Cosmic gamma rays with energies as high as 450 TeV (1012 eV) are detected by the ASgamma observatory at Tibet — which is run jointly by China and Japan. This shatters the old set of 75 TeV, which had been set by the High-Energy-Gamma-Ray Astronomy observatory on the Canary Islands.
ASgamma detected 2-4 gamma beams with energies at the 100-450 TeV range. The particles seem to arise at the Crab Nebula, and it can be actually a supernova remnant about 6000 light years a way. It can be home to a pulsar — a rapidly rotating neutron star that broadcasts a bright beam of electromagnetic radiation.
Astronomers believe that gamma beams in the 100-450 TeV scope are generated when much higher energy electrons at the petaelectronvolt (1015 eV) range socialize with the cosmic microwave background — radiation released just after the Big Bang that permeates the universe. These electrons are thought to be accelerated to such high energies by the swirling magnetic fields generated by the pulsar. Indeed, the ASgamma researchers clarify that the Crab Nebula pulsar as”probably the most powerful natural electron accelerator understood so far in our galaxy”.
ASgamma looks for high-energy gamma beams by discovering the shower of secondary particles that rain down in the world if a cosmic beam interacts with the air. By assessing the elements of a bathtub, physicists could work out what sort of cosmic beam led to the shower (gamma beam or charged particle) and the ability of the cosmic beam. Located at 4300 m above sea level, ASgamma does so with 2 kinds of detectors — plastic scintillators on the outside and Cherenkov detectors buried underground.
Today that cosmic gamma rays with energies above 100 TeV are detected, ASgamma scientists’re keen to discover other regions where electrons are accelerated to petaelectronvolt energies. This might help solve one of the most important mysteries of astrophysics — which exactly are the roots of the very highest energy cosmic rays?
A newspaper describing the observations was accepted for publication in Physical Review Letters and a pre print is available on arXiv.