Electronic Telegram No. 642
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 2006gr IN UGC 12071
     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 638), obtained on Sept. 23.23 UT by M. Calkins with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-Ia
supernova well before maximum light.  Cross-correlation with a library of
supernova spectra indicates that 2006gr is most similar to the type-Ia
supernova 1990N at -13 days from maximum light.  Adopting a recession
velocity of 10372 km/s for the host galaxy (Huchra et al. 1999, Ap.J. Suppl.
121, 287), the maximum absorption in the Si II line (rest 635.5 nm) is
blueshifted by roughly 19500 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      superseded by text appearing later in the printed IAU Circulars.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 24                (CBET 642)               Daniel W. E. Green