论文标题
由于大型麦哲伦云中的大量核心，检测银河系反射运动
Detection of the Milky Way reflex motion due to the Large Magellanic Cloud infall
论文作者
论文摘要
大型麦哲伦云是银河系中最大的卫星银河系，估计质量超过了银河系的十分之一。仅超过了大约50 kpc的最接近方法，并以327 km/s的惊人速度飞行，大型麦哲伦云会以多种方式影响我们的银河系，包括从银河系中心脱落银河系盘。在这里，我们报告了证据表明，银河系光盘在$ v _ {\ rm travel} = 32^{+4} _ { - 4} $ km/s的$ v _ {\ rm travel} = 32^{+4} $ km/s，以$（ELL，B）_ {\ Ell，B）_ { apex} =（56^{+9} _ { - 9}，-34^{+10} _ { - 9}）$度，该$度指向LMC轨迹的早期位置。在外光星和银河系卫星星系的运动学中检测到所得的反射运动，具有准确的距离，适当的运动和视线速度。我们的结果表明，我们的星系的动力学模型无法忽略大型麦哲伦云中心引起的重力扰动，也无法在无法纠正盘状反射运动的参考框架中对恒星光环的观察。恒星光环与Gaia天体结合的未来光谱调查将允许对银河系中大型麦哲伦云轨迹进行复杂的建模，从而用前所未有的细节限制了两个星系中的暗物质分布。
The Large Magellanic Cloud is the most massive satellite galaxy of the Milky Way, with an estimated mass exceeding a tenth of the mass of the Milky Way. Just past its closest approach of about 50 kpc, and flying by the Milky Way at an astonishing speed of 327 km/s, the Large Magellanic Cloud can affect our Galaxy in a number of ways, including dislodging the Milky Way disc from the Galactic centre-of-mass. Here, we report evidence that the Milky Way disc is moving with respect to stellar tracers in the outer halo ($40<r<120$ kpc) at $v_{\rm travel}=32^{+4}_{-4}$ km/s, in the direction $(\ell,b)_{\rm apex}=(56^{+9}_{-9},-34^{+10}_{-9})$ degrees, which points at an earlier location on the LMC trajectory. The resulting reflex motion is detected in the kinematics of outer halo stars and Milky Way satellite galaxies with accurate distances, proper motions and line-of-sight velocities. Our results indicate that dynamical models of our Galaxy cannot neglect gravitational perturbations induced by the Large Magellanic Cloud infall, nor can observations of the stellar halo be treated in a reference frame that does not correct for disc reflex motion. Future spectroscopic surveys of the stellar halo combined with Gaia astrometry will allow for sophisticated modelling of the Large Magellanic Cloud trajectory across the Milky Way, constraining the dark matter distribution in both galaxies with unprecedented detail.
