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The reconstruction of the CMB lensing bispectrum
Speaker
Alba Kalaja VSI Groningen (Groningen, the Netherlands)
Abstract
Weak gravitational lensing by the intervening large-scale structure (LSS) of the Universe is the leading non-linear effect on the anisotropies of the cosmic microwave background (CMB). The integrated line-of-sight gravitational potential that causes the distortion can be reconstructed from the lensed temperature and polarization anisotropies via estimators quadratic in the CMB modes. While previous studies have focused on the lensing power spectrum, upcoming experiments will be sensitive to the bispectrum of the lensing field, sourced by the non-linear evolution of structure. The detection of such a signal would provide additional information on late-time cosmological evolution, complementary to the power spectrum. However, the reconstruction process introduces a number of noise biases that significantly hinder the signal. Identifying these terms represents a first step towards detection. In this talk, I will discuss how we compute the leading noise biases of the bispectrum in the flat-sky limit, and how these results compare to simulations.
Date and Time
March 9 2023 4pm KST (= 7am UTC) Zoom link (active once the seminar starts)