Related papers: Relativistic Disc lines
We calculate the structure of a standard accretion disk with corona surrounding a massive Kerr black hole in general relativistic frame, in which the corona is assumed to be heated by the reconnection of the strongly buoyant magnetic fields…
Recurring outbursts associated with matter flowing onto compact stellar remnants (black-holes, neutron stars, white dwarfs) in close binary systems, provide strong test beds for constraining the poorly understood accretion process. The…
Although broad emission lines are the most reliable signature of the nuclear activity of a galaxy and the location of the emitting material is well measured by the reverberation method, the physical cause of the formation of the broad line…
X-ray reverberation in AGN, believed to be the result of the reprocessing of corona photons by the underlying accretion disk, has allowed us to probe the properties of the inner-most regions of the accretion flow and the central black hole.…
We consider a temporal response of relativistically broadened line spectrum of iron from black hole accretion irradiated by an X-ray echo under strong gravity. The physical condition of accreting gas is numerically calculated in the context…
Narrow spectral features in the 5--6 keV range were recently discovered in the X-ray spectra of a few active galactic nuclei. We discuss the possibility that these features are due to localized spots which occur on the surface of an…
We report that moderately eccentric flows around supermassive black holes (SMBHs), formed via either circumnuclear gas accretion or tidal disruption events, generate eccentricity cascades (from >0.8 to 0.2 outward), explaining…
This paper reviews the effects of general relativity in an X-ray spectrum reflected from a cold matter accreting onto a black hole. The spectrum consists of the iron K$\alpha$ line and the Compton reflection. We sketch the overall picture…
We present a detailed analysis of the spectral properties of the Seyfert 1 galaxy 1H0419-577, based on the archival XMM-Newton, NuSTAR and simultaneous Swift observations taken between 2002-2015. All the observations show a broad emission…
It has been suggested that the narrow cores of the Fe K$\alpha$ emission lines in Active Galactic Nuclei (AGNs) are likely produced in the torus, the inner radius of which can be measured by observing the lag time between the $V$ and $K$…
We have compared the 2001 XMM-Newton spectra of the stellar mass black hole binary XTE J1650-500 and the active galaxy MGC-6-30-15, focusing on the broad, excess emission features at ~4--7 keV displayed by both sources. Such features are…
The broadening of atomic emission lines by high-velocity motion of gas near accreting supermassive black holes is an observational hallmark of quasars. Observations of broad emission lines could potentially constrain the mechanism for…
We present a X-ray spectral analysis of a large sample of 25 'bare' active galactic nuclei, sources with little or no complicating intrinsic absorption, observed with Suzaku. Our work focuses on studying the potential contribution from…
Hard X-ray emission is ubiquitous in accreting black holes, both in Galactic binary systems and in Active Galactic Nuclei. I review the different spectra which can be seen from these systems, and possible ways of producing this emission.…
The observed iron K-alpha fluorescence lines in Seyfert-1 galaxies provide strong evidence for an accretion disk near a supermassive black hole as a source of the emission. Here we present an analysis of the geometrical and kinematic…
We present a spectroscopic analysis of XRISM and NuSTAR observations of the black hole X-ray binary GS~1354--64 during its 2026 outburst. A total number of 3.5 million photons are collected by the microcalorimeter Resolve on board XRISM,…
When Beppo-SAX measured the 0.1--12 keV spectrum of RE J1034+396, observations in the optical, UV and EUV were also taken within a few weeks. This multiwavelength spectrum placed very strong constraints on its unusually hot big blue bump…
The faintest ultraluminous X-ray sources (ULXs), those with 0.3-10 keV luminosities 1 < L_X/10^39 < 3 erg s^-1, tend to have X-ray spectra that are disk-like but broader than expected for thin accretion disks. These `broadened disk' spectra…
We present results from a deep Suzaku observation of the black hole in LMC X-1, supplemented by coincident monitoring with RXTE. We identify broad relativistic reflection features in a soft disc-dominated spectrum. A strong and variable…
[Abridged] Optically thick, geometrically thin accretion disks around supermassive black holes are thought to contribute to broad-line emission in type-1 active galactic nuclei (AGN). However, observed emission line profiles most often…