Dynamical modelling of the twisted galaxy PGC 046832
Dynamical modelling of the twisted galaxy PGC 046832
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扭曲星系的动态建模 PGC 046832
DOI：
10.1093/mnras/stab2852
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发表时间：
--
影响因子：
4.8
通讯作者：
Michael
中科院分区：
文献类型：
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作者：
den Brok;Krajnovic;Emsellem;Brinchmann;Maseda;Michael
我们分析了Abell3556最亮的星系团星系PGC-046832的VLT/MUSE观测结果。这个星系的速度结构令人震惊，沿着短轴有两次符号反转，沿着长轴有一次。我们使用三轴Schwarzschild模型来推断该星系的内在形状、中心黑洞质量和轨道分布。形状测定表明，该星系的中心是高度三轴的(几乎是长圆形的)，而外部是低三轴的(几乎是扁平的)。最佳拟合的Schwarzschild模型的轨道分布表明，沿投影短轴的运动反转是由内部长轴管子的分布和数量的轻微不对称驱动的。沿投影长轴的运动学反转是由星系中中等半径的高比例逆旋转轨道驱动的。使用Schwarzschild模型中轨道的化学标记，我们没有发现任何证据表明这些轨道与特定的恒星布居参数有关。虽然银河系的内部几乎肯定是通过一次或多次干燥的合并形成的，形成了长形，但外部部分与吸积和情景形成是一致的。虽然轴对称模型表明存在一个质量为∼6×109m和∼1010m⊙的超大质量黑洞(分别使用Schwarzschild和Jeans模型)，但三轴Schwarzschild模型只提供了∼2×109m⊙的上限。
We analyse VLT/MUSE observations of PGC 046832, the brightest cluster galaxy of Abell 3556. The velocity structure of this galaxy is startling and shows two reversals in sign along the minor axis, and one along the major axis. We use triaxial Schwarzschild models to infer the intrinsic shape, central black hole mass, and orbit distribution of this galaxy. The shape determination suggests that the galaxy is highly triaxial in the centre (almost prolate) but has a low triaxiality (almost oblate) in the outer parts. The orbit distribution of the best-fitting Schwarzschild model shows that the kinematic reversal along the projected minor axis is driven by a slight asymmetry in the distribution and amount of long axis tubes in the inner parts. The kinematic reversals along the projected major axis are driven by a high fraction of counter-rotating orbits at intermediate radii in the galaxy. Using chemical tagging of orbits in the Schwarzschild model, we do not find evidence for any association of these orbits with specific stellar population parameters. Although the inner part of the galaxy almost certainty formed through one or more dry mergers producing the prolate shape, the outer parts are consistent with both accretion andin situformation. While axisymmetric models suggests the presence of a supermassive black hole with mass ∼6 × 109and ∼1010M⊙(with Schwarzschild and Jeans modelling, respectively), triaxial Schwarzschild models provide only an upper limit of ∼2 × 109M⊙.