Original title: KM3NeT/ARCA stacking search for high-energy neutrino point sources: the case of ultra-luminous infrared galaxies and blazars
The KM3NeT Collaboration · September 2026
Space produces high-energy neutrinos, which are tiny, ghost-like particles that travel across the universe without stopping. Scientists want to know which objects in space create them. To find out, researchers used the KM3NeT/ARCA detector to search for these particles coming from three types of bright, active space sources: very bright infrared galaxies and two kinds of intense cosmic beacons called blazarsActive galaxies with jets pointed towards Earth, emitting high-energy radiation across the spectrum.. Instead of checking one object at a time, they stacked their data, combining the signals from multiple objects in each group to spot faint signals more easily. After looking through their collected data, the researchers found no statistically significant excess of neutrinos above normal atmospheric background noise from any of the three groups.
Imagine you're sorting through a huge pile of white shells on a beach, looking for a few rare blue ones that might be carried by a specific current. Most shells look similar, and the blue ones are so scarce that you might miss them among the thousands. In this paper, scientists are sifting through data from many galaxies, searching for rare neutrino signals that could be hidden in the background noise. By combining the data from all sources, they try to make the faint signal stand out, but still find no clear evidence.
This helps astrophysicists narrow down where high-energy neutrinos come from in space. By setting limits on these galaxies, it guides future searches for the actual sources.
The search did not find a statistically significant excess above background, so it only sets upper limits on neutrino emission. It relies on assumed models for the signal spectra and is based on 336 days of data from a specific detector configuration. The analysis does not cover all possible neutrino sources or time periods.
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KM3NeT/ARCA stacking search for high-energy neutrino point sources: the case of ultra-luminous infrared galaxies and blazars — The KM3NeT Collaboration
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.