A New Probe of Cosmic Birefringence Using Galaxy Polarization and Shapes
Cosmology and Nongalactic Astrophysics
2025-04-09 v2 Astrophysics of Galaxies
High Energy Physics - Phenomenology
Abstract
We propose a novel statistical method to measure cosmic birefringence and demonstrate its power in probing parity violation due to axions. Exploiting an empirical correlation between the integrated radio polarization direction of a spiral galaxy and its apparent shape, we devise an unbiased minimum-variance estimator for the rotation angle, which should achieve an uncertainty of -- per galaxy. Large galaxy samples from the forthcoming SKA continuum surveys, together with optical shape catalogs, promise a comparable or even lower noise power spectrum for the rotation angle than in the CMB Stage-IV (CMB-S4) experiment, with different systematics.
Cite
@article{arxiv.2402.18568,
title = {A New Probe of Cosmic Birefringence Using Galaxy Polarization and Shapes},
author = {Weichen Winston Yin and Liang Dai and Junwu Huang and Lingyuan Ji and Simone Ferraro},
journal= {arXiv preprint arXiv:2402.18568},
year = {2025}
}