Presentation #400.03 in the session Plenary 5.
The masses and orbits of directly imaged giant planets and brown dwarfs offer valuable tests of substellar evolutionary models and formation channels. The astrometric reflex motion induced by a companion on its host star can act as a novel approach to both find and characterize low-mass companions. We are carrying out a high-contrast imaging survey of stars showing both radial accelerations (from long-baseline RV programs) and astrometric accelerations (from Hipparcos and Gaia astrometry). Together these provide a 3D acceleration vector, enabling robust predictions of the mass and separation of the companion causing the acceleration. We will present initial results from this program including early discoveries, dynamical masses, and precise orbit constraints. Together these systems are providing rare tests of low-temperature evolutionary models across a broad range of masses, ages, and luminosities. Looking forward, this survey and search strategy will yield some of the best-suited targets for future deep observations with JWST and the ground-based ELTs.