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arXiv 1602.02791astro-ph.GA
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Milky Way中分子云的统一星表

A Uniform Catalog of Molecular Clouds in the Milky Way

Thomas S. Rice, Alyssa A. Goodman, Edwin A. Bergin, Christopher Beaumont, T. M. Dame

摘要:

Dame,Hartmann,& Thaddeus(2001)的全银河系CO巡天是迄今为止最统一、最大规模的银河系CO巡天。使用树状图为基础的分解,这一调查,我们提出了一个目录的1064个大规模的分子云在整个银河系平面。这个星表包含$2.5 \times 10^8$太阳质量,或银河系估计的H $_2$质量的$25^{+10.7}_{-5.8} \%$。我们通过多个象限跟踪一些旋臂中的云。拉森第一定律的功率指数,即尺寸-线宽关系,在所有区域都是0.5-可能是由于观测偏差-但在银河系内部的云在给定尺寸下系统地具有显着(~ 30%)更高的线宽,表明它们的线宽部分由银河系环境设定。内星系与外星系的云的质量函数在定性和定量上都是不同的。内银河系的质量谱最好用截断幂律来描述,幂指数为$γ=-1.6\pm0.1$,截断质量上限为$M_0 = (1.0 \pm 0.2) \times 10^7 M_\odot$,而外银河系的质量谱最好用非截断幂律来描述,截断质量上限为$γ=-2.2\pm0.1$,这表明内银河系比外银河系能够形成和容纳更多质量的GMC。此外,我们还模拟了银河系将如何出现在CO从河外的角度来看,与其他星系的CO地图进行比较。

英文摘要:

The all-Galaxy CO survey of Dame, Hartmann, & Thaddeus (2001) is by far the most uniform, large-scale Galactic CO survey. Using a dendrogram-based decomposition of this survey, we present a catalog of 1064 massive molecular clouds throughout the Galactic plane. This catalog contains $2.5 \times 10^8$ solar masses, or $25^{+10.7}_{-5.8} \%$ of the Milky Way's estimated H$_2$ mass. We track clouds in some spiral arms through multiple quadrants. The power index of Larson's first law, the size-linewidth relation, is consistent with 0.5 in all regions - possibly due to an observational bias - but clouds in the inner Galaxy systematically have significantly (~ 30%) higher linewidths at a given size, indicating that their linewidths are set in part by Galactic environment. The mass functions of clouds in the inner Galaxy versus the outer Galaxy are both qualitatively and quantitatively distinct. The inner Galaxy mass spectrum is best described by a truncated power-law with a power index of $γ=-1.6\pm0.1$ and an upper truncation mass $M_0 = (1.0 \pm 0.2) \times 10^7 M_\odot$, while the outer Galaxy mass spectrum is better described by a non-truncating power law with $γ=-2.2\pm0.1$ and an upper mass $M_0 = (1.5 \pm 0.5) \times 10^6 M_\odot$, indicating that the inner Galaxy is able to form and host substantially more massive GMCs than the outer Galaxy. Additionally, we have simulated how the Milky Way would appear in CO from extragalactic perspectives, for comparison with CO maps of other galaxies.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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