271 citations · 4.6k across the 192 of their papers we have counts for
9 papers · 2 filters
Thermal and Viscous Instability of Accretion Disc in AGN
Agnieszka Janiuk, Bozena Czerny
The standard accretion discs are known to be thermally and viscously unstable over a certain range of temperatures. In the inner disc regions there may develop radiation pressure d…
Radiation pressure instability as a variability mechanism in the microquasar GRS 1915+105
Agnieszka Janiuk, Bozena Czerny, Aneta Siemiginowska
Physical mechanism responsible for high viscosity in accretion disks is still under debate. Parameterization of the viscous stress as proved to be a successful representation…
On the effect of coronal outflow on spectra formation in galactic black hole systems
Agnieszka Janiuk, Bozena Czerny, Piotr T. Zycki
We present the results of both analytical and numerical calculations of the amplitude of the reflection component in X-ray spectra of galactic black hole systems. We take into acco…
What do the UV Spectra of Narrow-line Seyfert 1 Galaxies tell us about their BLR?
J. Kuraszkiewicz, B. J. Wilkes, B. Czerny +1
We study the UV spectra of narrow-line Seyfert~1 (NLSy1) galaxies and compare them with ``normal'' AGN. Similar to their optical lines, the NLSy1s show narrower UV lines. They are…
A cloud model of active galactic nuclei: the iron K-alpha line diagnostics
V. Karas, B. Czerny, Z. Abrassart +1
The origin and the profile of the iron K-alpha line from active galactic nuclei is being studied. The model with a quasi-spherical distribution of clouds around a compact galactic…
Variability Model for the Microquasar GRS 1915+105
Agnieszka Janiuk, Bozena Czerny, Aneta Siemiginowska +1
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…
Vertical structure of the accreting two-temperature corona and the transition to an ADAF
A. Różańska, B. Czerny
We investigate the model of the disc/corona accretion flow around the black hole. The model, parameterized by the total (i.e. disk plus corona) accretion rate, , mass of th…
Accretion and Emission Processes in AGN: the UV-X Connection
S. Collin, A. Abrassart, B. Czerny +2
The main characteristics of the average spectrum of radio quiet AGN in the UV and X-ray range are reviewed, and the emission mechanisms are discussed in the framework of accretion…
Toy model of obscurational variability in active galactic nuclei
A. Abrassart, B. Czerny
We propose an explanation of the variability of AGN based on a cloud model of accretion onto a black hole. These clouds, present at a distance of 10-100 Schwarzschild radii, possib…