Program: GS-2011B-Q-21

The red supergiant progenitor of the Type IIP Supernova (SN) 2008bk was detected in fortuitous pre-explosion Gemini and Very Large Telescope images. The properties of the progenitor are, however, complicated by the complex background at the SN site, contamination by unresolved blended sources, uncertainties in the degree of extinction and the photometric calibration of the pre-explosion images. With our already approved VLT and Hubble Space Telescope programs, to target SN 2008bk, we propose to acquire late-time images of the site of SN 2008bk using the same instruments and filters as the pre-explosion Gemini images. We request time to observe the site of SN 2008bk with Gemini-S GMOS and the g'r'i' filters to acquire accurate photometry of the progenitor (using image subtraction techniques). These crucial Gemini images will be part of accurate 8-color photometry, from the optical to near-IR, of the progenitor object, making it the best-constrained progenitor after SN 1987A. In achieving significantly better photometry of the progenitor, we aim to place the tightest constraints on the mass of the progenitor for this SN and the minimum mass threshold for stars to end their lives as core-collapse SNe.