# Detecting dark photon dark matter with Gaia-like astrometry observations

## TL;DR

This paper proposes using high-precision Gaia-like astrometry to detect ultralight dark photon dark matter through oscillations in stellar positions caused by their interaction with baryons or B-L charge.

## Contribution

It introduces a novel astrometry-based method to search for dark photon dark matter in the mass range of 10^{-23} to 10^{-21} eV, leveraging Gaia observations.

## Key findings

- Potential to detect dark photon dark matter in the specified mass range.
- Astrometry can provide promising sensitivities for dark matter detection.
- Method offers a new avenue for dark matter searches using stellar position data.

## Abstract

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.