Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps
We introduce and study the distribution of an estimator for the normalized bispectrum of the Cosmic Microwave Background (CMB) anisotropy. We use it to construct a goodness of fit statistic to test the coadded 53 and 90 GHz COBE-DMR 4 year maps for non-Gaussianity. Our results indicate that Gaussian...
| Main Authors: | , , |
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| Format: | Journal article |
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1998
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| _version_ | 1797052890429259776 |
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| author | Ferreira, P Magueijo, J Górski, K |
| author_facet | Ferreira, P Magueijo, J Górski, K |
| author_sort | Ferreira, P |
| collection | OXFORD |
| description | We introduce and study the distribution of an estimator for the normalized bispectrum of the Cosmic Microwave Background (CMB) anisotropy. We use it to construct a goodness of fit statistic to test the coadded 53 and 90 GHz COBE-DMR 4 year maps for non-Gaussianity. Our results indicate that Gaussianity is ruled out at the confidence level in excess of 98%. This value is a lower bound, given all the investigated systematics. The dominant non-Gaussian contribution is found near the multipole of order $\ell=16$. Our attempts to explain this effect as caused by the diffuse foreground emission from the Galaxy have failed. We conclude that unless there exists a microwave foreground emission which spatially correlates neither with the DIRBE nor Haslam maps, the cosmological CMB anisotropy is genuinely non-Gaussian. |
| first_indexed | 2024-03-06T18:37:02Z |
| format | Journal article |
| id | oxford-uuid:0b9a2320-9ed3-4a7a-bec9-c113dc8322bb |
| institution | University of Oxford |
| last_indexed | 2024-03-06T18:37:02Z |
| publishDate | 1998 |
| record_format | dspace |
| spelling | oxford-uuid:0b9a2320-9ed3-4a7a-bec9-c113dc8322bb2022-03-26T09:30:17ZEvidence for non-Gaussianity in the COBE DMR Four Year Sky MapsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:0b9a2320-9ed3-4a7a-bec9-c113dc8322bbSymplectic Elements at Oxford1998Ferreira, PMagueijo, JGórski, KWe introduce and study the distribution of an estimator for the normalized bispectrum of the Cosmic Microwave Background (CMB) anisotropy. We use it to construct a goodness of fit statistic to test the coadded 53 and 90 GHz COBE-DMR 4 year maps for non-Gaussianity. Our results indicate that Gaussianity is ruled out at the confidence level in excess of 98%. This value is a lower bound, given all the investigated systematics. The dominant non-Gaussian contribution is found near the multipole of order $\ell=16$. Our attempts to explain this effect as caused by the diffuse foreground emission from the Galaxy have failed. We conclude that unless there exists a microwave foreground emission which spatially correlates neither with the DIRBE nor Haslam maps, the cosmological CMB anisotropy is genuinely non-Gaussian. |
| spellingShingle | Ferreira, P Magueijo, J Górski, K Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title | Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title_full | Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title_fullStr | Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title_full_unstemmed | Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title_short | Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps |
| title_sort | evidence for non gaussianity in the cobe dmr four year sky maps |
| work_keys_str_mv | AT ferreirap evidencefornongaussianityinthecobedmrfouryearskymaps AT magueijoj evidencefornongaussianityinthecobedmrfouryearskymaps AT gorskik evidencefornongaussianityinthecobedmrfouryearskymaps |