Development of the Hubble Sequence of Galaxies at High Redshift

为了研究星系的形成和哈勃序列的起源，(1)我们利用斯巴鲁望远镜的深宽视场光学和近红外成像观测，研究了红移大于1的星系的颜色和星等分布的演化；(2)我们还利用斯巴鲁望远镜的深窄带成像，研究了z=3-5的大型延展发射线星云，这些星云很可能是处于形成阶段的大质量星系。根据哈勃深场的深近红外数据，我们揭示了星系恒星形成历史对恒星质量的依赖关系，表明在中红移和高红移星系中可以清楚地看到双峰色分布，而低质量天体具有相对均匀的颜色，并沿红移系统地演化。利用在斯巴鲁XMM/牛顿深部勘测场获得的宽视场多色数据，我们还研究了高红移星系的颜色和形态分布，以考察局部哈勃序列星系的祖先何时以及如何出现在结构形成的历史中。在帕雷尔，我们还在进行进一步的广域调查，以与斯皮策太空望远镜最近获得的结果进行比较。另一方面，我们利用斯巴鲁望远镜进行了深部和宽视场的窄带成像测量，以圈定大质量星系的形成区域。我们探测到了大量的巨大的延长的发射线星云，这些星云很可能是正在形成的大质量星系。这些结果发表在四篇期刊论文以及一些国内外会议和研讨会上。我们已经提交了另外两篇论文，并正在准备即将提交的另外三篇论文。

In order to study the formation of galaxies and the origins of the Hubble sequence, (i) we investigated the evolution of the color and magnitude distribution of the galaxies at redshift larger than one by the deep and wide-field optical and near-infrared imaging observation with the Subaru telescope, and (ii) we also conducted the study of large extended emission-line nebulae at z=3-5 which are likely to be the massive galaxies in their forming phase by the deep narrow-band imaging also using the Subaru Telescope.Based on the deep near-infrared data of the Hubble Deep Field, we revealed the stellar-mass dependence of the star-formation history of the galaxies and showed that the bimodal color distribution is clearly seen at intermediate and high redshift galaxies and the low-mass objects have relatively homogeneous color which evolves systematically along the redshift. Using the wide-field multi-color data obtained at the Subaru XMM/Newton Deep Survey field, we also studied the color and morphology distribution of high-redshift galaxies to investigate when and how the progenitors of the local Hubble sequence galaxies appear in the history of structure formation. In pararell, we are also conducting the further wide-area survey to compare with the results recently obtained by the Spitzer space telescopes. On the other hand, we proceeded the deep and wide-field narrow-band imaging survey with the Subaru telescope to delineate the regions of massive galaxy formation. We detected a significant number of the giant extended emission-line nebulae which are likely to be the massive forming galaxies.These results are reported in the four journal papers as well as a number of domestic and international conferences and workshop. We have submitted two more papers and are preparing three further more papers to be submitted soon.