A post-mortem investigation of the Type IIb supernova 2001ig

We present images taken with the Gemini Multi-Object Spectrograph on Gemini-South, in excellent (<0.5 arcsec) seeing, of supernova (SN) 2001ig in NGC 7424, ~1000 d after explosion. A point source seen at the site of the SN is shown to have colours inconsistent with being an H II region or a SN 1993J-like remnant, but can be matched to a late-B through late-F supergiant with AV < 1. We believe this object is the massive binary companion responsible for periodic modulation in mass-loss material around the Wolf-Rayet progenitor which gave rise to significant structure in the SN radio light curve. © 2006 The Authors. Journal compilation © 2006 RAS.