By Nadia Drake
Instead of clearing up a half-century-old mystery, scientists have tossed a bit of mud into an already murky pool of suspects behind high-energy cosmic rays. New results from the IceCube Collaboration now cast doubt on gamma-ray bursts as ready producers of these enigmatic particles that strike the Earth with energies exceeding 10 billion-billion electron volts.
But there’s some wiggle room in the evidence, and if theorists rejigger equations describing the cosmic objects, gamma-ray bursts could still be in the lineup, scientists report April 19 in Nature.
The new work is based on results from the IceCube neutrino telescope, a cubic kilometer of detectors buried beneath the South Pole. Over a period of two years, the telescope didn’t detect any of the neutrinos expected to arrive following 307 gamma-ray bursts. Neutrinos act as proxies indicating that cosmic rays are produced.