Active galactic nuclei often show relativistic outflows of matter, called jets. Astrophysical sources in which the jets are oriented towards Earth are called blazars. We study their simultaneous radio to gamma-ray spectral energy distributions (SEDs) from the TANAMI sample, with over 80 SEDs for 22 sources. The large amount of monitoring data from the TANAMI project allows us to construct dynamic SEDs, highlighting spectral changes in varying flux states. With the data, we can address key questions in AGN jet physics like the existence of the blazar sequence and the Fermi blazar's divide, the fundamental plane of black hole masses and the origin of the "big blue bump". Studying a large sample of AGN is fundamental in further addressing the question of whether jets are hadronic. In light of the recent tantalizing coincidences between outbursts of the blazars PKS 1424-418 and TXS 0506+056 and two IceCube neutrino events, we further study all 179 3LAC blazars consistent with HESE IceCube neutrinos above 100 TeV.
In our recent study, we construct the high-energy spectral energy distributions (SEDs). Adopting the IceCube neutrino spectrum of the extraterrestrial excess flux, and assuming that the neutrino and photon integrated energy fluxes are equal, we compute the expected neutrino event numbers. We emphasize, that the calorimetric photon energy fluxes obtained by integrating over the SED differ by a large margin from the Fermi-LAT fluxes alone. The resulting numbers are in good agreement with the observed neutrino events and constrain the hadronicness of blazars, suggesting that blazars contribute largely at these energies. In particular, we note that the non-detection of many gamma-ray bright blazars is still in agreement with the hadronic blazar model