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Identification of a Candidate Progenitor for SN 2012aw in M95

ATel #3991; Nancy Elias-Rosa (ICE/IEEC-CSIC), Schuyler D. Van Dyk (Spitzer Science Center/Caltech), Jean-Charles Cuillandre (CFHT), S. Bradley Cenko and Alexei V. Filippenko (UC Berkeley)
on 21 Mar 2012; 18:27 UT
Credential Certification: S. Bradley Cenko (cenko@astro.berkeley.edu)

Subjects: Optical, Supernovae, Transient

We report the detection of a probable candidate for the progenitor of the Type II-P SN 2012aw in M95 (NGC 3351; CBET #3054, ATel #3979) in deep archival Hubble Space Telescope (HST) WFPC2 image mosaics obtained between 1994 December and 1995 January in F555W and F814W by GO-5397 (PI: J. Mould), available from the Hubble Legacy Archive. We have isolated the location of the candidate in the F814W images, with an error circle radius of about 0.6 PC pixel (0.03"), matching these "drizzled" HST mosaics to short (10 s) i'-band exposures obtained on 2012 March 21.31 UT, under excellent observing conditions (0.6" seeing), using the MegaCam on the Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii. The progenitor candidate has magnitudes F555W >~ 26.75 and F814W = 23.48, measured from the ensemble of the individual WFPC2 exposures using Dolphot v2.0 (Dolphin 2000, PASP, 112, 1383). Not direct detection was found in the F439W images, the upper limit estimated is 27.33 mag. Assuming a distance modulus to the host galaxy of 30.0 mag (Freedman et al. 2001, ApJ, 553, 47) and only the Galactic foreground extinction of A_V = 0.09 and A_I = 0.05 mag (Schlegel, Finkbeiner, & Davis 1998, ApJ, 500, 525), this results in approximate absolute magnitudes M_V >~ -3.3 and M_I = -6.6, consistent with the brightness and color of a red supergiant star. Higher-resolution images of the SN are clearly needed to confirm this identification. Further study of this nearby, bright SN and its possible progenitor are ongoing.