R. U. Abbasi (Author), Mitsuhiro Abe (Author), T. Abu-Zayyad (Author), M. Allen (Author), R. Azuma (Author), E. Barcikowski (Author), J. W. Belz (Author), D. R. Bergman (Author), S. A. Blake (Author), J. P. Lundquist (Author)

Abstract

Evidence for a large-scale supergalactic cosmic-ray multiplet (arrival directions correlated with energy) structure is reported for ultra-high-energy cosmic-ray (UHECR) energies above 1019 eV using 7 years of data from the Telescope Array (TA) surface detector and updated to 10 years. Previous energy–position correlation studies have made assumptions regarding magnetic field shapes and strength, and UHECR composition. Here the assumption tested is that, because the supergalactic plane is a fit to the average matter density of the local large-scale structure, UHECR sources and intervening extragalactic magnetic fields are correlated with this plane. This supergalactic deflection hypothesis is tested by the entire field-of-view (FOV) behavior of the strength of intermediate-scale energy–angle correlations. These multiplets are measured in spherical cap section bins (wedges) of the FOV to account for coherent and random magnetic fields. The structure found is consistent with supergalactic deflection, the previously published energy spectrum anisotropy results of the TA (the Hotspot and Coldspot), and toy-model simulations of a supergalactic magnetic sheet. The seven year data posttrial significance of this supergalactic structure of multiplets appearing by chance, on an isotropic sky, is found by Monte Carlo simulation to be 4.2σ. The 10 years of data posttrial significance is 4.1σ. Furthermore, the starburst galaxy M82 is shown to be a possible source of the TA Hotspot, and an estimate of the supergalactic magnetic field using UHECR measurements is presented.

Keywords

extragalactic magnetic fields;ultra-high-energy cosmic radiation;cosmic rays;high energy astrophysics;astrophysical magnetism;cosmic ray astronomy;cosmic ray sources;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 524
COBISS: 50353923 Link will open in a new window
ISSN: 1538-4357
Views: 1735
Downloads: 122
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Other data

URN: URN:SI:UNG
Pages: str. 1-16
Volume: ǂVol. ǂ899
Issue: ǂno. ǂ1
Chronology: 2020
DOI: 10.3847/1538-4357/aba26c
ID: 12532890