Keeping track of a neutrino detector's moody underwater telescope

ANTARES, the Mediterranean's neutrino telescope, reconstructs high-energy cosmic events from the Cherenkov light signature of muons passing through water. To combine data across different observation periods, the team developed criteria to group runs with compatible detector configurations—mainly based on how many of the photomultiplier tubes were actually working. This keeps their statistical samples clean when combining observations taken under varying environmental and hardware conditions.