Revisiting bounds on neutrino dark matter interaction at spikes

Abstract

Interactions between high energy neutrinos produced in active galactic nuclei (AGNs) and the dark matter (DM) particles in the dense spike around the supermassive black holes may lead to attenuation of the flux. This consideration along with the observation of a sizeable flux from at least four AGNs have been used to derive bounds on the neutrino dark matter scattering cross section \cite{Cline:2023tkp,Cline:2022qld,Dixit:2026zkv}. We show that the attenuation strongly depends on the details of the microphysics parameters. In particular if the mediator is a vector boson with a mass much smaller than the center of mass energy of the neutrino and dark matter, the energy loss of the neutrino and therefore the flux attenuation will be negligible, relaxing the bounds.