2012ApJ...759....4M

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 (GRB 030329) taken between 672 and 2032 days after the burst. The VLA and WSRT data suggest a simple power-law decay in the flux at 5 GHz, 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 is placed on the proper motion, supporting the standard afterglow model for gamma-ray bursts.