CANDELS场中z=0.5-1.8恒星形成星系的等光强轮廓研究

发布时间：2018-06-07 01:07

本文选题：高红移 + 恒星形成　；参考：《沈阳师范大学》2017年硕士论文

【摘要】：高红移星系的结构是星系形成与演化研究目前最前沿的方向之一,但是由于高红移星系在静止坐标系辐射波段的红移和cosmic dimming效应,很久以来对高红移星系结构的研究进展缓慢。直到近10年来,借助于哈勃空间望远镜(HST)WFC3/近红外波段高分辨率图像数据,人们才对高红移星系的结构性质有了比较多的认识。星系的等光强轮廓性质与星系的内部结构性质紧密相关。通过研究星系的等光强轮廓性质及其随红移的演化,能为探索星系结构的演化提供线索。目前对中高红移星系的等光强轮廓的研究还是空白。在本文中,我们从CANDELS巡天的GOODS-S和UDS两个场中,一共选取了约4600个红移z=0.5-1.8的恒星形成星系(SFGs),并对它们的径向椭率(ε)轮廓和盘状/盒状(disky/boxy)参数轮廓进行了正确的测量。基于这些数据,我们首次对中高红移的恒星形成星系的椭率ε轮廓和轮廓在恒星质量——红移演化网格上的统计性质进行了分析。根据星系在每个红移区间内的相对大小,我们将样本星系划分成两类:“小”的恒星形成星系(SSFGs)和“大”的恒星形成星系(LSFGs),主要研究结果如下:(1)在低恒星质量(M*10 M⊙)端,侧向(edge-on)和面向(face-on)SSFGs均拥有接近水平的ε和轮廓,并且所有半径处的中值(median value)近似为0;然而,侧向LSFGs的椭率轮廓其主要特征是随半径单调上升,同时星系的中部区域呈现盘状(disky)特性(A40)。(2)在高恒星质量(M*10 M⊙)端,侧向SSFGs和LSFGs的椭率轮廓和A4轮廓均呈现先上升到最大值然后再下降的趋势。同时,星系的中部区域呈现更为显著的盘状特性。这些特征在更低红移(z1.4)或在更高质量(M*10.M⊙)端更为明显。(3)沿着恒星质量——红移网格上的演化路径,SSFGs和LSFGs的中心区域(R=1.5 kpc处)的椭率呈下降趋势。以上观测研究结果说明:在中高红移处,低质量SSFGs内可能还没有形成恒星盘(或其“恒星盘”与邻近宇宙中的盘星系具有不同的结构),而低质量LSFGs的结构与邻近盘星系的结构相似。在恒星形成星系朝低红移和高质量的演化过程中,内部区域的核球(大部分为伪核球,pseudo-bulge)和外围的恒星晕(outer stellar halo)伴随着其中间区域的盘的演化一并增长。
[Abstract]:The structure of Gao Hong shifted galaxies is one of the most advanced directions in the field of galaxy formation and evolution. However, due to the redshift and cosmic dimming effect of the Gao Hong shift galaxies in the stationary coordinate band, the research on the structure of the Gao Hong shifted galaxies has been slow for a long time. Only in the last 10 years, with the help of the Hubble Space Telescope (Hubble Space Telescope) with the help of high resolution image data in the near infrared band, the structure and properties of the Gao Hong shift galaxies have been well understood. The equiintensity profile of galaxies is closely related to the inner structure of galaxies. By studying the properties of isochromatic contours of galaxies and their evolution with redshift, we can provide clues for exploring the evolution of galaxy structure. At present, the study of the isochromatic profile of the Gao Hong shift galaxy is still blank. In this paper, from the GOODS-S and UDS fields of the CANDELS survey, we have selected about 4600 star forming galaxies with redshift zn 0.5-1.8, and measured their radial ellipsometry (蔚) profile and disk / box-shaped disky / boxyy parameter profile correctly. Based on these data, for the first time, we analyze the statistical properties of the ellipticity 蔚 profile and the profile of the star mass red-shift evolution grid of the star formation galaxy with the mid-Gao Hong shift. According to the relative size of galaxies in each redshift region, we divide the sample galaxies into two categories: "small" star forming galaxies (SSFGs) and "large" star forming galaxies (LSFGs1). Both the lateral edge-on) and the face-ona-facing SSFGs have nearly horizontal 蔚 and profile, and the median value at all radii is approximately zero. However, the ellipticity profile of the lateral LSFGs increases monotonously with the radius. At the same time, the central region of the galaxy presents a disk-like diskyproperty (A40). (2) at the end of 10 M) of high mass star, the ellipticity profile and A4 profile of lateral SSFGs and LSFGs increase to the maximum first and then decrease. At the same time, the central region of the galaxy presents a more significant disc-like feature. The ellipticity of these characteristics is more obvious at the lower redshift z1.4) or in the higher mass (10.M) end), along the evolution path of the star mass-red-shift grid and at the central region of LSFGs (R1. 5 kpc). The results of the above observations show that: at the middle Gao Hong shift, There may not be a stellar disk in low-mass SSFGs (or its "stellar disk" has different structures from disk galaxies in the adjacent universe, while the structure of low-mass LSFGs is similar to that of neighbouring disk galaxies. During the evolution of star forming galaxies towards low redness and high mass, the nuclear sphere in the inner region (mostly pseudo-bulge) and the outer star halo outer stellar are accompanied by the evolution of the disk in the middle region.
【学位授予单位】：沈阳师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P152

【参考文献】