Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory

ABDUL HALIM, A.; ABREU, P.; AGLIETTA, M.; ALLEKOTTE, I.; ALMEIDA CHEMINANT, K.; ALMELA, A.; ALOISIO, R.; ALVAREZ-MUÑIZ, J.; AMMERMAN YEBRA, J.; ANASTASI, G.A.; ANCHORDOQUI, L.; ANDRADA, B.; ANDRINGA, S.; ARAMO, C.; ARAÚJO FERREIRA, P.R.; ARNONE, E.; ARTEAGA VELÁZQUEZ, J.C.; ASOREY, H.; ASSIS, P.; AVILA, G.; AVOCONE, E.; BADESCU, A.M.; BAKALOVA, A.; BALACEANU, A.; BARBATO, F.; BARTZ MOCELLIN, A.; BELLIDO, J.A.; BERAT, C.; BERTAINA, M.E.; BHATTA, G.; BIANCIOTTO, M.; BIERMANN, P.L.; BINET, V.; BISMARK, K.; BISTER, T.; BITEAU, J.; BLAZEK, J.; BLEVE, C.; BLÜMER, J.; BOHÁ?OVÁ, M.; BONCIOLI, D.; BONIFAZI, C.; BONNEAU ARBELETCHE, L.; BORODAI, N.; BRACK, J.; BRICHETTO ORCHERA, P.G.; BRIECHLE, F.L.; BUENO, A.; BUITINK, S.; BUSCEMI, M.; BÜSKEN, M.; BWEMBYA, A.; CABALLERO-MORA, K.S.; CACCIANIGA, L.; CARACAS, I.; CARUSO, R.; CASTELLINA, A.; CATALANI, F.; CATALDI, G.; CAZON, L.; CERDA, M.; CHINELLATO, J.A.; CHUDOBA, J.; CHYTKA, L.; CLAY, R.W.; COBOS CERUTTI, A.C.; COLALILLO, R.; COLEMAN, A.; COLUCCIA, M.R.; CONCEIÇÃO, R.;

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

IOP PUBLISHING LTD

Año: 2024 vol. 2024

1475-7516

The combined fit of the measured energy spectrum and shower maximum depth distributions of ultra-high-energy cosmic rays is known to constrain the parameters of astrophysical models with homogeneous source distributions. Studies of the distribution of the cosmic-ray arrival directions show a better agreement with models in which a fraction of the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with catalogs such as that of starburst galaxies. Here, we present a novel combination of both analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data measured at the Pierre Auger Observatory. The model takes into account a rigidity-dependent magnetic field blurring and an energy-dependent evolution of the catalog contribution shaped by interactions during propagation. We find that a model containing a flux contribution from the starburst galaxy catalog of around 20% at 40 EeV with a magnetic field blurring of around 20◦ for a rigidity of 10 EV provides a fair simultaneous description of all three observables. The starburst galaxy model is favored with a significance of 4.5σ (considering experimental systematic effects) compared to a reference model with only homogeneously distributed background sources. By investigating a scenario with Centaurus A as a single source in combination with the homogeneous background, we confirm that this region of the sky provides the dominant contribution to the observed anisotropy signal. Models containing a catalog of jetted active galactic nuclei whose flux scales with the γ-ray emission are, however, disfavored as they cannot adequately describe the measured arrival directions.