An international research team, led by Hiroshima University, has conclusively identified a cosmic source capable of accelerating protons to extremely high energies — beyond one quadrillion electron volts (PeV). The object, previously known as LHAASO J1912+1014u and located in the constellation Aquila near the star Altair, has been confirmed as a proton PeVatron through multiwavelength observations and modeling. datelinewire.com +2
The team combined data from three major observatories: NASA’s Fermi Gamma-ray Space Telescope, the Nobeyama 45-meter telescope’s FOREST Unbiased Galactic Plane Imaging Survey (FUGIN), and the Chandra X-ray Observatory. This comprehensive approach allowed them to rule out alternative explanations and confirm the source’s role as a PeVatron.
Several lines of evidence supported the conclusion:
- The gamma-ray signal from the region extended smoothly from over 100 trillion electron volts (TeV) down to 400 million electron volts (MeV). This wide energy range made it unlikely that the source was primarily accelerating electrons.
- The distribution of GeV gamma rays closely matched the pattern of interstellar gas traced by FUGIN radio data. This alignment is expected when high-energy protons collide with surrounding gas and produce gamma rays. datelinewire.com +1
- Chandra’s X-ray observations revealed only very weak diffuse X-ray emission. A source dominated by accelerated electrons would generally be expected to produce stronger X-ray signals, so the faint emission further supported the proton explanation.
This discovery provides critical insights into the mechanisms that accelerate particles to such extreme energies, with implications for understanding galactic-scale astrophysical processes. The team noted that there are dozens of other potential PeVatron candidates in the Milky Way, and they plan to investigate these regions further using a similar multiwavelength approach to refine models of cosmic ray acceleration.
About the Author
