Molecular hydrogen in the Galaxy and galactic gamma rays.
Molecular hydrogen in the Galaxy and galactic gamma rays.
复制标题
银河系中的分子氢和银河伽马射线。
DOI：
10.1086/153862
复制
发表时间：
1975
期刊：
影响因子：
--
通讯作者：
C. Ryter
中科院分区：
文献类型：
--
作者：
F. Stecker;P. Solomon;N. Scoville;C. Ryter
最近调查的2.6厘米CO排放和100兆电子伏的伽玛辐射在银道面揭示惊人的相关性表明，这两种排放可能主要是成比例的视线列密度的H$分2$在银河系内部。无论是伽玛射线和CO数据表明一个突出的环或臂组成的冷云H$sub 2$在银河系的距离约。5 kpc，平均总氢密度相当于约5个原子cm$sup-3 $。在l/sup II/= 0度时，柱密度估计为H$sub 2$。在0度的估计进行比较，从红外和X射线吸收测量的估计。这些估计都是一致的，并表明，H$sub 2$是远远超过H i在银河系内部的丰富，是一个更令人满意的解释的伽马射线观测比以前的建议的关键。H$sub 2$在理解银河系$gamma$-射线观测中的重要性还体现在$gamma$-射线的银河纬度分布与致密尘埃云的相关性上。从计算中推断出的宇宙射线分布与银河系超新星遗迹相似，表明大多数宇宙射线都起源于银河系。（AIP）
Recent surveys of 2.6-cm CO emission and 100-MeV $gamma$-radiation in the galactic plane reveal striking correlation suggesting that both emissions may be primarily proportional to the line-of-sight column density of H$sub 2$ in the inner Galaxy. Both the $gamma$-ray and CO data suggest a prominent ring or arm consisting of cool clouds of H$sub 2$ at a galactocentric distance of approx. 5 kpc with a mean total hydrogen density equivalent to approx.5 atoms cm$sup -3$. Estimates are made of column densities of H$sub 2$ at l/sup II/=0degree. The estimates at 0degree are compared with estimates from infrared and X-ray absorption measurements. These estimates are all consistent and indicate that H$sub 2$ is far more abundant than H i in the inner Galaxy and is the key to a more satisfactory explanation of the $gamma$-ray observations than previous suggestions. The importance of H$sub 2$ in understanding galactic $gamma$-ray observations is also reflected in the correlation of galactic latitude distribution of $gamma$-rays and dense dust clouds. The deduced cosmic-ray distribution inferred from the calculations is similar to that of galactic supernova remnants, suggesting a galactic origin for most cosmic rays. (AIP)