2005IAUC.8575....4M

M. Modjaz, P. Challis, and R. Kirshner, Harvard-Smithsonian Center for Astrophysics; and T. Matheson, National Optical Astronomy Observatory, report that a spectrogram (range 350-740 nm) of SN 2005da (cf. IAUC 8570), obtained by P. Berlind on July 26.26 UT with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), reveals it to be a supernova, possibly a peculiar type-Ic supernova. No obvious lines of hydrogen or helium are detected. The spectrum consists of wide absorption features, similarly to peculiar type-Ic supernovae 1998bw and 2002ap (Foley et al. 2003, PASP 115, 1220). In contrast to the spectra of supernovae 1998bw and 2002ap, this new object's spectrum also exhibits a wide absorption trough at 585 nm, having removed the NED recession velocity of 4495 km/s for the host galaxy (from Falco et al. 1999, PASP 111, 438), which could be identified with Na I. There are peaks near 530 and 640 nm and absorptions near 470, 630, and 680 nm.