COLD MOLECULAR GAS IN MERGER REMNANTS. I. FORMATION OF MOLECULAR GAS DISKS
COLD MOLECULAR GAS IN MERGER REMNANTS. I. FORMATION OF MOLECULAR GAS DISKS
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DOI：
10.1088/0067-0049/214/1/1
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
J. Ueda;D. Iono;M. Yun;A. Crocker;D. Narayanan;S. Komugi;D. Espada;B. Hatsukade;H. Kaneko
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文献类型：
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作者：
J. Ueda;D. Iono;M. Yun;A. Crocker;D. Narayanan;S. Komugi;D. Espada;B. Hatsukade;H. Kaneko
我们使用 ALMA、CARMA、亚毫米阵列和 Plateau de Bure 干涉仪获得的新的存档干涉图，对 37 个光学选择的局部合并遗迹进行了 ≲1 kpc 分辨率 12CO 成像研究。我们用野边山射电天文台 45 m 望远镜获得的单碟测量值来补充子样本，用于估计气体分子质量 (107 − 11 M☉) 并评估干涉测量中缺失的通量。在具有强大 CO 检测的源中，我们发现 80% (24/30) 的样本在其速度场中显示出旋转分子气盘（包括核环）的运动学特征，并且这些盘的尺寸在 1.1 kpc 到 9.3 kpc 之间变化很大。 54%的源中分子气盘的尺寸比K波段有效半径更紧凑。这些小气盘可能是由过去的气体流入形成的，这些气体流入是由潜在合并事件期间的动力学不稳定触发的。另一方面，其余（46%）的源具有相对于恒星成分延伸的气体盘，可能形成具有中央恒星核球的晚期型星系。我们对观测数据的新汇编表明，核气盘和扩展分子气盘在合并的最后阶段很常见。这一发现与最近对富含气体的祖盘的重大合并模拟是一致的。最后，我们认为在高红移下观察到的一些自转支持的湍流盘可能是由最近经历过一次重大合并的星系产生的。
We present the ≲1 kpc resolution 12CO imaging study of 37 optically selected local merger remnants using new and archival interferometric maps obtained with ALMA, CARMA, the Submillimeter Array, and the Plateau de Bure Interferometer. We supplement a sub-sample with single-dish measurements obtained at the Nobeyama Radio Observatory 45 m telescope for estimating the molecular gas mass (107 − 11 M☉) and evaluating the missing flux of the interferometric measurements. Among the sources with robust CO detections, we find that 80% (24/30) of the sample show kinematical signatures of rotating molecular gas disks (including nuclear rings) in their velocity fields, and the sizes of these disks vary significantly from 1.1 kpc to 9.3 kpc. The size of the molecular gas disks in 54% of the sources is more compact than the K-band effective radius. These small gas disks may have formed from a past gas inflow that was triggered by a dynamical instability during a potential merging event. On the other hand, the rest (46%) of the sources have gas disks that are extended relative to the stellar component, possibly forming a late-type galaxy with a central stellar bulge. Our new compilation of observational data suggests that nuclear and extended molecular gas disks are common in the final stages of mergers. This finding is consistent with recent major-merger simulations of gas-rich progenitor disks. Finally, we suggest that some of the rotation-supported turbulent disks observed at high redshifts may result from galaxies that have experienced a recent major merger.