The Effect of Galaxy Interactions on Molecular Gas Properties
The Effect of Galaxy Interactions on Molecular Gas Properties
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DOI：
10.3847/1538-4357/aaeb92
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
H. Pan;Lihwai Lin;B. Hsieh;T. Xiao;Yang Gao;S. Ellison;J. Scudder;J. Barrera-Ballesteros;
中科院分区：
文献类型：
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作者：
H. Pan;Lihwai Lin;B. Hsieh;T. Xiao;Yang Gao;S. Ellison;J. Scudder;J. Barrera-Ballesteros;
星系间的相互作用通常伴随着恒星形成速率的提高。由于分子气体对恒星形成至关重要，因此确定星系相互作用是否影响分子气体性质以及影响程度是至关重要的。我们通过研究58个成对星系和154个对照星系的样本来研究相互作用对整体分子气体性质的影响。分子气体性质由JCMT， PMO和CSO望远镜的观测确定，并辅以xCOLD gas和JINGLE在12CO（1-0）和12CO（2-1）的调查数据。星系中的SFR、气体质量（）和气体分数（fgas）都比红移、质量和有效半径匹配的对照提高了约2.5倍，而恒星形成效率（SFE≡SFR/）的提高不到2倍。我们还发现，SFR和fgas的增强随着对分离的减小而增加，并且在恒星质量比较小的系统中更大。相反，SFE仅在近对（分离<20 kpc）和等质量体系中增强；因此，大多数星系成对地位于SFR -平面上与对照相同的参数空间。这是第一次用一个相对较大的样本和一个为单个星系精心挑选的控制样本来统计地探测分子气体特性对合并构型的依赖。我们得出结论，星系的相互作用确实改变了分子气体的性质，尽管这种影响的强度取决于合并的结构。
Galaxy interactions are often accompanied by an enhanced star formation rate (SFR). Since molecular gas is essential for star formation, it is vital to establish whether and by how much galaxy interactions affect the molecular gas properties. We investigate the effect of interactions on global molecular gas properties by studying a sample of 58 galaxies in pairs and 154 control galaxies. Molecular gas properties are determined from observations with the JCMT, PMO, and CSO telescopes and supplemented with data from the xCOLD GASS and JINGLE surveys at 12CO(1–0) and 12CO(2–1). The SFR, gas mass ( ), and gas fraction (fgas) are all enhanced in galaxies in pairs by ∼2.5 times compared to the controls matched in redshift, mass, and effective radius, while the enhancement of star formation efficiency (SFE ≡SFR/ ) is less than a factor of 2. We also find that the enhancements in SFR, and fgas, increase with decreasing pair separation and are larger in systems with smaller stellar mass ratio. Conversely, the SFE is only enhanced in close pairs (separation <20 kpc) and equal-mass systems; therefore, most galaxies in pairs lie in the same parameter space on the SFR– plane as controls. This is the first time that the dependence of molecular gas properties on merger configurations is probed statistically with a relatively large sample and a carefully selected control sample for individual galaxies. We conclude that galaxy interactions do modify the molecular gas properties, although the strength of the effect is dependent on merger configuration.