Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 x 1018 eV
Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 x 1018 eV
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DOI：
10.1126/science.aan4338
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发表时间：
2017-09-22
期刊：
影响因子：
56.9
通讯作者：
Zuccarello, F.
中科院分区：
文献类型：
--
作者：
Aab, A.;Abreu, P.;Zuccarello, F.
宇宙射线是来自外太空的原子核，达到自然界中观察到的最高能量。它们起源的线索来自于研究它们到达方向的分布。利用皮埃尔·俄歇天文台从76，800 km（2）sr年的总曝光量中记录的能量超过8 × 10（18）电子伏的3 × 10（4）宇宙射线，我们确定了到达方向上各向异性的存在。在大于5.2s的显著性水平下检测到的各向异性可以用振幅为6：5（-0.9）（+1.3）%的偶极子来描述，朝向赤Ascension α（d）= 100 +/- 10度和赤经δ（d）= -24（-13）（+12）度。这个方向表明了这些超高能粒子的银河系外起源。
Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 x 10(4) cosmic rays with energies above 8 x 10(18) electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km(2) sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2s level of significance, can be described by a dipole with an amplitude of 6:5(-0.9)(+1.3) percent toward right ascension alpha(d) = 100 +/- 10 degrees and declination delta(d) = -24(-13)(+12) degrees. That direction indicates an extragalactic origin for these ultrahighenergy particles.