论文标题
附近六个星系中巨型分子云和年轻星团的质量功能
Mass Functions of Giant Molecular Clouds and Young Star Clusters in Six Nearby Galaxies
论文作者
论文摘要
我们比较了六个星系中的年轻明星簇（年龄$ \ leq 10 $ MYR）和巨型分子云（GMC）的质量功能，这些星系涵盖了质量，金属性和星形形成率（LMC，M83，M51，M51，NGC 3627，Antennae和NGC 3256）。我们对两个种群执行Schechter函数的最大可能拟合，$ψ（M）= Dn/dm \ Propto m^β\ Exp（-m/m _*）$。我们发现，样本中的大多数GMC和群集质量功能与纯幂律分布一致（$ m_* \ rightarrow \ infty $）。 M51是唯一显示两个人群中截止截止值（$ m _*$）的证据的星系。因此，GMC和集群种群中的物理上部质量截止可能是例外，而不是规则。当我们执行PowerLaw拟合时，我们找到了一系列索引$β_ {\ rm pl} = - 2.3 \ pm0.3 $，对于我们的GMC样本，对于群集样本，$β_{\ rm pl} = - 2.0 \ pm0.3 $。这个结果是，$β_ {\ rm簇} \大约β_ {\ rm gmc} \ of -2 $，与群集形成的理论预测一致，并表明恒星形态效率在很大程度上与GMC中的质量无关。
We compare the mass functions of young star clusters (ages $\leq 10$ Myr) and giant molecular clouds (GMCs) in six galaxies that cover a large range in mass, metallicity, and star formation rate (LMC, M83, M51, NGC 3627, the Antennae, and NGC 3256). We perform maximum-likelihood fits of the Schechter function, $ψ(M) = dN/dM \propto M^β \exp(-M/M_*)$, to both populations. We find that most of the GMC and cluster mass functions in our sample are consistent with a pure power-law distribution ($M_* \rightarrow \infty$). M51 is the only galaxy that shows some evidence for an upper cutoff ($M_*$) in both populations. Therefore, physical upper mass cutoffs in populations of both GMCs and clusters may be the exception rather than the rule. When we perform power-law fits, we find a range of indices $β_{\rm PL}=-2.3\pm0.3$ for our GMC sample and $β_{\rm PL}=-2.0\pm0.3$ for the cluster sample. This result, that $β_{\rm Clusters} \approx β_{\rm GMC} \approx -2$, is consistent with theoretical predictions for cluster formation and suggests that the star-formation efficiency is largely independent of mass in the GMCs.
