Research on AGN

I have specialized in studies of AGN ever since my graduate studies at Caltech during 1968-1972. Following my early work on the emission lines of Seyfert galaxies, including photoionization modeling, I branched out in two main directions: (1) accretion disk models for the energy source in AGN, and (2) photoionization modeling of H II regions (discussed on a separate page).

A long standing interest has been the question of what AGN disks should look like. I have concentrated on the thermal emission from accretion disks, including the energy distribution and polarization. Recently I have been particularly interested in the strong polarization observed by HST in the Lyman continuum of some QSOs.

The paper "Powerful Flares from Recoiling Black Holes in Quasars" (G. A. Shields and E. W. Bonning 2008, ApJ 682:758) discusses a numerical simulation of an accretion disk disrupted by a recoiling black hole. An animation of the numerical simulation is here.


August 28, 2010
Department of Astronomy
UT Austin
Austin TX 78712