快速形成恒星的星系与星相邻,红移超过6
R Decarli1, F Walter1,2,3, B P Venemans1
1Max Planck Institut für Astronomie, Königstuhl 17, Heidelberg 69117, Germany.
Nature
|May 26, 2017
概括
巨大的早期星系需要高恒星形成率. 天文学家在红移z>6的类星体附近发现了四个这样的星系,每年恒星形成率超过100个太阳质量,为星系进化提供了线索.
科学领域:
- 宇宙的演化
- 星系的形成和演变
- 早期宇宙的天体物理学
背景情况:
- 大规模的圆星系在z ≈ 4意味着早期宇宙的恒星形成率很高 (z > 6).
- 之前的调查发现很少有星系在这些早期形成恒星的速度.
- 类星体宿主星系是唯一具有非常高的恒星形成率的已知来源,但它们是活跃的超大质量黑洞的宿主.
研究的目的:
- 在z > 6时研究高恒星形成率的星系的存在和属性.
- 在后来的宇宙时期观察到的大型圆星系的潜在祖先.
- 寻找高恒星形成率的星系, 没有活跃的超大质量黑洞.
主要方法:
- 在158微米的单离子碳 ([C ii]) 排放线的观测.
- 目标近距离的星系 (速度小于600公里/秒,线性偏移小于100千克) 到z>6个类星体.
- 远红外亮度选择为偶然的发现.
主要成果:
- 在四个伴星系中检测到[C ii]辐射到z>6个类星体.
- 这些伴星系的恒星形成率每年超过100个太阳质量.
- 这些伴星系的亮度,线宽和动态质量与类星系相似,但缺乏活跃超大质量黑洞的证据.
结论:
- 这项研究确定了在z>6的高恒星形成率的星系群,而不是类星体宿主.
- 这些伴星系可能是z ≈ 4观测到的大型圆星系的祖先.
- 这种系统的普遍存在 (25个被调查的类星体中有4个) 需要纳入星系形成的理论模型.
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