Electronic Telegram No. 173
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


SUPERNOVAE 2005cn AND 2005cr
     M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian Center
for Astrophysics, report that a spectrum (range 450-740 nm) of SN 2005cn
(cf. IAUC 8549), obtained on June 28.21 UT by M. Calkins and R. Hutchins
with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to
be a type-Ia supernova, with a spectral-feature age (Riess et al. 1997,
A.J. 114, 722) of about 3 (+/- 2) days after maximum light; the supernova
expansion velocity, derived from the minimum of Si II (rest 635.5 nm), and
adopting the NED recession velocity of 2065 km/s for the host galaxy (from
da Costa et al. 1998, A.J. 116, 1) is about 10000 km/s.  A spectrogram of
SN 2005cr (cf. IAUC 8552), obtained on June 28.19 UT, shows it to be a
type-Ia supernova, a few days before maximum light; the supernova expansion
velocity, derived from the minimum of Si II (rest 635.5 nm), and adopting
the NED recession velocity of 6437 km/s for the host galaxy (from
Drinkwater et al. 1996, MNRAS 279, 595) is about 11000 km/s.


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      superseded by text appearing later in the formal IAU Circulars.

                         (C) Copyright 2005 CBAT
2005 June 28                     (CBET 173)               Daniel W. E. Green