2008CBET.1397....1L

W. Li and A. V. Filippenko, University of California, Berkeley; S. D. Van Dyk, Spitzer Science Center, California Institute of Technology; S. Gonzalez, C. Contreras, and N. Morrell, on behalf of the Carnegie Supernova Project (CSP); and M. Hamuy, Universidad de Chile, report that they have isolated a possible progenitor for the type-II supernova 2008cn (cf. CBETs 1385, 1393) in Hubble Space Telescope images of NGC 4603 (GO programs 6439 and 7507) taken with the Wide Field Planetary Camera 2 (WFPC2). Geometrical transformation between a combined V-band image taken with the 1.0-m Swope telescope at Las Campanas Observatory on June 1.15 UT and the HST/WFPC2 images yields a precision of 1.0 WFPC2 pixel (0".1) for the supernova location on the WFPC2 images. Within the uncertainty of the position of 2008cn, an object is clearly detected in the F555W and F814W images, with a position of R.A. = 12h40m55s.64, Decl. = -40o58'12".9 (equinox 2000.0), a magnitude of I = 25.0, and a color of V-I = 1.4. Correcting the photometry with the Milky Way reddening of E(B-V) = 0.168 mag (Schlegel et al. 1998, Ap.J. 500, 525), and adopting the Cepheid distance modulus to NGC 4603 of 32.61 mag (Newman et al. 1999, Ap.J. 523, 506), the object has an absolute I-band magnitude of -7.9 and an intrinsic V-I color of 1.2 magnitudes, consistent with a red supergiant star in NGC 4603. Note that the photometry for the possible progenitor is preliminary and may be contaminated by nearby bright sources. More analysis is in progress, and efforts will be made to further improve the astrometric precision. A finder chart for the possible progenitor is provided at the following website URL: http://astro.berkeley.edu/~weidong/sn2008cn-prog.gif.