Active Galactic Nuclei: the known and the unknown
Seminar given by Volker Beckmann on Friday, March 2nd, at the François Arago Centre.
Abstract: In an upcoming text book (Beckmann & Shrader, 2012), we are discussing in depth the status of AGN research, the open questions and possibilities to answer them. In this presentation we present the main open issues. Is the central black hole rapidly spinning and can we proof this? What is the dominating accretion mechanism in AGN? Why do some AGN form jets and others don't and how do the jets start off? What keeps jets collimated out to disctances of 100 kpc? Is the emission of blazars dominated rather by synchrotron self-Compton or by external Compton processes? Which parameters are important in the unified model?
Concerning the environment and hosts, the relation between the AGN and the surrounding galaxy and starburst activity are a main issue of debate. And we also still lack an answer to the question, how super massive black holes were able to grow so fast in the early Universe, forming quasars as early as z~7.
I outline the status of related research, formulate the questions and try to hint at research projects able to tackle these fundamental topics.
Credits: Chandra X-ray observatory image of the radio galaxy Centaurus A