Probing the role of the galactic environment in the formation of stellar clusters, using M83 as a test bench
Probing the role of the galactic environment in the formation of stellar clusters, using M83 as a test bench
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DOI：
10.1093/mnras/stv1203
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发表时间：
2015-09-01
影响因子：
4.8
通讯作者：
Ryon, J.
中科院分区：
文献类型：
--
作者：
Adamo, A.;Kruijssen, J. M. D.;Ryon, J.
我们提出了一个研究的M83集群人口，覆盖盘的星系半径之间的0.45和4.5千秒差距。我们的目标是探索集群人口的属性作为一个函数的距离银河系中心。我们观察到星系团形成效率（Gamma，即在束缚星系团中发生的星星形成量）从内部区域的26%下降到星系外部的8%。在M83的不同区域内恢复的伽马值遵循相同的伽马与整个星系观测到的星星形成率密度关系。我们还探讨了初始集群质量函数（ICMF）作为银河距离的函数。我们观察到，在M83的外部区域（从-1.90 +/- 0.11到-2.70 +/- 0.14）和整个星系团（斜率为-2.18 +/- 0.07）的ICMF显著变陡。我们表明，这种变化的斜率反映了一个更根本的变化的“截断质量”的高质量端的分布。这可以用一个斜率为-2的Schechter函数来模拟，其指数截止质量（M-c）从内部区域到外部区域显著减小（从4.00到0.25 x 10（5）M圆点），而银河系M-c近似为1.60 x 10（5）M圆点。伽马和ICMF的趋势与观察到的σ（H-2）径向降低一致，因此与气体压力一致。随着气体压力下降，团簇形成的效率变得较低。我们的结论是，宿主星系环境似乎调节（1）锁定在星团中的恒星比例和（2）ICMF的质量上限，一致地描述了一个接近普遍的斜率-2截断在高质量端。
We present a study of the M83 cluster population, covering the disc of the galaxy between radii of 0.45 and 4.5 kpc. We aim to probe the properties of the cluster population as a function of distance from the galactic centre. We observe a net decline in cluster formation efficiency (Gamma, i.e. amount of star formation happening in bound clusters) from about 26 per cent in the inner region to 8 per cent in the outer part of the galaxy. The recovered Gamma values within different regions of M83 follow the same Gamma versus star formation rate density relation observed for entire galaxies. We also probe the initial cluster mass function (ICMF) as a function of galactocentric distance. We observe a significant steepening of the ICMF in the outer regions (from -1.90 +/- 0.11 to -2.70 +/- 0.14) and for the whole galactic cluster population (slope of -2.18 +/- 0.07) of M83. We show that this change of slope reflects a more fundamental change of the 'truncation mass' at the high-mass end of the distribution. This can be modelled as a Schechter function of slope -2 with an exponential cutoff mass (M-c) that decreases significantly from the inner to the outer regions (from 4.00 to 0.25 x 10(5) M-circle dot) while the galactic M-c is approximate to 1.60 x 10(5) M-circle dot. The trends in Gamma and ICMF are consistent with the observed radial decrease of the Sigma (H-2), hence in gas pressure. As gas pressure declines, cluster formation becomes less efficient. We conclude that the host galaxy environment appears to regulate (1) the fraction of stars locked in clusters and (2) the upper mass limit of the ICMF, consistently described by a near-universal slope -2 truncated at the high-mass end.