Extending KM3NeT’s Point-Source Searches to Lower Energies with KM3NeT/ORCA

AbstraktAbstract

Neutrino telescopes play a key role in multi-messenger astrophysics, providing unique insights into the still-unclear processes in our Universe and its active sources. With the goal of shedding light on these mysteries, the KM3NeT collaboration is deploying a deep-sea Cherenkov neutrino telescope in the Mediterranean Sea. It comprises two detectors: identical in their design but differing by size and density. KM3NeT/ARCA, off the coast of Sicily, is optimised for high energies in the TeV-PeV range to observe astrophysical neutrinos. KM3NeT/ORCA, off the coast of Toulon (France), is designed to detect GeV–TeV atmospheric neutrinos to study oscillations and mass ordering, thereby also detecting low-energy astrophysical neutrinos and extending KM3NeT’s reach to sources at lower energies than those accessible to KM3NeT/ARCA. This contribution presents the expected performances for the detection of point-like sources using the data collected by KM3NeT/ORCA from February 2020 to September 2023. For the first time, KM3NeT/ORCA data are used to perform a binned likelihood analysis, improving KM3NeT’s sensitivity to softer spectra and enhancing the prospects for detecting neutrino sources across a wider energy range. The discovery potential and sensitivity of KM3NeT/ORCA to point sources for different spectral assumptions and over the full sky are reported. As a first application of this analysis, the direction of KM3-230213A, the ultra-high energy event recently observed by KM3NeT, is inspected, and unblinding results from the surrounding region are presented.

Neutrino telescopes play a key role in multi-messenger astrophysics, providing unique insights into the still-unclear processes in our Universe and its active sources. With the goal of shedding light on these mysteries, the KM3NeT collaboration is deploying a deep-sea Cherenkov neutrino telescope in the Mediterranean Sea. It comprises two detectors: identical in their design but differing by size and density. KM3NeT/ARCA, off the coast of Sicily, is optimised for high energies in the TeV-PeV range to observe astrophysical neutrinos. KM3NeT/ORCA, off the coast of Toulon (France), is designed to detect GeV–TeV atmospheric neutrinos to study oscillations and mass ordering, thereby also detecting low-energy astrophysical neutrinos and extending KM3NeT’s reach to sources at lower energies than those accessible to KM3NeT/ARCA. This contribution presents the expected performances for the detection of point-like sources using the data collected by KM3NeT/ORCA from February 2020 to September 2023. For the first time, KM3NeT/ORCA data are used to perform a binned likelihood analysis, improving KM3NeT’s sensitivity to softer spectra and enhancing the prospects for detecting neutrino sources across a wider energy range. The discovery potential and sensitivity of KM3NeT/ORCA to point sources for different spectral assumptions and over the full sky are reported. As a first application of this analysis, the direction of KM3-230213A, the ultra-high energy event recently observed by KM3NeT, is inspected, and unblinding results from the surrounding region are presented.