arXiv 2004.029062020-04-06astro-ph.GAastro-ph.SR

银河系球状星团恒星质量函数的新认识

New Insight into the stellar mass function of Galactic globular clusters

H. Ebrahimi, A. Sollima, H. Haghi, H. Baumgardt, M. Hilker

备注：: 19 pages, 13 figures, accepted for publication by MNRAS
DOI：: 10.1093/mnras/staa969

摘要：

本文给出了32个银河系球状星团深测光数据的分析结果。我们分析了用哈勃太空望远镜高级巡天相机的宽视场通道观察到的69张平行视场图像，这些图像补充了覆盖这些星系团中心区域的球状星团金库项目中已有的测光方法。这一前所未有的数据集已被用来计算不同质量的恒星在这些星团中的相对比例（即现今的质量函数），方法是将观测到的恒星沿星团主序星和分析视场的分布与多质量动力学模型的预测进行比较。对于一个子样本的31个集群，我们也能够获得半质量半径，质光比和质量分数的黑暗遗迹使用现有的径向速度信息。我们发现，大多数球状星团具有单一的幂律质量函数$F(m) \propto m^α$与斜率$α>-1$的质量范围$0.2<m/\text{M}_{\odot}<0.8$。通过探索的结构/动力学和轨道参数之间的相关性，我们确认的质量函数的斜率和半质量弛豫时间之间的紧密联系已经在以前的工作中报道，和可能的二阶依赖于集群金属丰度。这可能表明初始条件和演化效应对现今质量函数形状的相对重要性。

英文摘要：

We present the results of the analysis of deep photometric data of 32 Galactic globular clusters. We analysed 69 parallel field images observed with the Wide Field Channel of the Advanced Camera for Surveys of the Hubble Space Telescope which complemented the already available photometry from the globular cluster treasury project covering the central regions of these clusters. This unprecedented data set has been used to calculate the relative fraction of stars at different masses (i.e. the present-day mass function) in these clusters by comparing the observed distribution of stars along the cluster main sequence and across the analysed field of view with the prediction of multimass dynamical models. For a subsample of 31 clusters, we were able to obtain also the half-mass radii, mass-to-light ratios and the mass fraction of dark remnants using available radial velocity information. We found that the majority of globular clusters have single power law mass functions $F(m) \propto m^α$ with slopes $α>-1$ in the mass range $0.2<m/\text{M}_{\odot}<0.8$. By exploring the correlations between the structural/dynamical and orbital parameters, we confirm the tight anticorrelation between the mass function slopes and the half-mass relaxation times already reported in previous works, and possible second-order dependence on the cluster metallicity. This might indicate the relative importance of both initial conditions and evolutionary effects on the present-day shape of the mass function.

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。

摘要：

英文摘要：

相关论文