2020ApJ...898..103S

The detection of a high-energy muon neutrino on 2017 September 22 by the IceCube neutrino detector coincides with the multiwavelength flaring from the BL Lac object TXS 0506+056, most likely confirming an active galactic nucleus as a source of high energy cosmic rays and neutrinos. Using the photohadronic model, we have explained the very high energy γ-rays observed by MAGIC telescopes a few days after the neutrino event and extend the model to calculate the neutrino flux at different windows consistent with the flaring period of TXS 0506+056 and compared with the IceCube and MAGIC estimates. We also use this model to estimate the neutrino flux from the flaring of FSRQ PKS B1424-418, which is believed to be associated with the 2 PeV neutrino event observed by IceCube.