Lecture Notes in Physics

Guthmann, A.W.; Georganopoulos, M.; Marcowith, A.; Manolakou, K.

1. 1 Schematic Picture of AGN Some galaxies are known to emit radiation with extremely high luminosities from a rather small volume in the ??ray, X-ray and UV continuum. Such active cores are the so-called Active Galactic Nuclei (AGN) and the radiation is commonly believed to be a result of gravitational energy released by matter spiraling around 9 a supermassive central black hole of about 10 M (see Fig. 1). Though the central engine which produces the enormous observed activity cannot be resolved observationally, a standard picture of an AGN has gradually emerged to explain the richness of the radiation spectra: • an accretion disk with radius from about 2 to 100 gravitational radii, R , g feeding the central black hole and emitting mainly in the UV and soft X-rays; • the broad line optically emitting clouds (BLR), which seem to be absent in 3 some sources (e. g. FRI, see hereafter) and extend up to a few 10 R from g the center.

Details

Published by: Springer

Publication Date: 2002-07-23

Format: Hardcover

ISBN-13: 9783540435181

DOI: 10.1007/3-540-46025-X

Dimensions: 234cm x156cm

Pages: 246