Multiwavelength Studies of Galaxy Evolution

星系演化的多波长研究

• 批准号: RGPIN-2015-03851
• 负责人: Webb, Tracy
• 金额: $ 1.6万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=678807
• 关键词: Multiwavelength; Studies; Galaxy; Evolution

***We live in a hierarchically organized universe. Over the past two decades, observational evidence and theoretical predictions have converged on a remarkably successful cosmological model -- cold Dark Matter with a  Dark Energy component -- that describes the formation and evolution of structure at all scales through the gravitational amalgamation of matter. The backbone of this process is  well understood, but the physics on the scales of stars, galaxies and galaxy clusters is very complex and controlled by multiple variables.   This research program seeks to understand these processes and, in particular, the processes which formed galaxies like our own Milky Way.  ***In hierarchical structure formation  small objects (with masses of a million suns - small galaxies) form first after the Big Bang and then combine over time to form the largest objects seen today (reaching masses of a million billion stars).   The act of coalescing galaxies is a violent and complex one which dramatically alters the physical state of the systems. Existing stars are redistributed, new populations of stars are produced in prodigious triggered bursts, and central supermassive black holes grow through infalling matter. Nevertheless, if we study galaxies in the universe today we see tight relationships between their properties which are indicative of underlying global processes.***For example, the mass, shape and overall age of a galaxy is dependent on its local environment.  Massive galaxies, that are elliptical and composed of old stars inhibit dense regions of the universe, with many other galaxies nearby.  Moderate mass galaxies like our own Milky Way, with on-going star formation and spiral structure live in more isolated regions.   My research program wants to understand the reasons behind trends such as these.***Because light takes a finite time to travel, we see distant galaxies  as they existed a long time ago.  We use the world's largest telescopes to observe the most distant galaxies in the universe at a much earlier stage in their formation.  By studying many galaxies at different times and in different environments we can piece together their evolutionary history. Using light emitted at different wavelengths we can measure the amount of stars a galaxy is composed of, the rate at which it is forming new stars, and whether it is growing a supermassive black hole at its center.  Its physical shape often provides clues to the processes it is experiencing - such as a major galaxy merger event.***We study large samples of galaxies in a quest to identify and understand global trends in their evolutionary phases.  Occasionally, we discover a unique object that, if studied in detail can provide a wealth of information on a particular aspect of galaxy formation.  By combining these two distinct approaches we can piece together a picture of how the rich and complex structure we see around us today was formed. *****

*我们生活在一个有层级组织的宇宙中。在过去的二十年里，观测证据和理论预测都汇聚在一个非常成功的宇宙学模型上--具有强大暗能量成分的冷暗物质--该模型描述了通过物质的引力融合在所有尺度上结构的形成和演化。这个过程的主干是众所周知的，但恒星、星系和星系团尺度上的物理学是非常复杂的，受多个变量控制。这个研究计划试图了解这些过程，特别是形成像我们银河系这样的星系的过程。在分层结构的形成中，小天体(质量为100万个太阳的小星系)首先在大爆炸后形成，然后随着时间的推移形成今天所见的最大的天体(达到10亿颗恒星的质量)。合并星系的行为是一个猛烈和复杂的行为，极大地改变了系统的物理状态。现有的恒星被重新分配，新的恒星群以惊人的触发爆发产生，中央超大质量黑洞通过流入的物质增长。然而，如果我们今天研究宇宙中的星系，我们会发现它们的性质之间存在着紧密的关系，这表明了潜在的全球过程。*例如，星系的质量、形状和整体年龄取决于其所在的环境。由老恒星组成的椭圆形大质量星系抑制了宇宙中致密区域的形成，附近还有许多其他星系。像我们银河系这样的中等质量星系，正在形成恒星和螺旋结构，生活在更孤立的区域。我的研究计划想要了解这些趋势背后的原因。*因为光需要有限的时间才能传播，我们看到遥远的星系，就像它们很久以前存在的样子。我们用世界上最大的望远镜在宇宙中最遥远的星系形成的更早阶段观察它们。通过研究不同时间、不同环境中的许多星系，我们可以拼凑出它们的进化史。使用不同波长发出的光，我们可以测量一个星系的恒星数量，它正在形成新恒星的速度，以及它是否在其中心形成一个超大质量黑洞。它的物理形状经常为它正在经历的过程提供线索--例如一个主要的星系合并事件。*我们研究大样本星系，以寻求识别和理解它们进化阶段的全球趋势。偶尔，我们会发现一个独特的物体，如果详细研究，可以提供关于星系形成特定方面的丰富信息。通过将这两种不同的方法结合起来，我们可以拼凑出一幅我们今天看到的丰富而复杂的结构是如何形成的图景。*****