Ultra-light bosons such as axions or axion-like particles (ALPs), are promising candidates to solve the dark matter problem. A unique way to detect such ALPs is to search for the periodic oscillation feature of the position angles of linearly polarized photons emitted from the regions where ALP dark matter forms a solitonic core. In this work, we use the high-resolution polarimetric measurements of the radiation near the super-massive black hole (SMBH) in the center of the Milky Way, i.e., Sagittarius A⋆ (Sgr A⋆), by a sub-array of the Event Horizon Telescope to search for the ultra-light ALPs. We derive upper limits on the ALP-photon coupling of ∼10−12GeV−1 for ALP masses of m∼(10−19−10−18)eV. Our results are stronger than that derived from the observations of SN1987A and a population of supernovae in the mass window of (10−19−10−17)eV. Improved polarimetric measurements with the full Event Horizon Telescope can further strengthen the constraints.
@article{arxiv.2008.13662,
title = {Testing the ALP-photon coupling with polarization measurements of Sagittarius A*},
author = {Guan-Wen Yuan and Ziqing Xia and Chengfeng Tang and Yaqi Zhao and Yi-Fu Cai and Yifan Chen and Jing Shu and Qiang Yuan},
journal= {arXiv preprint arXiv:2008.13662},
year = {2023}
}
Comments
Accepted for publication in JCAP. 13 pages, 2 figures