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arXiv · 2402.18568

A New Probe of Cosmic Birefringence Using Galaxy Polarization and Shapes

Weichen Winston Yin·Liang Dai·Junwu Huang·Lingyuan Ji·Simone Ferraro
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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 $5^\circ$--$ 15^\circ$ 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.

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Weichen Winston Yin, Liang Dai, Junwu Huang, Lingyuan Ji, Simone Ferraro. 2024-02-28. A New Probe of Cosmic Birefringence Using Galaxy Polarization and Shapes. https://arxiv.org/abs/2402.18568

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