Anisotropy and corotation of Galactic cosmic rays

Anisotropy and corotation of Galactic cosmic rays

The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

由于银河系中磁场的影响，银河宇宙射线的强度几乎是各向同性的。在此，我们利用西藏空气簇射阵列的大量数据样本，对从几太电子伏特（TeV）到数百太电子伏特能量的宇宙射线进行了二维高精度各向异性测量。除了揭示已知各向异性的更精细细节外，还在天鹅座区域方向附近发现了一个以恒星时为变量的银河宇宙射线各向异性的新成分。对于能量高达数百太电子伏特的宇宙射线，各向异性的所有成分都逐渐消失，这表明银河宇宙射线与当地银河磁场环境共转。这些结果对全面理解宇宙射线、超新星、磁场以及日球层和银河系动态环境具有广泛的意义。