Detecting dark photon dark matter with Gaia-like astrometry observations

Understand

A class of dark photon dark matter models with ultralight masses would lead to oscillation of a test body through a coupling with baryons or $B-L$ charge.

• This periodical oscillation of an observer results in swing of a star's apparent position due to the effect of aberration of light, which could be probed with high-precision astrometry observations of stars in the Milky Way.
• We propose to use the observations of stellar positions of a number of stars by Gaia to search for this kind of dark photon dark matter.
• We show that this astrometry method is able to give promising sensitivities to search for the dark photon dark matter in the mass range of $10^{-23}\sim10^{-21}$ eV.