蓝致密星系谱的星族合成  

Stellar Population Synthesis for the Spectra of Blue Compact Galaxies

作　　者：孔旭[1,2] 程福臻[1,2] 

机构地区：[1]中国科学技术大学天体物理中心 [2]中国科学院陕西天文台

出　　处：《天体物理学报》1998年第1期1-10,共10页

基　　金：国家自然科学基金

摘　　要：利用星团谱样本的星族合成方法，分析了四个蓝致密星系（ＢｌｕｅＣｏｍｐａｃｔＧａｌａｘｉｅｓ，ＢＣＧ）的光学谱．给出了在各个ＢＣＧ中，年龄和金属丰度不同的星族对星系５８７ｎｍ处连续谱流量贡献的比率，同时还给出ＢＣＧ内部恒星演化的历史和星系内部的红化值．通过对星系内部星族及光谱的分析，解决了ＢＣＧ研究中存在的这类星系年龄和其内部光学不可见物质等问题．结果表明ＢＣＧ是年老星系，其内部恒星形成过程为长时间的宁静相上叠加有短暂且剧烈恒星形成的爆发，其内部存在光学不可见物质，且至少有一部分为年老的球状星团；根据由光学连续谱和发射线计算星系的内红化值的不同，得出ＢＣＧ星系内部尘埃对连续谱和发射线的产生区遮挡程度不同．In order to study the optical spectra of four blue compact galaxies(BCG), we applied the population synthesis method based on a grid of star cluster spectra. This method allows us to determine the visible flux fraction from stellar components of different ages and metallicities,providing a direct estimate of the star formation history and the internal reddening of these BCGs. By analyzing the interior stellar component and its spectra. we solved two questions concerning BCGs, i.e. the age of BCGs and the question of the presence of an optically unseen mass component. It suggests that BCGs are old galaxies in which star formation occurs during short periods of strong activity separated by long quiescent phases. There are some unseen mass components in the BCGs, at least some of the unseen mass is due to old population. The amount of internal reddening is significantly smaller than the values derived from the Balmer decrement for the same object. This difference can be better understood if the stellar population and the ionized gas are not co spatial. A model of foreground clump dust, with different covering factors for the gas and the stars, is proposed to account for the difference in reddening.

关 键 词：星暴 蓝致密星系 红化 星族合成 

分 类 号：P145.3[天文地球—天体物理]