高红移星系的形态和大小演化研究

发布时间：2018-04-04 04:19

本文选题：高红移星系　切入点：星系形态　出处：《中国科学技术大学》2016年博士论文

【摘要】：高红移宇宙与我们熟悉的近邻宇宙迥然不同,在红移z～2的时代,很高比例的大质量星系仍然很活跃,同时它们的形态和我们近邻宇宙中的星系也有较大差别。为了检验当前星系形成和演化的理论模型,我们必须在很大的红移范围研究星系的物理性质。在过去的十几年中,研究者们提出了许多新颖的技术手段去对星系进行多波段观测研究,许多研究成果使人们对高红移星系的性质有了更深入的理解。相对于近邻星系,高红移星系(特别是z～2的红移范围)的研究有着非常重要的意义。首先,在红移z～2附近星系的宇宙恒星形成率密度(SFRD)和类星体(QSOs)数密度达到峰值；其次,星系的类型和形态也在z～2附近发生显著变化。再者、z～2的大质量星系被认为是近邻宇宙大质量早型星系的前身,对这些高红移星系进行研究可以对星系演化的理论模型提供观测上的约束。因此,我们的研究上作主要集中在红移z～2的范围。在本论文中,我们的研究包括三方面内容：(1)COSMOS场中遥远红星系DRG的物理性质研究;(2) COSMOS和GODDS-S场中的致密恒星形成星系cSFG的物理性质研究；(3)COSMOS场中宁静星系的大小演化机制研究。我们利用J-K1.16的颜色选择标准从COSMOS场中选出了4485个DRG星系,其中132个DRG有着HST/WFC3图像数据的形态学测量。非模型化形态参数的测量结果与静止系UVJ颜色分类得到的结果相一致：宁静DRG普遍是致密的,而恒星形成DRG一般有着延展的结构。我们发现在各个红移区间里,DRG的恒星形成率SFR和星族质量M*都呈现出紧密的“主序”关系。红外光度导出的恒星形成率SFR,R主导着DRG的总恒星形成率,这暗示出J—K1.16的颜色选择标准可以有效地选择出大质量的富尘埃的恒星形成星系。大质量的DRG通常有着较红的静止系U-V颜色,并且DRG的静止系U-V颜色随着红移的升高而逐渐变蓝,这表明大质量的星系有着较大的尘埃消光或年老的星族,而且它们随着宇宙时间演化。我们发现DRG跟其他几种主要的高红移星系选择方法有着不同程度的重叠,这说明DRG不是一类特殊的星系,它们也可以被其他的颜色判据选择到。我们对COSMOS场和GOODS-S场中的M*1010M⊙和2≤z≤3范围的致密恒星形成星系cSFG进行研究,来探索它们是否是延展恒星形成星系eSFG和致密宁静星系cQG之间的一种过渡类型。cSFG在主序上的分布和eSFG几乎相同并且占据着高质量端。在静止系U-V vs. V-J和U-B vs. MB图上,cSFG在各个颜色上都分布在eSFG和cQG之间,但是比“绿谷”星系更倾向于“红序列”。我们发现在非模型化形态参数分布图上,cSFG和cQG的分布几乎相同。大约有三分之一的cSFG显示出了明显的后并合形态,没有任何一个cSFG可以被认定为盘状星系。在星族和结构参数上,cSFG和cQG的分布极其相似,这暗示了cSFG是cQG的直接前身星系。同时,与eSFG和cQG相比,cSFG有着很高的AGN比例,这支持了这样的假设：从eSFG寅化到cSFG经历的富气体的剧烈耗散过程同时强化了恒星形成和黑洞的活动水平。以上的分析结果表明,cSFG极有可能是z2时eSFG演化到cQG过程中的一种过渡类型星系。最后,我们基于一个从COSMOS场中选择的pBzK星系样本,来研究宁静星系的大小和它形成时刻的红移之间的关系,来探索宁静星系表面上的大小演化是因为每一个星系单独增长,还是因为后加入的宁静星系有着较大的尺寸从而增大了宁静星系群体尺寸的平均值。我们从COSMOS场中在z、1.3-3和M*～10.7M(?)范围上选择了2738个宁静星系。我们用SED拟合的方法通过输入多重金属丰度来计算星系的年龄,然后我们用这个年龄导出星系形成时刻的红移。由于图像数据的信噪比很低,我们不能直接测量单个星系的大小,所以我们基于ACS I波段和CFHT Ks波段图像来叠加星系,进而测量星系的尺寸。我们的星系叠加和尺寸测量基于(1+zform)-1由上的五个区间。我们发现在较低的红移处,星系的尺寸大致与(1+zfom)-1成正比关系；而到了较高的红移处,这个趋势逐渐变平,并趋近于1 kpc。以上的分析结果表明,至少在较低红移处,宁静星系的大小演化主要是因为新加入宁静星系群体的星系有着较大的尺寸从而拉高了宁静星系群体尺寸的平均值,而不是因为次并合使得每一个星系单独增长。非耗散的次并合对星系尺寸的增长会起到一些作用,日不是主要原因。
[Abstract]:The high redshift universe we are familiar with the local universe totally different, at a redshift of Z ~ 2 times, a high proportion of the large galaxy is still very active, and their morphology and our neighboring galaxies in the universe are quite different. In order to test the theoretical model of the formation and evolution of galaxies, we have physical properties in red the scope of study of galaxies greatly. In the past decade, researchers have proposed many novel techniques to study multi band observations of galaxies, many research results make people on properties of high redshift galaxies have a more in-depth understanding. Compared to the neighboring galaxy, high redshift galaxies (especially Z ~ 2 the redshift range) has a very important significance of the research. First, at a redshift of Z ~ 2 nearby galaxies of the cosmic star formation rate density (SFRD) and quasars (QSOs) density reached the peak; secondly, the galaxy class Type and morphology in Z ~ 2 near the change significantly. Furthermore, the massive galaxy Z ~ 2 is considered to be the local universe massive early type galaxies predecessor of these high redshift galaxies can provide constraints on the observation of the theoretical model of the evolution of galaxies. Therefore, our research on the main concentrated in the range of 2 ~ Z redshift. In this thesis, our research includes three aspects: (1) physical properties of distant star system DRG COSMOS field; (2) the formation of physical properties of the cSFG Galaxy COSMOS and dense star in the GODDS-S field; (3) in the study of peaceful galaxies the size of the evolution mechanism of COSMOS field. We use the J-K1.16 color selection criteria selected 4485 DRG galaxies from the COSMOS field, one of the 132 DRG with morphological measurement of HST/WFC3 image data. The measurement results of morphological parameters of the non static model and UVJ color classification system The