THE FIRST MASSIVE BLACK HOLE SEEDS AND THEIR HOSTS
THE FIRST MASSIVE BLACK HOLE SEEDS AND THEIR HOSTS
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DOI：
10.1088/0004-637x/742/1/13
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
J. Bellovary;M. Volonteri;F. Governato;S. Shen;T. Quinn;J. Wadsley
中科院分区：
文献类型：
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作者：
J. Bellovary;M. Volonteri;F. Governato;S. Shen;T. Quinn;J. Wadsley
我们研究了高红移星系中第一批大质量黑洞(MBH)的形成，目的是提供对哪些星系拥有或不拥有MBH的洞察。在宇宙SPH+N体模拟中，我们采用了一种新的方法来形成星系晕中的种子黑洞。MBH晶种的形成由局部气体密度、温度和金属丰度直接决定，并受MBH形成的物理模型的推动。我们探索了种子黑洞种群作为晕质量和红移的函数，并研究了不同的MBH种子形成效率如何影响黑洞和它们的宿主之间的关系。种子黑洞倾向于形成质量在107M-109M☉之间的晕，并且由于金属在整个星系际介质中的扩散，在z=5附近的形成速率被抑制。我们发现，MBH的形成时间和黑洞的占有率是宿主晕质量的函数。当z=5时，质量为Mhalo>；3×109M☉的晕与种子形成效率无关，而较小晕的占有率随着黑洞形成效率的提高而增加。我们的模拟解释了为什么在一些无球和矮小星系中发现了MBH，但我们也预测它们在低质量系统中会越来越罕见。
We investigate the formation of the first massive black holes (MBHs) in high redshift galaxies, with the goal of providing insights to which galaxies do or do not host MBHs. We adopt a novel approach to forming seed black holes in galaxy halos in cosmological SPH+N-body simulations. The formation of MBH seeds is dictated directly by the local gas density, temperature, and metallicity, and motivated by physical models of MBH formation. We explore seed black hole populations as a function of halo mass and redshift, and examine how varying the efficiency of MBH seed formation affects the relationship between black holes and their hosts. Seed black holes tend to form in halos with mass between 107 and 109 M☉, and the formation rate is suppressed around z = 5 due to the diffusion of metals throughout the intergalactic medium. We find that the time of MBH formation and the occupation fraction of black holes are a function of the host halo mass. By z = 5, halos with mass Mhalo > 3 × 109 M☉ host MBHs regardless of the efficiency of seed formation, while the occupation fraction for smaller halos increases with black hole formation efficiency. Our simulations explain why MBHs are found in some bulgeless and dwarf galaxies, but we also predict that their occurrence becomes rarer and rarer in low-mass systems.