Evidence for Inside-out Galaxy Growth and Quenching of a z ∼ 2 Compact Galaxy From High-resolution Molecular Gas Imaging
Evidence for Inside-out Galaxy Growth and Quenching of a z ∼ 2 Compact Galaxy From High-resolution Molecular Gas Imaging
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DOI：
10.3847/1538-4357/ab3804
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
J. Spilker;R. Bezanson;B. Weiner;K. Whitaker;C. Williams
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文献类型：
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作者：
J. Spilker;R. Bezanson;B. Weiner;K. Whitaker;C. Williams
我们提出了高空间分辨率成像的CO（1-0）线的卡尔G。宇宙27289的央斯基甚大阵，一个巨大的致密恒星形成星系，z = 2.234。这个星系被选中是因为它的结构类似于z 2被动星系。我们以前的观察表明，它是非常气体贫相对于典型的SFG在这些红移，与快速过渡到静止的分子气体耗尽一致。新的数据表明，分子气体分数和分子气体耗尽时间/SFR在星系中心1-2 kpc处较低，在较大半径处上升至1 - 2-4 kpc。这些观测结果与COSMOS 27289将在外围之前立即停止内部区域的星星形成的情况一致，即，这是第一次通过对高红移宇宙中分子气体的观测发现这种现象。我们发现与星系猝灭的流体动力学模拟具有良好的定性和定量一致性，其中由于气体的快速消耗和疏散气体中心区域的流出，分子气体的中心抑制出现。我们的结果为星星形成的由内而外猝灭提供了独立证据，作为z 2静止星系的合理形成机制。
We present high spatial resolution imaging of the CO(1–0) line from the Karl G. Jansky Very Large Array of COSMOS 27289, a massive, compact star-forming galaxy (SFG) at z = 2.234. This galaxy was selected because of its structural similarity to z ∼ 2 passive galaxies. Our previous observations showed that it is very gas poor with respect to typical SFGs at these redshifts, consistent with a rapid transition to quiescence as the molecular gas is depleted. The new data show that both the molecular gas fraction, , and the molecular gas depletion time, /SFR, are lower in the central 1–2 kpc of the galaxy and rise at larger radii ∼2–4 kpc. These observations are consistent with a scenario in which COSMOS 27289 will imminently cease star formation in the inner regions before the outskirts, i.e., inside-out quenching, the first time this phenomenon has been seen via observations of molecular gas in the high-redshift universe. We find good qualitative and quantitative agreement with a hydrodynamical simulation of galaxy quenching, in which the central suppression of molecular gas arises due to rapid gas consumption and outflows that evacuate the central regions of gas. Our results provide independent evidence for inside-out quenching of star formation as a plausible formation mechanism for z ∼ 2 quiescent galaxies.