Extended anomalous foreground emission in the WMAP three-year data
Extended anomalous foreground emission in the WMAP three-year data
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DOI：
10.1086/587862
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发表时间：
2008-06-20
影响因子：
4.9
通讯作者：
Finkbeiner, Douglas P.
中科院分区：
文献类型：
--
作者：
Dobler, Gregory;Finkbeiner, Douglas P.
我们使用基于模板的多元线性回归方法研究了WMAP温度数据中银河漫辐射的光谱和形态特征，得到了以下结果。(1)我们证实了以前的观察，在尘埃相关的光谱颠簸，与Draine和Lazarian旋转尘埃模型一致。(2)我们还确认了银河系内部的“阴霾”信号，并认为它并不像最初认为的那样遵循自由-自由光谱，而是来自硬电子宇宙射线群的同步辐射。(3)在偏离以前的工作，我们允许光谱的H α相关的发射（这是用来跟踪自由的组件）浮动在适合，并发现它不遵循预期的自由的光谱。相反，在50 GHz附近有一个凸起，在20%的水平上修改了频谱，我们推测这是由温暖的电离介质中的旋转尘埃引起的。(4)所得互相关谱对映射零点不敏感，但对CMB估计量的选择敏感。在CMB估计的情况下，通过最小化方差的线性组合的WMAP波段，我们表明，每个模板和真正的CMB的互相关成比例的偏差总是存在的。该偏置可以大于某些频带中的任何前景信号。(5)最后，我们考虑的频率覆盖范围和灵敏度的普朗克使命，并建议线性组合系数的CMB模板，将减少统计和系统的不确定性在同步加速器和阴霾光谱超过一个数量级。
We study the spectral and morphological characteristics of the diffuse Galactic emission in the WMAP temperature data using a template-based multilinear regression, and obtain the following results. (1) We confirm previous observations of a bump in the dust-correlated spectrum, consistent with the Draine & Lazarian spinning dust model. (2) We also confirm the "haze" signal in the inner Galaxy, and argue that it does not follow a free-free spectrum as first thought, but instead is synchrotron emission from a hard electron cosmic-ray population. (3) In a departure from previous work, we allow the spectrum of H alpha-correlated emission (which is used to trace the free-free component) to float in the fit, and find that it does not follow the expected free-free spectrum. Instead there is a bump near 50 GHz, modifying the spectrum at the 20% level, which we speculate is caused by spinning dust in the warm ionized medium. (4) The derived cross-correlation spectra are not sensitive to the map zero points, but are sensitive to the choice of CMB estimator. In cases where the CMB estimator is derived by minimizing variance of a linear combination of the WMAP bands, we show that a bias proportional to the cross-correlation of each template and the true CMB is always present. This bias can be larger than any of the foreground signals in some bands. (5) Lastly, we consider the frequency coverage and sensitivity of the Planck mission, and suggest linear combination coefficients for the CMB template that will reduce both the statistical and systematic uncertainty in the synchrotron and haze spectra by more than an order of magnitude.