论文标题
银河中心的分子分数：中央分子和HI区域
Molecular Fraction in the Galactic Center: The Central Molecular and HI Zones
论文作者
论文摘要
通过映射银河系中心（GC）的分子分数，我们定量地解决了CMZ（中央分子区）的分子和中心的问题。 For this purpose we analyze the CO and HI-line archival data, and determine the column- (surface-) and volume-molecular fractions, $f_{\rm mol}^Σ$ and $f_{\rm mol}^ρ$, which are the ratio of column-mass density of H$_2$ projected on the sky to that of total gas (H$_2$ + HI) from the line intensities, and the \ htwo \ \ htwo \的体积质量密度与亮度温度的总气体比率。结果表明，$ f _ {\ rm mol}^σ$在CMZ中高达$ \ sim 0.9-0.95 $，而$ f _ {\ rm mol}^ρ$为$ 0.93-0.98 $ $ 0.93-0.98 $，在GC ARM I中，在GC ARM I和II中，II和II的最高价值为$ \ sim 0.98 $ 0.98 $ 0.98 $。扩展的分子环（EMR或平行四边形）的$ f _ {\ rm mol}^σ$作为$ \ sim 0.9-0.93 $。 We define the CMZ as the region with $f_{\rm mol}^Σ\ge 0.8-0.9$ between the shoulders of plateau-like distribution of H$_2$ column density from $l=-1^\circ.1$ to $+1^\circ.8$ having Gaussian vertical distribution with a half thickness of $\pm 0^\circ.2$. CMZ嵌入到中央HI区域（CHZ）中，该区域定义为$ l \ sim -2^\ circ $和$+2^\ Circ.5 $，$ b = -0^\ Circ.5 $和$+0^\ circ.5 $ 5 $之间的HI光盘。基于分析，我们讨论了CMZ和星际物理学的起源，例如从$ f _ {\ rm mol}^σ$和$ f _ {\ rm mol}^ρ$之间的差异推断出的分子和HI气体的体积填充因子。
By mapping the molecular fraction of the Galactic Center (GC), we quantitatively address the question of how much molecular and central the CMZ (Central Molecular Zone) is. For this purpose we analyze the CO and HI-line archival data, and determine the column- (surface-) and volume-molecular fractions, $f_{\rm mol}^Σ$ and $f_{\rm mol}^ρ$, which are the ratio of column-mass density of H$_2$ projected on the sky to that of total gas (H$_2$ + HI) from the line intensities, and the ratio of volume-mass densities of \Htwo\ to total gas from the brightness temperature, respectively. It is shown that $f_{\rm mol}^Σ$ is as high as $ \sim 0.9-0.95$ in the CMZ, and $f_{\rm mol}^ρ$ is $0.93-0.98$ in the GC Arms I and II attaining the highest value of $\sim 0.98$ toward Sgr B2. The expanding molecular ring (EMR, or the parallelogram) has a slightly smaller $f_{\rm mol}^Σ$ as $\sim 0.9-0.93$. We define the CMZ as the region with $f_{\rm mol}^Σ\ge 0.8-0.9$ between the shoulders of plateau-like distribution of H$_2$ column density from $l=-1^\circ.1$ to $+1^\circ.8$ having Gaussian vertical distribution with a half thickness of $\pm 0^\circ.2$. The CMZ is embedded in the Central HI Zone (CHZ), which is defined as an HI disc between $l\sim -2^\circ$ and $+2^\circ.5$, $b=-0^\circ.5$ and $+0^\circ.5$. Based on the analysis, we discuss the origin of CMZ and interstellar physics such as the volume filling factors of molecular and HI gases inferred from the difference between $ f_{\rm mol}^Σ$ and $f_{\rm mol}^ρ$.
