[IAUC] CBET 1185: 20071231 : SUPERNOVA 2007sw IN UGC 7228

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                                                  Electronic Telegram No. 1185
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 2007sw IN UGC 7228
     R. Quimby, California Institute of Technology; F. Yuan and C. Akerlof,
University of Michigan; and J. C. Wheeler, University of Texas, report the
discovery of a supernova (mag about 16.0) in unfiltered CCD images taken on
Dec. 29.49 UT using the 0.45-m ROTSE-IIIb telescope at the McDonald
Observatory.  The new object is located at R.A. = 12h13m36s.88, Decl. =
+46o29'36".1 (equinox 2000.0), which is 0".7 east and 2".2 south of the
center of UGC 7228.  SN 2007sw was found by subtracting a co-addition of
images taken between 2005 April and 2006 June (limiting mag about 18.7).
A spectrum (range 420-890 nm) of 2007sw, obtained on Dec. 30.39 with the
9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S.
Odewahn and E. Terrazas, shows it to be a type-Ia supernova.  The spectra are
similar to that of SN 2005ir (cf. CBET 277; IAUC 8629) a few days prior to
maximum light.  Adopting the redshift of the apparent host (z = 0.025;
Updated Zwicky Catalog, via NED), the expansion velocity derived from the
minimum of the Si II (rest 635.5 nm) line is about 14000 km/s.


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                         (C) Copyright 2007 CBAT
2007 December 31                 (CBET 1185)              Daniel W. E. Green