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arXiv 1502.05356astro-ph.CO
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利用宇宙红外背景对CMB进行去透镜处理

Delensing the CMB with the Cosmic Infrared Background

Blake D. Sherwin, Marcel Schmittfull

摘要:

由于与透镜B模式的混淆开始限制搜索原始B模式偏振的实验,用于使CMB偏振天空去透镜的鲁棒方法变得越来越重要。我们详细调查的可能性去透镜的CMB与宇宙红外背景(CIB),从尘埃恒星形成星系的辐射,这是一个很好的示踪剂的CMB透镜信号,以改善张量标量比$r$的约束。我们发现,CIB的地图,如目前的普朗克卫星地图在545 GHz,可以用来消除超过一半的透镜B模功率。计算不同的大规模结构的示踪剂的最佳组合去透镜,我们发现,共同添加CIB数据和外部弧分分辨率CMB透镜重建可以导致显着的额外改善去透镜性能。我们调查是否在CIB光谱的测量不确定性将降低去透镜性能,如果没有模型的CIB光谱被假定,而不是CIB光谱被边缘化,当约束$r$。我们发现,这种不确定性不会显着影响B模式调查小于几千度。即使对于较大的调查,它只会导致CIB去透镜性能的适度降低,特别是如果调查具有高(弧分)分辨率,这允许去透镜程序的自校准。虽然前景残差的影响还需要进一步的工作,我们的整体结论与当前CIB数据去透镜是乐观的:这种去透镜方法可以收紧$r$的约束的一个因素$\approx2.2$,并通过一个因素$\approx4$时,结合外部$\approx 3 μ$ K-arcmin透镜重建,而不需要建模的CIB属性。因此,CIB去透镜是下一代CMB偏振调查的一种有前途的方法。

英文摘要:

As confusion with lensing B-modes begins to limit experiments that search for primordial B-mode polarization, robust methods for delensing the CMB polarization sky are becoming increasingly important. We investigate in detail the possibility of delensing the CMB with the cosmic infrared background (CIB), emission from dusty star-forming galaxies that is an excellent tracer of the CMB lensing signal, in order to improve constraints on the tensor-to-scalar ratio $r$. We find that the maps of the CIB, such as current Planck satellite maps at 545 GHz, can be used to remove more than half of the lensing B-mode power. Calculating optimal combinations of different large-scale-structure tracers for delensing, we find that co-adding CIB data and external arcminute-resolution CMB lensing reconstruction can lead to significant additional improvements in delensing performance. We investigate whether measurement uncertainty in the CIB spectra will degrade the delensing performance if no model of the CIB spectra is assumed, and instead the CIB spectra are marginalized over, when constraining $r$. We find that such uncertainty does not significantly affect B-mode surveys smaller than a few thousand degrees. Even for larger surveys it causes only a moderate reduction in CIB delensing performance, especially if the surveys have high (arcminute) resolution, which allows self-calibration of the delensing procedure. Though further work on the impact of foreground residuals is required, our overall conclusions for delensing with current CIB data are optimistic: this delensing method can tighten constraints on $r$ by a factor up to $\approx2.2$, and by a factor up to $\approx4$ when combined with external $\approx 3 μ$K-arcmin lensing reconstruction, without requiring the modeling of CIB properties. CIB delensing is thus a promising method for the upcoming generation of CMB polarization surveys.

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