2003IAUC.8114....1G

P. Garnavich, University of Notre Dame; T. Matheson, Harvard- Smithsonian Center for Astrophysics (CfA); E. W. Olszewski, University of Arizona; P. Harding, Case Western Reserve University; and K. Z. Stanek, CfA, report that additional spectra of the afterglow of GRB 030329 (IAUC 8101) and suspected supernova (IAUC 8108) were obtained with the 6.5-m MMT reflector on Apr. 8.13 UT. The spectral features reported by Garnavich et al. (ibid.) continue to develop. Subtracting a scaled version of the power-law spectrum of Apr. 4.27 from that of Apr. 8.13 reveals an energy distribution remarkably similar to that of SN 1998bw a week before maximum light (Patat et al. 2001, Ap.J. 555, 900). This is the first spectral confirmation linking supernovae to classical gamma-ray bursts (GRBs). This spectrum can be seen at http://cfa-www.harvard.edu/~tmatheson/compgrb.jpg.