Shanghai Astronomical Observatory Astrophysics Colloquium

Title：Magpie simulation: studying the faintest satellite galaxies around the Milky Way

利用喜鹊模拟研究银河系周围卫星星系

Speaker：邵 实（国家天文台）

Time：3:00pm Dec. 28h (Thursday)

Tencent Meeting：42915400486 password: 6360

Location: Lecture Hall, 3rd floor

Report in English

Abstract：

Most tensions between Local Group observations and standard cosmological model (Lambda cold dark matter, LCDM) are associated with the faintest galaxies. For example, the ``missing satellites" problem: the overabundance of predicted LCDM subhalos compared to satellite galaxies known to exist in the Local Group. However, the Milky Way (MW) has systematically fewer satellite galaxies than predicted by simulations. The constraint on low-mass galaxies from simulations is weak, and this is mainly due to the limitation of the resolution---even the highest resolution cosmological simulation in the world is not yet able to resolve the galaxies of 10^5 Msun in stellar mass. Moreover, the disagreement could also be due to a combination of factors, such as our MW being an atypical system in LCDM (e.g. the plane of satellite), or due to our incomplete understanding of galaxy formation in low-mass galaxies. Thus, the formation mechanism of the faintest satellites in our MW is far from being understood. In this talk, I will introduce the state-of-the-art Magpie simulations that I am currently developing, in which, the simulated systems have similar kinematical characteristics to those observed for our MW, such as the Magellanic clouds and the plane of satellites. I will also talk about how to use the well-developed cosmological simulation code, GADGET-3, and the sophisticated semi-analytic models, GALFORM, to resolve the faintest satellites in the Magpie simulations. This project will offer us an opportunity to reveal the mystery of the formation and evolution of the faintest satellites that have been observed so far, and will also make us to better understand the assembly history of the MW dark matter halo.

银河系周围卫星星系对限制暗物质属性和了解银河系演化历史起着至关重要的作用。当前宇宙学流体数值模拟分辨率不足以解析全部卫星星系，是一个重大挑战。我将在报告中简要介绍目前数值模拟发展现状，并且介绍喜鹊模拟项目，该项目构建满足多种银河系观测特征的数值模拟大样本。利用流体模拟和星系形成半解析模型结合使用的新数值模拟方法，解析银河系最暗弱卫星星系，从而最终对标准冷暗物质宇宙学模型以及银河系演化历史给出更好的限制。

CV：

Dr. Shao is an associate researcher at NAOC. He was a postdoctoral researcher in the Institute for Computational Cosmology (ICC), Durham University. He obtained his PhD at the University of CAS and his BS from Nanjing University. His research interests include dark matter, galaxy formation, evolution of the Milky Way, etc.

邵实，国家天文台计算宇宙学团组副研究员。南京大学学士，中国科学院大学博士，英国杜伦大学计算天体物理中心博士后。主要从事暗物质属性，银河系形成演化，引力理论相关研究。

Koushare link to the recorded presentation