论文标题
大型麦哲伦云中心产生的银河系反射运动以恒星光环
Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
论文作者
论文摘要
我们介绍了银河系和大型麦哲伦云系统的N体模型的结果，并研究了由于盘的重骨位移，因此研究了恒星光环中的运动反射运动。与先前的研究一致，我们发现，在大型麦哲伦云中，银河系盘可能以40 km/s的速度移动。所得的反射运动在恒星光环的切向速度中可见为简单的偶极子。对于具有较长动力学时间的恒星，该信号是最强的，在位置速度数据中可以识别为具有较大启示剂的恒星，其动力学记忆仍然受到不受干扰的银河系潜力的代表。该信号在天空中的不同，具体取决于恒星示踪剂，并且可能与圆盘中心质量质量的速度达到相同的幅度，这使得反射运动成为基于恒星流和/或光滑的光滑卤水示踪剂（例如蓝色的水平平线分支或RR Lyrae stars）的模型的银河系潜在确定的偏见来源。
We present the results of N-body models of the Milky Way and Large Magellanic Cloud system and study the kinematic reflex motion in the stellar halo owing to the barycentre displacement of the disc. In agreement with previous studies, we find that the Milky Way disc may be moving at 40 km/s relative to the barycentre prior to the Large Magellanic Cloud infall. The resulting reflex motion is visible in tangential velocities of the stellar halo as a simple dipole. The signal is strongest for stars with long dynamical times, identifiable in position-velocity data as stars with large apocentres, whose dynamical memory is still well-represented by the unperturbed Milky Way potential. The signal varies across the sky depending on the stellar tracer and may be up to the same magnitude as the velocity of the disc centre-of-mass, making reflex motion a source of bias for Milky Way potential determinations based on the modeling of stellar streams and/or smooth halo tracers such as blue horizontal branch or RR Lyrae stars.
