H.E.S.S. observations of Sgr A

The Galactic Centre has been studied with the High Energy Stereoscopic System (H.E.S.S.) for over 10 years, showing a bright, complex gamma-ray morphology. Other than a strong point-like very-high-energy gamma-ray source coincident with the supermassive black hole Sgr A*, previous analyses also revealed a diffuse ridge of gamma-ray emission, indicative of a powerful cosmic-ray accelerator in this region. It has been widely studied in the multiwavelength, exhibiting flares from radio to X-ray, but in the VHE regime it has always been stable. A gas cloud called G2 was found travelling straight to the Galactic Centre in 2011. Accretion rate was expected to increase which might possibly lead to flares in different wavebands. The addition of a fifth telescope with 600 m2 mirror area to the centre of the H.E.S.S. array has increased the energy range accessible, allowing observations to take place down to 100 GeV and potentially below. The sensitivity is also increased which means it has better ability to detect VHE flares from the Galactic Centre. In this work, long-term study of Sgr A* with H.E.S.S. I and data involving H.E.S.S. II around pericentre passage time of G2 is presented. Varibility tests are also applied to check for transient events. The overall spectrum and spectra for individual years have been stable over the years. The results of variability tests also revealed stability in the flux.