The quest for PeVatrons, sources of galactic cosmic rays accelerated up to PeV energies, saw an exciting development in the last years, thanks to the many gamma-ray sources detected by ground array experiments at energy above 100 TeV. Among those sources, the supernova remnant SNR G106.3+2.7 (including the Boomerang PWN) is a promising PeVatron candidate for which the ultra-high energy emission can be explained with both hadronic and leptonic emission scenarios. It was detected with a very high significance detection above 100 TeV by LHAASO, making it a candidate for the emission of PeV protons.
Imaging Atmospheric Cherenkov Telescopes (IACTs) are ideal instruments to investigate the nature of the most energetic sources of the Universe in gamma-ray astronomy thanks to their optimal angular and energy resolution. The Cherenkov Telescope Array Observatory (CTAO) will be the leading instrument for observations between tens of GeV and hundreds of TeV thanks to an hybrid array of IACTs. It will allow for high resolution observation of the TeV sky in a complementary energy range with LHAASO. Using the LST-1, the Large-Sized Telescope prototype of the Cherenkov Telescope Array Observatory, together with the two neighbors IACTs of the MAGIC experiment, we are currently observing the SNR G106.3+2.7 at Large Zenith Angle (LZA), which allows us to explore the 1-50 TeV region of the energy spectrum.
I will give an overview of the CTAO and its first telescope, the LST-1. Then I will describe the status of the knowledge on galactic PeVatrons and present the work lead by CPPM on the observation of the SNR G106.3+2.7 with LST-1 and MAGIC.
