A Search for Photons with Energies Above 2 x 10(17) eV Using Hybrid Data from the Low-Energy Extensions of the Pierre Auger Observatory Abreu, P. Bueno Villar, Antonio Pierre Auger Collaboration Ultra-high-energy photons with energies exceeding 1017 eV offer a wealth of connections to different aspects of cosmic-ray astrophysics as well as to gamma-ray and neutrino astronomy. The recent observations of photons with energies in the 1015 eV range further motivate searches for even higher-energy photons. In this paper, we present a search for photons with energies exceeding 2 × 1017 eV using about 5.5 yr of hybrid data from the low-energy extensions of the Pierre Auger Observatory. The upper limits on the integral photon flux derived here are the most stringent ones to date in the energy region between 1017 and 1018 eV. 2022-09-06T11:17:51Z 2022-09-06T11:17:51Z 2022-07-08 journal article P. Abreu... [et al.]. 2022 ApJ 933 125. [https://doi.org/10.3847/1538-4357/ac7393] http://hdl.handle.net/10481/76548 10.3847/1538-4357/ac7393 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional American Astronomical Society