Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/7384
Title: Morphology of CMB fields—effect of weak gravitational lensing
Authors: Goyal, Priya
Pravabati, C
Appleby, S
Keywords: CMBR polarisation
gravitational lensing
Issue Date: Feb-2020
Publisher: IOP Publishing
Citation: Journal of Cosmology and Astroparticle Physics, Vol. 2020, No. 2, 020
Abstract: We study the morphology of the cosmic microwave background temperature and polarization fields using the shape and alignment parameters, β and α, that are constructed from the contour Minkowski tensor. The primary goal of our paper is to understand the effect of weak gravitational lensing on the morphology of the CMB fields. In order to isolate different physical effects that can be potentially confused with the effect of lensing, we first study the effect of varying the cosmology on α and β, and show that they are relatively insensitive to variation of cosmological parameters. Next we analyze the signatures of hemispherical anisotropy, and show that information of such anisotropy in α gets washed out at small angular scales and become pronounced only at large angular scales. For β we find characteristic distortions which vary with the field threshold. We then study the effect of weak gravitational lensing using simulations of lensed temperature and E and B modes. We quantify the distortion induced in the fields across different angular scales. We find that lensing makes structures of all fields increasingly more anisotropic as we probe down to smaller scales. We find distinct behaviour of morphological distortions as a function of threshold for the different fields. The effect is small for temperature and E mode, while it is significantly large for B mode. Further, we find that lensing does not induce statistical anisotropy, as expected from the isotropic distribution of large scale structure of matter. We expect that the results obtained in this work will provide insights on the reconstruction of the lensing potential.
Description: Restricted Access © IOP Publishing https://doi.org/10.1088/1475-7516/2020/02/020
URI: http://prints.iiap.res.in/handle/2248/7384
ISSN: 1475-7516
Appears in Collections:IIAP Publications

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