发表机构
University of Toledo; The Johns Hopkins University; University of Wyoming; Space Telescope Science Institute; Université Côte d’Azur; Observatoire de la Côte d’Azur; Laboratoire Lagrange; University of Cambridge; University of Michigan（托莱多大学; 约翰斯·霍普金斯大学; 怀俄明大学; 太空望远镜科学研究所; 蔚蓝海岸大学; 蔚蓝海岸天文台; 拉格朗日实验室; 剑桥大学; 密歇根大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
基于PHANGS巡天中38个旋涡星系的逾1.5万个星团，发现星团质量函数（幂律指数约-1.9）和年龄分布（幂律指数约-0.83）几乎不依赖于星系性质，表明早期存在与质量无关的强瓦解过程。
AI 中文摘要
我们展示了迄今为止对近邻星系中星团质量与年龄分布的最大规模研究。该分析基于PHANGS-HST巡天中38个旋涡星系内超过15,000个（36,000个）由人工（机器）分类的致密星团的统一选择目录，并采用了改进的光度SED年龄测定法，以缓解与红化和金属丰度相关的关键简并问题。这些星系在恒星形成率（SFR）及其恒星形成和分子气体的面密度（Sigma_SFR, Sigma_H2）上跨越约100倍的范围，并涵盖了广泛的形态类型。我们发现星团质量函数可很好地用幂律dN/dM ~ M^beta描述，其中beta=-1.9 ± 0.2，且该形状在我们样本中的所有星系及八个具有相似SFR的星系复合组中 remarkably 相似，与SFR、Sigma_SFR或Sigma_H2无显著依赖关系。星团年龄分布急剧下降，可用dN/dt ~ t^gamma描述，其中gamma=-0.83 ± 0.24，同样与宿主星系性质或星团质量几乎无关。质量与年龄分布的独立性意味着可分离的联合分布g(M,t) ~ M^beta t^gamma，并表明旋涡盘中的星团族群在其最初约十亿年内受强烈的、与质量无关的瓦解过程主导。这些结果为解释不同星系环境中的星团族群特征建立了基准，并为高红移年轻星团族群的研究提供了背景。
英文摘要
We present the largest study to date of star cluster mass and age distributions in nearby galaxies. The analysis is based on a uniformly selected catalog of over 15,000 (36,000) human (machine) classified compact clusters across 38 spiral galaxies in the PHANGS-HST survey, with improved photometric SED age dating that mitigates key degeneracies with reddening and metallicity. The galaxies span a factor of ~100 in star formation rate (SFR) and in their surface density of star formation and molecular gas (Sigma_SFR, Sigma_H2), and cover a broad range of morphologies. We find that cluster mass functions are well described by a power law, dN/dM ~ M^beta, with beta=-1.9 +/- 0.2, and that this shape is remarkably similar across all galaxies in our sample and eight composite groups of galaxies with similar SFRs, with no significant dependence on SFR, Sigma_SFR}, or Sigma_H2. Cluster age distributions decline steeply and can be described by dN/dt ~ t^gamma with gamma=-0.83 +/- 0.24, again with little dependence on host-galaxy properties or cluster mass. The independence of the mass and age distributions implies a separable joint distribution, g(M,t) ~ M^beta t^gamma, and suggests that cluster populations in spiral disks are dominated by strong, mass-independent dissolution over their first ~Gyr. These results establish a benchmark for interpreting cluster demographics across diverse galactic environments and provide context for studies of young cluster populations at high redshift.
Journal refPublished in the Astrophysical Journal 2026, Volume 1008, page 261
