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oai:recercat.cat:2445/1317612025-12-05T16:11:46Zcom_2072_1057col_2072_478904col_2072_478917

Non-Gaussianity and the CMB bispectrum: Confusion between primordial and lensing-Rees-Sciama contribution? Mangilli, Anna Verde, Licia Física de partícules Experiments Ones de gravetat Particle physics Experiments Gravity waves We revisit the predictions for the expected cosmic microwave background bispectrum signal from the cross-correlation of the primary-lensing-Rees-Sciama signal; we point out that it can be a significant contaminant to the bispectrum signal from primordial non-Gaussianity of the local type. This non-Gaussianity, usually parametrized by the non-Gaussian parameter f N L , arises, for example, in multifield inflation. In particular both signals are frequency-independent, and are maximized for nearly squeezed configurations. While their detailed scale-dependence and harmonic imprints are different for generic bispectrum shapes, we show that, if not included in the modeling, the primary-lensing-Rees-Sciama contribution yields an effective f N L of 10 when using a bispectrum estimator optimized for local non-Gaussianity. Considering that expected 1 − σ errors on f N L are < 10 from forthcoming experiments, we conclude that the contribution from this signal must be included in future constraints on f N L from the cosmic microwave background bispectrum. 2019-04-08T11:02:21Z 2019-04-08T11:02:21Z 2009-12-08 2019-04-08T11:02:21Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 1550-7998 https://hdl.handle.net/2445/131761 603912 eng Reproducció del document publicat a: https://doi.org/10.1103/PhysRevD.80.123007 Physical Review D, 2009, vol. 80, num. 12, p. 123007 https://doi.org/10.1103/PhysRevD.80.123007 info:eu-repo/grantAgreement/EC/FP7/202182/EU//ACT (c) American Physical Society, 2009 info:eu-repo/semantics/openAccess 11 p. application/pdf American Physical Society Articles publicats en revistes (Institut de Ciències del Cosmos (ICCUB))