An HST Study of the Supernovae Accompanying GRB 040924 and GRB 041006

We present the results from a Hubble Space Telescope ACS study of the supernovae (SNe) associated with gamma-ray bursts (GRBs) 040924 (z = 0.86) and 041006 (z = 0.71). We find evidence that both GRBs were associated with an SN 1998bw-like supernova dimmed by ~1.5 and ~0.3 mag, respectively, making GRB 040924 the faintest GRB-associated SN ever detected. We study the luminosity dispersion in GRB/XRF-associated SNe and compare to local Type Ibc SNe from the literature. We find significant overlap between the two samples, suggesting that GRB/XRF-associated SNe are not necessarily more luminous and do not necessarily produce more 56Ni than local SNe. Based on the current (limited) data sets, we find that the two samples may share a similar 56Ni production mechanism.