A scenario for the anisotropy of galactic cosmic rays related to nearby source and local interstellar magnetic field [HEAP]

http://arxiv.org/abs/2107.00313


Our recent work attempted to account for the anisotropy of galactic cosmic rays (GCRs) through the contribution of nearby Geminga SNR source, however the anisotropic phase of CRs is about $\sim R.A.= 5^h$ below 100 TeV, which deviates significantly from the experimental data. Recent observations of CR anisotropy indicate that the phase of the anisotropy of CRs below 100 TeV is coincident with local interstellar magnetic field $(l,b= 210.5^\circ,-57.1^\circ)$ observed by Interstellar Boundary Explorer (IBEX). In this work, we consider simultaneously the contributions of both local interstellar magnetic fields and nearby Geminga SNR source to anisotropy of CRs. We found that the anisotropic phase of CRs points to $\sim R.A.= 3^h$ that accord with local regular magnetic field below 100 TeV, which is due to effect of magnetic field deflection on CRs. We further analyze the influence of the ratio of perpendicular and parallel to the magnetic diffusion coefficient on the anisotropy of CRs. The results illustrate that with the decrease of ratio, the anisotropic phase of CRs changes from the direction of nearby source to local regular magnetic field below 100 TeV, meanwhile from the galactic center (GC) to opposite direction of local regular magnetic field above 100 TeV.

Read this paper on arXiv…

A. Li, Q. Yuan, W. Liu, et. al.
Fri, 2 Jul 21
64/67

Comments: 9 pages, 5 figures