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.
- Publication:
-
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- July 2020
- DOI:
- 10.1088/1475-7516/2020/07/005
- arXiv:
- arXiv:2001.05930
- Bibcode:
- 2020JCAP...07..005B
- Keywords:
-
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- High Energy Physics - Theory
- E-Print:
- 24+23 pages, 6 figures, code available at https://gitlab.com/mbiagetti/tensor_fossil, updated to published version