Fast and slow paths to quiescence: ages and sizes of 400 quiescent galaxies from the LEGA-C survey
Po-Feng Wu, Arjen van der Wel, Rachel Bezanson, Anna Gallazzi, Camilla Pacifici, Caroline M. S. Straatman, Ivana Barisic, Eric F. Bell, Priscilla Chauke, Josha … 展开作者
Po-Feng Wu, Arjen van der Wel, Rachel Bezanson, Anna Gallazzi, Camilla Pacifici, Caroline M. S. Straatman, Ivana Barisic, Eric F. Bell, Priscilla Chauke, Josha van Houdt, Marijn Franx, Adam Muzzin, David Sobral, Vivienne Wild
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Main part 16 pages, 13 figures. Appendix: 8 figures. Accepted by ApJ
We analyze stellar age indicators (D$_n$4000 and EW(H$δ$)) and sizes of 467 quiescent galaxies with $M_\ast \geq 10^{10} M_\odot$ at $z\sim0.7$ drawn from DR2 of the LEGA-C survey. Interpreting index variations in terms of equivalent single stellar population age, we find that the median stellar population is younger for larger galaxies at fixed stellar mass. The effect is significant, yet small; the ages of the larger and the smaller subsets differ by only $<500$ Myr, much less than the age variation among individual galaxies ($\sim1.5$ Gyr). At the same time, quiescent galaxies with the strongest H$δ$ absorption --- those experienced recent and rapid quenching events --- tend to be smaller than the average. These co-existing trends unify seemingly contradictory results in the literature; the complex correlations between size and age indicators revealed by our large sample of galaxies with high-quality spectra suggest that there are multiple evolutionary pathways to quiescence. Regardless of the specific physical mechanisms responsible for the cessation of star formation in massive galaxies, the large scatter in D$_n$4000 and EW(H$δ$) immediately implies that galaxies follow a large variety in evolutionary pathways. On the one hand, we see evidence for a process that slowly shuts off star-formation and transforms star-forming galaxies to quiescent galaxies without necessarily changing their structures. On the other hand, there is likely a mechanism that rapidly quenches galaxies, an event that coincides with dramatic structural changes, producing small post-starburst galaxies.
The LEGA-C galaxy survey: multiple quenching channels for quiescent galaxies at $z\sim1$
Université de Liège（列日大学）；Universiteit Gent（根特大学）；University of Pittsburgh（匹兹堡大学）；Max-Planck Institut für Astronomie（马克斯·普朗克天体物理研究所）；National Taiwan University（台湾大学）；National Center for Theoretical Sciences（国家理论科学中心）；University of Michigan（密歇根大学）；University of Cambridge（剑桥大学）
COSMOS2025: A Machine Learning Census of Massive Quiescent Galaxies at $2.5 < \text{z} < 5$
Institute for Advanced Studies in Basic Sciences (IASBS)（基础科学高等研究所）；Universität Bonn（波恩大学）；Institute for Research in Fundamental Sciences (IPM)（伊朗基本科学研究中心）
A combined VANDELS and LEGA-C study: the evolution of quiescent galaxy size, stellar mass and age from $\mathbf{\textit{z} = 0.6}$ to $\mathbf{\textit{z} = 1.3}$
Evolution in the orbital structure of quiescent galaxies from MAGPI, LEGA-C and SAMI surveys: direct evidence for merger-driven growth over the last 7 Gy
Radio AGN feedback sustains quiescence only in a minority of massive galaxies
University of Science and Technology of China（中国科学技术大学）；Shanghai AI Laboratory（上海人工智能实验室）；the Chinese University of Hong Kong（香港中文大学）；University of California, Riverside（加州大学河滨分校）；University of Massachusetts, Amherst（马萨诸塞大学阿默斯特分校）；Peking University（北京大学）；The University of Utah（犹他大学）
The LEGA-C of nature and nurture in stellar populations of galaxies at z~0.6-1.0: D4000 and H-delta reveal different assembly histories for quiescent galaxies in different environments
星系演化是由各种物理过程驱动的，这些物理过程预计在宇宙时间的不同暗物质晕和环境下以不同的速率进行。这种演化的记录保存在星系恒星星族中，我们可以使用吸收线光谱学来访问。本文利用大型LEGA-C巡天（DR 3）研究了COSMOS场中z~0.6-1.0的环境和恒星质量对恒星星族的影响。利用LEGA-C的统计能力和深度，我们揭示了在z~0.6-1.0的大质量星系群（M>10^10 M $_{\odot}$）的恒星质量与环境2D空间上D4000和H-δ等效宽度（EW）分布的显著梯度。D4000和H-delta EW主要取决于恒星质量，但在固定恒星质量时也取决于环境。通过将样本分为中心和卫星，并在恒星形成星系和静止星系方面，我们揭示了D4000和H-三角洲EW控制恒星质量时的显着环境趋势是由静止星系驱动的。无论是中心星系还是卫星星系，恒星形成星系都显示出D4000和H-δ EW，这些EW强烈依赖于它们的恒星质量，并且在0.6<z<1.0时完全独立于环境。卫星星系所看到的环境趋势完全是由仅适用于静止星系的趋势驱动的，再加上固定恒星质量下静止部分的强烈环境依赖性。我们的研究结果与最近的模拟预测一致，模拟预测指出大质量星系首先在超密度或最紧凑的暗物质晕中形成。
