Electronic Telegram No. 550
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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SUPERNOVAE 2006cz and 2006da
     S. Blondin, M. Modjaz, R. Kirshner, and P. Challis,
Harvard-Smithsonian Center for Astrophysics, report that a spectrum
(range 350-740 nm) of SN 2006cz (cf. IAUC 8721), obtained on June 17.24
UT by M. Calkins with the F. L. Whipple Observatory 1.5-m telescope (+
FAST), shows it to be a type-Ia supernova around maximum light.
Cross-correlation with a library of type-Ia-supernova spectra indicates
that 2006cz is most similar to the 1991T-like supernova 1998es (IAUC
7054) at 1 day past maximum.  Adopting a recession velocity of 12594
km/s for the host galaxy (from de Vaucouleurs et al. 1991, Third
Ref. Cat. of Bright Galaxies), the maximum absorption in the Si II
line (rest 635.5 nm) is blueshifted by 12000 km/s.
     Blondin et al. add that a spectrum (range 350-740 nm) of SN
2006da (cf. CBET 545), obtained on June 17.46 by Calkins, shows it to
be a type-Ia supernova around one week past maximum light.  Adopting
the NED recession velocity of 12345 km/s (catalogue redshift from the
Sloan Digital Sky Survey) for the host galaxy (whose 2MASX position is
given as R.A. = 23h27m48s.7, Decl. = +14d28'31", equinox 2000.0), the
maximum absorption in the Si II line (rest 635.5 nm) is blueshifted by
12000 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      superseded by text appearing later in the printed IAU Circulars.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 June 19                     (CBET 550)               Daniel W. E. Green