The Heart Of The Beast : The Relativistic Astrophysics Of Active Galactic Nuclei (speaker: Christopher Reynolds, University Of Maryland)

Tuesday November 3, 2015 4:00 pm
Marlar Lounge (37-252)

At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales, the outer accretion disk and molecular torus act as the reservoirs of gas for the continuing AGN activity. And on all scales from the black hole outwards, powerful winds are seen that probably affect the evolution of the host galaxy as well as regulate the feeding of the AGN itself.  In this talk, I will discuss how current and future X-ray spectroscopy can be used to study each of these components.  Specifically, (1) I shall discuss recent NuSTAR measurements of the high-energy cutoff in the X-ray continuum which are pushing us to conclude that X-ray coronae have electron temperatures regulated by electron-positron pair production. (2) I shall review the latest state of play regarding the measurement of SMBH spins, and show that the predominance of rapidly-rotating objects in current surveys of SMBH spin is entirely unsurprising once one accounts for the observational selection bias resulting from the spin-dependence of the radiative efficiency.   Finally, I shall discuss recent progress in our understanding of fast (v~0.1-0.3c), highly-ionized (mainly visible in FeXXV and FeXXVI lines), high-column density winds that may dominate quasar-mode galactic feedback.

Talk Host: Mark Bautz

Additional information about Christopher Reynolds