孔旭^1，*， 方官文^2，

（  1、中国科学技术大学天文学系,合肥　230026 ；       2、大理大学天文与科技史研究所,大理　671003；  ）

摘要： 基于CANDELS（Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey）5个深场巡天的多波段测光数据和HST（Hubble Space Telescope）近红外（F160W）高分辨率观测图像,利用BzK（${ m B-z}$和${ m z-K}$）双色图技术选取了1586个恒星形成星系（star forminggalaxies, sBzKs）和271个被动演化星系（passively evolving galaxies, pBzKs）,它们对应的红移平均值分别为$1.80pm0.49$和$1.73pm0.38$,并对这些大质量（恒星质量$M_{st}gtrsim10^{10}~M_{odot}$）星系的形态结构特征进行了研究。在sBzKs样本中, 静止光学波段形态呈现出椭圆、盘状和不规则结构特征的源所占比例依次为15%、18%和67%, 而对于pBzKs来说, 对应的比例分别是44%、37%和19%。另外,高红移sBzKs和pBzKs的有效半径（$r_{ m e}$）中值分别对应$2.52pm1.37$ kpc和$1.90pm1.02$ kpc, 明显小于近邻同类型相似质量的星系,表明随着红移减小,星系尺寸逐渐变大。
关键词： 天体物理；星系演化； 星系形态；星系结构；高红移星系

KONG Xu^1,*， FANG Guan-Wen^2,

（  1、Department of Astronomy, University of Science and Technology of China, Hefei 230026 ；       2、Institute for Astronomy and History of Science and Technology, Dali University, Dali 671003；  ）

Abstract： Using the multi-band photometry data of all five CANDELS (Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey) fields and the high-resolution HST WFC3 (Hubble Space Telescope Wide Field Camera 3) near-infrared imaging (F160W), we present a quantitative study of morphology and structure ofBzK-selected (two-color ${ m B-z}$ vs. ${ m z-K}$ diagram) Galaxies. The sample of 1857 BzKs including 1586 star-forming galaxies (sBzKs) and 271 passively evolving galaxies (pBzKs). The mean redshifts of sBzKs and pBzKs are $1.80pm0.49$ and $1.73pm0.38$, respectively. For the rest-frame optical morphologies of sBzKs (pBzKs), the fractionsof ellipticals, disks, and irregular galaxies correspond to 15% (44%), 18%(37%), and 67%(19%), respectively.Moreover, the median effective radii of sBzKs and pBzKs, corresponding to $2.52pm1.37$ kpc and $1.90pm1.02$ kpc, respectively. The findings show that the sizes of pBzKs (sBzKs) are smaller than that of present-day early-type (late-type) galaxies with analogous stellar mass at rest-frame optical wavelength, indicatingthe evolution of high-redshift massive galaxy size with redshift.
Keywords： astrophysics; galaxy evolution; galaxy morphology; galaxy structure; high redshift galaxies

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