Tuning into Cosmic Neutrinos with the Radio Neutrino Observatory in Greenland

Neutrinos are the ideal messenger for high-energy astrophysics. Weakly interacting and uncharged, they propagate undeterred and unabsorbed through the universe. In the last decade, we have observed a flux of high-energy (TeV-scale) neutrinos and through a multi-messenger lens — the combined observations of neutrinos and other messengers like photons — we are starting to see hints of energetic neutrino sources for the first time. At higher energies still, beyond the PeV scale, we can probe the most energetic sources of both neutrinos and cosmic rays, but current neutrino experiments become too small to observe a sizable flux. Instead, we can use embedded radio experiments which detect the coherent radio emission from neutrino interactions in ice using a sparse array of detectors to build up enormous neutrino targets. In this talk, I will describe in-ice detectors, focusing especially on the Radio Neutrino Observatory in Greenland (RNO-G), an experiment currently being built in Greenland and how it can serve as a testbed for the radio array for IceCube-Gen2.