一个巨大的紧静止星系在z=2与一个完整的爱因斯坦环在JWST成像
Pieter van Dokkum1, Gabriel Brammer2,3, Bingjie Wang4
1Department of Astronomy, Yale University, New Haven, CT USA.
Nature astronomy
|January 25, 2024
概括
由詹姆斯·韦伯太空望远镜观察到的大型星系是紧的,它们的核心形成得很早. 这项研究使用爱因斯坦环测量了原始星系核心的质量,揭示了暗物质或初始质量函数的潜在差异.
科学领域:
- 宇宙学的宇宙学是什么?
- 银河系的进化 银河系的进化
- 天体物理学 天体物理学
背景情况:
- 红移z≈2的大型星系是惊人的紧 (1-2 kpc半径).
- 目前的模型表明,巨大的星系形成"内外",核心由z≈2建立,后来通过合并增加了质量.
研究的目的:
- 呈现由詹姆斯·韦伯太空望远镜 (JWST) 观测到的具有完整爱因斯坦环的紧,大质量,静止星系.
- 在显著进化之前直接测量"原始"星系核心的质量.
- 为了研究这个早期大质量星系的质量分布和组成 (暗物质与恒星质量).
主要方法:
- 利用詹姆斯·韦伯太空望远镜的COSMOS-Web调查进行观测.
- 分析了一个完整的爱因斯坦环,由一个背景星系形成,将目标星系作为镜头.
- 计算了透镜星系核心的质量及其在6.6 kpc半径内的恒星质量.
主要成果:
- 测量了1.1 x 10^11 M的镜头质量,在6.6 kpc内.
- 在同一半径内确定了2.1 x 10^10 M (Chabrier IMF) 的恒星质量.
- 推断的暗物质质量为9.0 x 10^10 M.
结论:
- 透镜质量表明需要额外的质量超出恒星和可信的暗物质组成部分.
- 这种差异可以通过更高的暗物质密度或底重初始质量函数来解释.
- 这些发现提供了关于早期宇宙中大质量星系核心的形成和组成的见解.
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