Galactic Template Analysis with ANTARES

The observation of Galactic neutrinos, confirmed by IceCube in 2023, marks a major milestone in astroparticle physics. Underwater detectors like ANTARES, with superior angular resolution compared to IceCube selected events in their published results, provide a unique opportunity to refine our understanding of hadronic processes occurring in the Milky Way. By testing and fitting different phenomenological predictions of diffuse Galactic flux to neutrino data, we aim to constrain the mechanisms governing cosmic-ray progenitors, their transport, and their interactions with interstellar matter and radiation fields. For nearly three years, the ANTARES and KM3NeT collaboration has developed a dedicated template likelihood framework capable of finely convolving phenomenological templates with the detector response function. Unlike conventional methods, this approach maintains the full spatial and energetic dependence of both the Galactic models and the detector response, avoiding information loss through marginalization of the parameter space, and enabling a more precise comparison between theory and observation. This framework has been applied to the full ANTARES dataset, covering 15 years of live-time and incorporating both track-like and shower-like event topologies. In this contribution, the constraints obtained using six different phenomenological models will be presented with a focus on the characterization of the diffuse Galactic neutrino flux by ANTARES. Comparisons with results from IceCube will be briefly discussed to highlight the complementarity of the ice and sea experiments in probing the Galactic neutrino sky.