Hunting for Galactic PeVatrons in the X-ray Regime

Cosmic rays with energies up to a few PeV (10¹⁵ PeV) are believed to originate from our own galaxy. However, the origin of Galactic cosmic-rays has remained a mystery for over a century since their discovery. The H.E.S.S. observatory discovered a PeVatron within 10 parsecs of the center of our galaxy, which suggests that the supermassive balck hole Sgr A* may be responsible. Despite being one of the least active supermassive black holes, Sgr A* may have acted as a potent particle accelerator during its active stage in the past. In this presentation, I will describe our attempts to find multi-wavelength observational evidence that Sgr A* used to be a PeVatrons, and how we can reconstruct Sgr A* activity history in the past few million years. Finally, I will introduce our ongoing efforts to uncover and identify Galactic PeVatrons beyond the Galactic center and to test whether they bear a nature of supernova remnants, pulsar wind nebula or else.