标题： 低表面亮度盘星系的结构特征和恒星组成 显示英文标题

标题： Structural Characteristics and Stellar Composition of Low Surface Brightness Disk Galaxies

摘要： 我们提供了低表面亮度（LSB）盘星系样本的UBVI表面测光数据。 LSB盘星系可以很好地描述为指数盘，其尺度长度、中心表面亮度或旋转速度没有特定值。 事实上，尺度长度的分布与高表面亮度螺旋星系的分布无法区分，表明在表面密度的很大范围内存在动力学相似的星系（例如，具有可比Rv^2的星系）。 这些LSB星系呈现出明显的蓝色。 中心表面亮度与颜色之间完全没有相关性，排除了任何褪色情景。 同样，从HII区光谱推断出的氧丰度与颜色无关，因此低金属量不是导致蓝色颜色的主要原因。 尽管在缺乏显著恒星形成的情况下难以解释，最可能的情景是一种恒星种群，其平均年龄较年轻，源于后期形成和随后缓慢的演化。 这些特性表明，LSB盘起源于较低的初始密度，并相应地具有较晚的坍缩时间。 显示英文摘要

摘要： We present UBVI surface photometry of a sample of low surface brightness (LSB) disk galaxies. LSB disk galaxies are fairly well described as exponential disks with no preferred value for either scale length, central surface brightness, or rotational velocity. Indeed, the distribution of scale lengths is indistinguishable from that of high surface brightness spirals, indicating that dynamically similar galaxies (e.g., those with comparable Rv^2) exist over a large range in surface density. These LSB galaxies are strikingly blue. The complete lack of correlation between central surface brightness and color rules out any fading scenario. Similarly, the oxygen abundances inferred from HII region spectra are uncorrelated with color so the low metallicities are not the primary cause of the blue colors. While these are difficult to interpret in the absence of significant star formation, the most plausible scenario is a stellar population with a young mean age stemming from late formation and subsequent slow evolution. These properties suggest that LSB disks formed from low initial overdensities with correspondingly late collapse times.