Supermassive black holes (SMBH) at the centers of galaxies become active when they devour matter from around them at a high rate. Much is still unknown about how matter around Active Galactic Nuclei (AGN) is regulated. The pure unified model posits that the differences in the observed signatures from AGN occur only due to differences in observers’ viewing angles. The receding torus model offers an explanation for the observed decrease in obscured AGN fraction with luminosity (i.e., the dust sublimation radius is higher for more luminous AGN, making them unobscured in many more viewing angles).

Tonima Tasnim Ananna, PhD, postdoctoral associate, Dartmouth College, will present recent research which finds that matter around AGN is more definitively regulated by feeding rate (also known as Eddington ratio) rather than luminosity. This calls for a revision of the well-established Unified model and offers a clear path toward exploring AGN lifecycles using current and future missions.

Biography:
https://physics.dartmouth.edu/people/tonima-tasnim-ananna