Cosmic Structures: From Cosmology to Interstellar Medium

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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.