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)利用斯巴鲁望远镜的深广域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变；（ii）我们还利用斯巴鲁望远镜对z=3-5处可能是大质量星系形成阶段的大型扩展发射线星云进行了深窄带成像研究。基于哈勃深场的深近红外数据，揭示了星系的恒星形成历史与恒星质量的依赖关系，并表明在中高红移星系中可以明显地看到双峰色分布，而低质量天体则具有相对均匀的颜色，并沿着红移系统地演化。利用斯巴鲁XMM/牛顿深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，以探讨本地哈勃序列星系的祖先何时以及如何在结构形成历史中出现。与此同时，我们也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宽视场窄带成像调查，以描绘大质量星系形成的区域。我们发现了大量的巨型扩展发射线星云，它们很可能是大质量形成星系。这些结果在四篇期刊论文以及一些国内和国际会议和研讨会上报道。我们已经提交了两篇论文，正在准备另外三篇论文，即将提交。

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.