Galaxy mergers can rapidly shut down star formation
Galaxy mergers can rapidly shut down star formation
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星系合并可以迅速阻止恒星形成
DOI：
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发表时间：
2022
影响因子：
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通讯作者：
S. Gwyn
中科院分区：
文献类型：
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作者：
S. Ellison;S. Wilkinson;J. Woo;Ho;V. Wild;R. Bickley;D. Patton;S. Quai;S. Gwyn
星系合并引发了恒星的形成和中央超大质量黑洞的吸积。由于随后的能量反馈过程，长期以来人们一直认为恒星形成可能会在星系合并残余物中迅速消失。然而，这种对后期合并中广泛、快速淬灭的预测最近受到现代模拟的质疑，并且从未经过观察检验。在这里，我们对合并序列中长期预测的结束阶段进行了第一次实证评估。基于从紫外近红外光学北方巡天 (UNIONS) 中确定的约 500 个合并后星系的样本，我们发现，在前一次星爆发后迅速停止恒星形成的合并后星系的频率比非合并星系对照样本中预期的频率高 30-60 倍。在近距离星系对的样本中没有发现这样的过量现象，这表明合并确实可以导致恒星形成迅速停止，但这个过程仅在合并后才会显现。
Galaxy mergers trigger both star formation and accretion on to the central supermassive black hole. As a result of subsequent energetic feedback processes, it has long been proposed that star formation may be promptly extinguished in galaxy merger remnants. However, this prediction of widespread, rapid quenching in late stage mergers has been recently called into question with modern simulations and has never been tested observationally. Here we perform the first empirical assessment of the long-predicted end phase in the merger sequence. Based on a sample of ∼ 500 post-mergers identified from the Ultraviolet Near Infrared Optical Northern Survey (UNIONS), we show that the frequency of post-merger galaxies that have rapidly shutdown their star formation following a previous starburst is 30-60 times higher than expected from a control sample of non-merging galaxies. No such excess is found in a sample of close galaxy pairs, demonstrating that mergers can indeed lead to a rapid halt to star formation, but that this process only manifests after coalescence.