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arXiv 2510.04735astro-ph.GA
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银河系-大麦哲伦星云相互作用与基于模拟的推断

The Milky Way - Large Magellanic Cloud Interaction with Simulation Based Inference

University College London(伦敦大学学院);Center for Computational Astrophysics, Flatiron Institute(计算天体物理学中心,平顿研究所);Center for Astrophysics | Harvard & Smithsonian(哈佛-史密森尼天体物理中心);University of Maryland, College Park(马里兰大学帕克分校);The Ohio State University(俄亥俄州立大学)

Richard A. N. Brooks, Jason L. Sanders, Vedant Chandra, Nicolás Garavito-Camargo, Adam M. Dillamore, Adrian M. Price-Whelan, Yuan-Sen Ting

AI总结:

本文基于模拟推断方法,利用外晕星的运动数据约束银河系和大麦哲伦星云的性质及反射运动速度,得出大麦哲伦星云的质量和反射运动速度的估计值。

摘要:

大麦哲伦星云(LMC)向银河系(MW)的坠落使银河系的质心偏移,表现为外晕星速度的反射运动。我们使用基于模拟的推断框架,利用外银河系晕星的动力学数据约束MW、LMC及反射运动的性质。具体来说,我们使用外晕星的平均径向和切向速度,计算在距离和天区 bins 中的值。我们训练神经网络,利用128,000个条件于DESI和H3+SEGUE+MagE外晕调查的刚性MW-LMC模拟,估计参数后验分布。我们利用DESI或H3+SEGUE+MagE数据集,通过变化的调查天空覆盖和深度,约束反射运动速度和LMC在50 kpc内的质量。使用H3+SEGUE+MagE调查的径向和切向速度数据及天区四象限,我们报告了外晕样本的距离平均反射运动速度,即MW向LMC的运动速度为v_travel=26.4^{+5.5}_{-4.4} km s^{-1},同时得出LMC质量为M_LMC(<50 kpc)=9.2^{+1.9}_{-2.3}×10^{10} M_⊙。引用的不确定性是统计性的。我们的结果表明,LMC的总质量至少是MW的10-15%。此推断框架灵活,可应用于任何未来的调查,以快速约束外晕星速度测量的数据。

英文摘要:

The infall of the Large Magellanic Cloud (LMC) into the Milky Way (MW) has displaced the MW's centre of mass, manifesting as an observed reflex motion in the velocities of outer halo stars. We use a Simulation Based Inference framework to constrain properties of the MW, LMC and the induced reflex motion using the dynamics of outer MW halo stars. Specifically, we use the mean radial and tangential velocities of outer halo stars calculated in a set of distance and on-sky bins. We train neural networks to estimate parameter posterior distributions using a set of $128,000$ rigid MW--LMC simulations conditioned upon velocity data from the Dark Energy Spectroscopic Instrument (DESI) and the combined H3+SEGUE+MagE outer halo surveys. We constrain the reflex motion velocity and the enclosed LMC mass within $50 \, \rm kpc$ using the DESI or H3+SEGUE+MagE dataset while varying the survey sky coverage and depth. Using the radial and tangential velocity data from the H3+SEGUE+MagE survey and on-sky quadrants, we report a distance-averaged reflex motion velocity for the outer halo samples, the speed at which the MW lurches towards the LMC, of $v_{\rm{travel}} = 26.4^{+5.5}_{-4.4} \, \rm km \, \rm s^{-1}$, while simultaneously finding an enclosed LMC mass of $M_{\rm LMC}(< 50 \, \rm kpc) = 9.2^{+1.9}_{-2.3} \times 10^{10}\, \rm M_{\odot}$. Quoted uncertainties are statistical. Our results suggest that the LMC's total mass is at least $\approx 10-15 \%$ of that of the MW. This inference framework is flexible such that it can provide rapid constraints when applied to any future survey measuring the velocities of outer halo stars.

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。

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