TY - JOUR
T1 - The ultra-high-energy cosmic-ray sky above 32 EeV viewed from the Pierre Auger Observatory
AU - the Pierre Auger Collaboration
AU - Biteau, Jonathan
AU - Abreu, P.
AU - Aglietta, M.
AU - Albury, J. M.
AU - Allekotte, I.
AU - Almela, A.
AU - Alvarez-Muñiz, J.
AU - Alves Batista, R.
AU - Anastasi, G. A.
AU - Anchordoqui, L.
AU - Andrada, B.
AU - Andringa, S.
AU - Aramo, C.
AU - Araújo Ferreira, P. R.
AU - Arteaga Velázquez, J. C.
AU - Asorey, H.
AU - Assis, P.
AU - Avila, G.
AU - Badescu, A. M.
AU - Bakalova, A.
AU - Balaceanu, A.
AU - Barbato, F.
AU - Bar-Reira Luz, R. J.
AU - Becker, K. H.
AU - Bellido, J. A.
AU - Berat, C.
AU - Bertaina, M. E.
AU - Bertou, X.
AU - Biermann, P. L.
AU - Binet, V.
AU - Bismark, K.
AU - Bister, T.
AU - Biteau, J.
AU - Blazek, J.
AU - Bleve, C.
AU - Boháčová, M.
AU - Boncioli, D.
AU - Bonifazi, C.
AU - Bonneau Arbeletche, L.
AU - Borodai, N.
AU - Botti, A. M.
AU - Brack, J.
AU - Bretz, T.
AU - Brichetto Orchera, P. G.
AU - Briechle, F. L.
AU - Buchholz, P.
AU - Bueno, A.
AU - Buitink, S.
AU - Buscemi, M.
AU - Ventura, C.
N1 - Publisher Copyright:
© Copyright owned by the author(s).
PY - 2022/3/18
Y1 - 2022/3/18
N2 - The region of the toe in the cosmic-ray spectrum, located at about 45 EeV by the Pierre Auger Collaboration, is of primary interest in the search for the origin of ultra-high energy cosmic rays (UHECRs). The suppression of the flux with increasing energy can be explained by the interaction of UHECRs with intergalactic photons, resulting in a shrinking of the observable universe, and/or by cut-offs in acceleration potential at the astrophysical sources, yielding a high-rigidity sample of single (or few) UHECR species around the toe. The predominance of foreground sources combined with reduced deflections could thus offer a path towards localizing ultra-high energy accelerators, through the study of UHECR arrival directions. In this contribution, we present the results of blind and astrophysically-motivated searches for anisotropies with data collected above 32 EeV during the first phase of the Pierre Auger Observatory, i.e. prior to the AugerPrime upgrade, for an exposure of over 120,000 km2 yr sr. We have conducted model-independent searches for overdensities at small and intermediate angular scales, correlation studies with several astrophysical structures, and cross-correlation analyses with catalogs of candidate extragalactic sources. These analyses provide the most important evidence to date for anisotropy in UHECR arrival directions around the toe as measured from a single observatory.
AB - The region of the toe in the cosmic-ray spectrum, located at about 45 EeV by the Pierre Auger Collaboration, is of primary interest in the search for the origin of ultra-high energy cosmic rays (UHECRs). The suppression of the flux with increasing energy can be explained by the interaction of UHECRs with intergalactic photons, resulting in a shrinking of the observable universe, and/or by cut-offs in acceleration potential at the astrophysical sources, yielding a high-rigidity sample of single (or few) UHECR species around the toe. The predominance of foreground sources combined with reduced deflections could thus offer a path towards localizing ultra-high energy accelerators, through the study of UHECR arrival directions. In this contribution, we present the results of blind and astrophysically-motivated searches for anisotropies with data collected above 32 EeV during the first phase of the Pierre Auger Observatory, i.e. prior to the AugerPrime upgrade, for an exposure of over 120,000 km2 yr sr. We have conducted model-independent searches for overdensities at small and intermediate angular scales, correlation studies with several astrophysical structures, and cross-correlation analyses with catalogs of candidate extragalactic sources. These analyses provide the most important evidence to date for anisotropy in UHECR arrival directions around the toe as measured from a single observatory.
UR - http://www.scopus.com/inward/record.url?scp=85137935889&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:85137935889
SN - 1824-8039
VL - 395
JO - Proceedings of Science
JF - Proceedings of Science
M1 - 307
T2 - 37th International Cosmic Ray Conference, ICRC 2021
Y2 - 12 July 2021 through 23 July 2021
ER -