Probing cosmic rays with Fe Ka line structures generated by multiple ionization process
Probing cosmic rays with Fe Ka line structures generated by multiple ionization process
复制标题
利用多重电离过程产生的 Fe Ka 线结构探测宇宙射线
DOI：
10.1093/pasj/psaa055
复制
发表时间：
2020
影响因子：
2.3
通讯作者：
T. G. Tsuru
中科院分区：
文献类型：
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作者：
H. Okon;M. Imai;T. Tanaka;H. Uchida;T. G. Tsuru
超新星遗迹（SNRs）被认为是银河系宇宙线的主要加速场。最近的X射线研究揭示了一些SNR附近致密气体中的中性Fe Kα线发射，这可以最好地解释为在SNR中加速的亚相对论粒子对气体中Fe原子的K壳层电离。在这封信中，我们提出了一种限制在SNR中加速的粒子成分的新方法，这是目前未知的。当高能重离子与靶原子碰撞时，其强库仑场很容易引起靶的多个内壳层电子同时射出。这导致特征X射线线能量的变化，形成独特的光谱结构。在中性Fe Kα谱线中探测到这种结构，有力地支持了粒子电离的假设，并进一步提供了加速粒子中存在重离子的直接证据。利用原子碰撞数据，我们建立了不同射弹离子作用下Fe Kα线结构的模型。
Supernova remnants (SNRs) have been regarded as major acceleration sites of Galactic cosmic rays. Recent X-ray studies revealed neutral Fe Kα line emission from dense gas in the vicinity of some SNRs, which can be best interpreted as K-shell ionization of Fe atoms in the gas by sub-relativistic particles accelerated in the SNRs. In this Letter, we propose a novel method of constraining the composition of particles accelerated in SNRs, which is currently unknown. When energetic heavy ions collide with target atoms, their strong Coulomb field can easily cause simultaneous ejection of multiple inner-shell electrons of the target. This results in shifts in characteristic X-ray line energies, forming distinctive spectral structures. Detection of such structures in the neutral Fe Kα line strongly supports the particle ionization scenario, and furthermore provides direct evidence of heavy ions in the accelerated particles. We construct a model for the Fe Kα line structures by various projectile ions utilizing atomic-collision data.