ABSTRACT

While Cosmic Rays astronomy is severely blurred by random terrestrial, solar, galactic and extragalactic magnetic lenses, the highest 7 ray astronomy (above tens TeVs) became more or less blind because photon-photon opacity (electron pair production) at different energy windows. Indeed the Infrared-TeV opacity as well as a more severe BBR(2.75/Q-PeV cut­ off are bounding the TeVs -PeV 7 ray astronomy in a very nearby cosmic ( or even galactic) volumes. Therefore rarest TeVs gamma signals are at present the most extreme trace of High Energy Astronomy. However we observe copious cosmic rays at higher (^> 1015eV) energies almost isotropically spread in the sky. However UHECR astronomy must arise, because at largest energies (> 1019 eV) the magnetic cosmic lenses bending are almost un-effective and UHECR point to their astronomical sources. Because of it also a parasite UHE v astronomy is expected to be present as a necessary consequence of UHECR interaction and cut-off by photopion production on cosmic 2.75 BBR, the well known Greisen, Zatsepin, Kuzmin GZK cut-off [22],[34]. Moreover in a different scenario, the so called Z-Burst or Z-Shower model, UHECR above GZK cut-off are originated by UHE v scattering onto relic light v clustered as a dark hot halos; in this scenario UHE Astronomy is not just a consequence but itself the cause of UHECR signals. Let us remind, among the 7 TeVs discoveries, the signals of power-full Jets blazing to us from Galactic (Micro-Quasars) or extragalactic edges (BL Lacs). At PeVs energies astrophysical 7 cosmic rays should also be present, but, excluded a very rare and elusive CygA3 event, they have not being up date observed; only upper bounds are known at PeV energies. The missing 7 PeVs sources, as we mentioned, are very probably

absorbed by their own photon interactions (electron pairs creation) at the source environment and/or along the photon propagation into the cosmic Black Body Radiation (BBR) or into other diffused background radiation. Unfortunately PeVs charged cosmic rays, easily bend and bounded in a random walk by Galactic magnetic fields, loose their original directionality and their astronomical relevance; their tangled trajectory resident time in the galaxy is much longer (> 103 - 105) than any linear neutral trajectory, as gamma rays, making the charged cosmic rays more probable to be observed by nearly a comparable lenght ratio. However astrophysical UHE neutrino signals at 1013eV-1019eV (or even higher GZK energies) are unaffected by any radiation cosmic opacity and may easily open a very new exciting window toward Highest Energy sources. Being weakly interacting the neutrinos are ideal microscope to deeply observe in their accelerator (Jet,SN,GRB, Black Hole) cores. Other astrophysical v sources at lower energies (108 eV - 1012 eV) should also be present, at least at EGRET fluence level, but their signals are very probably drowned by the dominant diffused atmospheric u, secondaries of muon secondaries, produced as pion decays by the same charged (and smeared) UHE cosmic rays (while hitting terrestrial atmosphere): the so called diffused atmospheric neutrinos. Indeed the atmospheric neutrinos signal is being observed and its modulation has inferred the first conclusive evidence for a neutrino mass and for a neutrino flavour mixing. At lowest (MeVs) v energy windows, the abundant and steady solar neutrino flux, (as well as the prompt, but rare, neutrino burst from a nearby Super-Novae (SN 1987A)), have been, in last twenty years, successfully explored, giving support to neutrino mass reality. Let us mention that Stellar evolution, Supernova explosion but in particular Early Universe had over­ produced and kept in thermal equilibrium neutrinos whose relic presence here today pollute the cosmic spaces either smoothly (lightest relativistic v) or in denser clustered Hot halos ( eVs relic v masses). A minimal tiny (above 0.07 eV) v mass, beyond a Standard Model, are already making their cosmic energy density component almost two order of magnitude larger than the corresponding 2.75 K (Black Body Radiation) BBR radiation density. Moreover, as recently noted their relic presence may play a key role acting as a calorimeter of ZeV UHE neutrinos bom at cosmic edges, solving the GZK cut-off puzzle: The so called Z-burst or Z-WW Shower model [8], [9], [33], [15]. Here we concentrate on the possibility to detect a component of the associated UHE neutrino flux astronomy (above PeVs-EeV up to GZK energies) by UHE vT interactions in Mountain chains or in Earth Crust leading to Horizontal or Upward Tau Air-Showers [10], [16], [17]. 2

2. The UHE v km? detectors: AMANDA, ANTARES, ICECUBE.