论文标题
宇宙射线电子和北极刺的磁场
Cosmic-ray electrons and the magnetic field of the North Polar Spur
论文作者
论文摘要
最近对Erosita气泡的双极性的确认表明，众所周知的North Polar Spur（NPS）/Loop I可能是银河系子中10 kpc尺寸的遗物，而不是太阳附近的局部结构。借助NP的多波长观测值，可以提供宇宙射线电子（CRE）（CRE）的前所未有的精确参数约束，并且可以提供后震动晕片中的磁场。 CRE和磁场的参数可以通过分别通过逆康普顿散射和同步加速器的发射来独立得出NP的伽马射线和NP的无线电数据来独立得出。我们的主要结果是（1）CRE的能量密度为（3-6）$ \ times 10^{ - 14} $ erg cm $^{ - 3} $，光谱索引为$ p \ simeq 2.0 \ pm 0.1，$以下$下方的冷却能量低于5 GEV； （2）磁场强度为3美元$ g; （3）CRE的冲击加速度为（1-2）％。考虑到1.5的马赫数，CRE的高加速度效率和扁平光谱表明，在NP中可能会重新培养相对论电子。另外，当其马赫数很高时，在早期的时期内发生的冲击可以加速这些CRE，并且在整个震后的光环气体中有效扩散。此外，冷却中断的能源表明，冷却时间尺度为$ 10^7 $ yr，这与Erosita Bubbles的年龄一致。
The recent confirmation of the bipolarity of the eROSITA bubbles suggests that the well-known North Polar Spur (NPS)/Loop I probably is a 10 kpc sized relic in the Galactic halo and not a small local structure near the Sun. By virtue of multiwavelength observations of the NPS, unprecedentedly precise parameter constraints on the cosmic-ray electrons (CRes) and magnetic field in the post-shock halo medium can be provided. The parameters of the CRes and the magnetic field can be derived independently by modeling the gamma-ray and the radio data of the NPS via inverse Compton scattering and synchrotron emission, respectively. Our main results are (1) that the energy density of the CRe is (3-6)$\times 10^{-14}$ erg cm$^{-3}$, and the spectral index is $p\simeq 2.0\pm 0.1, $ below the cooling break energy of about 5 GeV; (2) that the magnetic field strength is 3 $μ$G; and (3) that the shock acceleration efficiency of the CRe is (1-2)%. Given the Mach number of 1.5, the high acceleration efficiency and flat spectrum of the CRe suggest that preexisting relativistic electrons may be reaccelerated in the NPS. Alternatively, these CRes could be accelerated by an evolving shock in the early epoch when its Mach number is high, and efficiently diffuse throughout the post-shock halo gas. In addition, the cooling break energy suggests that the cooling timescale is $10^7$ yr, which agrees with the age of the eROSITA bubbles.
