Effects of Rayleigh scattering on the CMB and cosmic structure
Effects of Rayleigh scattering on the CMB and cosmic structure
复制标题
瑞利散射对宇宙微波背景和宇宙结构的影响
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
C. Hirata
中科院分区：
文献类型：
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作者：
Elham Alipour;K. Sigurdson;C. Hirata
在复合过程中和复合后，除了与自由电子的汤姆逊散射外，光子还通过瑞利散射与中性氢和氦原子耦合。这种耦合既影响CMB各向异性，也影响宇宙中物质的分布。瑞利截面的频率依赖性打破了CMB温度和偏振各向异性的热性质，有效地增加了描述CMB强度和偏振统计所需变量的数量，而额外的原子耦合改变了CMB的物质分布和透镜。我们介绍了一种新的方法来捕捉瑞利散射对宇宙功率谱的影响。瑞利散射在353 GHz处修正了CMB温度和偏振各向异性，并修正了物质关联，修正幅度高达0.3。我们展示了瑞利信号，特别是热(瑞利)E偏振和瑞利(热)强度信号之间的互谱，即使在前景存在的情况下，未来的CMB任务也可能检测到瑞利信号，以及这些新信息如何有助于更好地约束宇宙学参数。
During and after recombination, in addition to Thomson scattering with free electrons, photons also coupled to neutral hydrogen and helium atoms through Rayleigh scattering. This coupling influences both CMB anisotropies and the distribution of matter in the Universe. The frequency-dependence of the Rayleigh cross section breaks the thermal nature of CMB temperature and polarization anisotropies and effectively doubles the number of variables needed to describe CMB intensity and polarization statistics, while the additional atomic coupling changes the matter distribution and the lensing of the CMB. We introduce a new method to capture the effects of Rayleigh scattering on cosmological power spectra. Rayleigh scattering modifies CMB temperature and polarization anisotropies at the $\sim\!1 \%$ level at $353 {\rm GHz}$ (scaling $\propto \nu^4$), and modifies matter correlations by as much as $\sim\!0.3\%$. We show the Rayleigh signal, especially the cross-spectra between the thermal (Rayleigh) E-polarization and Rayleigh (thermal) intensity signal, may be detectable with future CMB missions even in the presence of foregrounds, and how this new information might help to better constrain the cosmological parameters.