Chinese researchers from the Institute of High Energy Physics of the Chinese Academy of Sciences discovered a massive ultra-high-energy gamma-ray bubble in the Milky Way, solving the cosmic ray enigma. This innovative revelation in the Journal of Science Bulletin describes a super cosmic ray accelerator that generates particles over 10 PeV.
Chinese astronomers used the Large High Altitude Air Shower Observatory (LHAASO) to view the bubble structure in Cygnus as a vast sky region. The scientists then analyzed this bubble of space and found numerous photons with energy above 1 PeV, the highest being 2.5 PeV. This shows that a massive cosmic ray accelerator is constantly ejecting protons and electrons into interstellar space at 20 PeV.
Researchers believe Cygnus OB2, at the bubble’s center, is the best possibility for the super cosmic ray accelerator. Most ultraviolet stars in this zone are young, hot, and massive, with surface temperatures from 15,000 to 35,000 degrees Celsius and luminosities 100 to million times the Sun’s. The strong radiation pressure generates stellar winds, which reach 3,000 kilometers per second and efficiently accelerate particles.
According to LHAASO head scientist and CAS academician Cao Chen, “This is the first super cosmic ray accelerator identified as of now.” The LHAASO observatory in Daocheng County, southwest China, at 4,410 meters above sea level made this discovery possible. A suite of high-end technologies, including the world’s most sensitive ultra-high-energy gamma-ray telescope, allows LHAASO to research cosmic ray origin and transmission.
After spotting the “brightest-of-all-time” gamma-ray burst last June, the observatory made headlines. Future LHAASO discoveries of supercosmic ray accelerators may solve the cosmic ray origins of our galaxy.
