The imprint of primordial gravitational waves on the CMB intensity profile
Abstract
We use the induced geometry on the two dimensional transverse cross section of a photon beam propagating on a perturbed Friedmann-Robertson-Walker (FRW) spacetime to find the Cosmic Microwave Background (CMB) photon distribution over a telescope's collecting area today. It turns out that at each line of sight the photons are diluted along a transverse direction due to gravitational shearing. The effect can be characterized by two spin-weight-two variables, which are reminiscent of the Stokes polarization parameters. Similar to that case, one can construct a scalar and a pseudo-scalar function where the latter only gets contributions from the tensor modes. We analytically determine the power spectrum of the pseudo-scalar at superhorizon scales in a simple inflationary model and briefly discuss possible observational consequences.
Keywords
Cite
@article{arxiv.2105.02236,
title = {The imprint of primordial gravitational waves on the CMB intensity profile},
author = {Ali Kaya},
journal= {arXiv preprint arXiv:2105.02236},
year = {2021}
}
Comments
6 pages, 2 figures, to appear in Physics Letters B