scholarly journals Filaments of galaxies as a clue to the origin of ultrahigh-energy cosmic rays

2019 ◽  
Vol 5 (1) ◽  
pp. eaau8227 ◽  
Author(s):  
Jihyun Kim ◽  
Dongsu Ryu ◽  
Hyesung Kang ◽  
Suk Kim ◽  
Soo-Chang Rey
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Virgo Cluster ◽  
Ultrahigh Energy ◽  
High Concentration ◽  
Telescope Array ◽  
Ultrahigh Energy Cosmic Rays ◽  
To Come ◽  
Binomial Statistics ◽  
Arrival Directions

Ultrahigh-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 hotspot, that is, a high concentration of anisotropic arrival directions of UHECRs with energies above 5.7 Å ~ 1019eV. We report here the presence of filaments of galaxies, connected to the Virgo Cluster, in 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 6.1σ at correlation angle 3.4°. The probability that the above significance appears by chance is ~2.0 × 10−8(5.6σ). On the basis of 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 ≳ 20 nG, which need to be confirmed in future observations.

scholarly journals Arrival Directions of Ultrahigh-Energy Cosmic Rays

2019 ◽  
Vol 1208 ◽  
pp. 012013
Author(s):  
Alan G. Chávez-Meza ◽  
Juan C. Arteaga-Velázquez ◽  
Luis M. Villaseñor-Cendejas
Keyword(s):  
Cosmic Rays ◽  
Ultrahigh Energy ◽  
Ultrahigh Energy Cosmic Rays ◽  
Arrival Directions

scholarly journals A next-generation ground array for the detection of ultrahigh-energy cosmic rays: the Fluorescence detector Array of Single-pixel Telescopes (FAST)

2019 ◽  
Vol 210 ◽  
pp. 06003
Author(s):  
Toshihiro Fujii ◽  
Max Malacari ◽  
Justin Albury ◽  
Jose A. Bellido ◽  
Ladislav Chytka ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Full Scale ◽  
Pierre Auger Observatory ◽  
Detector Array ◽  
Ultrahigh Energy ◽  
Next Generation ◽  
Fluorescence Detector ◽  
Telescope Array ◽  
Ultrahigh Energy Cosmic Rays ◽  
Single Pixel

The origin and nature of ultrahigh-energy cosmic rays (UHECRs) is one of the most intriguing and important mysteries in astroparticle physics. The two largest observatories currently in operation, the Telescope Array Experiment in central Utah, USA, and the Pierre Auger Observatory in western Argentina, have been steadily observing UHECRs in both hemispheres for over a decade. We highlight the latest results from both of these experiments, and address the requirements for a next-generation UHECR observatory. The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for a next-generation UHECR observa-tory, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of the highest energy cosmic rays with an unprecedented aperture. We have developed a full-scale prototype consisting of four 200 mm photomultiplier-tubes at the focus of a segmented mirror of 1.6 m in diameter. Over the last three years, we installed three such prototypes at the Black Rock Mesa site of the Telescope Array Experiment. These telescopes have been steadily taking data since installation. We report on preliminary results of the full-scale FAST prototypes, including measurements of distant ultraviolet lasers and UHECRs. Futhermore, we discuss our plan to install an additional identical FAST prototype at the Pierre Auger Observatory. Possible benefits to the Telescope Array and the Pierre Auger Observatory include a comparison of the transparency of the atmosphere above both experiments, a study of the systematic uncertainty associated with their existing fluorescence detectors, and a cross-calibration of their energy and Xmax scales.

scholarly journals Future ground arrays for ultrahigh-energy cosmic rays: recent updates and perspectives

2019 ◽  
Vol 208 ◽  
pp. 15004 ◽  
Author(s):  
Toshihiro Fujii
Keyword(s):  
Cosmic Rays ◽  
Low Cost ◽  
Pierre Auger Observatory ◽  
Ultrahigh Energy ◽  
Next Generation ◽  
Large Area ◽  
Telescope Array ◽  
Particle Astrophysics ◽  
Ultrahigh Energy Cosmic Rays

The origin and nature of ultrahigh-energy cosmic rays (UHECRs) are one of the most intriguing mysteries in particle astrophysics and astronomy. The two largest observatories, the Pierre Auger Observatory and the Telescope Array Experiment, are steadily observing UHECRs in both hemispheres in order to better understand their origin and associated acceleration mechanisms at the highest energies. We highlight their latest results including on-going upgrades, AugerPrime and TA×4, and then address the requirements for a next-generation observatory. We share recent updates and perspectives for a future ground array of fluorescence detectors, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of the highest energy cosmic rays with an unprecedented aperture.

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