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Type-Ia SN 2012fr: no progenitor detected in pre-explosion HST image to M_V ~ -5.9 mag

ATel #4535; Or Graur (Tel-Aviv U., AMNH), Dan Maoz (Tel-Aviv U.)
on 1 Nov 2012; 22:01 UT
Credential Certification: Dan Maoz (Tel-Aviv University) (maoz@astro.tau.ac.il)

Subjects: Optical, Supernovae

We have analyzed archival Hubble Space Telescope WFPC2 images of NGC 1365 in F606W (~ V band, 560 s total) from 2001. We detect no sources within a 0.5'' radius of the location of the Type-Ia supernova SN 2012fr (PSN J03333599-3607377, ATel#4523), as determined by registering the HST images with images of the SN by Stu Parker and by Ivan Curtis (see http://www.rochesterastronomy.org/snimages ), using two bright stars near the SN. By planting fake point sources at the location of the SN, we obtain a 2-sigma flux limit of 25.3 mag in F606W. The Tully-Fisher-based distance modulus of NGC 1365 is 31.16+/-0.35 (Tully et al. 2009, AJ, 138, 323), and the Galactic extinction in this direction is A_V=0.056 (Schlafly et al. 2011, ApJ, 737, 103). Barring the possibility of extinction in the host galaxy, a progenitor or companion of SN 2012fr was therefore fainter than M_V ~ -5.9 mag, ruling out the presence of supergiants of such luminosity at the explosion site. An image showing the searched region of the HST data is at http://www.astro.tau.ac.il/~orgraur/sn2012fr.jpg