高红移大质量早型星系的形成及演化

发布时间：2018-01-16 01:16

本文关键词：高红移大质量早型星系的形成及演化　出处：《中国科学技术大学》2012年博士论文　论文类型：学位论文

【摘要】：在该论文中,我将介绍我在中国科学技术大学(USTC)及意大利国际研究生院(SISSA)以联合培养学生的身份攻读博士学位期间在星系形成领域得到的-些研究成果。研究的方向主要集中在高红移早型星系(ETGs)的形成及演化。近10年来,高红移星系形成及演化问题得到了越来越多的关注。最近的观测证据表明,类星体(QSOs)的形成及演化与高红移星系的形成及演化存在严格地联系。人们发展了两种常用的方法去研究星系形成。一种是利用半解析模型；另一种是数值模拟。后种方法假设在暗物质晕等级成团的框架下,重子成分(恒星和气体)同样通过连续的并合而等级成团的。不同于该假设,在意大利国际研究生院和意大利帕多瓦天文台的研究小组提出了一种椭球(speroidal)和类星体在高红移共同演化的物理模型。在该模型中,星系寄主的暗物质晕形成于两个主要阶段：一个是快速塌缩和并合阶段,另一个是缓慢吸积阶段。早型星系主要形成于前一阶段,众多物理过程(像气体冷却、塌缩,恒星形成,中央黑洞的吸积以及类星体的反馈)均发生在前一阶段。而后一阶段对早型星系的演化有很少的贡献。我的工作主要集中在两个方面：一是分析了在红移2附近原初星系中恒星形成和尘埃之间的联系；二是研究了恒星及类星体触发的大量气体外流对早型星系尺度演化的效应。此外,我还参与了HERSCHEL远红外亚毫米卫星ATI.AS项目巡天的数据分析工作。一些主要的结果如下：i)基于光学2850波段,从GOODS-MUSIC列表中,我们选择了一个高红移光谱证认的星系样本。我们能够利用星族合成的方法来研究该样本以得到它们的物理参数。同时,我们选择了一个包括低红移极亮红外星系(ULIRGs)及漩涡星系、恒星形成区的样本。由这个样本,我们重新对8微米光度L8μm和红外光度LIR联系进行了定标。我们发现通常的采用固定消光率的星族合成技术不能产生期待的8微米光度和红外光度联系。我们提出了一种新的方法：将红外光度作为一个参数加入到拟合之中,并且采用一个更普适Calzetti率。利用这种方法,我们能够更可信地决定高红移星系的恒星成分,即恒星形成率,尘埃消光和恒星年龄。我们证实了低光度星系平均有显著更年老的恒星成分,而且恒星质量也比高光度星系的恒星质量要低。这是一种观测的’downsizing'现象：低质量星系首先形成,但是它们的恒星形成持续时间更长。该现象与反等级成团现象一致。ii)我们指出观测到的高红移早型星系致密尺寸(千秒差距甚至亚千秒差距量级)是可被理论模型预测的,只要假设星系中的大部分恒星在冷气体的耗散塌缩过程中形成。已有的观测数据强烈建议大部分尺寸演化发生在红移一以上,而在红移一以内,尺度增加不超过40%。大部分高红移被动演化星系投影在有效半径内的恒星质量是具有相似恒星质量的本地早型星系投影在同样物理半径内的恒星质量的两倍。观测数据同样显示了高红移早型星系的尺度分布比对应本地早型星系的更宽。一部分高红移大质量早型星系已经具有和它们本地对应体(具有同样质量的本地早型星系)一样大的尺度。然后,另一部分高红移大质量早型星系比它们本地对应体的尺度要小四到六倍。所有的这些观测结果可以被解释,只要假设大部分尺度演化是源于大量气体外流而导致的尺度膨胀。通过恒星质量函数的限制,无气体的子并合仅可以增大两倍高红移大质量早型星系的有效半径。
[Abstract]:In this paper, I will introduce my graduate school at the University of Science & Technology China (USTC) and the Italy International Studies (SISSA) to co culture the identity of students during the PhD form field obtained some research achievements in the galaxy. The research direction is mainly concentrated in the early type galaxies at high redshift (ETGs) formation and evolution. 10 years, high redshift galaxy formation and evolution of the problem has been more and more attention. Recent observational evidence shows that quasars (QSOs) formation and evolution, formation and evolution of high redshift galaxies are strictly linked. People developed two kinds of methods to study the formation of galaxies. One is to use a semi analytical model; the other is a numerical simulation method. After the assumptions in the framework of the dark matter halo grade clusters, baryon components (stars and gas) and also through continuous and hierarchical clustering. Different from the assumption that, in The research team of Italy International Graduate School of Italy and the Padova Observatory presents an ellipsoid (speroidal) model and quasars at high redshift co evolution. In this model, the host galaxy halos of dark matter formed in two major stages: a rapid collapse and coalescence stage, another is the slow accretion phase. Early type galaxies are mainly formed in the first stage, many physical processes (such as gas cooling, collapse, star formation, central black hole accretion and Quasar feedback) occurred in the previous stage. There is little contribution to development and evolution of early type galaxies.
My work is mainly focused on two aspects: one is the analysis of the red shift between 2 near the original star formation and dust; two is a large amount of gas of the stars and quasars trigger outflow effect on early type galaxies scale evolution. In addition, I also participated in the HERSCHEL far infrared sub millimeter ATI.AS satellite project the survey data analysis. The main results are as follows: 2850) based on the I optical band, from the GOODS-MUSIC list, we chose a high redshift spectral identification of Galaxy samples. We can use population synthesis method to study the sample to obtain the physical parameters of them. At the same time, we chose a low the redshift ultraluminous infrared galaxies (ULIRGs) and spiral galaxies, star forming region samples. From this sample, we re on 8 micron m and L8 photometric infrared luminosity LIR contact the scaling. We Find the usual fixed rate of extinction population synthesis techniques cannot generate 8 micron luminosity expectations and infrared luminosity. We propose a new method: infrared spectrophotometer as a parameter is added to the fitting, and the use of a more pervasive Calzetti rate. Using this method, we can be more credible determine the stellar component of high redshift galaxies, the star formation rate, dust extinction and stellar age. We demonstrated that low luminosity galaxies average star elements significantly older, but also high quality star star quality to low luminosity galaxies. This is a phenomenon of "downsizing'observations: low mass galaxies formed first, but their star formation lasted longer. This phenomenon and the anti hierarchical clustering phenomenon.Ii) we point out that the high redshift observed early type galaxies dense size (kiloparsec or even sub thousand seconds The gap between magnitude) can be predicted by the theoretical models, as long as the dissipative collapse assumed most stars and galaxies in the cold gas condensation formed in the process of observation data. The existing strongly suggest that most of the size evolution occurred in a redshift above, and in less than a redshift, scale increase does not exceed 40%. most of the high redshift galaxies in the projection of passive evolution the effective radius of stars in the mass is two times with similar stellar mass of local early type galaxies in the same physical projection within the radius of the stellar mass. The data also shows the scale distribution ratio of early type galaxies at high redshift local early type galaxies more wide. A part of high redshift massive early type galaxies and has their local counterparts (with the same quality of local early type galaxies) as large scale. Then, another part of the high redshift massive early type galaxies than their local counterparts to scale To four to six times. All of these observations can be explained by the hypothesis, as long as the most scale evolution is due to the large amount of gas outflow caused by scale expansion. The stellar mass function limit, no gas sub and effective radius can only increase two times high redshift massive early type galaxies.

【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：P152

【共引文献】