High-energy neutrinos from blazars

The origin of the astrophysical neutrino signal detected by IceCube is still mysterious. Several extragalactic sources have been proposed as possible accelerators of the high energy protons (or nuclei) whose interaction with gas or radiation is expected to trigger the neutrino emission. The detection of the well reconstructed event IC-170922A on September 2017, potentially associated with the BL Lac TXS 0506+056 is drastically changing the scenario. I will discuss the interpretation of this event in the framework of the blazar models and the consequences for our knowledge of the jet physics.