@misc{10481/92273,
year = {2024},
month = {1},
url = {https://hdl.handle.net/10481/92273},
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 20º 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.},
organization = {Ministerio de Economía, Industria y Competitividad (FPA2017-85114-P
and PID2019-104676GB-C32)},
organization = {Xunta de Galicia (ED431C 2017/07)},
organization = {Junta de Andalucía
(SOMM17/6104/UGR, P18-FR-4314) Feder Funds},
organization = {RENATA Red Nacional Temática de
Astropartículas (FPA2015-68783-REDT)},
organization = {María de Maeztu Unit of Excellence (MDM-2016-0692)},
organization = {National Science
Foundation, Grant No. 0450696},
organization = {The Grainger Foundation; Marie Curie-IRSES/EPLANET},
organization = {European Particle Physics Latin American Network},
organization = {UNESCO},
publisher = {IOP Publishing},
keywords = {Ultra high energy cosmic rays},
keywords = {Cosmic ray experiments},
keywords = {Active galactic nuclei},
title = {Constraining models for the origin of ultra-highenergy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger Observatory},
doi = {10.1088/1475-7516/2024/01/022},
author = {Abdul Halim, A. and Bueno Villar, Antonio and Pierre Auger Collaboration, /},
}