arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1107.5579astro-ph.CO
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活动星系核驱动的星系尺度外流

Galaxy-Scale Outflows Driven by Active Galactic Nuclei

Jackson DeBuhr, Eliot Quataert, Chung-Pei Ma

摘要:

我们提出了流体动力学模拟的主要合并的星系和研究的影响,风所产生的活动星系核(AGN)对星际气体的AGN的宿主星系。我们考虑风的初始速度约为10,000 km/s,初始动量(能量)通量约为τ_w L/c(约为0.01 τ_w L),τ_w约为1-10。活动星系核风向上扫过,冲击波加热了周围的星际气体,导致了速度约为1000 km/s的星系尺度外流,最大质量外流率与恒星形成率相当,总喷出气体质量约为3 x 10^9太阳质量。活动星系核驱动的星系外流需要大的动量通量,τ_w > 3,以抑制黑洞宿主星系中的恒星形成和吸积。较弱的活动星系核风(τ_w < 3)仍然产生适度的星系尺度外流,但外流对周围的星际气体几乎没有全球影响。我们认为,这种机制的活动星系核的反馈可以合理地产生高速外流观察到的后星暴星系和大量的分子和原子外流观察到的本地超亮红外星系。此外,我们还推断出,从超亮红外星系流出的气流具有τ_w ~ 10,与我们发现的活动星系核风调节黑洞生长和建立M_BH-σ关系所需的量相当。最后,我们讨论的理论机制,可以导致AGN风的质量负载和动量/能量通量大到足以有显着的影响星系形成。

英文摘要:

We present hydrodynamical simulations of major mergers of galaxies and study the effects of winds produced by active galactic nuclei (AGN) on interstellar gas in the AGN's host galaxy. We consider winds with initial velocities ~ 10,000 km/s and an initial momentum (energy) flux of ~ tau_w L/c (~ 0.01 tau_w L), with tau_w ~ 1-10. The AGN wind sweeps up and shock heats the surrounding interstellar gas, leading to a galaxy-scale outflow with velocities ~ 1000 km/s, peak mass outflow rates comparable to the star formation rate, and a total ejected gas mass ~ 3 x 10^9 M_sun. Large momentum fluxes, tau_w > 3, are required for the AGN-driven galactic outflow to suppress star formation and accretion in the black hole's host galaxy. Less powerful AGN winds (tau_w < 3) still produce a modest galaxy-scale outflow, but the outflow has little global effect on the ambient interstellar gas. We argue that this mechanism of AGN feedback can plausibly produce the high velocity outflows observed in post-starburst galaxies and the massive molecular and atomic outflows observed in local ultra-luminous infrared galaxies. Moreover, the outflows from local ultra-luminous infrared galaxies are inferred to have tau_w ~ 10, comparable to what we find is required for AGN winds to regulate the growth of black holes and set the M_BH-sigma relation. We conclude by discussing theoretical mechanisms that can lead to AGN wind mass-loading and momentum/energy fluxes large enough to have a significant impact on galaxy formation.

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