부산대학교 도서관

The search for primordial B-mode polarization of the cosmic microwave background (CMB) is limited by the sample variance of B-modes produced at later times by gravitational lensing. Constraints can be improved by "delensing": using some proxy of the matter distribution to partially remove the lensing-induced B-modes. Current and soon-upcoming experiments will infer a matter map - at least in part - from the temperature anisotropies of the CMB. These reconstructions are contaminated by extragalactic foregrounds: radio-emitting galaxies, the cosmic infrared background, or the Sunyaev-Zel'dovich effects. Using the Websky simulations, we show that the foregrounds add spurious power to the angular autospectrum of delensed B-modes via non-Gaussian higher-point functions, biasing constraints on the tensor-to-scalar ratio, r. We consider an idealized experiment similar to the Simons Observatory, with no Galactic or atmospheric foregrounds. After removing point sources detectable at 143 GHz and reconstructing lensing from CMB temperature modes l