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arXiv 1102.3415astro-ph.CO
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CMB天空的像差:像差核的快速和精确计算

Aberrating the CMB sky: fast and accurate computation of the aberration kernel

J. Chluba

摘要:

众所周知,我们相对于宇宙微波背景(CMB)静止坐标系的运动引入了一个大的偶极CMB各向异性,其振幅为~beta=v/c~10^{-3}。此外,它应该导致一个小的统计各向同性的突破,这在更高的多极变得最显着。原则上,这可以用来确定我们的速度相对于CMB静止框架使用高角分辨率数据从普朗克,而不直接依赖于振幅和方向的CMB偶极子,使我们能够约束宇宙学模型中,宇宙偶极子产生部分从大规模的等曲率扰动,而不是完全运动诱导。在这里,我们推导出简单的递归关系,允许精确计算不同球谐系数之间的运动引起的耦合。虽然最低阶近似的耦合内核可以是不足的2-5倍,在多极l~1000-3000,使用我们的结果的像差内核,我们明确证实,对于统计检测的像差效应只有一阶项β物质。然而,这里给出的表达式并不限于β ~10^{-3},而是可以在更高的速度下使用。我们证明了这些公式的鲁棒性,说明了内核对β的依赖性,以及球谐指数l和m。

英文摘要:

It is well known that our motion with respect to the cosmic microwave background (CMB) rest frame introduces a large dipolar CMB anisotropy, with an amplitude ~beta=v/c~10^{-3}. In addition it should lead to a small breaking of statistical isotropy which becomes most notable at higher multipoles. In principle this could be used to determine our velocity with respect to the CMB rest frame using high angular resolution data from Planck, without directly relying on the amplitude and direction of the CMB dipole, allowing us to constrain cosmological models in which the cosmic dipole arises partly from large-scale isocurvature perturbations instead of being fully motion-induced. Here we derive simple recursion relations that allow precise computation of the motion-induced coupling between different spherical harmonic coefficients. Although the lowest order approximations for the coupling kernel can be deficient by factors of 2-5 at multipoles l~1000-3000, using our results for the aberration kernel we explicitly confirm that for a statistical detection of the aberration effect only first order terms in beta matter. However, the expressions given here are not restricted to beta~10^{-3}, but can be used at much higher velocities. We demonstrate the robustness of these formulae, illustrating the dependence of the kernel on beta, as well as the spherical harmonic indices l and m.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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