Cosmic Structures: from Cosmology to Interstellar Medium

宇宙结构：从宇宙学到星际介质

• 批准号: RGPIN-2017-03973
• 负责人: Pogosyan, Dmitri
• 金额: $ 2.19万
• 依托单位: University of Alberta
• 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=662347
• 关键词: Cosmic; Structures; Cosmology; Interstellar; Medium

This proposal covers research programs in statistical studies of astrophysical turbulence and in the theory of the filamentary Cosmic Web and its role in the properties of galaxies and clusters of galaxies.******Turbulence and Magnetic fields play critical role in many of the key astrophysical processes. Determining energy distribution in turbulent motions, strength, orientation and scaling of the magnetic fields, characteristics scales of energy injection and dissipation, relative strength of incompressible and compressible modes are of vital importance for understanding fundamental astrophysical process such as star formation, heat transport in interstellar and intra-cluster medium, acceleration of cosmic ray. In our Galaxy, in other galaxies, or in clusters of galaxies, magnetic fields are found to be carried around by complex turbulent motions of plasma, which results in characteristic correlations in the intensity and polarization of light emitted as Doppler shifted spectral lines or diffuse synchrotron radiation. Disentangling the quantitative properties of the magnetized turbulence from such observations is a complex task. We are developing rigorous statistical methods, based on modern models of the magnetized turbulence, and for a variety of observable data, to accomplish it.******Cosmologists are now confident in the overall picture of structure formation in our Universe. The complexity of our Universe came from tiny quantum fluctuations of matter at the very early era when the Universe rapidly inflated. Inhomogeneities later grew under the force of gravity into stars, galaxies and, at large scales, the galactic Web, leaving along the way the imprint on the Cosmic Microwave Background. At the earlier epoch the filamentary Web of dark matter and gas distribution was shown to affect the formation of the galaxies, while at present time it defines the inter-cluster environment. We shall study theoretically and numerically the connectivity of the filamentary pattern as it evolves from initial conditions to galactic and then cluster scales. Our goal is to answer questions such as how many filaments join the cluster, does this depend on the cluster properties, does it tell us how cluster was assembled, how long are filament arms, do filaments form a connected network or are disjoint, how these parameters evolve in time depending on a cosmological model; and, in this way, obtain a more complete description and understanding of the structure in the Universe. We will also investigate the effect being in filamentary environment has on galaxy properties, and in particular their spin by working towards detailed statistical theory of halo spin distribution within the large scale structures, that would be beneficial for understanding galaxy formation and for interpretation of the future galactic surveys.

该提案涵盖了天体物理学湍流统计研究和无限宇宙网理论及其在星系和星系团性质中的作用的研究计划。湍流和磁场在许多关键的天体物理过程中起着至关重要的作用。 确定湍流运动中的能量分布，磁场的强度、方向和标度，能量注入和耗散的特征尺度，不可压缩模和可压缩模的相对强度，对于理解星星形成、星际和团内介质中的热输运、宇宙线加速等基本天体物理过程具有重要意义。 在我们的银河系，在其他星系，或在星系团中，磁场被发现是由复杂的湍流运动的等离子体，这导致特征的相关性的强度和偏振的光发射多普勒频移谱线或扩散同步辐射。 从这样的观测中解开磁化湍流的定量性质是一项复杂的任务。我们正在开发严格的统计方法，基于磁化湍流的现代模型，以及各种可观察到的数据，以实现这一目标。宇宙学家现在对我们宇宙结构形成的整体图景充满信心。我们宇宙的复杂性来自于宇宙迅速膨胀的早期物质的微小量子波动。不均匀性后来在引力的作用下成长为恒星、星系，在大尺度上形成星系网，并在宇宙微波背景上留下沿着印记。在早期，暗物质和气体分布的网状结构被证明会影响星系的形成，而现在它定义了星系团间的环境。我们将从理论上和数值上研究从初始条件到星系尺度，再到星系团尺度的演化过程中，星系图案的连通性。我们的目标是回答这样的问题，如有多少细丝加入集群，这是否取决于集群的属性，它是否告诉我们集群是如何组装的，细丝臂有多长，细丝形成一个连接的网络还是不相交，这些参数如何根据宇宙学模型随时间演变;并且，通过这种方式，获得对宇宙结构的更完整的描述和理解。我们还将调查的效果是在大气环境对星系的属性，特别是他们的自旋工作对详细的统计理论的晕自旋分布在大尺度结构，这将有利于理解星系的形成和解释未来的星系调查。