Mass supply to active galactic nuclei by self-gravitational instability of gas

提出活动星系核释放的巨大能量来源于吸积到大质量黑洞中的气体的引力能。然而，由于气体主要分布在银河系中心之外，因此需要从气体的角动量转移来将气体从银河系中心之外供应到银河系中心。在核星暴星系中也需要类似的质量供给机制，在本研究中，我研究了弱棒势和fas的自引力对星系中心区气体运动的影响，以表明这些效应对角动量转移的影响是非常有效的。数值计算结果表明，气体聚集到Lindblad共振半径内后，由于自引力不稳定性形成气体团簇，由于气体团簇之间的碰撞造成能量损失和角动量损失，气体团簇向星系中心供气。第二年，将研究扩展到自引力气体和恒星的双分量模型，因为气体自引力对恒星系统来说是不可忽略的。最初，我假设自洽，弱杆势的恒星系统和研究气体和恒星运动。计算结果表明，气体通过Lindblad共振积累后，中心质量浓度的变化改变了恒星的结构，弱的棒结构由于气体与恒星的相互作用而变得更弱。这些结果表明，当足够的气体集中到银河系中心时，探测棒状结构是很容易的。我已经将本研究的一部分作为科学论文发表，我准备提交另一部分的论文。

It is proposed that huge energy released in active galactic nuclei comes from gravitational energy of gas accreting into massive black hole. However, since gas distributes mainly outside a galactic center, angular momentum transfer from gas is needed to supply gas from the outside galactic center to the galactic center. Similar mass supply mechanism is needed in nuclear starburst galaxies.In this research, I study the effects of weak bar potential and self-gravity of fas on the gas motion in galactic central region to show that angular momentum transfer by these effects is very effect.In the first year, I study self-gravitational gas motion in a fixed galaxy potential with weak bar component by numerical hydrodynamics. I got the numerical results that, after gas is accumulated into the radius of the inner Lindblad resonance, gas clumps are formed by self-gravitational instablility and gas supply into the galactic center due to the energy loss and angular momentum loss by collisions between these clumps.In the second year, I extend the study to the two-component model of self-gravitational gas and stars, since self-gravity of gas can not be neglected for stellar system. Initially I assumed self-consistent, weak bar potential of a stellar system and study gas and stellar motion. Our numerical results show that, after gas is accumulated by the inner Lindblad resonance, central mass concentration changes the stellar structure and weak barred structure become weaker by the gas and stellar interaction. These results indicate that, when sufficient gas concentrates into the galactic center, it is gard to detect bar structure.I have already published some parts of this study as scientific papers and I prepare to submit a paper for the other part.