An ALMA study of hub-filament systems - I. On the clump mass concentration within the most massive cores
An ALMA study of hub-filament systems - I. On the clump mass concentration within the most massive cores
复制标题
轮毂-细丝系统的 ALMA 研究 - I. 关于最大质量核心内的团块质量集中
DOI：
10.1093/mnras/stab2674
复制
发表时间：
2021
影响因子：
4.8
通讯作者：
Anderson M
中科院分区：
文献类型：
--
作者：
Anderson M
质量从秒差距尺度的团块转移到大质量恒星形成核心背后的物理过程仍然难以捉摸。我们研究了团簇形态与最终进入其最大质量核心（MMC）的质量分数之间的关系，作为红外亮度的函数，即团簇进化示踪剂。利用阿塔卡马大型毫米/亚毫米阵（阿尔马）12 m和阿塔卡马紧凑阵，我们调查了6个红外暗枢纽在2.9 mm连续，分辨率为1.3 arcsec。为了将我们的样本置于背景中，我们还重新分析了来自29个高质量表面密度ATLASGAL源样本的已发表的阿尔马数据。我们使用HerschelandSpitzer数据表征了团块的大小、质量、形态和红外亮度。在六个新观察到的枢纽，我们确定了67个核心，并发现MMC的质量在15和911 M之间，半径为0.018-0.156 pc。每个轮毂的MMC包含3- 24%的团块质量（fMMC），一旦核心质量标准化为核心半径中值，则为5- 36%。在这35个样本中，我们发现中心和非中心系统的中位数MMC值没有显著差异，这可能是样本偏倚的结果。然而，我们发现，fMMC是107.9倍大红外暗团块相比，红外明亮的。当将我们的六个红外暗中心样本与红外亮团块进行比较时，该因子增加到14.5。我们推测，枢纽灯丝系统有效地集中质量在其MMC早期在其演变过程中。随着团块的演变，它们的质量会增加，但这种增长不会导致更大质量的MMC的形成。
The physical processes behind the transfer of mass from parsec-scale clumps to massive star-forming cores remain elusive. We investigate the relation between the clump morphology and the mass fraction that ends up in its most massive core (MMC) as a function of infrared brightness, i.e. a clump evolutionary tracer. Using Atacama Large Millimeter/submillimeter Array (ALMA) 12 m and Atacama Compact Array, we surveyed six infrared dark hubs in 2.9 mm continuum at ∼3 arcsec resolution. To put our sample into context, we also re-analysed published ALMA data from a sample of 29 high-mass surface density ATLASGAL sources. We characterize the size, mass, morphology, and infrared brightness of the clumps usingHerschelandSpitzerdata. Within the six newly observed hubs, we identify 67 cores, and find that the MMCs have masses between 15 and 911 M⊙within a radius of 0.018–0.156 pc. The MMC of each hub contains 3–24 per cent of the clump mass (fMMC), becoming 5–36 per cent once core masses are normalized to the median core radius. Across the 35 clumps, we find no significant difference in the medianfMMCvalues of hub and non-hub systems, likely the consequence of a sample bias. However, we find thatfMMCis ∼7.9 times larger for infrared dark clumps compared to infrared bright ones. This factor increases up to ∼14.5 when comparing our sample of six infrared dark hubs to infrared bright clumps. We speculate that hub-filament systems efficiently concentrate mass within their MMC early on during its evolution. As clumps evolve, they grow in mass, but such growth does not lead to the formation of more massive MMCs.