Filaments of Galaxies as a Clue to the Origin of Ultra-High-Energy Cosmic Rays

Abstract

Ultra-high-energy cosmic rays (UHECRs) are known to come from outside of our Galaxy, but their origin still remains unknown. The Telescope Array (TA) experiment recently identified a high concentration in the arrival directions of UHECRs with energies above $5.7\times 10^{19}eV$, called hotspot. We here report the presence of filaments of galaxies, connected to the Virgo Cluster, on the sky around the hotspot, and a statistically significant correlation between hotspot events and the filaments. With 5-year TA data, the maximum significance of binomial statistics for the correlation is estimated to be 6.1 $\sigma$ at correlation angle 3.4 degree. The probability that the above significance appears by chance is $\sim 2.0\times 10^{-8}$ (5.6 $\sigma$). Based on this finding, we suggest a model for the origin of TA hotspot UHECRs; they are produced at sources in the Virgo Cluster, and escape to and propagate along filaments, before they are scattered toward us. This picture requires the filament magnetic fields of strength $\gtrsim 20$ nG, which need to be confirmed in future observations.

References in corpus (28)

• Gamma-Ray Bursts
• HyperLEDA. III. The catalogue of extragalactic distances
• Clusters of galaxies : observational properties of the diffuse radio emission
• A New Model of the Galactic Magnetic Field
• The Protogalactic Origin for Cosmic Magnetic Fields
• Turbulence and Magnetic Fields in the Large Scale Structure of the Universe
• Observation of a Large-scale Anisotropy in the Arrival Directions of Cosmic Rays above $8\times 10^{18}$ eV
• M87 at 90cm: A Different Picture
• Indications of Intermediate-Scale Anisotropy of Cosmic Rays with Energy Greater Than 57 EeV in the Northern Sky Measured with the Surface Detector of the Telescope Array Experiment
• Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter
• Constrained Simulations of the Magnetic Field in the Local Universe and the Propagation of UHECRs
• The Inner Jet of the Radio Galaxy M87
• The Extended Virgo Cluster Catalog
• Simulations of extragalactic magnetic fields and of their observables
• The Origin and Evolution of Cosmic Magnetism
• Cluster Accretion Shocks as Possible Acceleration Sites for Ultra High Energy Protons below the Greisen Cutoff
• Ultra-High Energy Cosmic Rays in a Structured and Magnetized Universe
• The Principal Axis of the Virgo Cluster
• Faraday Rotation Measure due to the Intergalactic Magnetic Field II: the Cosmological Contribution
• Low Frequency Radio Constraints on the Synchrotron Cosmic Web
• A Magnetized Local Supercluster and the Origin of the Highest Energy Cosmic Rays
• Limiting Magnetic Fields in the Cosmic Web with Diffuse Radio Emission
• Large-scale filamentary structures around the Virgo cluster revisited
• Search for correlations of the arrival directions of ultra-high energy cosmic ray with extragalactic objects as observed by the telescope array experiment
• Intergalactic Magnetic Field and Arrival Direction of Ultra-High-Energy Protons
• Distortion of Ultra-high-energy sky by Galactic Magnetic Field
• Resolving the rotation measure of the M87 jet on kilo-parsec scales
• Discovery of the kinematic alignment of early-type galaxies in the Virgo cluster

Cited by in corpus (6)

• A survey of the thermal and non-thermal properties of cosmic filaments
• Impact of Galaxy Clusters on UHECR propagation
• Radio Observations as a Probe of Cosmic Web Magnetism
• Evidence for UHECR origin in starburst galaxies
• High-Energy Neutrino Production in Clusters of Galaxies
• Propagation of ultra-high-energy cosmic rays in the magnetized cosmic web