School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, UK.
Arcetri Astrophysical Observatory, Istituto Nazionale di Astrofisica, Florence 50125, Italy.
Science. 2021 Feb 12;371(6530):713-716. doi: 10.1126/science.abc1893.
Cosmological models predict that galaxies forming in the early Universe experience a chaotic phase of gas accretion and star formation, followed by gas ejection due to feedback processes. Galaxy bulges may assemble later via mergers or internal evolution. Here we present submillimeter observations (with spatial resolution of 700 parsecs) of ALESS 073.1, a starburst galaxy at redshift [Formula: see text] when the Universe was 1.2 billion years old. This galaxy's cold gas forms a regularly rotating disk with negligible noncircular motions. The galaxy rotation curve requires the presence of a central bulge in addition to a star-forming disk. We conclude that massive bulges and regularly rotating disks can form more rapidly in the early Universe than predicted by models of galaxy formation.
宇宙学模型预测，早期宇宙中形成的星系经历了一个混乱的气体吸积和恒星形成阶段，随后由于反馈过程而将气体喷射出去。星系核球可能通过合并或内部演化而在稍后形成。在这里，我们展示了对 ALESS 073.1 的亚毫米观测结果（空间分辨率为 700 秒差距），这是一个在宇宙年龄为 12 亿年时红移为 [Formula: see text] 的爆发星系。该星系的冷气体形成了一个规则旋转的圆盘，几乎没有非循环运动。星系的旋转曲线要求存在一个中心核球，除了恒星形成盘之外。我们的结论是，在早期宇宙中，大规模的核球和规则旋转的圆盘可以比星系形成模型预测的更快地形成。
