Wilkinson Microwave Anisotropy Probe 5‐yr constraints on fnl with wavelets
Wilkinson Microwave Anisotropy Probe 5‐yr constraints on fnl with wavelets
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威尔金森微波各向异性探针对小波 fnl 的 5 年约束
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
S. Matarrese
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作者：
A. Curto;E. Martínez;P. Mukherjee;R. B. Barreiro;F. Hansen;M. Liguori;S. Matarrese
我们对威尔金森微波各向异性探测器 (WMAP) 5 年宇宙微波背景 (CMB) 温度各向异性数据图进行高斯性分析。我们使用几个基于球形墨西哥帽小波的三阶估计器。我们使用动机良好的非高斯模拟对局部非线性耦合参数 f nl 施加约束。我们以 6.9 arcmin 的分辨率分析 Q、V 和 W 频段的 WMAP 地图。我们使用 WMAP 团队推荐的 KQ75 遮罩，它遮盖了 28% 的天空。小波系数以 6.9 至 150 arcmin 的 10 个不同尺度进行评估。利用这些系数，我们计算用于执行 Χ 2 分析的三阶估计量。 Χ 2 统计量用于测试 WMAP 数据的高斯性以及约束 f nl 参数。我们的结果表明，WMAP 数据与高斯模拟兼容，并且对于组合的 V + W 地图，f nl 参数在 95% 置信水平 (CL) 下被限制为 -8 < f nl < + 111。该值已针对未检测到的点源的存在进行了校正，这在 V + W 图中添加了 Af nl = 3 ± 5 的正贡献。我们的结果与 WMAP 团队使用双谱获得的结果非常相似。
We present a Gaussianity analysis of the Wilkinson Microwave Anisotropy Probe (WMAP) 5-yr cosmic microwave background (CMB) temperature anisotropy data maps. We use several third-order estimators based on the spherical Mexican hat wavelet. We impose constraints on the local non-linear coupling parameter f nl using well-motivated non-Gaussian simulations. We analyse the WMAP maps at resolution of 6.9 arcmin for the Q, V, and W frequency bands. We use the KQ75 mask recommended by the WMAP team which masks out 28 per cent of the sky. The wavelet coefficients are evaluated at 10 different scales from 6.9 to 150 arcmin. With these coefficients, we compute the third order estimators which are used to perform a Χ 2 analysis. The Χ 2 statistic is used to test the Gaussianity of the WMAP data as well as to constrain the f nl parameter. Our results indicate that the WMAP data are compatible with the Gaussian simulations, and the f nl parameter is constrained to -8 < f nl < + 111 at 95 per cent confidence level (CL) for the combined V + W map. This value has been corrected for the presence of undetected point sources, which add a positive contribution of Af nl = 3 ± 5 in the V + W map. Our results are very similar to those obtained by the WMAP team using the bispectrum.