Speaker
Description
Ultra-high-energy cosmic rays (UHECRs) are the most energetic particles ever detected. Their production mechanisms remain unknown, but the conditions in which they are generated are likely to be extreme. Cosmic rays that achieve the highest energies are rare, and their flux at Earth is extremely low. As a result, next-generation experiments with large effective areas are required and under development.The Fluorescence detector Array of Single-pixel Telescopes (FAST) is one such project, that utilizes the atmospheric fluorescence detection technique. Although this limits observation time compared with ground particle detectors, it enables direct measurements of Xmax, a crucial parameter sensitive to the primary cosmic-ray composition. FAST will achieve large-area coverage by significantly reducing the cost of telescopes. This necessitates a simplified telescope compared to conventional designs. Demonstrating the feasibility of our telescope and observational method is essential.To validate the FAST concept, prototype telescopes have been deployed at the Pierre Auger Observatory and the Telescope Array experiment. In this talk/contribution, we report the latest analysis of energy spectra and $X_\mathrm{max}$ measurements using data collected since 2018, along with an assessment of potential systematic uncertainties. Additionally, we present the progress towards stereo observation using upgraded prototype telescopes.
| Collaboration(s) | The FAST collaboration |
|---|
