arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 2401.01028astro-ph.GA
收藏

矮透镜状星系的恒星形成历史

Star Formation Histories of Dwarf Lenticular Galaxies

Hong Bae Ann, Mira Seo

AI总结:

本文利用SDSS光谱重建148个矮透镜状星系的恒星形成历史,发现其经历约60亿年前和10亿年前两个主要恒星形成时期,且与矮椭圆星系相似,提示二者可能具有共同的非原初起源。

摘要:

恒星形成历史(SFHs)对于理解星系的形成与演化至关重要。我们基于斯隆数字巡天(SDSS)光谱,给出了148个矮透镜状星系(dS0s)的平均恒星形成历史。这些恒星形成历史揭示了两个不同的活跃恒星形成时期。第一个时期大约在60亿年前结束,主要形成了年老、贫金属(Z=0.0004)的恒星,约占恒星质量的60%和光度的30%。极端贫金属(Z=0.0001)恒星的稀缺表明在再电离时期存在预先增丰。恒星形成在这一初始阶段逐渐减弱。相比之下,第二个时期大约在10亿年前结束,在该时期中期出现了一个峰值,促成了具有中等金属丰度的中等年龄恒星族的形成。dS0星系的恒星形成历史显示出对恒星质量的明显依赖,质量更大的dS0更早形成恒星。但是,我们发现与外部旋臂和核化等形态学性质没有显著相关性。dS0星系的恒星形成历史与dE星系有许多相似之处,表明它们可能具有共同的起源,且大多并非原初起源。

英文摘要:

Star formation histories (SFHs) are essential for understanding galaxy formation and evolution. We present the mean SFHs of 148 dwarf lenticular galaxies (dS0s) derived from the Sloan Digital Sky Survey (SDSS) spectra. These SFHs reveal two distinct periods of active star formation. The first period, concluding approximately 6 Gyr ago, witnessed the formation of predominantly old, metal-poor (Z=0.0004) stars, accounting for approximately 60\% of the stellar mass and 30\% of the luminosity. The scarcity of extremely metal-poor (Z=0.0001) stars suggests pre-enrichment during the re-ionization era. Star formation gradually waned during this initial phase. In contrast, the second period, ending around 1 Gyr ago, exhibited a peak in the middle of the period, contributing to the formation of moderately old stellar populations with intermediate metallicity. The SFHs of dS0 galaxies show a clear dependence on stellar mass, with more massive dS0s forming stars earlier. But, we find no significant correlation with morphological properties such as outer spiral arms and nucleation. The SFHs of dS0 galaxies share many similarities with those of dE galaxies, suggesting a common origin, mostly not primordial.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