近日，西班牙天体生物学中心的Luca Costantin及其研究团队取得一项新进展。经过不懈努力，他们发现红移为3处的类银河系棒旋星系。相关研究成果已于2023年11月8日在国际权威学术期刊《自然》上发表。

该研究团队对红移zphop≈3的棒旋星系ceers-2112进行了详细观测。据观测结果显示，ceers-2112在宇宙仅20亿年时便已经成熟。其恒星质量(M_★= 3.9 × 10⁹ M_⊙)以及棒状形态使得ceers-2112被认为是银河系的祖先之一。在宇宙前40亿年的质量和结构组装历史中，ceers-2112的质量与银河系最为接近。研究人员进一步推断，在红移z≈3的时期，星系中的重子可能已经主导了暗物质。而高红移恒星棒可能在大约4亿年前形成，动态冷星盘则可能在红移z = 4-5（超过120亿年前）的时期形成。

据悉，本地宇宙中的众多大质量盘状星系，包括我们的银河系，在其中心区域均展现出了恒星棒状结构。恒星棒的形成主要出现在低红移的动态冷恒星盘中，因为在高红移的盘状星系中，强烈的气体湍流会抑制或延缓恒星棒的形成过程。此外，根据模拟预测，在类似银河系的祖先星系中，红移z = 1.5以上的恒星棒几乎不存在。

附：英文原文

Title: A Milky Way-like barred spiral galaxy at a redshift of 3

Author: Costantin, Luca, Prez-Gonzlez, Pablo G., Guo, Yuchen, Buttitta, Chiara, Jogee, Shardha, Bagley, Micaela B., Barro, Guillermo, Kartaltepe, Jeyhan S., Koekemoer, Anton M., Cabello, Cristina, Corsini, Enrico Maria, Mndez-Abreu, Jairo, de la Vega, Alexander, Iyer, Kartheik G., Bisigello, Laura, Cheng, Yingjie, Morelli, Lorenzo, Arrabal Haro, Pablo, Buitrago, Fernando, Cooper, M. C., Dekel, Avishai, Dickinson, Mark, Finkelstein, Steven L., Giavalisco, Mauro, Holwerda, Benne W., Huertas-Company, Marc, Lucas, Ray A., Papovich, Casey, Pirzkal, Nor, Seill, Lise-Marie, Vega-Ferrero, Jess, Wuyts, Stijn, Yung, L. Y. Aaron

Issue&Volume: 2023-11-08

Abstract: The majority of massive disk galaxies in the local Universe show a stellar barred structure in their central regions, including our Milky Way. Bars are supposed to develop in dynamically cold stellar disks at low redshift, as the strong gas turbulence typical of disk galaxies at high redshift suppresses or delays bar formation. Moreover, simulations predict bars to be almost absent beyond z = 1.5 in the progenitors of Milky Way-like galaxies. Here we report observations of ceers-2112, a barred spiral galaxy at redshift z_phot ≈ 3, which was already mature when the Universe was only 2 Gyr old. The stellar mass (M_★ = 3.9 × 10⁹M_⊙) and barred morphology mean that ceers-2112 can be considered a progenitor of the Milky Way, in terms of both structure and mass-assembly history in the first 2 Gyr of the Universe, and was the closest in mass in the first 4 Gyr. We infer that baryons in galaxies could have already dominated over dark matter at z ≈ 3, that high-redshift bars could form in approximately 400 Myr and that dynamically cold stellar disks could have been in place by redshift z = 4–5 (more than 12 Gyrs ago).

DOI: 10.1038/s41586-023-06636-x

Source: https://www.nature.com/articles/s41586-023-06636-x