In a historic breakthrough, the Large High Altitude Air Shower Observatory (LHAASO) has uncovered a colossal ultra-high-energy gamma-ray bubble structure within the Cygnus star-formation region. This groundbreaking finding marks the first time in human history that the origin of cosmic rays exceeding 10 Peta-Electronvolt (PeV) has been pinpointed, as revealed by the Institute of High Energy Physics of the Chinese Academy of Sciences (CAS) on Monday.
Cosmic rays, comprising charged particles predominantly composed of protons, have long puzzled scientists as they journey through space. The discovery of a distinctive break in the cosmic ray energy spectrum, known as the “knee,” around 1 PeV has heightened intrigue into their origins. While cosmic rays below this threshold are believed to stem from within the Milky Way, those above present a perplexing enigma.
LHAASO’s revelation of a mammoth ultra-high-energy gamma-ray bubble structure within the Cygnus region has unveiled a cosmic ray accelerator of unparalleled magnitude. Inside this cosmic crucible, photons exceeding 1 PeV, with the highest energy reaching an astonishing 2.5 PeV, hint at the presence of a super cosmic ray accelerator. Capable of propelling particles to energies surpassing 20 PeV, this accelerator injects them into the interstellar expanse, divulged the Institute of High Energy Physics.
Deep within this celestial bubble, scientists have discerned the presence of a cosmic ray accelerator, postulating it as the genesis of cosmic rays surpassing 10 Peta electron volts. They attribute this to a massive star cluster nestled at its heart, dubbing it the “O-star association” and “B-star association.”
This unprecedented identification of a super cosmic ray accelerator heralds a milestone in astrophysical understanding. As LHAASO continues its vigil, more such accelerators are anticipated to be unveiled, offering prospects of unraveling the cosmic ray conundrum that shrouds the Milky Way.
Moreover, LHAASO’s observation has unveiled a surge in cosmic ray density surrounding the bubble, surpassing typical levels within the Milky Way. This heightened density extends beyond the bubble’s confines, potentially elucidating previous anomalies in diffuse gamma-ray emissions.
Renowned astrophysicist Professor Elena Amato hailed the discovery’s significance, emphasizing its implications for cosmic ray transport models. She noted that these findings not only reshape our understanding of diffuse emissions but also enrich our comprehension of cosmic ray dynamics within the Galaxy.
Situated atop Mount Haizi in Southwest China’s Sichuan Province, LHAASO stands as a pinnacle of national scientific achievement. Operating at an altitude of 4410 meters, it represents the world’s most sensitive ultra-high-energy gamma-ray detection apparatus, paving the path for unprecedented insights into the mysteries of cosmic rays.
