R. U. Abbasi (Author),
Mitsuhiro Abe (Author),
T. Abu-Zayyad (Author),
M. Allen (Author),
R. Anderson (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 an intermediate-scale energy spectrum anisotropy has been found in the arrival directions of ultra-high energy cosmic rays for energies greater than 10^19.2 eV in the northern hemisphere using 7 years of Telescope Array surface detector data. A relative energy distribution test is done comparing events inside oversampled spherical caps of equal exposure, to those outside, using the Poisson likelihood ratio. The center of maximum significance is at 9h16m, 45°, and has a deficit of events with energies 10^19.2 ≤ E < 10^19.75 eV and an excess for E ≥ 10^19.75 eV. The post-trial probability of this energy anisotropy, appearing by chance anywhere on an isotropic sky, is found by Monte Carlo simulation to be 9 × 10−5 (3.74σ global).
Keywords
cosmic rays;astroparticle physics;anisotropy;large-scale structure;universe;
Data
Language: |
English |
Year of publishing: |
2018 |
Typology: |
1.01 - Original Scientific Article |
Organization: |
UNG - University of Nova Gorica |
UDC: |
524 |
COBISS: |
5616379
|
ISSN: |
1538-4357 |
Views: |
2341 |
Downloads: |
182 |
Average score: |
0 (0 votes) |
Metadata: |
|
Other data
URN: |
URN:SI:UNG |
Type (COBISS): |
Not categorized |
Pages: |
str. 1-6 |
Volume: |
ǂVol. ǂ862 |
Issue: |
ǂno. ǂ2 |
Chronology: |
2018 |
DOI: |
10.3847/1538-4357/aac9c8 |
ID: |
11578982 |