A Large-scale Kinematic Study of Molecular Gas in High-z Cluster Galaxies: Evidence for High Levels of Kinematic Asymmetry
A Large-scale Kinematic Study of Molecular Gas in High-z Cluster Galaxies: Evidence for High Levels of Kinematic Asymmetry
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DOI：
10.3847/1538-4357/acae96
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发表时间：
2022-09
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通讯作者：
W. Cramer;A. Noble;K. Massingill;J. Cairns;D. Clements;M. Cooper;R. Demarco;J. Matharu;M. McDonald;A. Muzzin;J. Nantais;G. Rudnick;H. Übler;E. van Kampen;T. Webb;G. Wilson;H. Yee
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作者：
W. Cramer;A. Noble;K. Massingill;J. Cairns;D. Clements;M. Cooper;R. Demarco;J. Matharu;M. McDonald;A. Muzzin;J. Nantais;G. Rudnick;H. Übler;E. van Kampen;T. Webb;G. Wilson;H. Yee
我们研究了由CO(2−1)中的阿塔卡马大毫米/亚毫米阵列追踪到的分子气体的分辨运动学，这些气体由三个不同星系团的25个星系团成员组成，红移为z∼1.6.这是首次对红移时的星系团星系的分子气体运动学进行大规模分析。通过运动学模型分别估计每个星系的进退面的自转曲线，我们量化了总圆速度的差异，以表征每个星系的整体运动学不对称性。在我们的样本中，我们能够建模的星系中有3/14的不对称程度与野外观测到的星系的不对称程度相似，这些星系的红移类似，主要是基于电离气体的观测。然而，这使得我们样本中的11/14星系具有明显更高的不对称性，其中一些星系的不对称度比在类似红移下观察到的场星系高出∼50倍。这些极端情况中的一些还具有在分子气体中看到的单边尾状形态，支持潮汐和/或冲压相互作用的情景。星系团和磁场在运动学不对称性上的这种明显差异表明，稠密环境的进化影响也在高红移宇宙中活跃，稠密环境被确定为低红移星系演化的主要驱动力。
We investigate the resolved kinematics of the molecular gas, as traced by the Atacama Large Millimeter/submillimeter Array in CO (2−1), of 25 cluster member galaxies across three different clusters at a redshift of z ∼ 1.6. This is the first large-scale analysis of the molecular gas kinematics of cluster galaxies at this redshift. By separately estimating the rotation curve of the approaching and receding sides of each galaxy via kinematic modeling, we quantify the difference in total circular velocity to characterize the overall kinematic asymmetry of each galaxy. 3/14 of the galaxies in our sample that we are able to model have similar degrees of asymmetry as that observed in galaxies in the field at similar redshift based on observations of mainly ionized gas. However, this leaves 11/14 galaxies in our sample with significantly higher asymmetry, and some of these galaxies have degrees of asymmetry of up to ∼50 times higher than field galaxies observed at similar redshift. Some of these extreme cases also have one-sided tail-like morphology seen in the molecular gas, supporting a scenario of tidal and/or ram pressure interaction. Such stark differences in the kinematic asymmetry in clusters versus the field suggest the evolutionary influence of dense environments, established as being a major driver of galaxy evolution at low redshift, is also active in the high-redshift universe.