  Asteroids with companions constitute an excellent sample for studying the
collisional and dynamical evolution of minor planets. The currently known
binary population were discovered by different complementary techniques that
produce, for the moment, a strongly biased distribution, especially in a range
of intermediate asteroid sizes (approximately 20 to 100 km) where both mutual
photometric events and high-resolution adaptive optic imaging are poorly
efficient. A totally independent technique of binary asteroid discovery, based
on astrometry, can help to reveal new binary systems and populate a range of
sizes and separations that remain nearly unexplored. In this work, we describe
a dedicated period detection method and its results for the Gaia DR3 data set.
This method looks for the presence of a periodic signature in the orbit
post-fit residuals. After conservative filtering and validation based on
statistical and physical criteria, we are able to present a first sample of
astrometric binary candidates, to be confirmed by other observation techniques
such as photometric light curves and stellar occultations.
