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arXiv 1004.0857astro-ph.CO
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大质量黑洞-速度色散关系和晕重子分数:正AGN反馈情形

The massive black hole-velocity dispersion relation and the halo baryon fraction: a case for positive AGN feedback

Joe Silk, Adi Nusser

摘要:

力平衡的考虑对活动星系核辐射动量输出率$L/c$施加了限制,$L/c$能够驱动银河超级风并再现所观察到的黑洞质量和球体速度色散之间的$\mbh -σ$关系。我们表明,黑洞不能提供足够的辐射动量,仅凭压力就能将气体驱逐出去。能量驱动的风给出了最近分析所支持的$\mbh -σ$缩放,但一旦冷却被纳入,能量也会下降。我们建议,恒星形成的外流触发增强云间介质湍流压力和挤压云可以提供必要的推动,并提出可能的测试这一假设。我们的假设同时可以解释观测到的晕重子分数。

英文摘要:

Force balance considerations put a limit on the rate of AGN radiation momentum output, $L/c$, capable of driving galactic superwinds and reproducing the observed $\mbh -σ$ relation between black hole mass and spheroid velocity dispersion. We show that black holes cannot supply enough momentum in radiation to drive the gas out by pressure alone. Energy-driven winds give a $\mbh -σ$ scaling favoured by a recent analysis but also fall short energetically once cooling is incorporated. We propose that outflow-triggering of star formation by enhancing the intercloud medium turbulent pressure and squeezing clouds can supply the necessary boost, and suggest possible tests of this hypothesis. Our hypothesis simultaneously can account for the observed halo baryon fraction.

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