Massive (?) starburst hosts of blue compact galaxies (BCGs) - Optical/near-IR observations of 4 BCGs and their companions
Massive (?) starburst hosts of blue compact galaxies (BCGs) - Optical/near-IR observations of 4 BCGs and their companions
复制标题
蓝色致密星系 (BCG) 的大质量（？）星暴宿主 - 4 个 BCG 及其伴星的光学/近红外观测
DOI：
10.1051/0004-6361:20020759
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发表时间：
2002
影响因子：
6.5
通讯作者：
G. Ostlin
中科院分区：
文献类型：
--
作者：
N. Bergvall;G. Ostlin
我们展示了 4 个发光贫金属蓝色致密星系 (BCG) 及其两个伴星系的光谱学和深光学/近红外光度测定。借助光谱演化模型（SEM）和表面光度测量得出的结构参数，我们讨论了星系中心星暴和晕群的特性。特别关注灰尘、化学不均匀性和星云发射污染对晕光的影响。光学/近红外颜色指数分布显示星暴和主体之间存在明显区别。宿主具有大质量椭圆形的光度剖面特征和显着的红色，这是典型的相对富含金属的老年恒星群的特征。这些特性与相对较低的光度相冲突。如果宿主具有异常大量的暗物质，可以阻碍金属从系统中流出，那么这种情况就可以得到最好的解释。光环和年轻星暴之间所显示的金属丰度的差异反驳了反复爆发的情况，并支持了两个群体的不同起源。我们得出的结论是，这些 BCG 正在经历早期型星系/厚盘与富含气体的星系或星系际 HI 云之间的合并，在许多方面让人想起大质量椭圆星系的延迟形成。
We present optical spectroscopy and deep optical/near-IR photometry of 4 luminous metal-poor blue compact galax- ies (BCGs) and two of their companions. With the aid of spectral evolutionary models (SEMs) and structural parameters derived from the surface photometry we discuss the properties of the central starbursts and the halo populations of the galaxies. Special attention is paid to the eects of dust, chemical inhomogeneities and contamination of nebular emission to the halo light. The optical/near-IR colour index profiles show a sharp distinction between the starburst and the host. The hosts have luminosity profiles characteristic of massive ellipticals and remarkably red colours, typical of a relatively metal-rich stellar population of old age. These properties are in conflict with the relatively low luminosities. The situation can best be explained if the hosts have an unusually large amount of dark matter that can hinder the outflow of metals from the system.The indicated dierence in metallicity between the halo and the young starburst disproves the recurrent burst scenario and supports dierent origins of the two populations. We conclude that these BCGs are undergoing mergers between early type galaxies/thick disks and gas-rich galaxies or intergalactic HI clouds, in many respects reminiscent of a retarded formation of massive ellipticals.