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The enhanced activity typical of the core of Seyfert galaxies can drivepowerful winds where high-energy phenomena can occur. In spite of their highpower content, the number of such non-jetted active galactic nuclei (AGN)detected in gamma rays is very limited. In this Letter, we report theidentification and measurement of the gamma-ray flux from NGC 4151, a Seyfertgalaxy located at about 15.8 Mpc. The source is known for hosting ultra-fastoutflows (UFOs) in its innermost core through X-ray spectroscopic observations,thereby becoming the first UFO host ever recognized in gamma rays. UFOs aremildly relativistic, wide opening angle winds detected in the innermost parsecsof active galaxies where strong shocks can develop. We interpret the gamma-rayflux as a result of diffusive shock acceleration at the wind termination shockof the UFO and inelastic hadronic collisions in its environment. Interestingly,NGC 4151 is also spatially coincident with a weak excess of neutrino eventsidentified by the IceCube neutrino observatory. We compute the contribution ofthe UFO to such a neutrino excess and we discuss other possible emissionregions such as the AGN corona.

Gamma-ray emission from the Seyfert galaxy NGC 4151 and multimessenger implications for ultra-fast outflows