10 years of IceCube data now publicly available at NASA’s HEASARC archive

The IceCube Collaboration has teamed up with NASA’s High-Energy Astrophysics Science Archive Research Center (HEASARC) to share 10 years of IceCube data with the public.

Supported by the Astrophysics Division of NASA’s Science Mission Directorate and a service of the Astrophysics Science Division at NASA’s Goddard Space Flight Center (GSFC), the HEASARC is the primary archive for high-energy astronomy orbital missions observing at extreme ultraviolet, X-ray, and gamma-ray wavelengths. The HEASARC’s website is a repository of archival data, multimission and mission-specific software and analysis tools, and information about current and past observatories and missions—all available for free to everyone.

“We’re honored to be able to provide broad community access to the IceCube data,” said Alan Smale, the HEASARC Director at NASA/GSFC. “Our driving purpose at the HEASARC is to make data easily accessible to our users, to enable sophisticated analyses and help to advance the field.”

The HEASARC Staff Scientist Antara Basu-Zych, who worked closely with the IceCube team on this release, added, “Going from multiwavelength to multimessenger information about these sources is extremely exciting for the HEASARC, and for the community. Having both the neutrino and high-energy electromagnetic signatures readily available will allow scientists much more insight into the physical processes at play.”

The IceCube Neutrino Observatory is an enormous neutrino detector that comprises 5,160 light sensors attached to 86 bundles of cable (called “strings”) that are buried in a cubic kilometer of ice a mile below the surface at the South Pole. A cooperative effort of the international IceCube Collaboration, its purpose is to detect astrophysical neutrinos: elusive, lightweight particles that are created by the most energetic phenomena in the universe.

IceCube construction began in winter of 2004, and it began taking data as a partially complete detector as soon as the first deployed strings were frozen in the ice. Construction was completed in December 2010, and IceCube started full operation in May 2011. This 10-year dataset includes track-like neutrino candidates detected by IceCube between April 2008 and July 2018, so some events were detected when IceCube was operating with just 40 strings.

The data contained in this release of IceCube’s point source sample show 3.3 sigma evidence of a cumulative excess of events from a catalog of 110 potential sources, primarily driven by four sources: NGC 1068, TXS 0506+056, PKS 1424+240, and GB6 J1542+6129. NGC 1068 gives the largest excess and appears to line up spatially with the hottest spot in the full northern sky search. These data have contributed to some of the past decade’s biggest discoveries in neutrino astrophysics, including the first evidence of an astrophysical high-energy neutrino source in the multimessenger detection of TXS 0506+056 in 2017.

“My hope is that by opening the data to the community, we will learn new things about the sources of astrophysical neutrinos,” said Marcos Santander, IceCube collaborator and assistant professor at the University of Alabama. “While the data is dominated by background events and therefore its analysis requires a strict statistical approach, there may be a potential astrophysical signal hiding in it that we haven’t found yet, and this provides a more user-friendly interface to explore our data.”

While this 10-year dataset was already freely available on IceCube’s website, its presence on the HEASARC archive allows it to be queried interactively. Astrophysicists looking to use IceCube’s data will be able to select neutrino candidate events based on position, energy, and time, then cross reference that information with other databases also available through the HEASARC. Since the HEASARC already stores data from dozens of NASA, ESA, and JAXA high-energy astrophysics missions in standard formats, the community is already familiar with using its interfaces.

“Our goal is to facilitate the access of the high-energy astrophysics community to our data to possibly enable new multimessenger analyses,” said Santander. “The data are publicly available, so we hope that any researcher interested in our data will be able to use it.”