7.3.2 Orbital model
Two different methods are used to carry out orbital fits to the astrometric data: (1) a hybrid implementation of a differential evolution Markov Chain Monte Carlo (DE-MCMC) algorithm and a (2) Genetic Algorithm (GA). All solutions published in Gaia DR3 were determined with a single-companion model, though the codes are designed to efficiently search for higher multiplicity models too. Both algorithms achieve convergence by maximising the same figure of merit, the Log-likelihood (). More details can be found in Holl et al. (2023b).