Long-term optical monitoring of GRB 030329.

We present photometric data for GRB 030329/SN 2003dh obtained over a year after the event. The decay rate of the SN is very similar to that of SN 1998bw. We discuss the “jitter” episode that occurred ∼ 50 – 65 days after the explosion and argue that it was produced by the GRB afterglow and not by the supernova. A spectrum obtained eight months after the explosion, combined with the late-time light curve, allow us to determine the amount of nickel. We find that at least 0.35 M⊙ of 56Ni was synthesized during the explosion; the total mass of 56Ni may be up to about 1 M⊙. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]