Microquasar V4641 Sgr and Its Deep Investigation with LACT as a Super-PeVatron of Cosmic Rays.

Several instruments, including LHAASO, have measured γ-ray emission from the direction of V4641 Sgr, a well known microquasar. The emission measured with LHAASO is best described as a power-law spectrum extending into the ultra-high-energy regime with no indication of a cutoff up to the energy of $0.8\mathrm{PeV}$ . Thus, this source represents a perfect candidate of a super-PeVatron, which accelerates cosmic-ray particles beyond $10\mathrm{PeV}$ . To prove this exciting hypothesis, a deeper investigation of this source is required. An important progress can be achieved using an array of Cherenkov telescopes, such as Large Array of imaging atmospheric Cherenkov Telescopes (LACT), observing the source at large zenith angles. In this paper, we show that already with the first 4 telescopes of LACT one will be able to constraint the key morphological features and the corresponding spectral variations in this source. This will provide the essential observational information for studying the acceleration of cosmic rays in this prominent source.