The Road to Opening the Very-High-Energy Neutrino Sky with the Trinity Neutrino Observatory

by Prof. Nepomuk Otte (School of Physics & Center for Relativistic Astrophysics Georgia Institute of Technology)

Tuesday 29 Jul 2025, 15:00 → 17:00 Europe/Berlin

Observations of high-energy neutrinos from TeV to PeV with IceCube have ushered in a new era in multi-messenger astrophysics. Notable achievements of the IceCube team include the detection of the diffuse flux of astrophysical neutrinos, identifying two potential neutrino sources associated with supermassive black holes, and observing our own Milky Way galaxy in neutrinos. While much of the neutrino sky remains dark at even higher energies due to the lack of sensitive instruments, observations and theory hint at the rich scientific potential of the very-high-energy (VHE, ranging from PeV to EeV) neutrino sky. For example, the KM3NET team reported an astonishing event exceeding 100 PeV last year, defying statistical expectations. Or the astrophysical neutrino flux, which does not exhibit signs of a turnover at PeV energies, may extend well into the VHE regime. We also expect VHE neutrinos to originate from the interactions between cosmic rays exceeding EeV and the Cosmic Microwave Background. Finally, an increasing body of literature discusses PeV neutrino emissions near supermassive black holes. Given the abundant scientific opportunities VHE neutrinos present, we are developing the Trinity Neutrino Observatory.

The Trinity Neutrino Observatory employs a system of imaging atmospheric Cherenkov telescopes designed to detect Earth-skimming tau neutrinos from distances of up to 200 kilometers. By carefully selecting the locations of these telescopes, Trinity can achieve full sky coverage with unmatched sensitivity, all at a fraction of the cost compared to other proposed experiments.

In this presentation, I will discuss Trinity's scientific objectives and share results from the Trinity Demonstrator, which has been operating since the fall of 2023 and serves as a pathfinder for the full observatory. Additionally, I will introduce Trinity One, the first complete telescope of the Trinity Neutrino Observatory, which will be the most sensitive very high-energy (VHE) neutrino instrument aimed at detecting point sources.