ASTRONOMY COLLOQUIUM - APRIL 4, 2006
Martin Elvis , Harvard-Smithsonian Center for Astrophysics
Quasar Structure and Cosmological Feedback
Feedback is the key to an interesting Universe. In particular, feedback from
quasars and their less luminous cousins, Active Galactic Nuclei (AGNs), has
been newly recognized as a potentially crucial input to multiple areas of
galaxy formation. However, so far, arguments using AGN feedback have been
forced to make simple assumptions: that all SMBHs accrete at the Eddington
limit while active and that 10% the accreted mass is successfully ejected.
To become a testable science, ''cosmological feedback'' from AGNs must use the details of the structure of quasar nuclei, both on a small scale, where the winds most likely arise, and on a larger scale, at the 'obscuring torus' of Unification Models.
I will report on new results that give the first good measurement of mass loss rate in an AGN wind, and on an emerging, more complex, view of the 'obscuring torus'. Both have strong implications for cosmological feedback from AGNs.