing program on the ULX NGC 1313 X-1 performed in 2017, combining $XMM$-$Newton$, $Chandra$ and $NuSTAR$, focusing on the evolution of the broadband ($\sim$0.3-30.0 keV) continuum…
We present five simultaneous UV/X-ray observations of IC4329A by AstroSat, performed over {a five-month} period. We utilize the excellent spatial resolution of the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat to reliably separate…
To understand the nature of supercritical accretion, we systematically analyze the {\it RXTE}/PCA data of GRS 1915+105 in its quasi-steady states, by choosing data with small variability during 1999 -- 2000. We apply a multicolor disk plus…
The Seyfert-1 galaxy NGC 3516 has undergone major spectral changes in recent years. In 2017 we obtained Chandra, NuSTAR, and Swift observations during its new low-flux state. Using these observations we model the spectral energy…
We present results from the Suzaku observation of the microquasar GRS 1915+105 performed during the 2005 October multiwavelength campaign. The data include both stable state (class \chi) and limit-cycle oscillation (class \theta). Correct…
(truncated version) The X-ray spectra of Galactic binary systems in the very high state show both strong disk emission and a strong, steep tail to high energies. We use simultaneous optical-ASCA-RXTE data from the black hole transient XTE…
We present detailed computations of the vertical structure of an accretion disc illuminated by hard X-ray radiation with the code {\sc titan-noar} suitable for Compton thick media. The energy generated via accretion is dissipated partially…
The formation of a cool disk in the innermost regions of black hole X-ray transient systems in the low hard state is investigated. Taking into account the combined cooling associated with the Compton and conductive energy transport…
We model an accretion disk atmosphere and corona photoionized by a central X-ray continuum source. We calculate the opacity and radiation transfer for an array of disk radii, to obtain the two-dimensional structure of the disk and its X-ray…
High-energy astrophysical systems frequently contain collisionless relativistic plasmas that are heated by turbulent cascades and cooled by emission of radiation. Understanding the nature of this radiative turbulence is a frontier of…
We examine heating and cooling in protostellar disks using 3-D radiation-MHD calculations of a patch of the Solar nebula at 1 AU, employing the shearing-box and flux-limited radiation diffusion approximations. The disk atmosphere is ionized…
This paper is devoted to self-consistent modeling of the magnetically supported accretion disk with optically thick warm corona based on first principles. In our model, we consider the gas heating by magneto-rotational instability (MRI)…
A soft X-ray excess above the 2-10 keV power law extrapolation is generally observed in AGN X-ray spectra. Presently there are two competitive models to explain it: blurred ionized reflection and warm Comptonisation. In the latter case,…
We present the analysis of publicly available NuSTAR, Suzaku and XMM-Newton observations of the symbiotic recurrent nova T CrB covering the 2006.77-2022.66 yr period. The X-ray spectra are analysed by adopting a model that includes a…
A type-I burst could influence the accretion process through radiation pressure and Comptonization both for the accretion disk and the corona/boundary layer of an X-ray binary, and vice versa. We investigate the temporal evolution of a…