The formation of the first quasars: The black hole seeds, accretion and feedback models
The formation of the first quasars: The black hole seeds, accretion and feedback models
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第一个类星体的形成：黑洞种子、吸积和反馈模型
DOI：
10.1093/mnras/stac1556
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发表时间：
2020
影响因子：
4.8
通讯作者：
L. Hernquist
中科院分区：
文献类型：
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作者：
Qirong Zhu;Yue;Yiting Li;Moupiya Maji;H. Yajima;R. Schneider;L. Hernquist
超大质量黑洞(SMBH)通常被认为是z≳6上观测到的发光类星体的中心引擎，但它们的天体物理起源仍然难以捉摸。为了研究这些遥远类星体的形成，我们对一个有利的晕进行了一系列放大模拟，它的质量为$\sim 10^{13}\，在z=6时为M_(OOT)$，并且有多次主要合并的历史，这是BH生长的理想条件。我们测试了$10-10^6的BH种子，以及各种吸积和反馈模型，包括薄盘吸积和细盘吸积。我们发现，充足的气体供应和有效的角动量输运是BH吸积的关键，而最终的BH质量强烈地依赖于种子质量和辐射效率，而种子质量和辐射效率又取决于反馈模型。在我们的模拟中，在薄和细盘吸积模型中，重的种子M10^4，RmM_OOT都可以被z∼6快速生长到$10^8-10^9的SMBH，只要具有λEdd≳0.6的近爱丁顿吸积的占空比保持在$4 0{Rm Ppercent}}$。特别是，对于一个$10^5的种子，我们的基准模型和无自旋的超临界吸积模型都产生了明亮的类星体，在z∼7.5时SMBHs为$10^9，rM Modot。另一方面，在我们的模拟中，光种子$Lesssim 10^3，Rm M_(Odot)$不能通过z∼6长到$10^8，\rM_(Oot)$。我们警告说，由于我们的数值方法和物理模型的限制，结果是不确定的，我们强调有必要用更先进的方法进一步研究BH种子的生长。
Supermassive black holes (SMBHs) of $\sim 10^9\, \rm M_{\odot }$ are generally believed to be the central engines of the luminous quasars observed at z ≳ 6, but their astrophysical origin remains elusive. To investigate the formation of these distant quasars, we perform a suite of zoom-in simulations on a favorable halo, with a mass of $\sim 10^{13}\, \rm M_{\odot }$ at z = 6 and a history of multiple major mergers, ideal for BH growth. We test BH seeds of $10 - 10^6\, \rm M_{\odot }$, and various accretion and feedback models, including thin-disk and slim-disk accretion. We find that abundant gas supply and efficient angular momentum transport by gravitational torques are critical to BH accretion, and that the final BH mass depends strongly on the seed mass and radiative efficiency which in turn depends on feedback model. In our simulations, heavy seeds of $\gtrsim 10^4\, \rm M_{\odot }$ can grow rapidly to SMBHs of $10^8 - 10^9\, \rm M_{\odot }$ by z ∼6 in both thin and slim disk accretion models, provided that the duty cycle of near-Eddington accretion with an Eddington ratio λEdd ≳ 0.6 is maintained at $\gtrsim 40{{\ \rm per\ cent}}$. In particular, for a $10^5\, \rm M_{\odot }$ seed, both our fiducial model and the super-critical accretion model with no spin produce bright quasars with SMBHs of $\sim 10^9\, \rm M_{\odot }$ at z ∼ 7.5. On the other hand, the light seeds of $\lesssim 10^3\, \rm M_{\odot }$ failed to grow to $10^8\, \rm M_{\odot }$ by z ∼ 6 in our simulations. We caution that the results are inconclusive due to limitations of our numerical methods and physical models, and we stress the need for further investigations on the growth of BH seeds with more advanced methods.