Prospects for Neutrino Target-of-Opportunity Observations with PBR

Astrophysical sources capable of accelerating ultra-high energy cosmic rays may also produce very-high energy neutrinos via interactions of the cosmic rays within their sources or their surrounding environments. Suborbital and space-based optical Cherenkov and radio detectors can also detect upward-going extensive air showers generated by decaying tau-leptons produced by the interactions of >~ 10 PeV cosmic tau neutrinos propagating through the Earth. POEMMA-Balloon with Radio (PBR), an upcoming NASA ultra-long duration balloon mission, will feature instruments to observe very-high energy cosmic-ray and neutrino extensive air showers via fluorescence, optical Cherenkov, and radio signals. One of PBR’s key science goals is to search for very-high energy neutrinos from steady and transient astrophysical sources. We discuss the prospects of detecting tau neutrinos from astrophysical sources with PBR. We also discuss our preparations for PBR’s neutrino Target-of-Opportunity program, including software being developed to process alerts and plan observations. PBR is planned to launch in Spring 2027.