Which AGN jets quench star formation in massive galaxies?
Which AGN jets quench star formation in massive galaxies?
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DOI：
10.1093/mnras/stab2021
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发表时间：
2021-02
影响因子：
4.8
通讯作者：
Kung-Yi Su;P. Hopkins;G. Bryan;R. Somerville;C. Hayward;D. Angl'es-Alc'azar;C. Faucher-Giguère;S. Wellons;J. Stern;Bryan A. Terrazas;T. K. Chan;Matthew E. Orr;C. Hummels;R. Feldmann;D. Kerevs
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文献类型：
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作者：
Kung-Yi Su;P. Hopkins;G. Bryan;R. Somerville;C. Hayward;D. Angl'es-Alc'azar;C. Faucher-Giguère;S. Wellons;J. Stern;Bryan A. Terrazas;T. K. Chan;Matthew E. Orr;C. Hummels;R. Feldmann;D. Kerevs
在没有额外加热的情况下，大质量星系（银河系质量以上）的晕气体的辐射冷却会产生超过观测到的冷气体或恒星。很可能需要来自活动星系核（AGN）喷流的加热，但喷流的性质仍不清楚。这对于星系模拟来说尤其具有挑战性，因为分辨率的数量级不足以解决喷流的形成和演化。在这样的尺度上，不确定的参数包括喷流能量形式[动能、热能、宇宙射线（CR）];能量、动量和质量通量;磁场;张角;进动;占空比。我们调查这些参数在$10^{14}\，{\rm M}_{\odot }$晕使用高分辨率非宇宙学磁流体动力学模拟与FIRE-2（反馈在现实环境中）恒星反馈模型，传导和粘度。我们探讨的情况下，定性地满足观测约束的晕气体和CR为主的射流最有效地淬火星系提供CR压力支持和修改的热不稳定性。温和的相对论性（100 MeV或10010 K）热等离子体射流工作，但需要10倍以上的能量输入。对于固定的能量通量，具有较高比能（较长冷却时间）的射流更有效地淬火。对于这种晕质量，动力射流在淬熄时是低效的，除非它们具有宽的开口或旋进角。磁场的作用也不大，除非在动力学喷流模型中，当磁能通量达到1044 erg s-1时，喷流茧会明显变宽。一个成功的射流模型的标准是一个最佳的能量通量和足够宽的射流茧在冷却半径足够长的冷却时间。
Without additional heating, radiative cooling of the halo gas of massive galaxies (Milky Way-mass and above) produces cold gas or stars exceeding that observed. Heating from active galactic nucleus (AGN) jets is likely required, but the jet properties remain unclear. This is particularly challenging for galaxy simulations, where the resolution is orders-of-magnitude insufficient to resolve jet formation and evolution. On such scales, the uncertain parameters include the jet energy form [kinetic, thermal, cosmic ray (CR)]; energy, momentum, and mass flux; magnetic fields; opening angle; precession; and duty cycle. We investigate these parameters in a $10^{14}\, {\rm M}_{\odot }$ halo using high-resolution non-cosmological magnetohydrodynamic simulations with the FIRE-2 (Feedback In Realistic Environments) stellar feedback model, conduction, and viscosity. We explore which scenarios qualitatively meet observational constraints on the halo gas and show that CR-dominated jets most efficiently quench the galaxy by providing CR pressure support and modifying the thermal instability. Mildly relativistic (∼MeV or ∼1010K) thermal plasma jets work but require ∼10 times larger energy input. For fixed energy flux, jets with higher specific energy (longer cooling times) quench more effectively. For this halo mass, kinetic jets are inefficient at quenching unless they have wide opening or precession angles. Magnetic fields also matter less except when the magnetic energy flux reaches ≳ 1044 erg s−1 in a kinetic jet model, which significantly widens the jet cocoon. The criteria for a successful jet model are an optimal energy flux and a sufficiently wide jet cocoon with a long enough cooling time at the cooling radius.