results agree: quiet DRG generally is dense, and star formation is generally DRG extension structure. We found that in each redshift interval, DRG star formation rate SFR and population quality M* exhibit close "main sequence". The star shape infrared luminosity derived rate SFR, R dominates the total star formation rate of DRG, suggesting that J - K1.16 color selection criteria can effectively select high quality dust rich star forming galaxies. The quality of DRG usually have a static U-V color is red, a color and DRG U-V red shift with increasing gradually this shows that blue, massive galaxy has a larger dust extinction or old population, and they with cosmic time evolution. We found that DRG and several other major selection methods have a high redshift galaxies with varying degrees of overlap, indicating that DRG is not A special class of galaxies, they can also be other options. The color criterion of compact star of COSMOS field and GOODS-S field in M*1010M, and 2 = z = 3, range of galaxy formation to cSFG research, to explore whether they are distributed and eSFG extended star formation as a transitional type between.CSFG and eSFG in the Galaxy dense star quiet line cQG in the main sequence and occupy almost the same high quality end. In the static system U-V vs. V-J and U-B vs. on MB, cSFG in various colors are distributed between eSFG and cQG, but the ratio of "green" galaxies tend to "red series". We found that in non the model of morphological parameters of distribution, distribution of cSFG and cQG are almost the same. There are about 1/3 cSFG shows a clear and close form, no one can be identified as cSFG disk galaxies. In population and structural parameters, cSFG and cQG The distribution is very similar, suggesting that cSFG is a direct predecessor of galaxy cQG. At the same time, compared with eSFG and cQG, cSFG has a very high proportion of AGN, which support the hypothesis that eSFG from Yin to violent dissipation of gas rich cSFG experience at the same time strengthen the star formation and black hole activity level. The analysis results show that cSFG is likely to be Z2 eSFG to a transitional type of galaxy evolution in the process of cQG. Finally, we have a choice in the COSMOS field from the pBzK Galaxy sample based on the size of the galaxy and quiet to study the relationship between the time shift of it, to explore the evolution of Galaxy size peace on the surface is because every galaxy alone growth, or because after adding the quiet galaxy has a larger size and increased the average size of the Galaxy Group quiet. We value from the COSMOS field in the Z, 1.3-3 and M* ~ 10.7M range (?) On the choice of 2738 quiet galaxies. We used SED method to fit through the input of heavy metals abundance to calculate the age of the galaxy, we then form the moment with this age derived redshift galaxies. Because of very low signal-to-noise ratio of the image data, we cannot directly measure the size of individual galaxies, so we ACS I band and CFHT Ks band image based on superposition of galaxies, galaxies and then measure the size. The size of our galaxy and overlay measurement based on interval -1 (1+zform) five by. We found that in low redshift galaxies, with roughly the size of (1+zfom) -1 is directly proportional to the redshift; higher, this trend flatten, and close to 1 kpc. above analysis results show that, at least in the low redshift galaxy evolution, the size of peace is mainly because the new Galaxy Galaxy Group added quiet with a larger size to pull up The mean value of the group size of quiet galaxies, rather than the sub conjunction, makes each galaxy grow independently. The non dissipative sub conjunction plays a role in the growth of Galaxy size, and days are not the main reason.

【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】：2016
【分类号】：P152

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