第一个恒星在原子中的红移20处的签名
Eli Visbal1, Rennan Barkana, Anastasia Fialkov
1Jefferson Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138, USA. evisbal@fas.harvard.edu
Nature
|June 23, 2012
概括
早期宇宙的恒星形成被不同的物质速度所抑制. 模拟显示了来自第一个恒星的21厘米增强的信号,可以用射电望远镜检测到.
科学领域:
- 宇宙学和天体物理学
- 早期宇宙研究研究 早期宇宙研究
- 第一个恒星形成.
背景情况:
- 在早期宇宙中,暗物质和重子物质以不同的速度移动,抑制了某些区域的恒星形成.
- 以前对早期恒星21厘米的信号 (红移20) 的估计忽略了诸如X射线气体加热和抑制增强等关键因素.
- 速度差异使得第一批恒星形成更大质量的光环 (约. 100万太阳质量) 比以前认为的要多.
研究的目的:
- 模拟第一个恒星在红移20处的分布.
- 为了结合不同物质速度的影响,X射线加热气体,以及对恒星形成的增强抑制.
- 为了预测这些早期恒星可观测到的21厘米的 signature.
主要方法:
- 进行了早期宇宙的大规模宇宙学模拟 (400兆帕秒盒).
- 包括暗物质-重子物质速度差异,X射线加热和恒星形成抑制的物理学.
- 分析了第一颗恒星的分布及其21厘米的信号.
主要成果:
- 来自第一颗恒星的21厘米的信号是一个增强的波动信号 (十毫克尔文) 在百兆分秒的尺度上.
- 信号呈现出一个平坦的功率频谱,具有突出的巴里昂声学振荡.
- 通过像默奇森广场阵列或低频阵列 (50-100 MHz) 这样的仪器,可以在1000小时的集成时间内实现观测灵敏度.
结论:
- 暗物质和重子物质的不同速度显著影响早期恒星形成和21厘米信号.
- 模拟的21厘米信号为第一颗恒星时代提供了一个新的可观测窗口.
- 未来的射电望远镜观测可以检测到这个预测的信号,为宇宙黎明提供了洞察力.
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