论文标题
硬光谱弥漫性伽马射线分量与银河系中的HII气体相关
A hard spectrum diffuse gamma-ray component associated with HII gas in the Galactic plane
论文作者
论文摘要
我们分析了12年的Fermi大面积望远镜伽马射线数据中的内部星系中心（l = 30 $^{\ circ} $，b = 0 $^{\ circ} $）和（l = 330 $^{\ circ} $，b = 0 $^{\ circ} $）。如前所述，我们发现在这些区域中弥漫性伽马射线发射的光谱很大。我们进一步推断，可以将弥漫性伽马射线从可能性分析中分为两个组成部分。一个组件与总气柱密度相关，并揭示了柔软的光谱，而另一个与HII气体相关联，并带有硬光谱。假设弥漫性伽马射线排放主要是通过宇宙射线（CRS）和环境气体之间的相互作用产生的，那么这两个组件是由CR群体分别为2.8（“软”）和2.3（“硬”）产生的。我们认为，硬CR人口可能来自CR加速器的附近。软CR种群的光谱形状和密度与太阳邻域测量相似，这意味着在银河系中具有相似密度和光谱形状的均匀Cr“海”。
We analyzed 12-year Fermi Large Area Telescope gamma-ray data in the inner Galaxy centered at (l=30$^{\circ}$, b=0$^{\circ}$) and (l=330$^{\circ}$, b=0$^{\circ}$). We found significant hardening of the spectrum of the diffuse gamma-ray emission in these regions as previously reported. We further deduced that the diffuse gamma rays can be divided into two components from the likelihood analysis. One component is associated with the total gas column density and reveals a soft spectrum, while the other is associated with the HII gas and presents a hard spectrum. Assuming the diffuse gamma-ray emissions are mainly produced through the interaction between cosmic rays (CRs) and the ambient gas, these two components are produced by the CR populations with spectral indices of 2.8 ("soft") and 2.3 ("hard"), respectively. We argue that the hard CR population may come from the vicinity of the CR accelerators. The soft CR population has a similar spectral shape and density as measured in the solar neighborhood, which implies a uniform CR "sea" with a similar density and spectral shape in the Galaxy.
