A High Angular Resolution Search for the Progenitor of the Type Ic Supernova 2004gt

Abstract

We report the results of a high spatial resolution search for theprogenitor of Type Ic supernova SN 2004gt, using the newly commissionedKeck laser guide star adaptive optics (LGSAO) system along with archivalHubble Space Telescope data. This is the deepest search yet performedfor the progenitor of any Type Ib/c event in a wide wavelength rangestretching from the far-UV to the near-IR. We determine that theprogenitor of SN 2004gt was most likely less luminous thanM_{V}=-5.5 mag and M_{B}=-6.5 mag. The massive starsexploding as hydrogen-deficient core-collapse supernovae should havelost their outer hydrogen envelopes prior to their explosion, eitherthrough winds-such stars are identified within our Galaxy as Wolf-Rayet(W-R) stars-or to a binary companion. The luminosity limits we set ruleout more than half of the known Galactic W-R stars as possibleprogenitors of this event. In particular, they imply that a W-Rprogenitor should have been among the more evolved (highly stripped,less luminous) of these stars, a concrete constraint on its evolutionarystate just prior to core collapse. The possibility of a less luminous,lower mass binary progenitor cannot be constrained. This studydemonstrates the power of LGS observations in furthering ourunderstanding of core collapse and the physics powering supernovae,gamma-ray bursts, and X-ray flashes.