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arXiv 0907.5086astro-ph.GA
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SCUBA旧目录中的红外暗云核心

Infrared Dark Cloud Cores in the SCUBA Legacy Catalogue

H. Parsons, M. A. Thompson, A. Chrysostomou

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18 pages, 3 tables, 10 figures
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摘要：

我们对Simon等人（2006）在SCUBA遗产目录中确定的候选红外暗云核心进行了调查。在对目录数据应用统一的噪声切割后，我们确定了154个在850 μ m处检测到的红外暗云核心和51个没有检测到的核心。我们从每个岩心的8 μ m消光系数中推导出柱密度，发现在850 μ m处检测到的IRDC具有更高的柱密度（平均值为1.7x10^22 cm-2），而在850 μ m处未检测到的岩心（平均值为1.0x10^22 cm-2）。结合灵敏度估计，我们认为在850 μ m处未检测到的岩心是低于SCUBA在850 μ m处灵敏度极限的低质量、低柱密度和低温岩心。对于在850微米处检测到的核心的子样本（包含在MIPSGAL区域内的核心），我们发现三分之二与24微米源有关。与24微米辐射无关的核心要么是可能尚未形成恒星的“无星”IRDC核心，要么是包含低于MIPSGAL检测极限的低质量YSO。我们看到那些“无星”的IRDC核心和与24微米发射相关的IRDC核心来自相同的柱密度群体，并且具有相似的质量。如果我们假设没有24 μ m嵌入源的核心处于嵌入物体的核心的早期进化阶段，我们得出了几个10^3-10^4年的静止阶段的统计寿命。最后，我们保守的预测，将观察到的IRDCs的数量由顶点望远镜银道面调查（ATLASGAL），赫歇尔红外银道面调查（Hi-GAL），JCMT银道面调查（JPS）和SCUBA-2“全天”调查（SASSy）。

英文摘要：

We present an investigation of candidate Infrared Dark Cloud cores as identified by Simon et al. (2006) located within the SCUBA Legacy Catalogue. After applying a uniform noise cut to the Catalogue data we identify 154 Infrared Dark Cloud cores that were detected at 850um and 51 cores that were not. We derive column densities for each core from their 8um extinction and find that the IRDCs detected at 850um have higher column densities (a mean of 1.7x10^22 cm-2) compared to those cores not detected at 850um (a mean of 1.0x10^22 cm-2). Combined with sensitivity estimates, we suggest that the cores not detected at 850um are low mass, low column density and low temperature cores that are below the sensitivity limit of SCUBA at 850um. For a subsample of the cores detected at 850um those contained within the MIPSGAL area) we find that two thirds are associated with 24um sources. Cores not associated with 24um emission are either ``starless'' IRDC cores that perhaps have yet to form stars, or contain low mass YSOs below the MIPSGAL detection limit. We see that those ``starless'' IRDC cores and the IRDC cores associated with 24um emission are drawn from the same column density population and are of similar mass. If we then assume the cores without 24um embedded sources are at an earlier evolutionary stage to cores with embedded objects we derive a statistical lifetime for the quiescent phase of a few 10^3-10^4 years. Finally, we make conservative predictions for the number of observed IRDCs that will be observed by the Apex Telescope Galactic Plane Survey (ATLASGAL), the Herschel Infrared Galactic Plane Survey (Hi-GAL), the JCMT Galactic Plane Survey (JPS) and the SCUBA-2 ``All Sky'' Survey (SASSy).

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