8th HEAD Meeting, 8-11 September, 2004
Session 26 AGN/Galactic Nuclei
Poster, Friday, September 10, 2004, 9:00am-10:00pm

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[26.09] Origin of AGN outbursts

A. Siemiginowska (CfA), A. Janiuk, B. Czerny (CAMK)

We discuss the AGN intermittent activity. Accretion onto a supermassive black hole (SMBH) is generally accepted as the basis of AGN activity, however there are still many questions about properties of the accretion flow as well as the fuel supply to the innermost regions of the host galaxy. There is growing evidence that the AGN activity could be intermittent, however the origin of this intermittency has not been identified. Several large scale processes have been discussed including mergers and feedback. However, processes related directly to the accretion disk can influence AGN activity as well. In this paper we link evolution of the accretion disk to AGN activity and describe different stages of AGN activity and corresponding timescales. This evolution scenario is decoupled from any external fuel supply, although it requires a continuous fuel supply into an accretion region. The amount of radiative energy and the duration of outbursts depend on the model parameters. We discuss the model, predicted timescales and related observations.

This work was supported in part by NASA grants GO-09820.01-A, NNG04GF98G and NAS8-39073.

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.