Electronic Telegram No. 641
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html


SUPERNOVA 2006gt
     Further to IAUC 8622, R. Quimby and P. Mondol, University of Texas,
report the discovery of an apparent supernova in unfiltered CCD images
taken with the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory.
SN 2006gt is located at R.A. = 0h56m17s.30, Decl. = -1d37'46".0 (equinox
2000.0), which is 10".8 west and 13".5 south of the center of the apparent
host galaxy.  Available approximate magnitudes for 2006gt:  Sept. 18.26 UT,
18.5; 22.25, 18.2; 23.25, 17.8.  The new object was found by subtracting a
co-addition of images taken between 2005 July 16 and Nov. 7 (limiting mag
about 19.1) from the 2006 September images.  A spectrum (420-890 nm) of
2006gt, obtained on Sept. 23.29 with the 9.2-m Hobby-Eberly Telescope (+
Marcario Low-Resolution Spectrograph) by H. Edelmann and F. Deglman, shows
it to be a type-Ia supernova.  The spectrum is similar to that of SN 1992A
around maximum light.  Adopting the apparent host-galaxy redshift (z =
0.045, from Smith et al. 2004, A.J. 128, 1558, via NED), the expansion
velocity derived from the minimum of the Si II 635.5 nm feature is 10600
km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2006 CBAT
2006 September 23                (CBET 641)               Daniel W. E. Green