论文标题
部分可观测时空混沌系统的无模型预测
Detection of diffuse gamma-ray emission towards a massive star forming region hosting Wolf-Rayet stars
论文作者
论文摘要
银河宇宙射线中看到的同位素和元素丰度意味着宇宙射线（CR）核的$ \ sim20 \％$可能是由大型狼射线（WR）恒星合成的。数十年来，已经提出了托管WR和OB-type恒星的大型恒星簇作为潜在的银河宇宙射线加速器，尤其是通过在风终止冲击时进行扩散的冲击加速度。在这里，我们报告了{\ em fermi}大面积望远镜数据的分析，该数据朝着Masgomas-6a的方向，这是一个年轻的大型明星群集候选者，托有两个WR恒星。我们在Masgomas-6a附近检测到具有$ \ rm {ts} = 183 $的扩展$γ$ ray源，在空间上与两个无关{\ em fermi} 4fgl源相吻合。我们还使用银河系成像滚动绘画项目中的数据介绍了该区域中分子云的CO观察结果。 $γ$ -RARE的发射强度与Masgomas-6a距离分子气体的分布非常相关，表明这些伽马射线可能是由Masgomas-6a中大型恒星加速的CR产生的。 Masgomas-6a的$ 3.9 {\ rm \ kpc} $，扩展源的光度为$（1.81 \ pm0.02）\ times 10^{35} {\ rm \ rm \ rm \ erg \ erg \ s^{ - 1}} $。具有$ \ sim 10^{37} {\ rm erg \ s^{ - 1}} $的动力学发光度，在恒星风中，WR星能够通过Cosmic ray $ PP $互动引起的$γ$ - ray射击通过中性派衰减来供电。 GEV源的尺寸和能量需求表明，CR扩散系数小于银河系介质中的CR扩散系数，表明在分子云中强烈抑制Cr扩散。
Isotopic and elemental abundances seen in Galactic cosmic rays imply that $\sim20\%$ of the cosmic-ray (CR) nuclei are probably synthesized by massive Wolf-Rayet (WR) stars. Massive star clusters hosting WR and OB-type stars have been proposed as potential Galactic cosmic-ray accelerators for decades, in particular via diffusive shock acceleration at wind termination shocks. Here we report the analysis of {\em Fermi} Large Area Telescope's data towards the direction of Masgomas-6a, a young massive star cluster candidate hosting two WR stars. We detect an extended $γ$-ray source with $\rm{TS}=183$ in the vicinity of Masgomas-6a, spatially coincident with two unassociated {\em Fermi} 4FGL sources. We also present the CO observational results of molecular clouds in this region, using the data from the Milky Way Imaging Scroll Painting project. The $γ$-ray emission intensity correlates well with the distribution of molecular gas at the distance of Masgomas-6a, indicating that these gamma rays may be produced by CRs accelerated by massive stars in Masgomas-6a. At the distance of $3.9{\rm \ kpc}$ of Masgomas-6a, the luminosity of the extended source is $(1.81\pm0.02)\times 10^{35}{\rm \ erg \ s^{-1}}$. With a kinetic luminosity of $\sim 10^{37}{\rm erg \ s^{-1}}$ in the stellar winds, the WR stars are capable of powering the $γ$-ray emission via neutral pion decay resulted from cosmic ray $pp$ interactions. The size of the GeV source and the energetic requirement suggests a CR diffusion coefficient smaller than that in the Galactic interstellar medium, indicating strong suppression of CR diffusion in the molecular cloud.
