The Pierre Auger Observatory is the world-wide largest cosmic ray detector covering an area of 3000 km². It is operated by a collaboration of more than 400 scientists from 17 countries. The aim of the observatory is the study of the highest energy particles of the Universe – ultra-high energy cosmic rays. About 15 full-array-size-equivalent years of exposure have been accumulated up to the end of 2022 with the Auger Observatory in the old configuration, referred to as Phase I.
Data from Phase I of the Auger Observatory have revolutionized our understanding of high energy phenomena linked to the most violent processes in the Universe. Scientific breakthroughs have been achieved in several fields. The new perspectives opened by these results called for an upgrade of the observatory, with the main aim of collecting new information about the primary mass of the highest energy cosmic rays on a shower-by-shower basis. The full-efficiency data taking with the upgraded array will start in 2025 and will add data for 10 more years.
The extension of the International Agreement will provide the administrative foundation to continue the operation of the Pierre Auger Observatory in the upcoming Phase II, operating the upgraded detector.
On November 16, 2024, the representatives of the funding agencies signed the extension of the agreement in a formal ceremony, combined with a visit to the Pierre Auger Observatory the next day, which included a tour of the fluorescence detectors and the HEAT telescopes at the Coihueco site, and the infill array with the upgraded AugerPrime surface detectors.
