Ja En つくば宇宙フォーラム
第161回
Probing Dark Energy and Dark Matter Using AGN and the CMB
直川 史寛 氏
東京大学
要旨
Planck, WMAP, and the Atacama Cosmology Telescope have recently reported a potential signal of cosmic birefringence, which refers to a rotation of the polarization plane, in the CMB polarization map (e.g. Eskilt & Komatsu 2022, Palazuelos & Komatsu 2025). This signal violates the parity symmetry of the Universe and, if confirmed, would strongly suggest new physics beyond the standard framework. In particular, axion-like particles (ALPs), which are candidates for dark matter and dark energy, have attracted attention as a possible origin of this effect (e.g. Fujita et al. 2021). However, there are still observational challenges in confirming cosmic birefringence (e.g. Minami et al. 2019, Nakatsuka et al. 2022). In this talk, we review the basics of the CMB and cosmic birefringence and discuss the current observational status. We also discuss ways to confirm the signal and introduce an independent test using active galactic nuclei (e.g. Carroll et al. 1990, Naokawa 2026).