How gas flows shape the stellar-halo mass relation in the EAGLE simulation
How gas flows shape the stellar-halo mass relation in the EAGLE simulation
复制标题
EAGLE 模拟中气体流动如何影响恒星与光晕的质量关系
DOI：
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
J. Schaye
中科院分区：
文献类型：
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作者：
P. Mitchell;J. Schaye
观测到的星系恒星质量函数和预测的暗物质晕质量函数之间的形状差异通常主要由反馈过程来解释。反馈可以通过将气体赶出星系，通过调制气体第一次进入星系（即，预防性反馈），并通过激发喷泉流回收风材料。我们提出并应用一种方法来解开这些影响的流体动力学模拟星系的形成。我们建立了一个线性耦合微分方程模型，通过构造再现了EAGLE宇宙学模拟中星系和晕的气体流动。通过改变该模型中的个别项，我们隔离了星星形成、通过流出的喷射、第一次流入和风再循环对SHM关系的相对影响。我们发现，对于晕质量M200 < 10 M的SHM关系主要是由从星系和晕的喷射组合形成的，而对于较大的M200预防性反馈也很重要。再循环的影响和星星形成的效率很小。我们表明，如果，而不是M200，我们使用的累积质量的暗物质，下降的第一次，SHM关系的演变几乎消失。这表明，演化是由于晕质量的定义，而不是星系形成的物理效率的演变。最后，我们证明，在环银河系介质的质量是更敏感的气体流动，特别是回收，比恒星和星际介质的情况。
The difference in shape between the observed galaxy stellar mass function and the predicted dark matter halo mass function is generally explained primarily by feedback processes. Feedback can shape the stellar-halo mass (SHM) relation by driving gas out of galaxies, by modulating the first-time infall of gas onto galaxies (i.e., preventative feedback), and by instigating fountain flows of recycled wind material. We present and apply a method to disentangle these effects for hydrodynamical simulations of galaxy formation. We build a model of linear coupled differential equations that by construction reproduces the flows of gas onto and out of galaxies and haloes in the EAGLE cosmological simulation. By varying individual terms in this model, we isolate the relative effects of star formation, ejection via outflow, first-time inflow and wind recycling on the SHM relation. We find that for halo masses M200 < 10 M the SHM relation is shaped primarily by a combination of ejection from galaxies and haloes, while for larger M200 preventative feedback is also important. The effects of recycling and the efficiency of star formation are small. We show that if, instead of M200, we use the cumulative mass of dark matter that fell in for the first time, the evolution of the SHM relation nearly vanishes. This suggests that the evolution is due to the definition of halo mass rather than to an evolving physical efficiency of galaxy formation. Finally, we demonstrate that the mass in the circum-galactic medium is much more sensitive to gas flows, especially recycling, than is the case for stars and the interstellar medium.