Electronic Telegram No. 645
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)
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SUPERNOVA 2006gt
     S. Blondin, M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian
Center for Astrophysics, report that a spectrum (range 350-740 nm) of 2006gr
(cf. CBET 641), obtained on Sept. 25.37 UT by P. Berlind with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-Ia
supernova around maximum light, confirming the identification of Quimby et
al. (cf. CBET 641).  However, the Si II absorption at 580 nm is stronger
than in "normal" type-Ia supernovae, and absorption due to Ti II is present
near 420 nm, as in the subluminous supernova 1991bg (see a comparison plot at
http://www.cfa.harvard.edu/oir/Research/supernova/spectra/sn2006gt_comp.gif).
Adopting the NED recession velocity of 13422 km/s (from Smith et al. 2004,
A.J. 128, 1558) for the host galaxy (whose 2MASX position is given as R.A. =
0h56m18.1s, Decl. = -1d37m33s, equinox 2000.0), the maximum absorption in the
Si II (rest 635.5 nm) line is blueshifted by roughly 10500 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2006 CBAT
2006 September 25                (CBET 645)               Daniel W. E. Green