Speaker
Description
On February 13, 2023, at 01:16:47 UTC, the KM3NeT neutrino telescope detected KM3-230213A, an ultra-high-energy neutrino event without an identified electromagnetic counterpart. Its unknown origin motivates a multi-energy follow-up to probe astrophysical scenarios capable of producing neutrinos across a broad energy range. We present a coordinated analysis with IceCube spanning MeV to sub-TeV energies, searching for time-correlated or precursor neutrino emission associated with KM3-230213A. First, we investigate thermal MeV-scale neutrino bursts using the supernova data stream. Such emission is expected from dense environments such as core-collapse supernovae, collapsars, and neutron star mergers, where neutrinos are produced via thermal processes. These signals, with typical energies of 10–30 MeV and durations from milliseconds to seconds, may precede high-energy emission and probe the central engine. Second, we perform a follow-up using the ELOWEN sample, primarily sensitive to neutrinos in the 0.5–5 GeV range. This energy regime is expected to arise from quasi-thermal processes, such as proton–neutron collisions in relativistic outflows, and provides a bridge between thermal MeV emission and higher-energy non-thermal components. Finally, we analyze the IceCube GRECO dataset, optimized for neutrinos between 10 GeV and 1 TeV, which extends the sensitivity to the higher-energy part of possible quasi-thermal emission and toward the transition to non-thermal emission. Motivated by models predicting multi-component emission, we search for time-correlated signals consistent with the direction of KM3-230213A. We will present the planned search strategy and the sensitivities of each study.
