Abstract
The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons—cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3–6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.
Recommended Citation
"Ultrahigh-energy Photons Up To 1.4 Petaelectronvolts From 12 Γ-ray Galactic Sources," Nature, vol. 594, no. 7861, pp. 33 - 36, Nature Research, Jun 2021.
The definitive version is available at https://doi.org/10.1038/s41586-021-03498-z
Department(s)
Physics
International Standard Serial Number (ISSN)
1476-4687; 0028-0836
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2025 Nature Research, All rights reserved.
Publication Date
03 Jun 2021
PubMed ID
34002091
Comments
National Natural Science Foundation of China, Grant 2018YFA0404201