An estimator for statistical anisotropy from the CMB bispectrum
An estimator for statistical anisotropy from the CMB bispectrum
复制标题
CMB 双谱统计各向异性的估计器
DOI：
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
A. Riotto
中科院分区：
文献类型：
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作者：
N. Bartolo;E. Dimastrogiovanni;M. Liguori;S. Matarrese;A. Riotto
宇宙微波背景（CMB）的各种数据分析提供了统计各向同性破坏的观测线索。其中一些特征可以在暴涨理论中的原始矢量场的框架内进行研究，暴胀理论通常在功率谱和高阶相关函数中都显示出一定程度的统计各向异性。受这些观察结果和原始矢量场研究的最新理论发展的启发，我们开发了从 CMB 温度各向异性的三点函数中提取统计各向异性信息所需的形式。我们采用简化的矢量场模型，并对曲率波动的双谱进行参数化，以便将有关统计各向异性的所有信息编码在一些参数 LM （测量各向同性双谱振幅的各向异性）中。对于这样的模板双谱，我们计算 ?LM 和预期信噪比的最佳估计量。我们估计，对于 fNL 30，像普朗克这样的实验可以对小至 10% 的双谱各向异性与各向同性振幅的比率敏感。我们的结果是对来自功率谱分析的信息的补充，并且特别与那些统计各向异性在功率谱中被抑制但在双谱中不可忽略的模型相关。
Various data analyses of the Cosmic Microwave Background (CMB) provide observational hints of statistical isotropy breaking. Some of these features can be studied within the framework of primordial vector fields in inflationary theories which generally display some level of statistical anisotropy both in the power spectrum and in higher-order correlation functions. Motivated by these observations and the recent theoretical developments in the study of primordial vector fields, we develop the formalism necessary to extract statistical anisotropy information from the three-point function of the CMB temperature anisotropy. We employ a simplified vector field model and parametrize the bispectrum of curvature fluctuations in such a way that all the information about statistical anisotropy is encoded in some parameters ?LM (which measure the anisotropic to the isotropic bispectrum amplitudes). For such a template bispectrum, we compute an optimal estimator for ?LM and the expected signal-to-noise ratio. We estimate that, for fNL 30, an experiment like Planck can be sensitive to a ratio of the anisotropic to the isotropic amplitudes of the bispectrum as small as 10%. Our results are complementary to the information coming from a power spectrum analysis and particularly relevant for those models where statistical anisotropy turns out to be suppressed in the power spectrum but not negligible in the bispectrum.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.
影响因子：
5
作者：
Pontzen A
通讯作者：
Pontzen A
CMB 各向同性异常模型的可测试偏振预测
影响因子：
5
作者：
Dvorkin C
通讯作者：
Dvorkin C