DENSE CORE PROPERTIES IN THE INFRARED DARK CLOUD G14.225-0.506 REVEALED BY ALMA
DENSE CORE PROPERTIES IN THE INFRARED DARK CLOUD G14.225-0.506 REVEALED BY ALMA
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DOI：
10.3847/1538-4357/833/2/209
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发表时间：
2016-10
期刊：
影响因子：
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通讯作者：
S. Ohashi;P. Sanhueza;H. Chen;Qizhou Zhang;G. Busquet;F. Nakamura;A. Palau;K. Tatematsu
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文献类型：
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作者：
S. Ohashi;P. Sanhueza;H. Chen;Qizhou Zhang;G. Busquet;F. Nakamura;A. Palau;K. Tatematsu
我们使用阿塔卡马大型毫米/亚毫米阵列 (ALMA) 以 3 毫米连续发射对红外暗云 G14.225-0.506 进行了密集核心调查。该调查涵盖了角分辨率为 (∼0.03 pc) 的两个轮毂-灯丝系统。我们确定了 48 个致密核心。 48 个核心中的 20 个是原恒星，因为它们与年轻恒星物体 (YSO) 和/或 X 射线点源有关，而其他 28 个核心可能是前恒星，与已知的红外或 X 射线发射无关。使用 APEX 870 μm 连续发射，我们还确定了托管这些核心的 18 个团块。通过使用 ALMA N2H+ 和 VLA/Effelsberg NH3 分子系数据进行维里分析，我们发现维里参数随着尺度从细丝到团块、再到核心的减小而呈下降趋势。岩心的维里参数为 0.1-1.3，表明岩心可能正在经历动力塌陷。星前核心候选者的累积核心质量函数的幂律指数为 ，质量范围为 1.5 到 22 。我们没有发现巨大的前恒星或原恒星核心。之前的研究表明该区域尚未产生大质量的O型恒星。因此，大质量恒星应该是通过从周围介质中吸积大量气体而在恒星核心中形成的。另一种可能性是，低质量的 YSO 通过从由细丝供给的母核中吸积而变得巨大。这两种可能性可能与全球等级制度崩溃的情况一致。
We have performed a dense core survey toward the Infrared Dark Cloud G14.225-0.506 at 3 mm continuum emission with the Atacama Large Millimeter/Submillimeter Array (ALMA). This survey covers the two hub-filament systems with an angular resolution of (∼0.03 pc). We identified 48 dense cores. 20 out of the 48 cores are protostellar due to their association with young stellar objects (YSOs) and/or X-ray point-sources, while the other 28 cores are likely prestellar and unrelated with known IR or X-ray emission. Using APEX 870 μm continuum emission, we also identified the 18 clumps hosting these cores. Through virial analysis using the ALMA N2H+ and VLA/Effelsberg NH3 molecular line data, we found a decreasing trend in the virial parameter with decreasing scales from filaments to clumps, and then to cores. The virial parameters of 0.1–1.3 in cores indicate that cores are likely undergoing dynamical collapse. The cumulative core mass function for the prestellar core candidates has a power law index of , with masses ranging from 1.5 to 22 . We find no massive prestellar or protostellar cores. Previous studies suggest that massive O-type stars have not been produced yet in this region. Therefore, high-mass stars should be formed in the prestellar cores by accreting a significant amount of gas from the surrounding medium. Another possibility is that low-mass YSOs become massive by accreting from their parent cores that are fed by filaments. These two possibilities might be consistent with the scenario of global hierarchical collapse.