CMB lensing: polarization, large-scale structure and the primordial bispectrum

Pearson, Ruth (2014) CMB lensing: polarization, large-scale structure and the primordial bispectrum. Doctoral thesis (PhD), University of Sussex.

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Abstract

Gravitational lensing of photons in the Cosmic Microwave Background (CMB) can be
described by an integrated potential along the line of sight, the CMB lensing potential.
Covariances in maps of the CMB are generated by the lensing effect, and are used to
reconstruct the lensing potential itself, which is a useful probe of the matter distribution.
The CMB lensing potential has been measured to high significance with CMB temperature
data. However, signal to noise for lensing reconstruction from CMB polarization data is
expected to be much better due to the presence of the lensing B-mode. Upcoming data
from ground based CMB polarization instruments will provide high resolution maps over
small patches of the sky. This will provide much better lensing reconstruction, but also
presents data analysis challenges. This thesis begins with an introduction to the field
of CMB lensing and CMB lensing reconstruction. The second chapter details the biases
present in reconstructing the lensing potential from CMB polarization maps considering
first the full sky, and then small patches of sky. It also shows that using the pure-B mode
formalism for the CMB polarization leads to improved lensing reconstruction over the naive
case on the cut sky. Given the upcoming improvement in the CMB lensing reconstruction,
it is expected that cross-correlations of the CMB lensing with other structure tracers,
such as galaxies, will yield improved information for cosmology. It is also expected that
the CMB lensing will become useful to help constrain uncertainties in the galaxy power
spectrum, and provide information on the linear galaxy bias and redshift distribution. The
third chapter of the thesis forecasts the power of cross correlation science for a number
of galactic and non-galactic parameters. Finally, the CMB lensing effects the level of
non-Gaussianity observed in the CMB. The fourth chapter of the thesis is a study of the
lensing effect on the primordial squeezed bispectrum. We conclude in the fifth chapter.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics > QC0350 Optics. Light
Q Science > QC Physics > QC0801 Geophysics. Cosmic physics
Depositing User: Library Cataloguing
Date Deposited: 29 May 2014 11:54
Last Modified: 18 Sep 2015 14:59
URI: http://sro.sussex.ac.uk/id/eprint/48418

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