Rayleigh Scattering and Microwave Background Fluctuations
Rayleigh Scattering and Microwave Background Fluctuations
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瑞利散射和微波背景波动
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Ostriker
中科院分区：
文献类型：
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作者：
Qingjuan Yu;D. Spergel;J. Ostriker
在重组时期，宇宙背景光子不仅通过汤普森散射与自由电子耦合，而且通过瑞利散射与中性氢耦合。对于 z = 800 处光子能量分布峰值附近的光子，后者的影响约为 2%，而在 z = 1100 时，后者的影响约为 0.2%。计算中包含瑞利散射会降低固定红移处的 Silk 阻尼，改变最后散射表面的位置，并改变声波的传播。我们估计这些影响的幅度。对于微波各向异性探头 (MAP)，瑞利散射最多使各向异性光谱增加 0.1%。对于普朗克测量仪的最高频率，瑞利散射的影响更为显着（在 ν ~ 550 GHz 和多极数 l ~ 1000 时各向异性频谱减少 3%）。低频和高频频谱之间的相对差异是由多极 l 函数的振荡造成的，振荡幅度在 100 至 550 GHz 之间高达 0.5%。瑞利散射也会减慢辐射与物质之间的解耦，但效果小得难以察觉。
During the recombination epoch, cosmic background photons coupled not only to free electrons through Thompson scattering, but also to neutral hydrogen through Rayleigh scattering. This latter is a ~2% effect for photons near the peak of the photon energy distribution at z = 800 and a ~0.2% effect at z = 1100. Including Rayleigh scattering in the calculation reduces Silk damping at fixed redshift, alters the position of the surface of last scattering, and alters the propagation of acoustic waves. We estimate the amplitude of these effects. For the Microwave Anisotropy Probe (MAP), Rayleigh scattering increases the anisotropy spectrum by 0.1% at the most. For the highest frequencies of the Planck Surveyor, the effects of Rayleigh scattering are much more dramatic (decreasing the anisotropy spectrum by 3% at ν ~ 550 GHz and multipole number l ~ 1000). The relative difference between the spectra of low and high frequencies is imposed by an oscillation with a function of multipole l, and the oscillation amplitude is up to 0.5% between 100 and 550 GHz. Rayleigh scattering also slows the decoupling between radiation and matter, but the effect is undetectably small.