SIMBAD references

S. J. Smartt, J. R. Maund, and M. A. Hendry, Institute of Astronomy, Cambridge, report that the position of SN 2003gd lies on deep pre-explosion archive images from the Hubble Space Telescope (+ WFPC2) and Gemini North (+ GMOS). Differential astrometry, using an image obtained at the William Herschel Telescope (+ Aux Port Camera) by C. R. Benn on June 15.2 UT, indicates the presence of a progenitor star (V = 26.1 ± 0.15) in the 3100-s F606W WFPC2 image at a distance of 0".06 ± 0".2 from the supernova position. The star has an absolute magnitude of M_V = -3.5, assuming the distance and foreground reddening given by Smartt et al. (2002, Ap.J. 572, L147). The apparent progenitor (I approximately 23.8, V-I = +2.3) is detected on the GMOS i' band (0".6 seeing) but is close to a neighboring star that is resolved in the HST F606W image. The color and absolute magnitude suggest that this star is a red supergiant, probably of spectral type M, with luminosity log (L/L_sun) approximately 4 and a relatively low mass in the range 8-10 M_sun. Smartt et al. add that they will use the HST override program to observe SN 2003gd (with ACS), so as to obtain a significant reduction in the astrometric error, as well as to determine the extinction in this region. Given the likelihood of a progenitor detection, observations of this supernova at all wavelengths are strongly encouraged.