利用N体模拟研究银河系与仙女座星系的并合

Merger of the Milky Way and the Andromeda Galaxy with N-body Simulations

银河系的邻居仙女座星系(M31)是本星系群中恒星质量最大的成员。观测表明,M31正与银河系相互接近,且两者极有可能在未来发生并合。N体模拟作为研究星系并合的有力工具,在过去半个世纪内取得了长足的发展,也在有关银河系与M31并合的定量研究中发挥了巨大的作用。随着星系结构理论的丰富、观测水平的提高以及N体模拟软件技术的成熟,银河系与M31并合的图像也越来越清晰与完善。简要介绍了银河系与仙女座星系并合模拟研究的工作流程,回顾了各步骤所用到的理论模型或软件条件于近几十年内取得的发展,选取各阶段代表性模拟结果进行比较;最后给出了未来的研究趋势与改进方向。

The Local Group contains nearly one hundred galaxies of various sizes and shapes,including the Milky Way(MW),the Andromeda Galaxy(M31),the Triangulum Galaxy(M33),the Magellanic Clouds and so on.M31 is the most massive and brightest galaxy in the Local Group.Studies of the Local Group have significant implications for understanding the interactions and evolution of galaxies,as well as cosmology.According to the hierarchical clustering theory of the universe,galaxies grow through mergers.In addition to numerous satellite galaxy mergers in the Local Group,there may also be a future merger between the two large galaxies,the Milky Way and M31.Observations indeed indicate that M31 and the Milky Way are approaching each other and will merge in the future.As a powerful tool for studying galaxy mergers,N-body simulation has rapidly matured during the past half century and played an important role in our quantitative understanding of galaxy mergers.Thanks to the development of galaxy structure theories,observational capabilities and N-body simulation software,information about the Milky Way and M31 has become increasingly clear,thus our understanding of the merger between the Milky Way and M31 has become more detailed.This article presents a brief overview of N-body simulations of the merger between M31 and MW,with an emphasis on the simulation procedure,as well as a comparison of recent results.Valuable future directions are also discussed.