Author: Publisher:
ISBN:
Category : Active galaxies
Languages : en
Pages : 0
Book Description
Variability of Active Galactic Nuclei
Author: Variability of Active Galactic Nuclei
Author: Hugh Richard MillerPublisher:
ISBN: 9780521412957
Category : Science
Languages : en
Pages : 387
Book Description
Active galactic nuclei (AGN), the most powerful objects in the universe, continue to receive a great deal of attention from observational astronomers & theorists. This book collects the results presented at a meeting held at Georgia State University in May 1990 on the topic of variability in active galactic nuclei. It is clear that careful analysis of variability over many wave bands is likely to give clues to the nature of the central engine in AGN. The contributions are grouped in themes: multifrequency variability, UV-optical-IR variability, radio variability, & X-ray variability. One of the most exciting results reported here is that many blazars exhibit micro-variability. There is an important group of papers on NGC 5548 & other Seyfert galaxies. The meeting in Atlanta provided the first opportunity for discussion for those who participated in the worldwide campaign to observe NGC 5548, & new results are also announced for many quasars, Seyfert galaxies, BL Lacertae objects, & radio galaxies. The observational data are interspersed with theoretical insights that enable us to better understand the physical conditions & processes in galactic nuclei, including giant black holes thought to lurk in their cores.
Active Galactic Nuclei
Author: Volker BeckmannPublisher: John Wiley & Sons
ISBN: 352766680X
Category : Science
Languages : en
Pages : 390
Book Description
Active Galactic Nuclei This AGN textbook gives an overview on the current knowledge of the Active Galacitc Nuclei phenomenon. The spectral energy distribution will be discussed, pointing out what can be observed in different wavebands. The different physical models are presented together with formula important for the understanding of AGN physics. Furthermore, the authors discuss the AGN with respect to its environment, host galaxy, feedback in galaxies and in clusters of galaxies, variability, etc. and finally the cosmological evolution of the AGN phenomenon. This book includes phenomena based on new results in the X-Ray and gamma-ray domain from new telescopes such as Chandra, XMM-Newton, the Fermi Gamma-Ray Space Telescope, and the VHE regime not mentioned so far in AGN books. Those and other new developments as well as simulations of AGN merging events and formations, enabled through latest super-computing capabilities. From the contents: The observational picture of AGN Radiative processes The central engine AGN types and unification AGN through the electromagnetic spectrum AGN variability Environment Quasars and cosmology Formation, evolution and the ultimate fate of AGN What we do not know (yet)
Variability of Active Galactic Nuclei
Author: Marek A. AbramowiczProbing the Inner Regions of Active Galactic Nuclei Through Variability Analysis
Author: Ella GuiseA Statistical Study of the Optical Variability of Active Galactic Nuclei
Author: Malav Mahendra ShahVariability of Active Galactic Nuclei
Author: Claudia Megan UrryPublisher:
ISBN:
Category : Active galaxies
Languages : en
Pages : 39
Book Description
X-ray Studies of the Central Engine in Active Galactic Nuclei with Suzaku
Author: Hirofumi NodaPublisher: Springer
ISBN: 9812877215
Category : Science
Languages : en
Pages : 164
Book Description
The aim of this research was to use the X-ray satellite Suzaku to establish a picture of a central engine that effectively converts the gravitational energy of accreting matter onto the supermassive black hole to a huge amount of radiation in an active galactic nucleus. Although the engine is known to consist of a Comptonizing corona and an accretion disk, its image has remained unclear because primary emissions, coming directly from the engine, cannot be identified in X-ray spectra without models. The book describes a technique of time variability assisted spectral decomposition to model-independently examine X-ray signals, and how this was applied to the Suzaku archive data of active galactic nuclei. As a result, at least three distinct primary X-ray components have been discovered in an X-ray from an active galactic nucleus, presumably indicating a novel picture that the engine is composed of multiple coronae with different physical properties in an accretion flow. Furthermore, the determination of the spectral shapes of the primary X-rays has a significant impact on estimations of black hole spins, because it is essential to quantify reprocessed X-ray spectra. The successful model-independent decomposition of X-ray spectral components with flux variations of active galactic nuclei is likely to be effective in future data analyses from the soon-to-be-launched Japanese X-ray satellite ASTRO-H, which is capable of achieving unprecedented fine spectros copy and broad energy band coverage.
The Physics and Evolution of Active Galactic Nuclei
Author: Hagai NetzerPublisher: Cambridge University Press
ISBN: 1107021510
Category : Science
Languages : en
Pages : 369
Book Description
A comprehensive introduction to the theory underpinning our study of active galactic nuclei and the ways we observe them.
Author: James Charles Manners