发表机构
DTU Space, Technical University of Denmark; DARK, Niels Bohr Institute, University of Copenhagen; Department of Astrophysical Sciences, Princeton University; Department of Astronomy, Boston University; Center for Computational Astrophysics, Flatiron Institute; Department of Physics and Astronomy, University of Pennsylvania; Department of Astronomy and DiRAC Institute, University of Washington（丹麦技术大学空间中心; 哥本哈根大学尼尔斯·玻尔研究所DARK研究中心; 普林斯顿大学天体物理学系; 波士顿大学天文系; 平顿研究所计算天体物理中心; 宾夕法尼亚大学物理与天文学系; 华盛顿大学天文系及DiRAC研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用FIRE-2 m12m模拟和X-Stream代码，探究河外恒星流的时变晕效应，发现部分恒星流可推断暗物质晕属性，为河外星系的暗物质研究提供新方法。
AI 中文摘要
即将开展和正在进行的巡天将在银河系以外的星系周围探测到数千条恒星流。来自银河系的研究表明，银晕的时变演化在塑造恒星流方面发挥着关键作用，但这一问题对于河外恒星流而言仍未得到探索。我们使用FIRE-2 m12m宇宙学 zoom-in 模拟，将其模拟观测为包含三条恒星流的河外系统，以研究晕时变性如何影响河外系统的前身天体和宿主晕推断。结果显示，若仅考虑近心点附近的潮汐剥离，三条m12m恒星流中有两条可在静态晕中得到良好重现。我们将河外恒星流拟合代码X-Stream应用于每条模拟观测的恒星流，获得宿主暗物质晕和恒星流属性的约束。仅利用天球上的形态，再固定前身天体的径向速度，我们将恢复的轨道和晕参数与FIRE-2 m12m的真实值进行比较。对于带有环形段的最长恒星流，我们得到了关于前身天体和晕属性无偏的强约束；对于最短的恒星流，我们能得到轨道参数的限制，但除非纳入更暗、更延展的残骸，否则无法约束前身天体和晕质量；对于质量最大的恒星流，其无法在静态晕中良好重现，恢复的轨道参数存在偏差，反映了未建模的时变性。我们得出结论，在某些情况下，来自河外矮星系的恒星流残骸成像可用于推断现今的暗物质晕属性，即使是在宇宙学环境中。
英文摘要
Upcoming and ongoing surveys will detect thousands of stellar streams around galaxies other than the Milky Way. Studies from the Milky Way have shown that time-dependent evolution of the Galactic halo plays a key role in shaping stellar streams, but remains unexplored for extragalactic stellar streams. We use the FIRE-2 m12m cosmological zoom-in simulation, mock observed as an extragalactic system including three stellar streams, to examine how halo time-dependence affects progenitor and host halo inference from extragalactic systems. We show that two of the three m12m streams are well reproduced in a static halo if we only allow for tidal stripping near pericenter. We apply the extragalactic stream fitting code X-Stream to each mock observed stream, and obtain constraints on the host dark matter halo and stream properties. Using on-sky morphology alone and then fixing the progenitor radial velocities, we compare recovered orbits and halo parameters to the FIRE-2 m12m ground truth. For the longest stream with a looped segment, we find unbiased strong constraints on progenitor and halo properties. For the shortest stream, we find limits on orbital parameters, but no constraints on progenitor and halo mass unless we include fainter, more extended debris. For the most massive stream, which was not well produced in a static halo, the recovered orbital parameters are biased, reflecting unmodeled time-dependence. We conclude that imaging of stream debris from extragalactic dwarf galaxies can, in some cases, be used to infer present-day dark matter halo properties, even in a cosmological environment.
CommentsSubmitted to ApJ, 34 pages, 22 figures
