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.********************

星系是由什么组成的？ 一个大的螺旋星系，如银河系（MW）或仙女座（M31）的通常图像显示了一个旋转的恒星，气体，尘埃，螺旋臂和中央隆起的磁盘。 ** 但从20世纪70年代开始，我们的星系图像膨胀，因为我们积累了星系嵌入在扩展的暗物质晕中的证据。 最近，对MW和M31外围的观测揭示了丰富的恒星结构，其形式为卫星星系和从卫星上潮汐剥离的恒星流。 最后，对结构形成的宇宙学模拟表明，晕中的暗物质是混沌的，甚至可能比恒星更混沌。 我的研究将集中在卫星和subhalo人口的关键方面。 这项研究在很大程度上是由观测和计算天体物理学的显着进步驱动的，并将对银河系动力学，宇宙结构形成和暗物质探测领域产生影响。 最近，我和我的合作者分析了太阳附近恒星的分布及其运动，以揭示MW盘中似乎存在的垂直波。 我们将这一发现解释为MW与其卫星之间最近和附近遭遇的证据。 我对这些波的研究将在各个方面进行。 我已经获得了额外的数据，这些数据正在由我小组的研究生进行分析。 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盘的相互作用。 泛仙女座考古调查已经获得了前所未有的M31和它的同伴M33的全景照片。 我们的观察表明，M31正在蚕食它的卫星，而M33可能在最近的过去与M31有过近距离接触。 这些想法得到了我和Dubinski（多伦多）进行的N体模拟的支持，有助于推进我们对宇宙结构形成和暗物质在本星系群中分布的理解。