On the abundance of carbon monoxide in galaxies - A comparison of spiral and Magellanic irregular galaxies
On the abundance of carbon monoxide in galaxies - A comparison of spiral and Magellanic irregular galaxies
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关于星系中一氧化碳的丰度——螺旋星系和麦哲伦不规则星系的比较
DOI：
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
D. Elmegreen
中科院分区：
文献类型：
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作者：
B. Elmegreen;M. Morris;D. Elmegreen
已在 52 个方向上寻找六个不规则麦哲伦型星系的 CO 排放，在 10 km/s 线宽的典型检测极限为 0.04 K 时获得零结果。搜索的位置对应于明亮的OB星团、H II区域、H I峰和暗云的位置。在两个案例中，观测覆盖了三分之一的光学星系。在距低质量 SA(s)dm 星系 NGC 7793 核心 2.6 毫米处检测到 CO。结果表明，麦哲伦不规则星系中 CO 发射的平均表面亮度低于该星系和其他已研究的螺旋星系。对此讨论了两类解释，包括（1）基于不规则星际云的加热速率较低，从而导致二氧化碳温度较低的解释，以及（2）基于二氧化碳丰度较低的解释。
CO emission has been sought in 52 directions toward six irregular, Magellanic-type galaxies, with null results at a typical detection limit of 0.04 K for a line width of 10 km/s. The positions searched correspond to those of bright OB star clusters, H II regions, H I peaks, and dark clouds. In two cases, one-third of the optical galaxy was covered by the observations. CO has been detected at 2.6 mm toward the nucleus of the low-mass SA(s)dm galaxy NGC 7793. The results imply that the mean surface brightness of CO emission in Magellanic irregulars is less than that of the Galaxy and other spirals which have been studied. Two categories of explanations for this are discussed, including (1) those based on a lower heating rate for interstellar clouds in irregulars, and thus a lower CO temperature, and (2) those based on a lower CO abundance.