AI 中文总结
本文针对超致密矮星系中大质量黑洞起源不明的问题，提出AGB恒星气体在中等质量黑洞周围形成吸积盘为黑洞供能的机制，通过光滑粒子流体动力学模拟验证了该机制的可行性，为观测到的超致密矮星系的黑洞形成提供了验证方向。
AI 中文摘要
近期观测发现，许多超致密矮星系（UCD）包含大质量黑洞（MBH），其质量通常占UCD总质量的10%-15%，部分甚至高达40%。然而，UCD最初是由大质量黑洞形成，还是从中等质量黑洞（IMBH）演化而来，目前尚不清楚。本文提出一种机制：渐近巨星分支（AGB）恒星抛射出的气体在中等质量黑洞周围形成吸积盘，为黑洞生长提供燃料。我们采用光滑粒子流体动力学模拟，一方面模拟气体盘的形成与演化，该气体盘最终可演化成吸积盘；另一方面研究气体盘的特性如何依赖于模型。研究发现，气体盘的质量随UCD质量的增长幅度大于随中等质量黑洞质量的增长幅度。对于质量为100倍太阳质量（100 M☉）的低质量中等质量黑洞，大部分气体质量可被束缚在盘中，这表明低质量黑洞可利用所提出的机制。阻碍吸积盘形成的主要因素是盘中新恒星的形成，这不仅会导致气体被移除，还会通过引力扰动产生影响。最后，对黑洞总生长量的估算列出了一系列观测到的UCD，这些UCD可能通过所提出的机制形成了大质量黑洞，这对验证该机制具有重要意义。未来针对此类UCD形成的模拟将有助于呈现本文研究结果的完整图景。
英文摘要
Recent observations have found many ultra-compact dwarf galaxies (UCDs) that contain massive black holes (MBHs) typically consisting of $10\%-15\%$ of their total mass, with some as high as $40\%$. However, whether UCDs initially started with MBHs or grew from intermediate-mass black holes (IMBHs) is unclear. We propose a mechanism in which AGB stars have their gas ejected which forms an accretion disk around an IMBH to fuel BH growth. We used smooth particle hydrodynamical simulations to (i) model the creation and evolution of gas disks that can finally evolve into accretion disks and to investigate (ii) how the properties of the gas disk depend on the model. We find that the amount of mass in the disk increases more with UCD mass than with IMBH mass. For lower-mass IMBHs of $100 \text{ M}_\odot$, a majority of the gas mass present can be trapped in a disk, leading to the idea that lower-mass BHs can utilise the proposed mechanism. The main mechanism working against accretion disk formation is the creation of new stars within the disk, not just through the removal of gas but through gravitational disruption as well. Finally, an estimation of the total BH growth provides a list of observed UCDs which could have formed MBHs using the proposed mechanism which can be useful for verifying the proposed mechanism. Future simulations aimed at modelling the formation of such UCDs can be employed to provide a full picture of the results presented in this paper.
Comments22 pages, 26 figures
