Search for contained neutrino events at energies above 30 TeV in 2 years of data


Neutrino observations are a unique probe of the universe’s highest energy phenomena: neutrinos are able to escape from dense environments that photons cannot and are unambiguous tracers of hadronic interaction processes, in particular the acceleration of cosmic rays. As cosmic ray protons and nuclei are accelerated, they interact with gas and background light to produce particles such as charged pions and kaons which then decay, emitting neutrinos. We report on results of an all-sky search for these neutrinos at energies above 30 TeV in the cubic kilometer antarctic IceCube observatory between May 2010 and May 2012.

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to approximately 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds.

Combined, both searches reject a purely atmospheric origin for the twenty-eight events at the  level. These twenty-eight events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector, IceCube Collaboration, Science 342, 1242856 (2013). DOI: 10.1126/science.1242856

See paper at

Data release

Search for contained neutrino events at energies above 30 TeV in 2 years of data

Click here to download (.zip, 18MB)

Included in the download are the following files:

  • – contains the neutrino effective areas (see Fig. 7A) for the individual neutrino flavors after analysis cuts. Versions of the effective areas for only upgoing and downgoing events and for events in bins of cos(zenith) are provided in addition (not shown in the paper).
  • eventsummary.txt – contains the information listed in Table 1 in text file format. Event times are given as fractional MJD.
  • eventviews.pdf – contains event displays for each of the 28 events.

Data release updated on December 21, 2015.

**This data has been updated in a new analysis using four years of IceCube data. See more details here.

For any questions about this data release, please write to