标题： 南半球遥远的银河系晕：LMC诱导的动力学摩擦尾迹的特征 显示英文标题

标题： The distant Milky Way halo from the Southern hemisphere: Characterization of the LMC-induced dynamical-friction wake

摘要： 大麦哲伦云（LMC）落入银河系晕的进程影响了我们星系中恒星和暗物质的分布。绘制这次相遇的观测后果图可以告诉我们这两个星系的属性、它们相互作用的细节，并可能区分不同的暗物质模型。 N体模拟预测，在重子物质和暗物质中，沿着LMC轨道后方都会有一个局部过密区域，称为尾迹。 我们在预计尾迹所在的四个方向上使用VIRCAM和DECam收集了宽视场、深度近红外和光学测光数据，覆盖了预期会跨越其大部分预测密度对比的天空区域。 我们识别出超过400颗恒星，这些恒星包括两种不同的示踪物——接近主序星转折点的恒星和红巨星——它们描绘了60到100千秒差距之间的晕，推导出了作为天球位置和银河中心半径函数的恒星晕密度。 我们检测到了（1）在70千秒差距处晕的径向密度剖面中的一个断裂，这是北方晕研究中未观察到的；以及（2）一个从70千秒差距开始的明显的晕过密区域，其密度对比度稳步增加至尾迹预计的当前位置。 如果这个过密区域确实是LMC的尾迹，其峰值密度对比度与所考虑的最大质量LMC模型一样显著。 来自未识别亚结构的污染可能会使我们的尾迹探测产生偏差，因此需要更广域的具有相似深度的调查来确认。 显示英文摘要

摘要： The infall of the Large Magellanic Cloud (LMC) into the Milky Way's halo impacts the distribution of stars and dark matter in our Galaxy. Mapping the observational consequences of this encounter can inform us about the properties of both galaxies, details of their interaction, and possibly distinguish between different dark matter models. N-body simulations predict a localized overdensity trailing the LMC's orbit both in baryonic and dark matter, known as the wake. We collected wide-field, deep near-infrared, and optical photometry using VIRCAM and DECam across four fields along the expected wake, covering the sky region expected to span most of its predicted density contrast. We identify over 400 stars comprising two different tracers - near main sequence turn-off stars and red giants - that map the halo between 60-100 kpc, deriving stellar halo densities as a function of sky position and Galactocentric radius. We detect (1) a break in the halo radial density profile at 70 kpc not seen in Northern halo studies, and (2) a clear halo overdensity starting also at 70 kpc, with density contrast increasing steadily toward the expected current location of the wake. If this overdensity is the LMC wake, its peak density contrast is as pronounced as the most massive LMC model considered. Contamination from unidentified substructures may bias our wake detections, so wider-area surveys with similar depth are needed for confirmation.