FROM DATA PRODUCTION TO SEARCH FOR GALACTIC COSMICRAY SOURCES WITH THE PIERRE AUGER OBSERVATORY

Astroparticle physics, at the crossroads of astrophysics and particle physics, investigates ultra-high-energy cosmic rays (UHECRs), the most energetic particles known in the Universe. Despite decades of research, their origins remain elusive. These particles are detected through extensive air showers, cascades of secondary particles produced when UHECRs interact with the Earth's atmosphere. However, their low flux, less than one particle per square kilometer per century, makes detection extremely challenging. This PhD thesis, titled From Data Production to Search for Galactic Cosmic Ray Sources with the Pierre Auger Observatory, delves into the entire process of UHECR detection, from data production to the search for potential Galactic sources. The research is conducted using the Pierre Auger Observatory in Argentina, the largest cosmic ray observatory in the world, which employs a hybrid detection system to record cosmic ray events. Central to this setup is the Surface Detector (SD), consisting of 1660 water-Cherenkov detectors spread over 3000 square kilometers. This detector continuously records data with a 100% duty cycle, providing crucial information on the energy, direction, and composition of cosmic rays. The thesis emphasizes the meticulous processes involved in data production, including performance monitoring, event selection, and techniques to ensure high-quality datasets for analysis. A key contribution is the development of a new method for correlating cosmic ray events with potential sources in our Galaxy, using data sets above and below 1 EeV to investigate different energy thresholds and distances. This targeted search for neutron sources places new upper limits on their flux from potential Galactic objects, offering valuable insights into the nature and origins of UHECRs. The work represents a significant step forward in cosmic ray research, enhancing our understanding of data production processes and advancing the search for galactic cosmic ray sources.