Primordial Gravitational Waves from Galaxy Intrinsic Alignments
Abstract
Galaxy shapes have been observed to align with external tidal fields generated by the large-scale structures of the Universe. While the main source for these tidal fields is provided by long-wavelength density perturbations, tensor perturbations also contribute with a non-vanishing amplitude at linear order. We show that parity-breaking gravitational waves produced during inflation leave a distinctive imprint in the galaxy shape power spectrum which is not hampered by any scalar-induced tidal field. We also show that a certain class of tensor non-Gaussianities produced during inflation can leave a signature in the density-weighted galaxy shape power spectrum. We estimate the possibility of observing such imprints in future galaxy surveys.
Cite
@article{arxiv.2001.05930,
title = {Primordial Gravitational Waves from Galaxy Intrinsic Alignments},
author = {Matteo Biagetti and Giorgio Orlando},
journal= {arXiv preprint arXiv:2001.05930},
year = {2020}
}
Comments
24+23 pages, 6 figures, code available at https://gitlab.com/mbiagetti/tensor_fossil, updated to published version