南极星流光谱巡天（S5）中Antlia 2和Crater 2的动力学
Kinematics of Antlia 2 and Crater 2 from The Southern Stellar Stream Spectroscopic Survey (S5)
摘要：
我们提出了新的光谱观测弥漫银河系卫星星系Antlia 2和火山口2，采取的一部分，南方恒星流光谱调查（S5）。新的观测结果使每个星系中已确认的成员星数量增加了一倍，并使Antlia 2的光谱观测空间范围增加了一倍以上。一个完整的运动学分析，包括盖亚EDR 3自行，检测到一个明确的速度梯度在Antlia 2和一个试探性的速度梯度在陨石坑2。速度梯度的大小和方向是一致的粒子流模拟的潮汐中断。此外，Antlia 2的轨道和运动学需要一个模型，其中包括由大麦云引起的银河系的反射运动。我们还发现，Antlia 2的金属丰度以前被高估了，所以它依赖于经验光度-金属丰度关系，可能只是现在才经历大量的恒星质量损失。根据目前的动力学模型，Antlia 2的90%以上的恒星都是在潮汐中失去的，这与更新后的金属丰度所暗示的恒星质量损失很低相矛盾。总的来说，新的运动学测量支持这些大型和扩展的矮球状星系的起源潮汐中断的情况。
英文摘要：
We present new spectroscopic observations of the diffuse Milky Way satellite galaxies Antlia 2 and Crater 2, taken as part of the Southern Stellar Stream Spectroscopic Survey (S5). The new observations approximately double the number of confirmed member stars in each galaxy and more than double the spatial extent of spectroscopic observations in Antlia 2. A full kinematic analysis, including Gaia EDR3 proper motions, detects a clear velocity gradient in Antlia 2 and a tentative velocity gradient in Crater 2. The velocity gradient magnitudes and directions are consistent with particle stream simulations of tidal disruption. Furthermore, the orbit and kinematics of Antlia 2 require a model that includes the reflex motion of the Milky Way induced by the Large Magellanic Cloud. We also find that Antlia 2's metallicity was previously overestimated, so it lies on the empirical luminosity-metallicity relation and is likely only now experiencing substantial stellar mass loss. Current dynamical models of Antlia 2 require it to have lost over 90% of its stars to tides, in tension with the low stellar mass loss implied by the updated metallicity. Overall, the new kinematic measurements support a tidal disruption scenario for the origin of these large and extended dwarf spheroidal galaxies.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
