@article{2c64db22a50045b3a4fd92c758ba2d48,
title = "A Search for Photons with Energies above 2 × 1017eV Using Hybrid Data from the Low-Energy Extensions of the Pierre Auger Observatory",
abstract = "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.",
author = "{the Pierre Auger Collaboration} and P. Abreu and M. Aglietta and Albury, {J. M.} and I. Allekotte and Cheminant, {K. Almeida} and A. Almela and J. Alvarez-Mu{\~n}iz and Batista, {R. Alves} and Yebra, {J. Ammerman} and Anastasi, {G. A.} and L. Anchordoqui and B. Andrada and S. Andringa and C. Aramo and Ferreira, {P. R.Ara{\'u}jo} and E. Arnone and Vel{\'a}zquez, {J. C.Arteaga} and H. Asorey and P. Assis and G. Avila and E. Avocone and Badescu, {A. M.} and A. Bakalova and A. Balaceanu and F. Barbato and Bellido, {J. A.} and C. Berat and Bertaina, {M. E.} and G. Bhatta and Biermann, {P. L.} and V. Binet and K. Bismark and T. Bister and J. Biteau and J. Blazek and C. Bleve and J. Bl{\"u}mer and M. Boh{\'a}{\v c}ov{\'a} and D. Boncioli and C. Bonifazi and Arbeletche, {L. Bonneau} and N. Borodai and Botti, {A. M.} and J. Brack and T. Bretz and Orchera, {P. G.Brichetto} and Briechle, {F. L.} and P. Buchholz and A. Bueno and C. Ventura",
note = "Publisher Copyright: {\textcopyright} 2022. The Author(s). Published by the American Astronomical Society.",
year = "2022",
month = jul,
day = "1",
doi = "10.3847/1538-4357/ac7393",
language = "American English",
volume = "933",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "American Astronomical Society",
number = "2",
}