Fig. 1: Illustration of detecting extragalactic axion-like dark matter (DM) with polarization measurements of FRBs. | Communications Physics

Fig. 1: Illustration of detecting extragalactic axion-like dark matter (DM) with polarization measurements of FRBs.

From: Detecting extragalactic axion-like dark matter with polarization measurements of fast radio bursts

Fig. 1: Illustration of detecting extragalactic axion-like dark matter (DM) with polarization measurements of FRBs.The alternative text for this image may have been generated using AI.

The interaction between photons and ALPs leads to modifications in the dispersion relations, resulting in a difference in phase velocity between the two modes. This phenomenon, known as cosmic birefringence, causes changes in the polarization angles (PAs) of the light. If axion-like DM is distributed around the FRB 20220912A's host galaxy, ALP-induced PA oscillations (ϕ(t)) can emerge. The repeating FRBs enable us to monitor their polarization properties long-term to detect axion-like DM on extragalactic distance scales.

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