We present VLBI and archival Karl G. Jansky Very Large Array (VLA) and Westerbork Synthesis Radio Telescope (WSRT) observations of the radio afterglow from the gamma-ray burst (GRB) of 2003 March 29 (GRB030329) taken between 672 and 2032days after the burst. The VLA and WSRT data suggest a simple power-law decay in the flux at 5GHz, with no clear signature of any rebrightening from the counterjet. We report an unresolved source at day 2032 of size 1.18 ± 0.13 mas, which we use in conjunction with the expansion rate of the burst to argue for the presence of a uniform, interstellar-medium-like circumburst medium. A limit of <0.067 mas yr-1 is placed on the proper motion, supporting the standard afterglow model for gamma-ray bursts.
- Gamma-ray burst: general
- Gamma-ray burst: individual (GRB 030329)