The Core Mass Function across Galactic Environments. II. Infrared Dark Cloud Clumps
The Core Mass Function across Galactic Environments. II. Infrared Dark Cloud Clumps
复制标题
跨银河环境的核心质量函数。
DOI：
10.3847/1538-4357/aacb7c
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Shuo Kong
中科院分区：
文献类型：
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作者：
Mengyao Liu;J. Tan;Yu Cheng;Shuo Kong
我们使用阿塔卡马大型毫米/亚毫米阵列通过 1.3 毫米连续发射，分辨率为 ∼1 英寸，研究了 7 个红外暗云 (IRDC) 中 32 个致密团块内的核心质量函数 (CMF)。我们通过树状图算法识别出 107 个核心，中位半径约为 0.02 pc。它们的质量范围为 0.261 至 178 M⊙。应用完整性校正后，我们将组合的 IRDC CMF 与形式的幂律进行拟合，并得出 M ≥ 0.79 M⊙ 时的指数为 α ≃ 0.86 ± 0.11，M ≥ 1.26 M⊙ 时的指数为 α ≃ 0.70 ± 0.13，这是一个比 Salpeter 恒星初始质量函数指数 1.35 明显更上重的分布。我们还将这些 IRDC 簇 CMF 结果与使用类似方法导出的更进化的原星团 G286 中测量的结果进行了直接比较，在这些质量范围内分别具有 α ≃ 1.29 ± 0.19 和 1.08 ± 0.27。这些结果暗示，特别是对于完整性校正适度的 M ≥ 1.26 M⊙ 范围，与更进化的 G286 原星团的全球环境相比，IRDC 团块的高压早期环境中的 CMF 可能是头重脚轻的。然而，需要更大的岩心样本来探测这些不同的环境，以更好地确定这种潜在 CMF 变化的稳健性。
We study the core mass function (CMF) within 32 dense clumps in seven infrared dark clouds (IRDCs) with the Atacama Large Millimeter/submillimeter Array via 1.3 mm continuum emission at a resolution of ∼1″. We have identified 107 cores with the dendrogram algorithm, with a median radius of about 0.02 pc. Their masses range from 0.261 to 178 M⊙. After applying completeness corrections, we fit the combined IRDC CMF with a power law of the form and derive an index of α ≃ 0.86 ± 0.11 for M ≥ 0.79 M⊙ and α ≃ 0.70 ± 0.13 for M ≥ 1.26 M⊙, which is a significantly more top-heavy distribution than the Salpeter stellar initial mass function index of 1.35. We also make a direct comparison of these IRDC clump CMF results to those measured in the more evolved protocluster G286 derived with similar methods, which have α ≃ 1.29 ± 0.19 and 1.08 ± 0.27 in these mass ranges, respectively. These results provide a hint that, especially for the M ≥ 1.26 M⊙ range where completeness corrections are modest, the CMF in high pressure, early-stage environments of IRDC clumps may be top-heavy compared to that in the more evolved, global environment of the G286 protoclusters. However, larger samples of cores probing these different environments are needed to better establish the robustness of this potential CMF variation.