The Final Word on the Progenitor of the Type II-Plateau Supernova SN 2006my

By registering pre-supernova (pre-SN) and post-supernova (post-SN) images, usually taken at high resolution, roughly three dozen core-collapse supernovae have now had the properties of their progenitor stars either directly measured or (more commonly) constrained by establishing upper limits on their luminosities. Here we reexamine the particularly vexing case of supernova SN 2006my, a classic nearby Type II-Plateau supernova (SN II-P) whose explosion site had been fortuitously imaged by the Hubble Space Telescope (HST) twelve years prior to the explosion, enabling three independent investigations to be carried out. In the first, Li et. al. (2007) reported spatial coincidence between SN 2006my and a (possibly extended) source with properties deemed consistent with those of a red supergiant (i.e., the type of progenitor expected for an SN II-P). Subsequent analyses by Leonard et al. (2008) and Crockett et al. (2010), however, refuted the Li et al. detection claim, but recognized that existing data did not permit a definitive resolution of the issue, since the SN 2006my localizations still placed it on *part* of the putative progenitor's point-spread-function in the pre-SN frames, just no longer at its center. To definitively establish the association/non-association of SN 2006my with the source identified in the pre-SN images, we have acquired new HST images of the site of SN 2006my (long after SN 2006my has faded beyond detection), and here report the final results of our study (i.e., whether any of the proposed progenitor object's light has now disappeared). We also report preliminary results from a similarly carried out investigation into the progenitor of the Type Ib SN 2007fo. Support for Program numbers HST-GO-12282 and HST-GO-12170 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.