A distant starburst galaxy emerges as a likely cosmic neutrino source
A team led by Yuji Urata has identified a bright, gravitationally lensed, dusty star-forming galaxy — nicknamed the “Shadow Blaster” and located about 11 billion light-years away — as the strongest candidate yet for the source of a single high-energy neutrino detected by the IceCube observatory in Antarctica. The neutrino, IC 210922A, arrived on September 22, 2021 carrying an estimated 750 tera-electronvolts, more than 100 times the energy of the largest human-built particle accelerators. The work was published in Nature Astronomy on June 17.
The result matters because most of the cosmic neutrino “background” IceCube sees has no identified origin. The two previously implicated sources — the blazar TXS 0506+056 and the galaxy NGC 1068 — together explain only a few percent of it. The team’s modeling suggests compact, dust-shrouded starburst galaxies like this one could produce up to roughly 20 percent of the total, pointing to a population of hidden emitters rather than a handful of exceptional objects.
A completed IceCube hardware upgrade, which added more than 600 more sensitive optical sensors earlier in 2026, is expected to enable a reanalysis of 15 years of archived detections that could test whether this class of galaxy holds up as a major contributor.