The source LHAASO J1912+1014u has been classified as a proton PeVatron, based on gamma-ray observations above 0.1 PeV from LHAASO and supporting data from Fermi-LAT and Chandra.

Previously labeled a supernova remnant in 2024, the object’s multiwavelength analysis from radio to gamma rays now clarifies it as a proton accelerator.

By integrating radio, GeV, TeV, and X-ray observations, the researchers built a comprehensive model that reinforces the proton PeVatron interpretation.

The study highlights the value of a broad, multi-instrument approach—combining Tibet AS-gamma, LHAASO, Fermi-LAT, FUGIN, and Chandra—to identify proton PeVatrons and advance understanding of cosmic-ray acceleration.

The researchers anticipate many more proton PeVatrons in the Milky Way and plan to examine additional candidates to determine their prevalence and characteristics.

This discovery places LHAASO J1912+1014u among Milky Way candidates for proton PeVatrons and opens the door to systematic follow-up studies to uncover the nature of its accelerators and the objects driving the process.

Distinguishing protons from electrons as gamma-ray producers is challenging, and the multi-instrument strategy was crucial in overcoming this hurdle.

Key collaborators include Naoto Nakahara, Hidetoshi Sano, Takeru Murase, Tomohiko Oka, and Hiromasa Suzuki, with participation from international institutions and funding agencies across the US, France, Italy, Japan, Sweden, and more.

The discovery was made by an international team led by Hiroshima University and published in The Astrophysical Journal on July 16, 2026.

Multiwavelength data from Fermi-LAT, FOREST/FUGIN, Chandra, Tibet AS-gamma, and LHAASO underpinned the finding reported by the team.