Perspectives in Astroparticle physics from High Energy Neutrinos

Neutrino telescopes are ushering us into a new era for astroparticle physics: the recent discovery of a diffuse flux at the TeV-PeV range by the IceCube collaboration clearly opens a new window to the cosmos. At the same time, these events also constitute the most energetic neutrinos ever measured (well beyond the energies achievable at man-made accelerators) and may offer an important diagnostic tool for physics and astrophysics, especially when taking into account that there is no compelling explanation for their origin, yet. It has been widely recognized that neutrino telescope data, especially if used in a multi-messenger context, can help clarifying the acceleration of (hadronic) cosmic rays in both the Galactic and the extragalactic environment, have a potential for unveiling new classes of astrophysical sources, can constrain some exotic neutrino properties and perhaps shed light on some of the deepest mystery in current physics, like the nature of Dark Matter. Currently, several programs are ongoing for the upgrade of the existing facilities or the development of next generation ones and it is very timely to review the status of this rapidly developing field, with a desirable synergy between theory and experimental communities.