Directional Variations of the Non-Gaussianity Parameter f_NL
We investigate local variations of the primordial non-Gaussianity parameter f_NL in the WMAP data, looking for possible influence of foreground contamination in the full-sky estimate of f_NL. We first improve the needlet bispectrum estimate in (Rudjord et al. 2009) on the full-sky to f_NL= 73 +/- 31...
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ftdatacite:10.48550/arxiv.0906.3232 2023-05-15T18:22:47+02:00 Directional Variations of the Non-Gaussianity Parameter f_NL Rudjord, Øystein Hansen, Frode K. Lan, Xiaohong Liguori, Michele Marinucci, Domenico Matarrese, Sabino 2009 https://dx.doi.org/10.48550/arxiv.0906.3232 https://arxiv.org/abs/0906.3232 unknown arXiv https://dx.doi.org/10.1088/0004-637x/708/2/1321 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Cosmology and Nongalactic Astrophysics astro-ph.CO FOS Physical sciences article-journal Article ScholarlyArticle Text 2009 ftdatacite https://doi.org/10.48550/arxiv.0906.3232 https://doi.org/10.1088/0004-637x/708/2/1321 2022-04-01T14:58:47Z We investigate local variations of the primordial non-Gaussianity parameter f_NL in the WMAP data, looking for possible influence of foreground contamination in the full-sky estimate of f_NL. We first improve the needlet bispectrum estimate in (Rudjord et al. 2009) on the full-sky to f_NL= 73 +/- 31 using the KQ75 mask on the co-added V+W channel. We find no particular values of f_NL estimates close to the galactic plane and conclude that foregrounds are unlikely to affect the estimate of f_NL in the V and W bands even for the smaller KQ85 mask. In the Q band however, we find unexpectedly high values of f_NL in local estimates close to the galactic mask, as well as significant discrepancies between Q band estimates and V/W band estimates. We therefore conclude that the Q band is too contaminated to be used for non-Gaussianity studies even with the larger KQ75 mask. We further noted that the local f_NL estimates on the V+W channel are positive on all equatorial bands from the north to the south pole. The probability for this to happen in a universe with f_NL = 0 is less than one percent. : 6 pages, 2 figures, included section on non-Gaussian maps, references added Text South pole DataCite Metadata Store (German National Library of Science and Technology) South Pole |
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Cosmology and Nongalactic Astrophysics astro-ph.CO FOS Physical sciences |
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Cosmology and Nongalactic Astrophysics astro-ph.CO FOS Physical sciences Rudjord, Øystein Hansen, Frode K. Lan, Xiaohong Liguori, Michele Marinucci, Domenico Matarrese, Sabino Directional Variations of the Non-Gaussianity Parameter f_NL |
topic_facet |
Cosmology and Nongalactic Astrophysics astro-ph.CO FOS Physical sciences |
description |
We investigate local variations of the primordial non-Gaussianity parameter f_NL in the WMAP data, looking for possible influence of foreground contamination in the full-sky estimate of f_NL. We first improve the needlet bispectrum estimate in (Rudjord et al. 2009) on the full-sky to f_NL= 73 +/- 31 using the KQ75 mask on the co-added V+W channel. We find no particular values of f_NL estimates close to the galactic plane and conclude that foregrounds are unlikely to affect the estimate of f_NL in the V and W bands even for the smaller KQ85 mask. In the Q band however, we find unexpectedly high values of f_NL in local estimates close to the galactic mask, as well as significant discrepancies between Q band estimates and V/W band estimates. We therefore conclude that the Q band is too contaminated to be used for non-Gaussianity studies even with the larger KQ75 mask. We further noted that the local f_NL estimates on the V+W channel are positive on all equatorial bands from the north to the south pole. The probability for this to happen in a universe with f_NL = 0 is less than one percent. : 6 pages, 2 figures, included section on non-Gaussian maps, references added |
format |
Text |
author |
Rudjord, Øystein Hansen, Frode K. Lan, Xiaohong Liguori, Michele Marinucci, Domenico Matarrese, Sabino |
author_facet |
Rudjord, Øystein Hansen, Frode K. Lan, Xiaohong Liguori, Michele Marinucci, Domenico Matarrese, Sabino |
author_sort |
Rudjord, Øystein |
title |
Directional Variations of the Non-Gaussianity Parameter f_NL |
title_short |
Directional Variations of the Non-Gaussianity Parameter f_NL |
title_full |
Directional Variations of the Non-Gaussianity Parameter f_NL |
title_fullStr |
Directional Variations of the Non-Gaussianity Parameter f_NL |
title_full_unstemmed |
Directional Variations of the Non-Gaussianity Parameter f_NL |
title_sort |
directional variations of the non-gaussianity parameter f_nl |
publisher |
arXiv |
publishDate |
2009 |
url |
https://dx.doi.org/10.48550/arxiv.0906.3232 https://arxiv.org/abs/0906.3232 |
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South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_relation |
https://dx.doi.org/10.1088/0004-637x/708/2/1321 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.0906.3232 https://doi.org/10.1088/0004-637x/708/2/1321 |
_version_ |
1766202200819761152 |