[IAUC] CBET 1171: 20071218 : SUPERNOVAE 2007so AND 2007sq

[IAUC mailing list]

                                                  Electronic Telegram No. 1171
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html


SUPERNOVAE 2007so AND 2007sq
     S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf
of the CfA Supernova Group, reports that a spectrogram (range 350-740 nm) of
2007so (cf. CBET 1168), obtained by M. Calkins on Dec. 16.20 UT with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-Ia
supernova around three weeks past maximum light.  Cross-correlation with a
library of supernova spectra using the Supernova Identification code (SNID;
Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2007so is most similar
to the type-Ia supernova 1989B at 19 days past maximum.
     Blondin et al. add that a spectrum (range 350-740 nm) of 2007sq (cf. CBET
1170), obtained as above on Dec. 16.47 by Calkins, shows it to be a reddened
type-II supernova around two weeks past maximum light.  Cross-correlation with
a library of supernova spectra using the SNID code indicates that 2007sq is
most similar to the type-II-plateau supernova 2004et at 10 days past maximum.
Adopting a recession velocity of 4573 km/s for the host galaxy (from Mathewson
and Ford, Ap.J. Suppl. 107, 97), the maximum absorption in the H_alpha line
(rest 656.3 nm) is blueshifted by roughly 10000 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      superseded by text appearing later in the printed IAU Circulars.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 December 18                 (CBET 1171)              Daniel W. E. Green