Journal article
Evidence for non-Gaussianity in the COBE DMR Four Year Sky Maps
- Abstract:
- 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.
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Authors
- Journal:
- Astrophys.J. More from this journal
- Volume:
- 503
- Pages:
- L1-L4
- Publication date:
- 1998-03-21
- DOI:
- Keywords:
- Pubs id:
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pubs:208135
- UUID:
-
uuid:0b9a2320-9ed3-4a7a-bec9-c113dc8322bb
- Local pid:
-
pubs:208135
- Source identifiers:
-
208135
- Deposit date:
-
2012-12-19
Terms of use
- Copyright date:
- 1998
- Notes:
- 16 pages, 3 figs uses aasms4.tex, revised and accepted to Ap. J. Lett
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