We present a mid-infrared analysis of star-formation activity in the Large Magellanic Cloud's molecular ridge (south of 30 Doradus). The Magellanic Clouds are a rare laboratory in which extragalactic star-formation diagnostics can be tested at high spatial resolution. The southern part of the molecular ridge is particularly interesting as a potential extreme in the range of molecular cloud conditions, because of the apparent paucity (in optical tracers) of star formation compared to its gas mass. Our Spitzer observations are sensitive to protostars 3 M ☉, and we estimate a total star-formation luminosity of 5 × 106 L ☉ in 2 × 106 M ☉ of molecular material. Detailed modeling of individual infrared-detected star-formation regions yields a total mass of star formation in the region consistent with that predicted by the gas surface density via the Schmitt-Kennicutt relation. The star-formation activity is distributed in rather low-luminosity regions, so the total star-formation rate determined by our infrared analysis is higher than would be predicted simply by the total Hα and 24 μm luminosities. Detailed analysis in very nearby galaxies, like the Magellanic Clouds, allows us to test and better understand the scaling relations used in unresolved and distant star-formation regions. Finally, we analyze the star-formation regions in the context of their individual molecular clouds and find that clouds with a higher ratio of CO mass to virial mass are more vigorously forming stars.
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机译：我们提出了大麦哲伦星云的分子脊（Doradus南部30）的恒星形成活动的中红外分析。麦哲伦星云是一个罕见的实验室，可以在太空中以高空间分辨率测试银河系外恒星形成诊断。由于在分子云条件范围内潜在的极端情况，分子脊的南部特别令人感兴趣，因为与气体质量相比，恒星形成的明显缺乏（在光学示踪剂中）。我们的Spitzer观测值对3 M pro的原恒星很敏感，并且我们估计在2×106 M☉的分子材料中总的恒星形成光度为5×106 L☉。对单个红外检测到的恒星形成区域进行详细的建模，可以得出该区域恒星形成的总质量，该质量与通过Schmitt-Kennicutt关系由气体表面密度预测的质量一致。恒星形成活动分布在相当低的发光度区域，因此通过我们的红外分析确定的总恒星形成率高于简单的总Hα和24μm光度所预测的恒星形成率。在极近的星系（如麦哲伦星云）中进行的详细分析，使我们能够测试和更好地理解在未解析和遥远的恒星形成区域中使用的比例关系。最后，我们在单个分子云的背景下分析了恒星形成区域，发现具有较高CO质量与病毒质量比的云更强烈地形成了恒星。
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