How to sparkle in gamma rays

by Sarah Wagner

Wednesday Apr 22, 2026, 1:00 PM → 2:00 PM Europe/Madrid

IFAE Seminar Room (In-person)

If visible to the human eye, the night sky would sparkle in gamma rays. This flickering arises from the extreme variability of blazar jets (alongside gamma-ray bursts and galactic sources). In this talk, I introduce active galactic nuclei (AGN) and blazars which are powered by supermassive black holes at the centers of galaxies. I present the established blazar classification into Flat Spectrum Radio Quasars (FSRQs) and BL Lac objects (BLLs), traditionally defined by their emission-line properties. I then show that their gamma-ray variability also differs systematically. Using stochastic time-series modeling with Ornstein–Uhlenbeck processes, I characterize blazar light curves in terms of variability amplitude and correlation timescale. FSRQs exhibit faster, more erratic variability, while BLLs show smoother, longer-memory behavior. These results suggest that variability is not just a byproduct, but a probe of the underlying jet physics—offering new constraints on the environments and emission mechanisms powering gamma-ray blazars.