Accretion processes on a black hole

SK Chakrabarti - Physics Reports, 1996 - Elsevier
We describe astrophysical processes around a black hole keeping primarily the physics of
accretion in mind. In Section 1, we briefly discuss the formation, evolution and detection of …

HESS observations of PKS 2155-304

F Aharonian, AG Akhperjanian, KM Aye… - Astronomy & …, 2005 - aanda.org
The high-frequency peaked BL Lac PKS 2155-304 at redshift has been detected with high
significance (~ 45σ) at energies greater than 160 GeV, using the HESS stereoscopic array of …

Very High Energy Gamma Rays from PKS 2155–304

PM Chadwick, K Lyons, TJL McComb… - The Astrophysical …, 1999 - iopscience.iop.org
The close X-ray–selected BL Lac PKS 2155-304 has been observed using the University of
Durham Mark 6 very high energy (VHE) gamma-ray telescope during 1996 …

Spiral shocks in accretion disks as a contributor to variability in active galactic nuclei

SK Chakrabarti, PJ Wiita - … Journal-Part 1 (ISSN 0004-637X) …, 1993 - adsabs.harvard.edu
We simulate the variations in emission from accretion disks subjected to nonaxisymmetric
tidal perturbations generated by masses within or passing through the disk, using a two …

[HTML][HTML] Multiwavelength monitoring of the BL Lacertae object PKS 2155-304. 4: Multiwavelength analysis

R Edelson, J Krolik, G Madejski… - … Journal, Part 1 …, 1995 - adsabs.harvard.edu
Multiwavelength monitoring of the BL Lacertae object PKS 2155-304. 4: Multiwavel ADS
Classic is now deprecated. It will be completely retired in October 2019. This page will …

Hybrid accretion disks in active galactic nuclei. I-Structure and spectra

A Wandel, EP Liang - Astrophysical Journal, Part 1 (ISSN 0004 …, 1991 - adsabs.harvard.edu
We provide a unified treatment of the two distinct states of vertically thin AGN accretion disks:
a cool (T~ 10^ 6^ K) optically thick solution, and a hot (T_e_~ 10^ 9^ K, optically thin …

Optical variability properties of high luminosity AGN classes

CS Stalin, R Sagar, PJ Wiita - Journal of Astrophysics and Astronomy, 2004 - Springer
We present the results of a comparative study of the intranight optical variability (INOV)
characteristics of radio-loud and radioquiet quasars, which involves a systematic intra-night …

Multi-wavelength monitoring of the bl lacertae object pks 2155-304 ii. the rosat observations

W Brinkmann, L Maraschi, A Treves… - … , Vol. 288, p. 433 …, 1994 - adsabs.harvard.edu
Extensive ROSAT PSPC observations of the BL Lac object PKS 2155-304 carried out
between November 12 and November 15, 1991 revealed the source to be in a bright state …

Time-dependent models of two-phase accretion discs around black holes

M Mayer, JE Pringle - Monthly Notices of the Royal Astronomical …, 2007 - academic.oup.com
We present time-dependent simulations of a two-phase accretion flow around a black hole.
The accretion flow initially is composed of an optically thick and cool disc close to the mid …

What Do the Ultraviolet Spectra of Narrow-Line Seyfert 1 Galaxies Tell Us about Their Broad-Line Regions?

J Kuraszkiewicz, BJ Wilkes, B Czerny… - The Astrophysical …, 2000 - iopscience.iop.org
We study the UV spectra of narrow-line Seyfert 1 (NLSy1) galaxies and compare them with"
normal" active galactic nuclei. Similar to their optical lines, the NLSy1s show narrower UV …