Speaker
Description
The Pierre Auger Observatory is the most sensitive detector to ultra-high-energy (UHE) photons. In particular, the hybrid detection technique, combining the fluorescence detector (FD) with the surface detector array (SD), provides a powerful tool for the identification of photon-induced extensive air showers above 1 EeV.
Photon-induced air showers are characterized by a deeper atmospheric depth of the shower maximum ($X_\mathrm{max}$) and a reduced muon content compared to hadron-induced showers. In this contribution, we present a dedicated search for UHE photons with energies above 1 EeV using hybrid events collected over more than 15 years of operation of the Pierre Auger Observatory. The analysis strategy is based on a combination of observables measured by the FD and SD, optimized to maximize the sensitivity in this energy range. In this context, $X_\mathrm{max}$ is directly measured by the FD, while the muonic component is inferred by exploiting the universality property of extensive air showers. Upper limits on the diffuse flux of photons above 1 EeV are reported.
