[IAUC] CBET 1350: 20080423 : SUPERNOVA 2008by

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                                                  Electronic Telegram No. 1350
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 2008by
     F. Yuan, University of Michigan; R. Quimby, California Institute of
Technology; D. Chamarro, 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 17.2) in unfiltered CCD images
taken on Apr. 19.21 UT with the 0.45-m ROTSE-IIIb telescope at McDonald
Observatory.  The new object is located at R.A. = 12h05m20s.98, Decl. =
+40o56'45".6 (equinox 2000.0; uncertainty < 1"), which is 1".9 east and 1".2
north from the apparent host galaxy (which itself has magnitude r = 18.9 in
the Sloan Digital Sky Survey catalogue).  A finding chart of 2008by can be
found at http://www.rotse.net/rsvp/j120521.0+405646/j120521.0+405646.jpg.
Spectroscopy (420-890 nm) of 2008by, obtained on Apr. 22.10 with the 9.2-m
Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S.
Rostopchin and V. Riley, shows it to be a type-Ia supernova.  The spectra
are similar to those of SN 2005cg at about five days after explosion (Quimby
et al. 2006, Ap.J. 636, 400).  Narrow emission lines of H-alpha and O III
(likely from the host galaxy) indicate a redshift of z = 0.045.


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                         (C) Copyright 2008 CBAT
2008 April 23                    (CBET 1350)              Daniel W. E. Green