标题： NGST和2<z<5时代星系演化的物理探索 显示英文标题

标题： NGST and the Physical Exploration of Galaxy Evolution During the Era 2<z<5

摘要： NGST为绘制哈勃空间望远镜深光学巡天无法覆盖的“黑暗时代”提供了前所未有的机会。 然而，同样重要的动机是深入了解宇宙历史的后期阶段，包括2<z<5时期，此时大多数星系被认为正在形成并经历恒星形成率、化学成分以及最终形态特征的剧烈变化。 我们需要解决的一个重要问题是，在中等红移处是否存在已建立的大型系统。 在该领域最近的观测和理论进展背景下，我将回顾NGST在此红移范围内的作用，并考虑下一代8米级地面望远镜在未来十年可能取得的进展。 显示英文摘要

摘要： NGST offers unprecedented opportunities for charting the `dark ages' beyond the limits of the deep optical surveys conducted with HST. An equally important motivation, however, is a detailed physical understanding of the later stages of cosmic history including the period 2<z<5 when most galaxies are thought to assemble and undergo dramatic changes in their star formation rate, chemical content and, ultimately, their morphological characteristics. An important question we need to resolve is the extent to which established massive systems might exist at moderate redshifts. In the context of recent observational and theoretical progress in this area, I review the role NGST could play in this redshift range taking into account the likely progress made in the next decade with the new generation of 8-m class ground-based telescopes