Electronic Telegram No. 351
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 2005mz AND 2005na
     M. Modjaz, R. Kirshner, P. Challis, and S. Blondin,
Harvard-Smithsonian Center for Astrophysics, report that spectra
(range 350-740 nm) of SN 2005mz (CBET 347) and of SN 2005na (CBET
350), obtained on Jan. 3.13 and 4.34 UT (respectively) by P.
Berlind with the F. L. Whipple Observatory 1.5-m telescope (+
FAST), show them to be type-Ia supernovae, with spectral-feature ages
(Riess et al. 1997, A.J. 114, 722) of about 3 and 1 (+/- 2) days
before maximum light, respectively.  Adopting recession velocities of
5264 and 7891 km/s for the host galaxies of 2005mz and 2005na,
respectively (both from Falco et al. 1999, PASP 111, 438), the
maximum absorption in the Si II line (rest 635.5 nm) is blueshifted
by about 11000 km/s in both supernovae.  The spectrum of SN 2005mz
exhibits strong Si II (rest 597.2 nm) and is similar to spectra of SN
1999by (Garnavich et al. 2004, Ap.J. 613, 1120) taken a few days
before maximum, indicating that this may be a subluminous event.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2006 CBAT
2006 January 4                   (CBET 351)               Daniel W. E. Green