Speaker
Description
Radio observations employing the very long baseline interferometry (VLBI) technique offer a crucial insight into the structure and dynamics of Gamma-Ray Burst (GRB) jets. Specifically, VLBI serves as a fundamental tool for measuring the apparent superluminal expansion (in on-axis GRBs) and proper motion (in off-axis GRBs) of the GRB blast wave. These measurements enable constraints on the outflow geometry and characterisation of the circum-burst medium, complementary to light curve and spectral modelling. This presentation will highlight the significant contribution of VLBI to GRB science, with a particular focus on recent results concerning GRB221009A, the brightest GRB recorded to date. For the latter, the observed size evolution probed by VLBI measurements suggests that the reverse shock and the forward shock dominate the afterglow emission at different frequencies and times. Lastly, future prospects for GRB research through radio interferometry will be discussed.
