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Point source contamination in CMB non-Gaussianity analyses

Babich, Daniel and Pierpaoli, Elena (2008) Point source contamination in CMB non-Gaussianity analyses. Physical Review D, 77 (12). Art. No. 123011. ISSN 2470-0010.

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In this paper we analyze the biasing effect of point sources, either thermal Sunyaev-Zeldovich clusters or standard radio sources, on the estimated strength of the non-Gaussianity in the cosmic microwave background (CMB). We show that the biggest contribution comes from the cross correlation of the CMB with the matter density rather than from the Poisson term which is conventionally assumed in these calculations. For the three year WMAP data, we estimate that point sources could produce a non-Gaussian signature equivalent to a bias in fNL of 0.35, 0.24, -0.097, -0.13 in the Ka, Q, V, and W bands, respectively. The level of bias we find is largely insufficient to explain the very high fNL values recently detected by Yadav and Wandelt. For Planck, we estimate the point source bispectra to contaminate the fNL estimator with a bias of 1.3, 0.34, -0.25, -0.48 at 30, 44, 70, 100 GHz, respectively. These results depend on the assumed redshift distribution of the point sources. However, given the projected Planck sensitivity of DeltafNL~=5 (95% C.L.), a good estimate of point sources' properties including their number density and redshift distribution is essential before deriving strong conclusions on primordial non-Gaussianity.

Item Type:Article
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Pierpaoli, Elena0000-0002-7957-8993
Additional Information:©2008 The American Physical Society. (Received 27 March 2008; published 23 June 2008) D.B. acknowledges financial support from the Betty an Gordon Moore Foundation and would like to thank Sterl Phinney, Daisuke Nagai, and Eiichiro Komatsu for helpful conversations. E.P. is supported by NSF Grant No. AST–0649899,NASA Grant No. NNX07AH59G, Planck Subcontract No. 1290790, and JPL SURP No. 1314616. She would also like to thank Kevin Huffenberger and Joachin Gonzales-Nuevo for useful conversations. We also thank Kendrick Smith for helpful comments on a draft of the paper.
Group:TAPIR, Moore Center for Theoretical Cosmology and Physics
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
NASANNX07AH59G, Planck Subcontract No. 1290790
Issue or Number:12
Record Number:CaltechAUTHORS:BABprd08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11112
Deposited By: Archive Administrator
Deposited On:15 Jul 2008 19:18
Last Modified:18 Nov 2020 23:32

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