Astronomy & Astrophysics Seminar: Sizing up the continuum emitting regions in quasars

Abstract:

There are significant gaps in our understanding of accretion phenomena in quasars with implications for understanding the cosmic census of supermassive black holes, and their interaction with the environment. As quasar accretion disks (ADs) are unresolved by current instruments, microlensing and reverberation data provide the means by which their fundamental properties may be probed. The application of these techniques over the past decade has pointed to quasar ADs being larger than predicted by standard theory by a factor of a few, thereby motivating a slew of refined AD models. In this talk, recently acquired reverberation data from the Wise observatory will be presented that challenge claims for over-sized ADs, and hint that a possible solution to the size-conundrum lies in the interpretation of the data. The data further reveal the presence of a previously under-appreciated quasar emission component, which may be associated with the inner broad-line region. Implications of our findings for quasar physics and phenomenology will be briefly discussed.

Seminar Organizer: Dr. Omer Bromberg