Discovery of the Ultra-High-Energy gamma-ray source LHAASO J2002+3238 spatially associated with SNR G69.7+1.0

Abstract

The origin of Galactic PeV cosmic rays is still under debate. Shell-type supernova remnants (SNRs) are proposed to be one of the candidate sources of Galactic PeV cosmic rays, but observational evidence is lacking. Here we report LHAASO’s detection on a point source J2002+3238 with a significance of 5.8 sigma above 25 TeV and 6.8 sigma above 100 TeV. The spectrum is consistent with a power-law spectrum with no cutoff. Inside the error region of the source, a shell-type SNR G69.7+1.0 is found locating only 0.07 ◦ away from the best-fit location of the source, suggesting a strong association between the UHE gamma-ray source and the SNR. This provides strong evidence on SNRs as possible PeV accelerators.