A. Abdul Halim (Author), Andrej Filipčič (Author), J. P. Lundquist (Author), S. U. Shivashankara (Author), Samo Stanič (Author), Serguei Vorobiov (Author), Danilo Zavrtanik (Author), Marko Zavrtanik (Author)

Abstract

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 10EV 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.

Keywords

ultra high energy cosmic rays;cosmic ray experiments;Pierre Auger Observatory;active galactic nuclei;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 52
COBISS: 181667587 Link will open in a new window
ISSN: 1475-7516
Views: 330
Downloads: 7
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Pages: str. 1-40
Volume: ǂVol. ǂ2024
Issue: ǂno. ǂ1, [article no.] 022
Chronology: Jan. 2024
DOI: 10.1088/1475-7516/2024/01/022
ID: 22454771
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