第一代恒星与星系何时、怎样产生?

When and how did the first stars and galaxies form?

第一代恒星与星系的形成标志着宇宙从原初的平滑状态到当前的成团状态的转变.标准宇宙学模型认为第一代恒星在红移等于30左右开始形成.本文梳理了第一代恒星的形成理论,并借助数值模拟手段介绍了恒星形成过程中的重要物理机制.文章首先讨论了暗物质晕的演化及晕中原初气体的落入与冷却;然后,考虑了第一代恒星的反馈效应及其对吸积过程的影响,这决定了第一代星系的性质.在不久的将来,现代的大型望远镜将实现对第一代星系的探测.

The formation of the first stars and galaxies marks the transformation of the Universe from its smooth initial state to its clumpy current state.In standard cosmological models,the first generation of stars began to form at redshift z=30.Here,we survey the theory of the formation of the first stars,with a focus on the results of numerical simulations to illustrate a number of the key processes that define their properties.We firstly discuss the evolution of the dark matter halos and the infall and cooling of the primordial gas within them.We then consider the interplay between protostellar accretion and feedback that serves to determine the character of the first galaxies.Modern large telescopes will discover the first galaxies in the near future.