The Stellar Content of 10 Dwarf Irregular Galaxies
The Stellar Content of 10 Dwarf Irregular Galaxies
复制标题
10 个矮不规则星系的恒星含量
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
U. Hopp
中科院分区：
文献类型：
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作者：
R. Schulte;U. Hopp
我们讨论了已分解恒星的形态、色等图和频率，以及电离气体的形态，以及未分解恒星的表面亮度分布和基本光分布的颜色。我们指出，在所研究的星系中，有一半的星系存在H II区和年轻的星团，这些星团位于已分解恒星的主体之外。这似乎与自传播恒星形成的假说相冲突。所有的样本星系都有H II区和年轻的大质量恒星，年龄从几个Myr到大约10 Myr。对于年龄超过50英里的超巨星来说，不完全已经是单星光度测量中的一个问题。然而，我们也可以从未分辨恒星的综合颜色中洞察恒星的内容。未分解恒星的光分布比已分解恒星的分布更广，形状更规则、更椭圆形。我们提供了样本星系的椭圆度、中心表面亮度和尺度长度。背景光的颜色表明了样本星系的一系列恒星形成历史，其中一个极端的星系颜色由古老的、缺乏金属的人群主导，而另一个极端则由最近的恒星诞生事件主导。这些结果提供了对孤立的晚类型星系的恒星含量和恒星形成历史的洞察。
We discuss the morphologies, color-magnitude diagrams, and frequencies of the resolved stars together with the morphology of the ionized gas, as well as the surface brightness profiles and colors of the underlying light distributions of unresolved stars. We point out the occurrence in half of the galaxies studied of H II regions and young stellar associations located well outside of the main body of resolved stars. This appears to be in conflict with the hypothesis of self-propagating star formation. All of the sample galaxies contain H II regions and young massive stars with ages of a few Myr to around 10 Myr. For supergiants beyond an age of about 50 Myr, incompleteness is already a problem in the single-star photometry. However, we can also gain insight into the stellar content from the integrated colors of the unresolved stars. The light distribution of the unresolved stars is more extended than that of the resolved stars and is of a more regular and elliptical shape. We provide ellipticities, central surface brightnesses and scale lengths for the sample galaxies. The background-light colors indicate a range of star formation histories for the sample galaxies, with galaxy colors at one extreme being dominated by the old, metal-poor population and at the other extreme by the most recent star-birth event. The results provide insight into the stellar content and the star formation histories of isolated, late-type galaxies.