COOLING, AGN FEEDBACK, AND STAR FORMATION IN SIMULATED COOL-CORE GALAXY CLUSTERS
COOLING, AGN FEEDBACK, AND STAR FORMATION IN SIMULATED COOL-CORE GALAXY CLUSTERS
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DOI：
10.1088/0004-637x/811/2/73
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发表时间：
2015-03
期刊：
影响因子：
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通讯作者：
Yuan Li;Greg L. Bryan;M. Ruszkowski;G. Voit;Brian W. O’Shea;M. Donahue
中科院分区：
文献类型：
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作者：
Yuan Li;Greg L. Bryan;M. Ruszkowski;G. Voit;Brian W. O’Shea;M. Donahue
冷核星系团中活动星系核（agn）反馈的数值模拟成功地避免了经典的冷却流，但往往产生过多的冷气体。我们进行了自适应网格模拟，包括动量驱动的AGN反馈、自引力、恒星形成和恒星反馈，重点研究了孤立冷核星团中冷却、AGN加热和恒星形成之间的相互作用。由AGN射流和湍流触发的冷团块形成了数十千兆元长的丝状结构。这种低温气体为恒星形成和超大质量黑洞（SMBH）提供能量，引发AGN爆发，增加星团内介质（ICM）的熵并降低其冷却速率。在1-2 Gyr内，恒星的形成完全消耗了冷空气，导致AGN的短暂关闭。ICM迅速冷却并重新形成多相气体，随后是另一个恒星形成周期/AGN爆发。在6.5 Gyr内，我们观察到三个这样的周期。我们模拟的星团与冷核星团的观测结果有很好的一致性。ICM冷却通过AGN加热动态平衡，并保留了冷芯外观。最小冷却时间与自由落体时间之比通常在几到20 ？>。恒星形成速率（SFR）的范围很广，从0到几百M⊙yr−1 ？>，平均为~ 40 M⊙yr−1 ？>。瞬时SMBH吸积速率在短时间尺度上变化较大，但其平均值与SFR相关性较好。没有恒星反馈或自引力的模拟也产生了类似的定性结果，但较低的SMBH反馈效率（0.1%比1%）导致恒星过多。
Numerical simulations of active galactic nuclei (AGNs) feedback in cool-core galaxy clusters have successfully avoided classical cooling flows, but often produce too much cold gas. We perform adaptive mesh simulations that include momentum-driven AGN feedback, self-gravity, star formation, and stellar feedback, focusing on the interplay between cooling, AGN heating, and star formation in an isolated cool-core cluster. Cold clumps triggered by AGN jets and turbulence form filamentary structures tens of kpc long. This cold gas feeds both star formation and the supermassive black hole (SMBH), triggering an AGN outburst that increases the entropy of the intracluster medium (ICM) and reduces its cooling rate. Within 1–2 Gyr, star formation completely consumes the cold gas, leading to a brief shutoff of the AGN. The ICM quickly cools and redevelops multiphase gas, followed by another cycle of star formation/AGN outburst. Within 6.5 Gyr, we observe three such cycles. There is good agreement between our simulated cluster and the observations of cool-core clusters. ICM cooling is dynamically balanced by AGN heating, and a cool-core appearance is preserved. The minimum cooling time to free-fall time ratio typically varies between a few and ≳ 20 ?> . The star formation rate (SFR) covers a wide range, from 0 to a few hundred M ⊙ yr − 1 ?> , with an average of ∼ 40 M ⊙ yr − 1 ?> . The instantaneous SMBH accretion rate shows large variations on short timescales, but the average value correlates well with the SFR. Simulations without stellar feedback or self-gravity produce qualitatively similar results, but a lower SMBH feedback efficiency (0.1% compared to 1%) results in too many stars.