Speaker
Description
Since two decades ago the IceCube Neutrino Observatory has been detecting ~TeV-PeV neutrinos from mostly unidentified extraterrestrial sources. So far, active galactic nuclei (AGN), powered by supermassive black holes (SMBH), are theoretically and observationally the most likely source candidates. The hottest spot in the diffuse ~TeV neutrino sky is a weakly jetted Seyfert-II AGN, while the most promising associations with individual ≳100 TeV neutrinos were made with jetted AGN pointing at Earth (a.k.a. blazars). To definitively answer if jetted AGN systematically emit ≳100 TeV neutrinos, we compiled the largest catalog of 7918 blazars to date and obtained decade-long optical light curves for most of them. We then searched for a spatio-temporal correlation between these blazar light curves and IceCube's first catalog of a few hundred of ≳100 TeV neutrino events, while assuming that neutrinos are expected at the brightest optical outbursts. Under this phenomenological assumption, we found that a global blazar-neutrino correlation cannot be confidently established, inline with the result of our previous study in the radio band. We estimated that fewer than ~8% of ≳100TeV neutrinos are from major blazar outbursts, alluding to substantial contribution from other (SM)BH-powered systems. In my talk, I will present our state-of-the-art correlation study and its surprising results, which are of interest to all SMBH and AGN researchers.