SEDIGISM-ATLASGAL: dense gas fraction and star formation efficiency across the Galactic disc
SEDIGISM-ATLASGAL: dense gas fraction and star formation efficiency across the Galactic disc
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DOI：
10.1093/mnras/staa2512
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发表时间：
2020-09
影响因子：
4.8
通讯作者：
J. Urquhart;C. Figura;J. Cross;M. Wells;T. Moore;D. Eden;S. Ragan;A. Pettitt;A. Duarte-Cabral-A.-D
中科院分区：
文献类型：
--
作者：
J. Urquhart;C. Figura;J. Cross;M. Wells;T. Moore;D. Eden;S. Ragan;A. Pettitt;A. Duarte-Cabral-A.-D
通过结合覆盖银河盘中大部分分子物质的两项调查，我们研究了旋臂在恒星形成过程中所起的作用。我们将APEX望远镜大面积探测到的星团与其母星系巨型分子云(GMC)进行了匹配，并利用这些GMC质量、测热光度和同时发表的一篇论文中获得的积分星团质量来估计稠密气体分数(DGFGMC=∑mCump/mGmc)和瞬时恒星形成效率(SfEgmc=∑lclump/mgmc)。我们发现，与ATLASGAL团块有关的分子物质集中在旋臂上(∼60%分布在旋臂的±10$\rM，S)。我们已经寻找了这些物理参数的值相对于它们与螺旋臂的接近程度的变化，但没有发现任何可能归因于螺旋臂的增强的证据。基于不同调查的许多类似研究的综合结果表明，虽然螺旋臂位置在云形成和HI到H2的转化中起作用，但随后的恒星形成过程似乎更多地依赖于局部环境效应。这使我们得出结论，向旋臂方向看到的恒星形成活动的增强是源拥挤的结果，而不是任何物理过程的结果。
By combining two surveys covering a large fraction of the molecular material in the Galactic disc, we investigate the role spiral arms play in the star formation process. We have matched clumps identified by APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) with their parental giant molecular clouds (GMCs) as identified by SEDIGISM, and use these GMC masses, the bolometric luminosities, and integrated clump masses obtained in a concurrent paper to estimate the dense gas fractions (DGFgmc = ∑Mclump/Mgmc) and the instantaneous star formation efficiencies (i.e. SFEgmc = ∑Lclump/Mgmc). We find that the molecular material associated with ATLASGAL clumps is concentrated in the spiral arms (∼60 per cent found within ±10 $\rm {km\,s}^{-1}$ of an arm). We have searched for variations in the values of these physical parameters with respect to their proximity to the spiral arms, but find no evidence for any enhancement that might be attributable to the spiral arms. The combined results from a number of similar studies based on different surveys indicate that, while spiral-arm location plays a role in cloud formation and H i to H2 conversion, the subsequent star formation processes appear to depend more on local environment effects. This leads us to conclude that the enhanced star formation activity seen towards the spiral arms is the result of source crowding rather than the consequence of any physical process.