[IAUC] CBET 1502: 20080910 : SUPERNOVA 2008fn

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                                                  Electronic Telegram No. 1502
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 2008fn
     F. Yuan, University of Michigan; R. Quimby, California Institute of
Technology; D. Chamarro, University of Michigan; A. Uecker, Indiana
University of Pennsylvania; M. D. Sisson and C. Akerlof, University of
Michigan; and J. C. Wheeler, University of Texas, on behalf of the ROTSE
collaboration, report the discovery of a supernova (mag about 17.1) on an
unfiltered CCD image taken on Aug. 4.17 UT (found by subtracting a reference
image built from images taken in Aug. 2007) with the 0.45-m ROTSE-IIIb
telescope at McDonald Observatory.  The new object is located at R.A. =
16h21m48s.53, Decl. = +37o03'41".0 (equinox 2000.0; uncertainty < 1"),
which is 2".1 north of the center of the apparent host galaxy (whose SDSS
redshift is z = 0.030).  SN 2008fn was observed to rise to mag about 16.8
on Aug. 10.18 and then decay to mag about 17.4 on Aug. 20.14.  A finding
chart of 2008fn can be found at the following website URL:
http://www.rotse.net/rsvp/j162148.53+370341/j162148.53+370341.jpg.
The ROTSE magnitudes quoted above are unfiltered, calibrated to R
magnitudes from the USNO-B1.0 catalogue.
     E. Y. Hsiao, M. L. Graham, C. J. Pritchet, and D. Balam, Department of
Physics and Astronomy, University of Victoria, report that a noisy
spectrogram (range 390-703 nm, resolution 0.3 nm) of 2008fn, obtained on
Sept. 10.23 UT with the 1.82-m Plaskett Telescope of the National Research
Council of Canada, shows it to be a type-Ibc supernova at 2 weeks past
maximum light.  According to the 'superfit' matching program of Howell et al.
(2005, Ap.J. 634, 1190), the best fit is to the spectrum of SN 2002ap at
12 days past maximum light.  The fit is consistent with the redshift of the
presumed host galaxy, 2MASX J16214855+3703386 (z = 0.0298, Sloan Digital
Sky Survey Data Release 3).  One cannot rule out the possibility that the
object is a late-time type-Ia supernova.


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                         (C) Copyright 2008 CBAT
2008 September 10                (CBET 1502)              Daniel W. E. Green