The Structure of the Super-Star Clusters in NGC 1569 from Hubble Space Telescope WFPC2 Images
The Structure of the Super-Star Clusters in NGC 1569 from Hubble Space Telescope WFPC2 Images
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哈勃太空望远镜 WFPC2 图像中 NGC 1569 中超级星团的结构
DOI：
10.1086/310579
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
M. Tosi
中科院分区：
文献类型：
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作者：
G. de Marchi;M. Clampin;L. Greggio;C. Leitherer;A. Nota;M. Tosi
我们提出了高分辨率的观测超星团在附近的不规则星系NGC 1569，获得了与WFPC 2上的哈勃太空望远镜。我们的分析表明，这些星系团中最明亮的NGC 1569 A是由两个角间距为~0.″2的星系团叠加而成的。最近的地基光谱显示，红超巨星和沃尔夫-拉叶星都与NGC 1569 A有关。根据目前的演化模型，这一发现需要在同一个星团中共存两个非同时代的恒星种群。我们发现NGC 1569 A是双重简化的解释，因为红超巨星和沃尔夫-拉叶星可能属于不同的星团。我们得出的三个集群的半光半径为1.6-1.8 pc，小于以前的HST观测所示。这些超星系团中最明亮的星系团的大小、质量和光度证实了这些天体可能是年轻的球状星团，从而强化了先前的结论。
We present high-resolution observations of the super-star clusters in the nearby irregular galaxy NGC 1569, obtained with the WFPC2 on board the Hubble Space Telescope. Our analysis shows that the brightest of these clusters, NGC 1569A, results from the superposition of two clusters with an angular separation of ~0.″2. Recent ground-based spectroscopy revealed that both red supergiant and Wolf-Rayet stars are associated with NGC 1569A. According to current evolutionary models, this finding requires the coexistence of two noncoeval stellar populations within the same cluster. Our discovery that NGC 1569A is double simplifies the interpretation, since red supergiants and Wolf-Rayet stars may belong to different clusters. We derive for the three clusters half-light radii of ~1.6-1.8 pc, smaller than indicated by previous HST observations. The size, mass, and luminosity of the brightest of these superclusters confirm that these objects could be young globulars, reinforcing previous conclusions.