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Non-Gaussianity in WMAP data due to the correlation of CMB lensing potential with secondary anisotropies

Calabrese, Erminia ORCID:, Smidt, Joseph, Amblard, Alexandre, Cooray, Asantha, Melchiorri, Alessandro, Serra, Paolo, Heavens, Alan and Munshi, Dipak 2010. Non-Gaussianity in WMAP data due to the correlation of CMB lensing potential with secondary anisotropies. Physical Review D 81 (4) , 043529. 10.1103/PhysRevD.81.043529

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We measure the skewness power spectrum of the CMB anisotropies optimized for a detection of the secondary bispectrum generated by the correlation of the CMB lensing potential with integrated SachsWolfe effect and the Sunyaev-Zel’dovich effect. The covariance of our measurements is generated by Monte Carlo simulations of Gaussian CMB fields with noise properties consistent with WMAP 5-year data. When interpreting multifrequency measurements we also take into account the confusion resulting from unresolved radio point sources. We analyze Q, V and W-band WMAP 5-year raw and foregroundcleaned maps using the KQ75 mask out to lmax ¼ 600. We find no significant evidence for a nonzero nonGaussian signal from the lensing-secondary correlation in all three bands and we constrain the overall amplitude of the cross-power spectrum between CMB lensing potential and the sum of SZ and ISW fluctuations to be 0:42 � 0:86 and 1:19 � 0:86 in combined V and W-band raw and foreground-cleaned maps provided by the WMAP team, respectively. The point-source amplitude at the bispectrum level measured with this skewness power spectrum is higher than previous measurements of point-source nonGaussianity. We also consider an analysis where we also account for the primordial non-Gaussianity in addition to lensing-secondary bispectrum and point sources. The focus of this paper is on secondary anisotropies. Consequently the estimator is not optimized for primordial non-Gaussianity and the limit we find on local non-Gaussianity from the foreground-cleaned V þ W maps is fNL ¼ 13 � 62, when marginalized over point sources and lensing-ISW/SZ contributions to the total bispectrum.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QB Astronomy
Publisher: American Physical Society
ISSN: 1550-7998
Date of First Compliant Deposit: 10 October 2017
Date of Acceptance: 25 September 2009
Last Modified: 05 May 2023 23:33

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