S E M I N A R IDepartament d'Astronomia i Astrofísica
Universitat de València
High resolution studies of AGN: CTA102 and others
Christian M. Fromm
Max-Planck-Institut fuer Radioastronomie, Bonn, Alemanya
Seminari del departament d'Astronomia i Astrofísica
Dimecres 03 març 2010
Important information can be obtained from radio observations of active galactic nuclei (AGN), including single-dish light-curve analysis and multi-frequency very-long-baseline interferometry (VLBI) observations. We will present our study of the historical 2006 radio flare in the radio source CTA 102, where the shock-in-jet model and the hypothesis of an over-pressured jet during this flare were tested. For our analysis, we used single-dish observations as well as three multi-frequency VLBI observations. From the light curve analysis we identify the three different radiation loss stages, where the synchrotron stages shows a unexpected double peak structure. The evolution of the spectral parameters along the jet during the flaring event are extracted from VLBI observations and confirm our assumed model. The double peak structure can be explained by a change in the viewing angle and leads to a Doppler boosting of the flux densities around 2006.1. Prospectives of numerical simulations and studies on another sources will be presented as well.