Millimeter Observations of GRB 030329: Continued Evidence for a Two-Component Jet

We present the results of a dedicated campaign on the afterglow of GRB 030329with the millimeter interferometers of the Owens Valley Radio Observatory(OVRO), the Berkeley-Illinois-Maryland Association (BIMA), and with the MAMBO-2bolometer array on the IRAM 30-m telescope. These observations allow us totrace the full evolution of the afterglow of GRB 030329 at frequencies of 100GHz and 250 GHz for the first time. The millimeter light curves exhibit twomain features: a bright, constant flux density portion and a steep power-lawdecline. The absence of bright, short-lived millimeter emission is used to showthat the GRB central engine was not actively injecting energy well after theburst. The millimeter data support a model, advocated by Berger et al., of atwo-component jet-like outflow in which a narrow angle jet is responsible forthe high energy emission and early optical afterglow, and a wide-angle jetcarrying most of the energy is powering the radio and late optical afterglowemissionComment: Accepted to ApJ