CMB 3-point functions generated by non-linearities at recombination
摘要
We study the 3-point functions generated at recombination in the squeezed triangle limit, when one mode has a wavelength much larger than the other two and is outside the horizon. The presence of the long wavelength mode cannot change the physics inside the horizon but modifies how a late time observer sees the anisotropies. The effect of the long wavelength mode can be divided into a redefinition of time and spatial scales, a Shapiro time delay and gravitational lensing. The separation is gauge dependent but helps develop intuition. We show that the resulting 3-point function corresponds to an f_NL < 1 and that its shape is different from that created by the f_NL (or local) model.
引用
@article{arxiv.astro-ph/0405428,
title = {CMB 3-point functions generated by non-linearities at recombination},
author = {Paolo Creminelli and Matias Zaldarriaga},
journal= {arXiv preprint arXiv:astro-ph/0405428},
year = {2016}
}
备注
16 pages, 4 figures. Expanded introduction of sec.2. Published version