论文标题
四个银河系GMC中的星形 - 天然气密度关系：恒星反馈的影响
The Star Formation-Gas Density Relation in Four Galactic GMCs: Effects of Stellar Feedback
论文作者
论文摘要
我们介绍了j = 2-1发射CO和$^{13} $ CO的4个银河巨型分子云（GMC）的地图。我们使用LTE分析来得出CO激发温度和色谱柱密度的地图以及总分子气柱密度的分布，即$σ_{gas} $。通过与Lewis等人的结果近似，通过冷冻到冷尘晶粒对CO的耗竭来解释。 （2021）源自{\ it herschel}的Far-ir观测值。年轻恒星物体（YSO）的表面密度是从已发布的目录中获得的。平均YSO表面密度表现出对$σ_{gas} $的幂律依赖性，指数为0.9至1.9。气柱密度概率分布函数（PDFS）显示延伸到高柱密度的幂律尾巴。 Sonic Mach数字，$ M_S $的分布在3 gmcs的$ m_s \ sim 5-8 $中得到了高峰；四分之一的分布最高为$ m_s = 30 $，这可能是多个OB恒星反馈效果的结果。 Pokhrel等人的方法论的分析。 （2021）发现我们的GMC样本显示了比Pokhrel等人所发现的较浅的幂律关系。 （2021）对于恒星形成率与$ <σ_{gas}> $和vs. $ <σ_{gas}>/t_ {ff} $在不同的云样本中。我们讨论了恒星形成云的两个样本的可能差异，以及恒星反馈对气体密度与恒星形成速率之间关系的影响。
We present maps of 4 galactic giant molecular clouds (GMCs) in the J=2-1 emission of both CO and $^{13}$CO. We use an LTE analysis to derive maps of the CO excitation temperature and column density and the distribution of total molecular gas column density, $Σ_{gas}$. The depletion of CO by freeze-out onto cold dust grains is accounted for by an approximation to the results of Lewis et al. (2021) which were derived from far-IR observations with {\it Herschel}. The surface density of young stellar objects (YSOs) is obtained from published catalogs. The mean YSO surface density exhibits a power-law dependence on $Σ_{gas}$, with exponents in the range 0.9 to 1.9. Gas column density probability distribution functions (PDFs) show power-law tails extending to high column densities. The distributions of sonic Mach number, $M_S$ are sharply peaked at $M_S \sim 5 - 8$ for 3 GMCs; a fourth has a broad distribution up to $M_S =30$, possibly a result of feedback effects from multiple OB stars. An analysis following the methodology of Pokhrel et al. (2021) finds that our sample of GMCs shows power-law relations that are somewhat shallower than found by Pokhrel et al. (2021) for the star formation rate vs. $<Σ_{gas}>$ and vs. $<Σ_{gas}>/t_{ff}$ in a different sample of clouds. We discuss possible differences in the two samples of star-forming clouds and the effects of stellar feedback on the relation between gas density and star formation rate.
