High-order angular correlation functions and their harmonic counterpart, the polyspectra, offer a great opportunity to study the physics of spherical random fields. The best example of such a field is represented by the Cosmic Microwave Background (CMB) radiation, a relic from the hot phases of our Universe. But even the Large Scale Structure (LSS) as traced by galaxies can be treated in the same way when considering shells of iso-redshift. Both CMB and LSS are the most relevant source of cosmological information available today. This thesis offers a review of the analytical framework of spherical random distributions and polyspectra together with the now so-called standard cosmological model. The physics of inflation and the evolution of tiny quantum almost Gaussian fluctuations that eventually evolved into both CMB and LSS is also presented in details. The high-order angular polyspectra considered here are the Bispectrum and the Trispectrum. The former has been applied to LSS simulated data, the latter on CMB simulated data. The results of the analysis show that both of them could be useful in the next future in order to constrain cosmological parameters from real data. A three-year journey to understand how primordial fluctuations grew in the structures we see today.
ANGULAR HIGH-ORDER CORRELATION FUNCTIONS IN COSMOLOGY: LSS BISPECTRUM AND CMB TRISPECTRUM / A. Troja ; tutor: D. Maino, E. Sefusatti ; coordinatore: F. Ragusa. DIPARTIMENTO DI FISICA, 2017 Jul 24. 29. ciclo, Anno Accademico 2016. [10.13130/troja-antonino_phd2017-07-24].
ANGULAR HIGH-ORDER CORRELATION FUNCTIONS IN COSMOLOGY: LSS BISPECTRUM AND CMB TRISPECTRUM
A. Troja
2017
Abstract
High-order angular correlation functions and their harmonic counterpart, the polyspectra, offer a great opportunity to study the physics of spherical random fields. The best example of such a field is represented by the Cosmic Microwave Background (CMB) radiation, a relic from the hot phases of our Universe. But even the Large Scale Structure (LSS) as traced by galaxies can be treated in the same way when considering shells of iso-redshift. Both CMB and LSS are the most relevant source of cosmological information available today. This thesis offers a review of the analytical framework of spherical random distributions and polyspectra together with the now so-called standard cosmological model. The physics of inflation and the evolution of tiny quantum almost Gaussian fluctuations that eventually evolved into both CMB and LSS is also presented in details. The high-order angular polyspectra considered here are the Bispectrum and the Trispectrum. The former has been applied to LSS simulated data, the latter on CMB simulated data. The results of the analysis show that both of them could be useful in the next future in order to constrain cosmological parameters from real data. A three-year journey to understand how primordial fluctuations grew in the structures we see today.File | Dimensione | Formato | |
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