Preparation for the Scientific use of the CAGIRE Infrared Camera

Sammanfattning

Gamma-ray bursts (GRBs) are highly energetic and luminous explosions that are used to study stellar evolution, relativistic jets, and black holes. Furthermore, they are used to probe the early universe to understand the epoch of the first stars. To observe the most distant GRBs, infrared detectors are crucial, as the Lyman-$\alpha$ break shifts towards longer wavelengths as the GRB's redshift increases. SVOM, a mission for GRB observation, has a ground follow-up telescope, COLIBRÍ, which will soon have a near-infrared camera, CAGIRE. Currently, the final tests and preparations of CAGIRE are in progress at Institut de Recherche en Astrophysique et Planétologie (IRAP). I detail here my participation in the scientific preparation of CAGIRE and document the procedures and modifications that were done to CAGIRE during my internship. The tests to ensure CAGIRE's compliance with its requirements are: studying the detector's response to a black body in order to find the instrumental background and using a star projector to confirm the alignment procedures of the system and to observe the detector when illuminated by point sources. In addition, a possibility to study the temporal evolution of rapidly fading GRB afterglows is added to the preprocessing pipeline of CAGIRE. The results confirm that CAGIRE is compliant with its requirements. The instrumental background, 2.7 ADU/frame/pixel, remains below the 3.8 ADU/frame/pixel limit. The alignment can be performed with the requested precision, and the alignment system has the required ranges. Finally, the enhanced preprocessing pipeline enables the detailed study of the evolution of the brightest GRBs, magnitude $\leq$ 16. Consequently, CAGIRE is ready for a review with the collaborating institutes. If the review is successful, the integration of CAGIRE into COLIBRÍ can begin.