Cosmic Structures: From Cosmology to Interstellar Medium

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早期宇宙迅速膨胀时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，在大尺度上成长为星系网，并在沿着的宇宙微波背景（CMB）上留下印记。 但基本问题也被提出来了：我们如何才能窥探大爆炸前早期暴胀阶段的细节？什么是“暗物质”和“暗能量”，成功的模型必须假设在宇宙中占主导地位？在3D星系星表中观测到的星系组成的虚拟宇宙网是如何形成的，它是有组织的吗？我们对宇宙的大部分了解，都来自于对大尺度物质分布的统计分析，以及被视为随机场的CMB天空图。我打算对这些场进行的几何分析有可能回答这些新的中心问题。关键是要寻找偏离正常的几何统计，所谓的“高斯”，行为。 我已经发展了先进的理论描述这种非高斯性。 应用于CMB，它可以告诉我们通货膨胀模型是否可以区分，甚至是反驳。应用到今天的结构演化中，它可能有助于我们确定难以捉摸的“暗能量”是什么。 我们的另一个项目是研究宇宙磁力。磁场在许多关键的天体物理过程中起着至关重要的作用。了解宇宙磁场的最好方法之一是研究电子在磁力线周围螺旋运动时产生的同步辐射图。 在我们的银河系，其他星系或星系团中，磁场被发现是由等离子体的复杂湍流运动携带的，这导致了我们可以观察到的同步加速器信号中的特征相关性。从这样的观测中解开磁化湍流的性质是一项复杂的任务。我们提出了严格的方法，基于现代模型的磁化湍流，以实现这一点。

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 an early era when the Universe was rapidly inflating. Inhomogeneities later grew under the force of gravity into stars, galaxies and, at large scales, the galactic Web, leaving an imprint on the Cosmic Microwave Background (CMB) along the way. But fundamental questions have also been raised: How can we peek into details of that early inflationary stage before the Big Bang? What are the 'dark matter' and 'dark energy' that successful models have to assume to dominate in the Universe? How did the filamentary Cosmic Web of galaxies observed in 3D galactic catalogues come into being and is it organized? Much of what we know about the Universe, we learned from statistical analysis of the large scale distribution of matter and CMB sky-maps treated as random field. Geometrical analysis of such fields that I propose to pursue has the potential to answer these new central questions. The key is to look for deviations in geometrical statistics from the normal, so-called "Gaussian", behaviour. I have developed advanced theoretical description of such non-Gaussianity. Applied to CMB, it may tell us whether inflationary models can be distinguished between, or even disproved. Applied to present day evolution of the structure, it may help us to determine what the elusive "dark energy" is. Our other project studies cosmic magnetism. Magnetic fields play a critical role in many of the key astrophysical processes. One of the best ways to learn about cosmic magnetic fields is by studying maps of synchrotron emission arising from electrons spiraling around magnetic field lines. In our Galaxy, other galaxies, or clusters of galaxies, magnetic fields are found to be carried around by complex turbulent motions of plasma, which results in characteristic correlations in the synchrotron signature that we can observe. Disentangling the properties of the magnetized turbulence from such observations is a complex task. We are putting forward rigorous methods, based on modern models of the magnetized turbulence, to accomplish this.