138 research outputs found
Cosmology from weak lensing of CMB
The weak lensing effect on the cosmic microwave background (CMB) induces
distortions in spatial pattern of CMB anisotropies, and statistical properties
of CMB anisotropies become a weakly non-Gaussian field. We first summarize the
weak lensing effect on the CMB (CMB lensing) in the presence of scalar, vector
and tensor perturbations. Then we focus on the lensing effect on CMB statistics
and methods to estimate deflection angles and their power spectrum. We end by
summarizing recent observational progress and future prospect.Comment: 25 pages, 5 figures, to appear in PTEP Special Section "CMB
Cosmology
Lensing reconstruction from a patchwork of polarization maps
The lensing signals involved in CMB polarization maps have already been
measured with ground-based experiments such as SPTpol and POLARBEAR, and would
become important as a probe of cosmological and astrophysical issues in the
near future. Sizes of polarization maps from ground-based experiments are,
however, limited by contamination of long wavelength modes of observational
noise. To further extract the lensing signals, we explore feasibility of
measuring lensing signals from a collection of small sky maps each of which is
observed separately by a ground-based large telescope, i.e., lensing
reconstruction from a patchwork map of large sky coverage organized from small
sky patches. We show that, although the B-mode power spectrum obtained from the
patchwork map is biased due to baseline uncertainty, bias on the lensing
potential would be negligible if the B-mode on scales larger than the blowup
scale of noise is removed in the lensing reconstruction. As examples of
cosmological applications, we also show 1) the cross-correlations between the
reconstructed lensing potential and full-sky temperature/polarization maps from
satellite missions such as PLANCK and LiteBIRD, and 2) the use of the
reconstructed potential for delensing B-mode polarization of LiteBIRD
observation.Comment: 22 pages, 11 figures, replaced to match the published version in JCA
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