For over a century, scientists have been observing very high-power charged particles known as cosmic rays coming from outside Earth’s environment. The origins of these particles are very troublesome to pinpoint because the particles themselves don’t travel on a straight route to Earth. Even gamma rays, a kind of high-energy photon that gives more insight, are absorbed when crossing long distances.
The IceCube Neutrino Observatory, an range of optical modules buried in a cubic kilometer of ice at the South Pole, looks for cosmic-ray sources inside and outside our galaxy—extending to galaxies over billions of light-years away—utilizing hints from fleeting particles referred to as neutrinos.
These neutrinos are anticipated to be generated by cosmic-ray collisions with gas or radiation close to the sources.
Unlike cosmic rays, neutrinos aren’t absorbed or diverted on their way to Earth, making them a practical device for finding and perceiving cosmic accelerators.
If scientists can discover a source of high-energy astrophysical neutrinos, this might be a smoking gun for a cosmic-ray source.
After a decade of searching for origins of astrophysical neutrinos, a new all-sky search provides the most delicate probe of time-built-in neutrino emission of point-like sources. The IceCube Collaboration shows the results of this scan in a paper presented lately to Physical Review Letters.
The main problem in searching for astrophysical neutrino sources with IceCube is the overwhelming background of events produced by cosmic-ray interactions in the atmosphere.