Formation and Evolution of Elliptical Galaxies and Globular Cluster Systems

我们通过分析椭圆星系及其周围的恒星星族和热X射线气体的性质，以及星系周围球状星团系统的特征，研究了椭圆星系的形成和演化。1首先，我们建立了一个新的化学和光谱演化模型，适用于任何星星形成历史的星系。2将该模型应用于Virgo星系团中椭圆星系周围球状星团的光度和色函数，发现这些球状星团形成于12-18 Gyr前，形成时间为2-3 Gyr。2其次，我们整理了射电选择椭圆星系的光谱能量分布数据，发现z ≥ 2的星系有明显的大尺度星星形成的证据，而较近的星系则没有。4.我们拍摄了28个旋涡星系球的光谱，令人信服地证明了球的光度-金属丰度关系与椭圆星系的光度-金属丰度关系是一致的。2-4强烈地表明椭圆形气体形成 ...更多信息 在宇宙演化的早期，原星系坍缩和耗散星星的形成主导了松弛期。[5]椭圆星系周围的热X射线气体的铁丰度应该至少等于甚至大于椭圆星系的平均恒星铁丰度，然而我们用ASCA X射线卫星获得的铁丰度要低得多。本文根据我们的天体物理学知识，通过详细的调查，得出结论：用于数据处理的等离子体程序中，铁L线的基本原子物理数据一定有问题。[6]通过正确使用太阳陨石铁丰度，我们重新估算了团内介质中元素的相对丰度比，发现ICM中铁的起源应该主要是Ia型超新星，而不是II型超新星，这与最近文献中的说法相反。5-6从化学进化的角度对2-4的结论给予了进一步的支持。最后，我们认为直接探测星星形成时期的椭圆星系是非常重要的，而在CO光度峰处的探测效果最好。7为了将CO光度的演化纳入我们的模型，我们研究了盘星系中CO和HI气体的空间分布，得到了CO到H_2分子的转换因子，它与气体金属丰度成反比。这一新的认识可以应用于我们下一步的CO射电观测寻找形成椭圆星系的星星。少

We have studied the formation and evolution of elliptical galaxies by analysing the nature of stellar populations and the hot X-ray gas in and around elliptical galaxies as well as the characteristics of globular cluster systems around galaxies. 1 First, we have built a new chemical and spectral evolution model for galaxies of any star formation history. 2 By appling this model to the luminosity and color function of globular clusters around elliptical galaxies in Virgo cluster, we find that these cluster formed about 12-18 Gyrs ago in 2-3 Gyrs. 2 Next, we have compiled the spectral energy distribution data of radio-selected elliptical galaxies, and find that galaxies at z >= 2 show a conspicuous evidence for large scale star formation, while those nearer do not. 4 We have taken spectra of 28 bulges of spiral galaxies and convincingly show that the luminosity-metallicity relation of bulges is identical to that of elliptical galaxies. 2-4 strongly suggest that formation of elliptical ga … More laxies was dominated by protogalactic collapse and dissipational star formation early in the evolution of the universe. 5 The iron abundance of the hot X-ray gas around elliptical galaxies should be at least equal to or even more than the mean stellar iron abundance of ellipticals, and yet we have obtained much lower iron abundances by using ASCA X-ray satelite. Through a detailed investigation based on our knowledges on astrophysics, we reach to a conclusion that there must be something wrong in the fundamental atomic physics data of iron L-lines in the plasma code used for data reduction. 6 We have carefully re-estimated the relative abundance ratios of elements in the intracluster medium, by correctly using the solar meteoritic iron abundance, and find that the origin of iron in the ICM should be mainly in type Ia supernovae and not in type II,contrary to the recent claims in the literature. 5-6 give another support from chemical evolution approach to the conclusion reached by 2-4. Finally, we believe it is of prime importance to detect directly elliptical galaxies at star formation epoch, which could be best detected in CO luminosity peak. 7 To involve the evolution of CO luminosity in our model, we study the spatial distribution of CO and HI gas in disk galaxies and obtain the conversion factor from CO to H2 molecules that is inversely proportinal to the gas metallicity. This new knowledge could be applied to our next step for a search of star forming ellipticals by CO radio observation. Less