<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre"^^ . "The Galactic Centre is a unique and complex astrophysical region, characterised by dense molecular gas, bright point-like sources in very high energies, and a potential PeVatron cosmic-ray accelerator. It is also a key target for indirect dark matter searches, due its high dark matter density and its proximity. However, the region’s complexity, along with challenges posed by line-of-sight superposition of gas and dust emissions, complicates efforts to isolate gamma-ray sources and study cosmic-ray propagation.\r\nThis thesis presents a comprehensive study of the Galactic Centre environment using multi-wavelength data, focusing on the distribution of gas and dust and the analysis of gamma-rays. A refined decomposition of the interstellar medium is achieved through employing a new method in decomposing molecular and atomic line emission, from HI and several CO isotopologue data. By distinguishing the gas in the central molecular zone and the Galactic disk as well as incorporating atomic and molecular contributions, a more accurate description of the gas distribution is derived. This improved gas template allows for a more realistic estimate of cosmic-ray energy density across the Galactic Centre.\r\nThe dust thermal emission is fitted using single- and two-component modified Planck functions. A clear deviation from linearity has been observed for the dust opacity as a function of the hydrogen column density, indicating that a simple correlation between dust emission and gas column density is not sufficient.\r\nThe second part of the thesis includes gamma-ray data from the H.E.S.S. telescopes, an array of imaging atmospheric Cherenkov telescopes. A novel background rejection technique, ABRIR, is developed and implemented within the H.E.S.S. analysis software. ABRIR uses time-based image cleaning and muon tagging to improve signal extraction from high-energy gamma-ray data. Its performance is validated through a detailed comparison of Galactic Centre observations with and without the method, showing enhanced source significance and reduced spectral uncertainties.\r\nFinally, the thesis explores the future observational potential of the Southern Wide-field Gamma-ray Observatory (SWGO), a ground-based water Cherenkov detector. Currently under development, SWGO will be the first large-scale water Cherenkov detector in the southern hemisphere. Using updated instrument response functions and simulated observations of the Galactic Centre, the expected performance of various array and tank configurations is assessed. SWGO’s sensitivity to WIMP dark matter annihilation is also evaluated.\r\nIn summary, this thesis contributes with a new description of the gas and dust in the Galactic Centre, an improved background rejection method for H.E.S.S., and prospect estimates for the Galactic Centre observation with SWGO, to the field of Galactic Centre studies at very-high and ultra-high energies."^^ . "2025" . . . . . . . "Helena Xiayi"^^ . "Ren"^^ . "Helena Xiayi Ren"^^ . . . . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (PDF)"^^ . . . "Ren_Dissertation_v1.pdf"^^ . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (Other)"^^ . . . . . . "indexcodes.txt"^^ . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Very-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre (Other)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #36960 \n\nVery-High-Energy and Ultra-High-Energy Gamma-ray emission from the Galactic Centre\n\n" . "text/html" . . . "520 Astronomie"@de . "520 Astronomy and allied sciences"@en . . . "530 Physik"@de . "530 Physics"@en . .