A measurement of E-mode polarisation spectrum of the cosmic microwave background with the POLARBEAR experiment

Abstract

The cosmic microwave background (CMB) stands as one of the most interesting subjects of astronomical surveys. The CMB light carries information about the history and the origin of the universe. Polarisation of the CMB can be decomposed and transformed in to E-mode and B-mode polarisation. My thesis focuses on the measurement of E-mode polarisation power spectrum of the cosmic microwave background using 150 Ghz data taken from July 2014 to December 2016 with the POLARBEAR experiment. POLARBEAR is an on-going cosmic microwave background experiment that began taking data in 2012. The target area of observation for the data in this thesis is a large patch of sky of over 600 deg2. A continuously rotating half wave plate was installed in the POLARBEAR telescope and heavily influences the overall data analysis. This thesis is outlined as followed. Chapter 1 reviews the standard model of cosmology, and explain the physics of the CMB and CMB polarisation. Chapter 2 describes the POLARBEAR experiment. Chapter 3 gives a brief review of the continuously rotating half wave plate and its impacts on recorded data. Chapter 4 describes the calibration of the recorded data. Chapter 5 describes the pipeline to process the recorded data. Chapter 6 details on the validation of the established power spectrum pipeline, the data selected following Chapter 5, and the estimation of systematics in POLARBEAR data. Chapter 7 details on the E-mode power spectrum estimated from the selected data. I use the measured E-mode power spectrum in combination with other data sets: Planck 2018, ACTPol, SPT-SZ, and BAO data to constrain cosmological parameters. The combined data set is consistent with the standard Lambda Cold Dark Matter model of cosmology. I also consider extensions to the standard model, and present improved constraints on these extensions. Chapter 8 summaries preceding chapters and gives an outlook on the Simons Array, the successor of the POLARBEAR experiment.