Seminario: Elina Lindfors (University of Turku)

Over the past decade, the IceCube Neutrino Observatory has detected a few hundreds of high-energy (HE) neutrinos from cosmic sources. Despite numerous studies searching for their origin, it is still not known which source populations emit them. A few confident individual associations exist with active galactic nuclei (AGN), mostly with blazars which are jetted AGN whose jet points in our direction. Nonetheless, on a population level, blazar-neutrino correlation strengths are rather weak. To definitively answer if jetted AGN systematically emit >~100 TeV neutrinos: (1) we compiled the largest catalog of blazars and their optical light curves to date; and (2) we searched for a spatio-temporal correlation between these blazar light curves and IceCube’s first catalog 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 neutrino events came from major blazar outbursts, alluding to substantial contributions from other systems. In my talk, I will present this state-of-the-art correlation study and outlook for further searches with next generation of instruments.