In a new catalogue compiled by researchers, nine sources of extremely high-energy gamma rays have been identified. All nine sources produce gamma rays with energies over 56 trillion electron volts (TeV) -- more than eight times the energy of the most powerful proton beams produced at particle accelerators on Earth -- and three emit gamma rays extending to 100 TeV and beyond, making these the highest-energy sources ever observed in our galaxy. The catalogue helps to explain where the particles originate and how they are produced with such extreme energies.
The catalogue was compiled by researchers with the High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, including nine University of Maryland physicists. "The very-high-energy gamma rays we detect are produced by interactions of even higher energy charged particles near their source," said Jordan Goodman, a Distinguished University Professor of Physics at UMD and US lead investigator and spokesperson for the HAWC collaboration.
"Charged particles are bent in the magnetic fields of our galaxy and don't point back to their origin. Gamma rays, like light, travel in straight lines allowing us to use them to map the sources of the high-energy emission. HAWC, which is a wide field-of-view instrument, views the overhead sky 24/7 giving us a deep exposure to look for the rare high energy gamma-ray events," Goodman added.
The catalogue of high-energy sources was accepted for publication in the journal Physical Review Letters. Higher-energy astrophysical particles have previously been detected, but this is the first time specific galactic sources have been pinpointed for such high-energy particles. All of the sources have extremely energetic pulsars nearby. The number of sources detected may indicate that ultra-high-energy emission is a generic feature of powerful particle winds coming from pulsars embedded in interstellar gas...