论文标题
弥漫性分子气中的CO发射和CO热点
CO emission and CO hotspots in diffuse molecular gas
论文作者
论文摘要
我们观察到$λ$ 3mm \ cotw，\ coth，\ coei，\ hcop，hcn和cs发射，沿着视线沿着视线的分子气体发出\ ebv \ $ \ $ 0.1-1-1-1-1-1-1。 Directions were mostly chosen for their proximity to sightlines toward background mm-wave continuum sources studied in \hcop\ absorption, at positions where maps of \cotw\ at 1\arcmin\ resolution showed surprisingly bright integrated CO J=1-0 emission \WCO\ = 5-12 K-\kms\ but we also observed in L121 near \zoph.当数据在\ cotw \和\ coth \亮度的广泛范围内考虑时，就会出现连贯性。 \ wco/\ wth \ and n（\ cotw）/n（\ coth）为\ wco \ $ \ la 5 $ k- \ kms \ and n（co）$ \ la 5 \ la 5 \ times 10^{15} \ pcc $，较大的\ wco \ wco \ n（co）。 n（\ coth）/n（\ coei）$> 20-40 $（$3σ$）与内在比率$^{13} $ c/$ c/$^{18} $ = 8.4，从选择性的光电解相结合和增强\ coth的组合。如果\ cotw \从\ hcop \与电子的热重组中形成\ cotw \，则观察值是可以理解的，之后通过吸热碳同位素与$^{13} $ c \ p交换观察到的\ coth \ forms。 \ wcs/\ wco \突然增加\ wco \ $ \ ga 10 $ k- \ kms \ and \ wcs/\ whcop \是bimodal，显示了两个具有N（cs）/n（\ hcop）$ \大约5 $和1.25的分支。由于CO的形成和\ HCOP \激发均涉及\ HCOP \和环境电子之间的碰撞，因此对CO和\ HCOP \发射的比较表明，Co Hotspots仅占据了较小的N（CO）的小区域，仅占据了较小的N（CO），其圆柱密度的一小部分是它们所在的介质的介质密度。 \ HCOP/CO和HCN/CO亮度比为1-2 \％，对确定真实密集气体的影响有明显的影响。
We observed $λ$3mm \cotw, \coth, \coei, \hcop, HCN and CS emission from diffuse molecular gas along sightlines with \EBV\ $\approx$ 0.1 - 1 mag. Directions were mostly chosen for their proximity to sightlines toward background mm-wave continuum sources studied in \hcop\ absorption, at positions where maps of \cotw\ at 1\arcmin\ resolution showed surprisingly bright integrated CO J=1-0 emission \WCO\ = 5-12 K-\kms\ but we also observed in L121 near \zoph. Coherence emerges when data are considered over a broad range of \cotw\ and \coth\ brightness. \WCO/\Wth\ and N(\cotw)/N(\coth) are 20-40 for \WCO\ $\la 5$ K-\kms\ and N(CO) $\la 5\times 10^{15}\pcc$, increasing with much scatter for larger \WCO\ or N(CO). N(\coth)/N(\coei) $> 20-40$ ($3σ$) vs. an intrinsic ratio $^{13}$C/$^{18}$O = 8.4, from a combination of selective photodissociation and enhancement of \coth. The observations are understandable if \cotw\ forms from the thermal recombination of \hcop\ with electrons, after which the observed \coth\ forms via endothermic carbon isotope exchange with $^{13}$C\p. \WCS/\WCO\ increases abruptly for \WCO\ $\ga 10$ K-\kms\ and \WCS/\Whcop\ is bimodal, showing two branches having N(CS)/N(\hcop) $\approx 5$ and 1.25. Because CO formation and \hcop\ excitation both involve collisions between \hcop\ and ambient electrons, comparison of the CO and \hcop\ emission shows that the CO hotspots are small regions of enhanced N(CO) occupying only a small fraction of the column density of the medium in which they are embedded. \hcop/CO and HCN/CO brightness ratios are 1-2\% with obvious implications for determinations of the true dense gas fraction.
