Halo Substructure and the Dynamics of Disk Galaxies

晕子结构和盘状星系的动力学

• 批准号: 138134-2013
• 负责人: Widrow, Lawrence
• 金额: $ 1.82万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=668522
• 关键词: Halo; Substructure; Dynamics; Disk; Galaxies

What constitutes a galaxy? The usual image of a large spiral galaxy such as the Milky Way (MW) or Andromeda (M31) shows a rotating disk of stars, gas, dust, spiral arms, and a central bulge. **But beginning in the 1970's, our image of the galaxy swelled as we amassed evidence that galaxies are embedded in extended halos of dark matter. More recently, observations of the outskirt of the MW and M31 have revealed a wealth of stellar structure in the form of satellite galaxies and streams of stars that were tidally stripped from satellites. Finally cosmological simulations of structure formation indicate that dark matter in halos is clumpy, perhaps even more so than the stars.** My research will focus on key aspects of the satellite and subhalo populations. The research is driven, in large part, by the remarkable advances in observations and computational astrophysics and will have implications for the fields of galactic dynamics, cosmological structure formation, and dark matter detection.** Recently, my collaborators and I analysed the distribution of stars in the solar neighbourhood and their motions to reveal what appear to be vertical waves in the MW's disk. We have interpreted this discovery as evidence for a recent and nearby encounter between the MW and one of its satellites. My investigations of these waves will proceed on a variety of fronts. I have obtained additional data, which is being analyzed by graduate students in my group. Other students are using theoretical analysis and numerical simulations to study the interaction of satellite galaxies and stellar disks.** The Pan-Andromeda Archaeological Survey has obtained an unprecedented panoramic picture of M31 and its companion, M33. Our observations suggest that M31 is cannibalizing its satellites while M33 may have had a close encounter with M31 in the recent past. These ideas, bolstered by N-body simulations performed by me and Dubinski (Toronto), help advance our understanding of cosmological structure formation and the distribution of dark matter in the Local Group.********************

什么构成银河系？ 大型螺旋星系的通常图像，例如银河系（MW）或仙女座（M31），显示了恒星，气体，灰尘，螺旋臂和中央凸起的旋转磁盘。 **但从1970年代开始，我们的星系形象膨胀了，因为我们积累了证据表明星系嵌入了深色物质的扩展光环中。 最近，对MW和M31郊区的观察表明，卫星星系和恒星流的形式揭示了丰富的恒星结构，这些恒星从卫星中潮湿剥离。 最终，对结构形成的宇宙学模拟表明，光环中的暗物质是块状的，甚至比星星更重要。 这项研究在很大程度上是由观察和计算天体物理学的显着进步所驱动的，并且将对银河动态，宇宙学结构形成和暗物质检测的领域具有影响。太阳街区的星星及其动议揭示了MW磁盘中似乎是垂直波的内容。 我们将这一发现解释为MW与其卫星之一的最近和附近相遇的证据。 我对这些海浪的调查将在各种方面进行。 我已经获得了其他数据，该数据正在由我小组的研究生分析。 其他学生正在使用理论分析和数值模拟来研究卫星星系和恒星磁盘的相互作用。 我们的观察结果表明，M31正在吞噬其卫星，而M33最近可能与M31接触。 这些想法是由Me和Dubinski（多伦多）进行的N体模拟的支持，有助于提高我们对宇宙学结构形成和暗物质在本地组中的分布的理解。************************************* *******