Key points are not available for this paper at this time.
HESS J1813-178 is one of the brightest and most compact TeV -ray sources, and whether its -ray emission is associated with supernova remnant (SNR), pulsar wind nebula (PWN) or young stellar cluster (YSC) is still under debate. By analysing the GeV -ray data in the field of HESS J1813-178 using 14 years of PASS 8 data recorded by the Fermi Large Area Telescope (Fermi-LAT), we report the discovery of three different sources with different spectra in this region. The hard source with a power law spectral index of 2. 11 0. 08 has a small size extension, which is spatially and spectrally coincident with the TeV -ray emission from HESS J1813-178. CO observations display the dense molecular clouds surrounding HESS J1813-178 in the velocity range of 45-60 km s^ -1. The possible origins of the -ray emission from HESS J1813-178 are discussed, including SNR G12. 82-0. 02, the PWN driven by the energetic X-ray pulsar PSR J1813-1749, and YSC Cl 1813-178. However, none of them can be ruled out clearly. Note that the maximum energy of protons in the hadronic model should exceed a few hundred TeV, which makes HESS J1813-178 to be a promising PeVatron. The detailed LHAASO data analysis about the morphology and spectrum would be helpful to investigate the origin of the -ray emission in this region and test its PeVatron nature.
Guo et al. (Mon,) studied this question.