标题： 星系气体动力学不对齐在EAGLE中的研究：不对齐星系中超大质量黑洞的增强增长 显示英文标题

标题： Stellar-gas kinematic misalignments in EAGLE: enhanced SMBH growth in misaligned galaxies

摘要： 恒星-气体运动失调是一种瞬态现象，在$\sim11\%$的本星系群中观测到。 根据目前的模型，失调的气体预计将在$\sim0.1$ Gyr的时间尺度上失去角动量并放松到银河系平面，从而将气体推向星系的中心区域。 最近的观测研究发现，在失调的星系中，活动星系核的发生率更高。 我们使用EAGLE模拟来探索恒星-气体失调与中心黑洞（BH）活动增强（介于$0 < z < 1$之间）之间的联系。 我们选取了恒星质量为 $M_{*}\geqslant \mathrm{10^{9.5}}$ M$_\odot$ 的 $\sim5600$ 个星系作为样本，这些星系具有长期恒星-气体排列、反向旋转和不稳定错位（非共面）的特征。 在 $0.5$ Gyr的时间窗口内，我们发现经历不稳定错位的星系在弛豫过程中系统性地增强了黑洞的生长。 长期反向旋转的星系与排列整齐的星系相比，黑洞的生长几乎没有差异。 我们认为，这种增强的黑洞生长是由不稳定错位气体盘中角动量损失所驱动的，这种损失能够将气体向内推向黑洞附近。 在$z\approx0.1$，我们发现那些在前$\approx2$ Gyr 内有更长时间处于不稳定恒星-气体运动学错位的星系中，超质量黑洞的出现频率更高，这与对照行为一致的星系相比。 与观测结果一致，我们得出结论，在EAGLE中，错位系统中的黑洞活动增强，并且超质量黑洞的存在可能表明过去曾出现过恒星-气体运动学错位。 显示英文摘要

摘要： Stellar-gas kinematic misalignments are a transient phenomenon observed in $\sim11\%$ of the local galaxy population. According to current models, misaligned gas is expected to lose angular momentum and relax into the galactic plane on timescales of $\sim0.1$ Gyr, driving gas toward the central regions of the galaxy. Recent observational studies have found a higher incidence of active galactic nuclei in misaligned galaxies. We use the EAGLE simulation to explore the connection between stellar-gas misalignments and enhanced central black hole (BH) activity between $0<z<1$. We use a sample of $\sim5600$ galaxies with a stellar mass of $M_{*}\geqslant \mathrm{10^{9.5}}$ M$_\odot$ that feature long-lived stellar-gas alignment, counter-rotation, and unstable misalignments (non-coplanarity). Over time windows of $0.5$ Gyr, we find that galaxies experiencing an unstable misalignment have systematically enhanced BH growth during relaxation. Galaxies with long-term counter-rotation show little difference in BH growth compared to aligned galaxies. We suggest that this enhanced BH growth is driven by loss of angular momentum in unstable misaligned gas discs which is able to drive gas inward toward the vicinity of the BH. At $z\approx0.1$, we find a greater incidence of overmassive BHs in galaxies that have spent a greater fraction of time with unstable stellar-gas kinematic misalignments over the preceding $\approx2$ Gyr compared to control samples of aligned galaxies. In agreement with observations, we conclude that BH activity is enhanced in misaligned systems in EAGLE and suggest that the presence of overmassive BHs may be indicative of a past stellar-gas kinematic misalignment.