Cosmic-ray hotspot may have been found
DOI: 10.1063/PT.5.028071
Science : High-energy cosmic rays, which are composed of rare, exceptionally energetic protons and light atomic nuclei, cause large cascades of particles when they strike Earth’s atmosphere. Their origin has not been established, but data from the Telescope Array may have revealed a likely source. Between 2008 and 2013, the 700-km2 array of 507 particle detectors in New Mexico found 72 cosmic rays with energies greater than 57 × 1018 eV. Of those, 19 came from a region of the sky about 20° in radius. Because the number of total events is low, the signal is not strong enough to constitute a discovery. The high energy of the particles suggests that they originate within 500 million light-years of Earth. However, there are no obvious sources present in the detected region.
