Searches for Ultra-High-Energy Photons at the Pierre Auger Observatory Abreu, P. Bueno Villar, Antonio Pierre Auger Collaboration Photons Ultra-high energies Air showers Pierre Auger Observatory Upper limits Transients The Pierre Auger Observatory, which is the largest air-shower experiment in the world, offers unprecedented exposure to neutral particles at the highest energies. Since the start of data collection more than 18 years ago, various searches for ultra-high-energy (UHE, E & 1017 eV) photons have been performed, either for a diffuse flux of UHE photons, for point sources of UHE photons or for UHE photons associated with transient events such as gravitational wave events. In the present paper, we summarize these searches and review the current results obtained using the wealth of data collected by the Pierre Auger Observatory. 2022-12-12T09:41:54Z 2022-12-12T09:41:54Z 2022-11-02 info:eu-repo/semantics/article The Pierre Auger Collaboration. Searches for Ultra-High-Energy Photons at the Pierre Auger Observatory. Universe 2022, 8, 579. [https://doi.org/10.3390/universe8110579] https://hdl.handle.net/10481/78389 10.3390/universe8110579 eng http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Atribución 4.0 Internacional MDPI