Modelling feedback from stars and black holes in galaxy mergers
Modelling feedback from stars and black holes in galaxy mergers
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DOI：
10.1111/j.1365-2966.2005.09238.x
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发表时间：
2004-11
影响因子：
4.8
通讯作者：
V. Springel;T. Matteo;L. Hernquist
中科院分区：
文献类型：
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作者：
V. Springel;T. Matteo;L. Hernquist
我们描述的技术，将反馈星星形成和黑洞（BH）吸积到模拟孤立和合并的星系。目前，这些过程的细节无法在银河系尺度的模拟中解决。因此，我们的基本方法涉及形成粗粒度的星际介质（ISM）和BH吸积的属性表示从基本的物理假设，使这些影响可以包括在解决尺度。我们说明了我们的方法使用多相描述的恒星形成气体。来自星星形成的反馈使高密度气体加压，改变了其有效状态方程（EOS）。我们表明，这使得更大的气体比例比可能在早期的数值工作的稳定星系模型的建设。我们扩展的模型，包括处理气体吸积到中央超大质量黑洞的星系。假设热耦合的一小部分的热光度的吸积BH周围的气体，我们展示了这种反馈如何调节BH的增长。在富含气体的星系合并，我们观察到一个复杂的相互作用时，恒星爆发和中央活动星系核（AGN）活动的潮汐相互作用触发强烈的气体核流入。一旦一个吸积的超大质量黑洞增长到一个临界尺寸，反馈终止了它的进一步增长，并在一个强大的类星体驱动的风中从中心区域排出气体。因此，我们的模拟方法是能够解决耦合过程的气体动力学，星星的形成和BH吸积在星系的形成。
We describe techniques for incorporating feedback from star formation and black hole (BH) accretion into simulations of isolated and merging galaxies. At present, the details of these processes cannot be resolved in simulations on galactic scales. Our basic approach therefore involves forming coarse-grained representations of the properties of the interstellar medium (ISM) and BH accretion starting from basic physical assumptions, so that the impact of these effects can be included on resolved scales. We illustrate our method using a multiphase description of star-forming gas. Feedback from star formation pressurizes highly overdense gas, altering its effective equation of state (EOS). We show that this allows the construction of stable galaxy models with much larger gas fractions than possible in earlier numerical work. We extend the model by including a treatment of gas accretion onto central supermassive BHs in galaxies. Assuming thermal coupling of a small fraction of the bolometric luminosity of accreting BHs to the surrounding gas, we show how this feedback regulates the growth of BHs. In gas-rich mergers of galaxies, we observe a complex interplay between starbursts and central active galactic nuclei (AGN) activity when the tidal interaction triggers intense nuclear inflows of gas. Once an accreting supermassive BH has grown to a critical size, feedback terminates its further growth and expels gas from the central region in a powerful quasar-driven wind. Our simulation methodology is therefore able to address the coupled processes of gas dynamics, star formation and BH accretion during the formation of galaxies.