标题： 蓝致密矮星系的恒星族和恒星形成特性 显示英文标题

标题： The Stellar Population and Star Formation Properties of Blue Compact Dwarf Galaxies

摘要： 我们研究了通过将Gil de Paz等(2003)的样本与斯隆数字巡天数据发布6 (SDSS DR6)交叉相关选择的一组蓝致密矮星系(BCDs)的恒星种群、恒星形成历史和恒星形成特性。该样本包括31个BCDs，它们在星系参数上覆盖了一个很大的范围。使用恒星种群合成方法，我们推导出这些BCDs的恒星种群并重建了恒星形成历史。我们的研究证实，BCDs并不是经历第一次恒星形成的年轻系统，而是正在进行恒星爆发活动的老系统。恒星质量加权年龄可以达到10 Gyr，而光度加权年龄对于大多数星系可能要年轻多达$\sim 3$个数量级($\sim 10$Myr)。基于多波长数据，我们还研究了综合恒星形成特性。我们样本星系的SFR跨度几乎达到3个数量级，从几个$10^{-3}$到$\sim1\,M_\odot$yr$^{-1}$，中位数为$\sim 0.1\, M_\odot$yr$^{-1}$。 我们发现，样本中约90%的BCDs其出生率参数（当前SFR与平均过去SFR的比值）$b>2-3$。 我们进一步讨论当前SFR与综合星系恒星质量的相关性，并探讨SFR与金属量之间的联系。 显示英文摘要

摘要： We study the stellar populations, star formation histories and star formation properties for a sample of blue compact dwarf galaxies (BCDs) selected by cross-correlating the Gil de Paz et al. (2003) sample with the Sloan Digital Sky Survey Data Release 6 (SDSS DR6). The sample includes 31 BCDs, which span a large range in galactic parameters. Using a stellar population synthesis method, we derive the stellar populations and reconstruct the star formation histories for these BCDs. Our studies confirm that BCDs are not young systems experiencing their first star formation but old systems undergoing a starburst activity. The stellar mass-weighted ages can be as old as 10 Gyr while the luminosity-weighted ages might be up to $\sim 3$ orders of magnitude younger ($\sim 10$ Myr) for most galaxies. Based on multi-wavelength data, we also study the integrated star formation properties. The SFR for our sample galaxies spans nearly 3 orders of magnitude, from a few $10^{-3}$ to $\sim1\,M_\odot$ yr$^{-1}$, with the median value of $\sim 0.1\, M_\odot$ yr$^{-1}$. We find that about 90% BCDs in our sample have their birthrate parameter (the ratio of the current SFR to the averaged past SFR) $b>2-3$. We further discuss correlations of the current SFR with the integrated galactic stellar mass and explore the connection between SFR and metallicity.