论文标题
射手座B2周围HOCN的空间分布
Spatial distribution of HOCN around Sagittarius B2
论文作者
论文摘要
分子气体中的HOCN和HNCO丰度比可以告诉我们它们的形成机制的信息。我们对HOCN，HNCO和HNC $^{18} $ o线进行了高敏性映射观测值，该线围绕Sagittarius B2（SGR B2），IRAM 30M望远镜在3毫米波长处进行。 HNCO 4 $ _ {04} $ - 3 $ _ {03} $和HOCN 4 $ _ {04} $ - 3 $ _ {03} $用于获得HNCO与HOCN的丰度比率。 HNCO 4 $ _ {04} $ - 3 $ _ {03} $与Hnc $^{18} $ 4 $ 4 $ _ {04} $ - 3 $ _ {03} $的比率。观察到HOCN和HNCO的丰度比范围为0.4％至0.7％，大多数位置与气体谷物模型非常吻合。但是，观察到HOCN的相对丰度向SGR B2的方向增强，HOCN与HNCO的丰度比为$ \ sim $ 0.9％。这样做的原因仍然需要进一步调查。基于HNCO和HNC $^{18} $ O线的强度比，我们更新了同位素比为$^{16} $ o/$ o/$ o/$^{18} $ O的同位素比为296 $ \ pm $ $ $ 54 sgr b2 in Sgr b2。
HOCN and HNCO abundance ratio in molecular gas can tell us the information of their formation mechanism. We performed high-sensitivity mapping observations of HOCN, HNCO, and HNC$^{18}$O lines around Sagittarius B2 (Sgr B2) with IRAM 30m telescope at 3-mm wavelength. HNCO 4$_{04}$-3$_{03}$ and HOCN 4$_{04}$-3$_{03}$ are used to obtain the abundance ratio of HNCO to HOCN. The ratio of HNCO 4$_{04}$-3$_{03}$ to HNC$^{18}$O 4$_{04}$-3$_{03}$ is used to calculate the optical depth of HNCO 4$_{04}$-3$_{03}$. The abundance ratio of HOCN and HNCO is observed to range from 0.4% to 0.7% toward most positions, which agrees well with the gas-grain model. However, the relative abundance of HOCN is observed to be enhanced toward the direction of Sgr B2 (S), with HOCN to HNCO abundance ratio of $\sim$ 0.9%. The reason for that still needs further investigation.Based on the intensity ratio of HNCO and HNC$^{18}$O lines, we updated the isotopic ratio of $^{16}$O/$^{18}$O to be 296 $\pm$ 54 in Sgr B2.
