Environmental Dependence of Galaxy Formation in Cosmological Hydrodynamical Simulations

宇宙流体动力学模拟中星系形成的环境依赖性

• 批准号: ST/I004459/2
• 负责人: Ian McCarthy
• 金额: $ 44.38万
• 依托单位: Liverpool John Moores University
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FI004459%2F2
• 关键词: Environmental; Dependence; Galaxy; Formation; Cosmological

Galaxies are a fundamental building block of our observable universe. They come in a wide range of shapes, sizes, and masses. Remarkably, in spite of the fact that we have known about the existence of galaxies external to our own (and their varying properties) for almost a century, we still do not have a good physical understanding of how these systems formed and evolved over time. An important clue to the mystery of galaxy formation comes from the fact that we see systematic variations in the properties of galaxies in different environments. For example, galaxies found in large gravitationally-bound associations, called galaxy groups and clusters, are typically roundish (or more precisely ellipsoidal) in appearance and are largely composed of old, red stars. Isolated galaxies, by contrast, often have prominent discs composed of young stars, along with substantial quantities of cold gas and dust. This tells us that there are one or more physical processes that can transform the nature of galaxies when they become a member of a group or cluster. Astrophysicists have proposed a large number of processes that may be capable of transforming galaxies in dense environments. However, determining which of the proposed processes (if any) is the culprit is made difficult by the fact that the evolution of the system is highly non-linear. In other words, it can only be studied in detail through direct numerical computation using large supercomputers, which solve the equations that govern gravity and hydrodynamics. The proposed research would employ state-of-the-art supercomputer simulations to develop a coherent framework for the role that environment plays in the formation and evolution of galaxies. Previous attempts at this using such simulations were significantly hindered by lack of resolution (i.e., the computers were not powerful enough to simulate galaxies in sufficient detail) and by relatively crude approximations to important processes such as radiative cooling of the gas and heating of the gas by supernova explosions and neglect of outflows launched by supermassive black holes (which is now believed to be a crucial ingredient). The simulations will be directly confronted with the latest observations. What is particularly exciting to me about the proposed research is the potential for major surprises. The proposed research represents the first serious attempt to study the role that environment plays in galaxy formation using large hydrodynamical computer simulations, which is a new, powerful tool in the astrophysicist's tool-kit. Detailed comparisons of the simulations with data obtained from the latest generation of telescopes should lead to major breakthroughs in our understanding of which transformation processes are most important for shaping the properties of galaxies and how they work in detail. Resolving this issue would represent a major step towards developing a detailed physical theory of galaxy formation, since the majority of galaxies in the universe today are members of galaxy groups and clusters. I have a great deal of optimism that in the coming years we can really begin to understand the process of galaxy formation and transformation and that the proposed research will be an important part of achieving that goal.

星系是我们可观察到的宇宙的基本基础。它们具有各种形状，大小和质量。值得注意的是，尽管我们知道了近一个世纪以来（及其不同特性）外部的星系的存在，但我们仍然对这些系统如何随着时间的推移形成和演变而没有很好的物理理解。星系构成奥秘的一个重要线索来自以下事实：我们看到不同环境中星系性质的系统变化。例如，在重力结合的大型关联中发现的星系，称为星系组和簇，通常在外观上是圆形的（或更精确的椭圆形），并且很大程度上由旧的红色星星组成。相比之下，孤立的星系通常具有由年轻恒星组成的突出盘，以及大量的冷气和灰尘。这告诉我们，有一个或多个物理过程可以改变星系的性质，当它们成为组或集群的成员时。天体物理学家提出了大量的过程，这些过程可能能够在密集的环境中转化星系。但是，由于系统的演变高度非线性，确定罪魁祸首（如果有）是罪魁祸首。换句话说，只能通过使用大型超级计算机直接计算来详细研究它，从而解决了控制重力和流体动力学的方程式。拟议的研究将采用最先进的超级计算机模拟来开发环境在星系形成和演变中所扮演的角色的连贯框架。 Previous attempts at this using such simulations were significantly hindered by lack of resolution (i.e., the computers were not powerful enough to simulate galaxies in sufficient detail) and by relatively crude approximations to important processes such as radiative cooling of the gas and heating of the gas by supernova explosions and neglect of outflows launched by supermassive black holes (which is now believed to be a crucial ingredient).模拟将直接面对最新的观察结果。对于拟议的研究，对我来说特别令人兴奋的是产生重大惊喜的潜力。拟议的研究代表了使用大型流体动力计算机模拟研究环境在星系组中扮演的作用的首次认真尝试，这是天体物理学家工具套件中一种新的功能强大的工具。对模拟的详细比较与从最新一代望远镜获得的数据的详细比较应导致我们对哪些转换过程的理解，对于塑造星系的性质以及它们详细工作的工作最为重要。解决这个问题将代表着发​​展星系形成的详细物理理论的重大步骤，因为当今宇宙中的大多数星系是星系组和集群的成员。我有很多乐观的态度，即在未来几年中，我们可以真正开始了解星系形成和转型的过程，而拟议的研究将是实现这一目标的重要组成部分。

项目成果

Star formation quenching in simulated group and cluster galaxies: when, how, and why?

• DOI: 10.1093/mnras/stu2293
• 发表时间: 2014-10
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Y. Bahé;I. McCarthy

The redshift evolution of massive galaxy clusters in the MACSIS simulations

MACSIS 模拟中大质量星系团的红移演化

• DOI: 10.1093/mnras/stw2722
• 发表时间: 2017
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: Barnes D

The similarity of the stellar mass fractions of galaxy groups and clusters

• DOI: 10.1093/mnras/stt1965
• 发表时间: 2013-09
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: J. M. Budzynski;Sergey E. Koposov;I. McCarthy;V. Belokurov

Are group- and cluster-scale dark matter haloes overconcentrated?

• DOI: 10.1093/mnras/stt1585
• 发表时间: 2013-08
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: M. Auger;J. M. Budzynski;V. Belokurov;Sergey E. Koposov;I. McCarthy