Formation and evolution of young massive clusters in galaxy mergers: the SMUGGLE view
Formation and evolution of young massive clusters in galaxy mergers: the SMUGGLE view
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星系合并中年轻大质量星团的形成和演化：SMUGGLE 观点
DOI：
10.1093/mnras/stac1136
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发表时间：
2022
影响因子：
4.8
通讯作者：
Torrey, Paul
中科院分区：
文献类型：
--
作者：
Li, Hui;Vogelsberger, Mark;Bryan, Greg L.;Marinacci, Federico;Sales, Laura V.;Torrey, Paul
星系合并是已知的主机丰富的年轻大质量星系团（YMC）人口，其形成机制仍然没有得到很好的理解。在这里，我们提出了一个高分辨率的星系合并模拟与明确的星星形成和恒星反馈处方，以调查合并如何影响星际介质和YMC的属性。与孤立星系的受控模拟相比，在合并中，致密和高压气体的质量分数要高得多。因此，分子云和YMC的质量函数变得更浅，并延伸到更高的质量。此外，团簇形成效率显着提高，并与星星形成率，表面密度和气体压力呈正相关。我们跟踪了YMCs的轨道，并研究了合并过程中潮汐场的时间演化。在合并初期，潮汐场强度与YMC质量λtid λ M0.71正相关，系统地影响了YMC质量函数的形状和年龄分布。在稍后的时间，大多数YMC紧密跟随其宿主星系的轨道，由于动力学摩擦而逐渐沉入合并残余的中心，并通过有效的潮汐破坏迅速溶解。有趣的是，在第一次通过期间形成的YMCs，主要是在潮汐尾巴和桥梁，分布在广泛的银河中心半径，大大增加了他们的生存能力，因为在合并系统的外围弱得多的潮汐场。这些YMC是有希望的球状星团的候选者，生存到今天。
Galaxy mergers are known to host abundant young massive cluster (YMC) populations, whose formation mechanism is still not well-understood. Here, we present a high-resolution galaxy merger simulation with explicit star formation and stellar feedback prescriptions to investigate how mergers affect the properties of the interstellar medium and YMCs. Compared with a controlled simulation of an isolated galaxy, the mass fraction of dense and high-pressure gas is much higher in mergers. Consequently, the mass function of both molecular clouds and YMCs becomes shallower and extends to higher masses. Moreover, cluster formation efficiency is significantly enhanced and correlates positively with the star formation rate surface density and gas pressure. We track the orbits of YMCs and investigate the time evolution of tidal fields during the course of the merger. At an early stage of the merger, the tidal field strength correlates positively with YMC mass, λtid∝M0.71, which systematically affects the shape of the mass function and age distribution of the YMCs. At later times, most YMCs closely follow the orbits of their host galaxies, gradually sinking into the centre of the merger remnant due to dynamical friction, and are quickly dissolved via efficient tidal disruption. Interestingly, YMCs formed during the first passage, mostly in tidal tails and bridges, are distributed over a wide range of galactocentric radii, greatly increasing their survivability because of the much weaker tidal field in the outskirts of the merger system. These YMCs are promising candidates for globular clusters that survive to the present day.