One–Two Quench: A Double Minor Merger Scenario
One–Two Quench: A Double Minor Merger Scenario
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DOI：
10.3847/1538-4357/abeb15
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发表时间：
2020-09
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影响因子：
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通讯作者：
N. N. Sanchez-N.;M. Tremmel;J. Werk;A. Pontzen;C. Christensen;T. Quinn;S. Loebman;Akaxia Cruz
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文献类型：
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作者：
N. N. Sanchez-N.;M. Tremmel;J. Werk;A. Pontzen;C. Christensen;T. Quinn;S. Loebman;Akaxia Cruz
使用N体+光滑粒子流体动力学代码，ChaNGa，我们确定了两个合并驱动的过程磁盘中断和超大质量黑洞（SMBH）的反馈，共同工作，淬火L * 星系超过7 Gyr。具体来说，我们研究的星星形成的模拟银河系（MW）模拟，由两个小卫星的相互作用驱动的停止。这两个相互作用都发生在100亿年内，卫星的质量都比它们的类兆瓦宿主星系小5-20倍。使用Roth等人的基因改造过程，我们生成了一组四个放大的MW质量星系，由于它们的组装历史的微小变化，所有这些星系都表现出独特的星星形成历史。在这四种情况中的两种情况下，星系被z = 1淬灭。因为这些都是受控的修改，我们能够隔离两个紧密间隔的小合并事件的影响，其相对时间决定了MW质量的主星系是否熄灭。这一个两个冲压工程：（1）燃料SMBH在其峰值吸积率和（2）破坏冷，气态盘的主机星系。最终的结果是，来自SMBH的反馈彻底而突然地结束了星系的星星形成。我们寻找并找到一个类似的淬火事件在Romulus 25，流体动力学（25 Mpc）3体积模拟，表明该机制是常见的，即使在一个小样本的MW质量淬火星系在z = 0。
Using the N-body+Smoothed particle hydrodynamics code, ChaNGa, we identify two merger-driven processes—disk disruption and supermassive black hole (SMBH) feedback—which work together to quench L * galaxies for over 7 Gyr. Specifically, we examine the cessation of star formation in a simulated Milky Way (MW) analog, driven by an interaction with two minor satellites. Both interactions occur within ∼100 Myr of each other, and the satellites both have masses 5–20 times smaller than that of their MW-like host galaxy. Using the genetic modification process of Roth et al., we generate a set of four zoom-in, MW-mass galaxies all of which exhibit unique star formation histories due to small changes to their assembly histories. In two of these four cases, the galaxy is quenched by z = 1. Because these are controlled modifications, we are able to isolate the effects of two closely spaced minor merger events, the relative timing of which determines whether the MW-mass main galaxy quenches. This one–two punch works to: (1) fuel the SMBH at its peak accretion rate and (2) disrupt the cold, gaseous disk of the host galaxy. The end result is that feedback from the SMBH thoroughly and abruptly ends the star formation of the galaxy by z ≈ 1. We search for and find a similar quenching event in Romulus25, a hydrodynamical (25 Mpc)3 volume simulation, demonstrating that the mechanism is common enough to occur even in a small sample of MW-mass quenched galaxies at z = 0.