Photometry of 3 {gamma}-ray burst supernovae

For GRB 130215A/SN 2013ez, we also present optical spectroscopy at t-t0=16.1d, which covers rest-frame 3000-6250{AA}. Based on FeII (5169) and SiII (6355), our spectrum indicates an unusually low expansion velocity of 4000-6350km/s, the lowest ever measured for a GRB-SN.

Additionally, we determined the brightness and shape of each accompanying SN relative to a template supernova (SN 1998bw), which were used to estimate the amount of nickel produced via nucleosynthesis during each explosion. We find that our derived nickel masses are typical of other GRB-SNe, and greater than those of SNe Ibc that are not associated with GRBs. For GRB 130831A/SN 2013fu, we used our well-sampled R-band light curve (LC) to estimate the amount of ejecta mass and the kinetic energy of the SN, finding that these too are similar to other GRB-SNe.