Electronic Telegram No. 889
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 2007aq AND 2007ar
     S. Blondin, M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian
Center for Astrophysics, report that a spectrogram (range 350-740 nm) of
2007aq (cf. CBET 885), obtained by E. Falco on Mar. 16.21 UT with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-II
supernova roughly one month past explosion.  The spectrum is similar to that
of the type-II-plateau supernova 2004et at 28 days past explosion.  Adopting
a recession velocity of 6292 km/s for the host galaxy [from "The Updated
Zwicky Catalog" (UZC), http://tdc-www.harvard.edu/uzc/], the maximum
absorption in the H_beta line (rest 486.1 nm) is blueshifted by roughly 7000
km/s.
     Blondin et al. add that a spectrum (range 350-740 nm) of 2007ar (cf.
CBET 886), obtained on Mar. 16.36 by Falco, shows it to be a type-Ia
supernova around one week past maximum light.  Cross-correlation with a
library of supernova spectra indicates that 2007ar is most similar to the
type-Ia supernova 1996X at 8 days past maximum.  Adopting a recession
velocity of 15869 km/s for the host galaxy (from UZC), the maximum
absorption in the Si II line (rest 635.5 nm) is blueshifted by roughly
13000 km/s.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2007 CBAT
2007 March 16                    (CBET 889)               Daniel W. E. Green