[IAUC] CBET 1621: 20081217 : SUPERNOVA 2008ih

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                                                  Electronic Telegram No. 1621
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2008ih
     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.


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                         (C) Copyright 2008 CBAT
2008 December 17                 (CBET 1621)              Daniel W. E. Green