2008CBET.1621....1S

D. Sand, Harvard-Smithsonian Center for Astrophysics and Las Cumbres Observatory Global Telescope Network; M. L. Graham and C. Bildfell, University of Victoria; D. W. Just, S. Herbert-Fort, and S. Sivanandam, Steward Observatory; C. J. Pritchet and H. Hoekstra, Leiden University; and D. Zaritsky, Steward Observatory, report the discovery of a supernova on g'- and r'-band images obtained at the Canada-France-Hawaii Telescope (CFHT) with Megacam on Nov. 6 (the new object then being at magnitudes g' = 18.57 ± 0.03 and r' = 18.58 ± 0.03) and 25 (g' = 19.25 ± 0.03, r' = 19.06 ± 0.03). The supernova was also apparent in imaging obtained prior to discovery at the Steward 2.29-m reflector (+ 90Prime camera) on Oct. 25 at g' = 21.20 ± 0.04 and r' = 21.17 ± 0.05. Spectroscopic confirmation was obtained on Nov. 28 with GMOS-N on the Gemini telescope, showing 2008ih to be a type-Ia supernova at z = 0.061 and around 15 days past maximum (via the publicly available Supernova Identification code of Blondin and Tonry 2007, Ap.J. 666, 1024). SN 2008ih is located at R.A. = 2h57m26s.41, Decl. = +12o58'07".6 (equinox 2000.0); no host galaxy is visible to g' and r' magnitudes about 24.0 (although further imaging will be obtained once the supernova has faded). SN 2008ih is likely associated with the galaxy cluster Abell 399 (z = 0.072), being 450" (615 kpc) from the cluster's brightest member galaxy. Pending further deep imaging, 2008ih is likely to be either a genuine intracluster supernova (e.g. Gal-Yam et al. 2003, A.J. 125, 1087) or on the outskirts of a nearby Abell 399 member at position end figures 26s.22, 15".6; a spectrum of this galaxy from the same long-slit spectrogram as 2008ih shows it to be at z = 0.064 (SN 2008ih is > 8 effective galaxy radii from this apparent galaxy's center; there is some evidence that 2008ih is in a low-surface-brightness tidal tail associated with this galaxy). Analysis will continue.