The nearby active galaxy NGC 1275, has widely been detected from radio to gamma rays. Its spectral energy distribution (SED) shows a double-peak feature, which is well explained by synchrotron self-Compton (SSC) model. However, recent TeV detections
might suggest that very-high-energy $gamma$-rays (E$geq$100 GeV) may not have a leptonic origin. We test a lepto-hadronic model to describe the whole SED through SSC emission and neutral pion decay resulting from p$gamma$ interactions. Also, we estimate the neutrino events expected in a Km$^3$ Cherenkov telescope.
Markarian 421 (Mrk 421) is one of the brightest, fastest and closest BL Lac object known. Its very high energy (VHE) spectrum has been successfully modeled with both leptonic and hadronic models and not conclusive results have been achieved yet about
the origin of its VHE emission. Here we investigate the possibility that a fraction of the VHE flares of Mrk 421 are due to hadronic processes and calculate the expected neutrino flux associated. We introduce the obtained neutrino flux in a Monte Carlo simulation to see the expectation for a Km$^{3}$ Cherenkov neutrino telescope.
Very high energy gamma-ray emission of Fanaroff-Riley I objects is not univocally explained by a single emission model. Leptonic models with one and multi-zone emission regions, occurring in the jet of these objects, are usually used to describe the
broadband spectral energy distribution. A correlation between the X-ray and TeV emission is naturally expected within leptonic models whereas a lack of correlation between these two observables represents a challenge and favors the hadronic scenarios. This is the case of M87 as we show here by analyzing its TeV and X-ray emission recorded in the last decade. Furthermore, we point out that the spectra obtained by MAGIC, H.E.S.S. and VERITAS telescopes cannot be described with the same leptonic model introduced by the Fermi-LAT collaboration. We introduce hadronic scenarios to explain the TeV gamma-ray fluxes of this radiogalaxy as products of Fermi-accelarated protons interacting with seed photons in the jet or thermal particles in the giant lobes. By fitting this part of spectral energy distribution as pion decay products, we obtain the expected neutrino counterpart and the luminosity of accelerating protons in the jet and/or lobes. With the expected neutrino fluxes we investigate, through Monte Carlo simulations, the possibility to see the signal from M87 with a Km$^{3}$ neutrino telescope, and compare the results with what has been seen by IceCube experiment up to now. Finally we constrain the features of giant lobes through the observations performed at ultra high energies by TA experiment.
