Observing ultra-high energy cosmic rays and cosmic neutrinos with POEMMA*

The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) is designed to detect ultra-high energy (UHE) cosmic rays and possibly cosmic neutrinos above 20 EeV by observing the air fluorescence produced by extensive air showers (EASs), and cosmic neutrinos above 20 PeV by sensing the Cherenkov signal from upward-moving EASs induced by Earth-interacting tau neutrinos. POEMMA consists of two identical satellites flying in loose formation in 525 km altitude orbits, both equipped with a a wide field-of-view (45º) Schmidt optical design with an optical collecting area of over 6 m2. The hybrid focal surface of each telescope includes a fast (1 μs) near-ultraviolet camera for fluorescence observations and an ultrafast (10 ns) optical camera for Cherenkov observations. The POEMMA spacecraft will have sensitivity over the full celestial sky, and is designed to quickly re-orientate to follow up transient neutrino sources and obtain currently unparalleled neutrino flux sensitivity. In a 5-year mission, POEMMA will probe the most energetic phenomena of the universe, enabling unprecedented studies of transient and steady sources of UHE cosmic rays and cosmic neutrinos, and of physics beyond the standard model.