一个巨大的静止星系,红移3.717
Karl Glazebrook1, Corentin Schreiber2, Ivo Labbé2
1Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122, Australia.
Nature
|April 7, 2017
概括
在早期宇宙中发现了停止恒星形成的巨大星系. 通过光谱测量确认一个红移3.717的星系,
科学领域:
- 宇宙学与银河系外的天文学
- 星系的形成和演变
背景情况:
- 在早期宇宙中,巨大的静止星系由于紫外线的辐射可以忽略,因此在观测上具有挑战性.
- 之前的近红外调查发现了这样的星系在红移z≈2,模型解释了它们在z≈3−4的快速形成.
- 更深入的调查表明,大量静止星系的红移甚至更高,但这些并没有被理论模型预测.
研究的目的:
- 通过光谱检测证实大质量静止星系的存在,其红移率非常高 (z > 3).
- 研究这些早期大质量星系的形成时间和过程.
- 测试和可能修改早期星系组合的现有理论模型.
主要方法:
- 使用极深的近红外测量对候选星系进行初步识别.
- 进行光谱观测以确认红移和恒星质量.
- 分析吸收线谱以评估当前的恒星形成活动和推导星系年龄.
主要成果:
- 通过光谱学证实了一个巨大的静止星系,红移z=3.717,恒星质量为1.7×10^11太阳质量.
- 确定银河系的年龄几乎是当时宇宙的一半, 没有目前恒星形成的迹象.
- 推断大多数恒星是在宇宙历史上10亿年内通过极端的星爆迅速形成的.
结论:
- 这个巨大的静止星系在z=3.717的存在表明,显著的星系组合比目前的模型预测的要早得多.
- 形成这样一个星系所需的快速,早期的星体爆发阶段挑战了我们对早期星系形成过程的理解.
- 这些发现需要对描述早期宇宙中大质量星系的理论框架进行实质性修订.
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