Collaborative Research: The Hierarchical Mergers of Low Mass Galaxies

天文观测表明，大型星系之间的碰撞是暴力事件。在碰撞过程中，星系形成了许多恒星，星系的形状发生了变化。有时，被称为矮小星系的小星系会在碰撞过程中与较大的星系合并。其他时候，碰撞会产生长长的恒星列，被抛入星系之间的空间。研究人员对矮星系的合并进行了数值模拟，并对合并后的残余物进行了研究。在这个项目中，他们将改进他们的模拟，并将模拟结果与新的观测结果进行比较。新的望远镜，如大型天文望远镜(LSST)，被设计用来研究宇宙中最小和最暗的星系。用这些望远镜很快就会发现更多相互碰撞的矮星系。研究人员将使用他们的模拟来更好地了解星系的合并历史。这个话题对于理解我们银河系的形成历史很重要。这一合作项目将利用哥伦比亚大学和亚利桑那大学现有的强有力的外展努力。他们将扩大Time Step计划，该计划将惠及代表性不足的少数族裔，并发展一个社区，在他们的整个学术生涯中为他们提供支持。他们还将支持制作流行的YouTube视频的研究生，这些视频回答了公众最热门的天文学问题。研究人员将通过提高宇宙模拟的质量分辨率和对更大体积的空间进行建模来改进他们之前的模拟。他们计划在我们银河系附近的区域模拟矮星系对。他们将动态匹配模型，并探索矮小星系合并的作用。研究人员还将使用高分辨率、仅限暗物质的宇宙学模拟来创建矮子晕对的模拟目录。他们将把观测到的矮小星系对的数量与兰姆达冷暗物质宇宙模型的预期进行比较。

Astronomical observations show that collisions between large galaxies are violent events. During collisions galaxies form many stars, and the galaxies change shape. Sometimes small galaxies, called dwarf galaxies, merge with larger galaxies during collisions. Other times the collisions produce long trains of stars thrown out into the space between galaxies. The investigators have numerically simulated the mergers of dwarf galaxies and studied the remnants of these mergers. In this project, they will improve their simulations and compare the simulations with new observations. New telescopes, like the Large Synoptic Survey Telescope (LSST), are designed to study the smallest and faintest galaxies in the Universe. Many more colliding dwarf galaxies are soon to be discovered with these telescopes. The investigators will use their simulations to better understand the merger history of galaxies. This topic is important for understanding the history of formation of our own Milky Way galaxy. This collaborative project will leverage strong existing outreach efforts at both Columbia University and The University of Arizona. They will expand the TIMESTEP program, which reaches under-represented minorities and develops a community to support them throughout their academic careers. They will also support graduate students who produce popular YouTube videos, which answer top public astronomy questions.The investigators will improve their previous simulations by increasing mass resolution of the cosmological simulations and by modeling larger volumes of space. They plan to model dwarf galaxy pairs in the region near our Milky Way galaxy. They will dynamically match the models and explore the role of dwarf-dwarf galaxy mergers. The investigators will also create a simulated catalog of dwarf sub-halo pairs using the high-resolution, dark-matter-only, cosmological simulation. They will compare the observed dwarf galaxy pair counts with expectations of Lambda Cold Dark Matter cosmological models.