Collaborative Research: The Hierarchical Mergers of Low Mass Galaxies

天文观测表明，大星系之间的碰撞是剧烈的事件。 在碰撞过程中，星系形成了许多恒星，星系改变了形状。 有时候，小星系，称为矮星系，在碰撞过程中与较大的星系合并。 其他时候，碰撞产生了长长的恒星列车，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，并研究了这些合并的残余物。 在这个项目中，他们将改进他们的模拟，并将模拟与新的观测结果进行比较。 新的望远镜，如大型综合巡天望远镜（LSST），旨在研究宇宙中最小和最暗的星系。 很快，这些望远镜就会发现更多的碰撞矮星系。 研究人员将利用他们的模拟来更好地了解星系的合并历史。 这个主题对于了解我们银河系的形成历史非常重要。 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大外联工作。 他们将扩大TIMESTEP计划，该计划覆盖代表性不足的少数民族，并建立一个社区，在他们的学术生涯中为他们提供支持。 他们还将支持研究生制作热门YouTube视频，这些视频回答了公众天文学的热门问题。研究人员将通过提高宇宙学模拟的质量分辨率和模拟更大体积的空间来改进他们以前的模拟。 他们计划在我们银河系附近建立矮星系对模型。 他们将动态地匹配模型，并探索矮-矮星系合并的作用。 研究人员还将使用高分辨率、仅含暗物质的宇宙学模拟创建一个矮次晕对的模拟目录。 他们将把观测到的矮星系对计数与Lambda冷暗物质宇宙学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.