CMB Data Analysis in the example of the POLARBEAR experiment and the LiteBIRD experiment

Abstract

In this dissertation, I briefly go through my subject areas -- from Astrophysics, Cosmology, to Cosmic Microwave Background (CMB) radiation; and Data Science & High-Performance Computing. I go through the beginning of the Universe briefly in Part I and introduce the Physics of the CMB in Part II. Then I move on to how it can be observed experimentally, mathematically, and computationally in Part III. In Parts IV, V and VI, I write about 2 specific CMB experiments -- POLARBEAR & LiteBIRD, together with my research involved in them. In Part V, an original research on a measurement of the CMB $B$-mode at sub-degree scales is presented using the 3rd-5th seasons of POLARBEAR observations. This demonstrates the capability of a single medium aperture telescope with a Continuously Rotating Half-Wave Plate (CRHWP) to target both the low-$\ell$ and high-$\ell$ $B$-mode science at $50 \leq \ell \leq 3000$. In Part VI, the effect of detector crosstalk systematics on the CMB power-spectra is studied in detail in the example of the LiteBIRD experiment. An analytical, map-domain solution is developed, a computational simulation method is implemented, and the two predictions are compared using the LiteBIRD experiment design specification. The general agreement of the two shows that the analytical model well describes the LiteBIRD experiment, and can be used to calculate the systematic effects without performing time-consuming time-domain simulations with high degree of accuracy. This can be used to forecast the amount of crosstalk systematics and to develop mitigation strategies. A mitigation strategy is presented, which is a hardware-based mitigation method that minimizes the crosstalk systematic effects in the 2pt power-spectra. Parts I-IV are introductory material summarizing well-known knowledge in the field; Parts V and VI are original research.