[IAUC] CBET 1358: 20080429 : SUPERNOVAE 2008bv, 2008bw, 2008ca, AND 2008cb

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                                                  Electronic Telegram No. 1358
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVAE 2008bv, 2008bw, 2008ca, AND 2008cb
     J. M. Silverman, T. N. Steele, A. V. Filippenko, R. J. Foley, and D.
Poznanski, University of California, Berkeley, report that inspection of CCD
spectra (range 320-920 nm), obtained on Apr. 28 UT with the Keck I 10-m
telescope (+ LRIS), shows that SN 2008bv (CBET 1345) is a type-Ia supernova
near maximum brightness, significantly reddened.  Removing the host-galaxy
recession velocity of 16400 km/s (from narrow emission lines), the minimum of
the Si II 635.5-nm absorption feature is found to be blueshifted by about
13400 km/s.  SN 2008bw (CBET 1346) is also a type-Ia supernova, probably 2-3
weeks past maximum brightness.  Removing the host-galaxy recession velocity
of 9931 km/s (Falco et al. 1999, PASP 111, 438), the minimum of the Si II
635.5-nm absorption feature is found to be blueshifted by about 11200 km/s.
SN 2008ca (CBET 1355) is a type-Ia supernova at redshift 0.1315 (from narrow
lines).  Using a principal-component analysis (Foley et al. 2007,
ArXiV:0710.2338), a significant amount of galaxy contamination is removed;
the SNID routine (Blondin and Tonry, 2007, Ap.J. 666, 1024) then shows the
remaining spectrum to be similar to that of type-Ia supernovae about one
month past maximum light.  Likewise, SN 2008cb (CBET 1355) is a type-Ia
supernova about 1 month past maximum.  Using the "superfit" fitting routine
(Howell et al. 2005, Ap.J. 634, 1190), the spectrum resembles that of SN
1994D at 20 days past maximum brightness with a significant amount of galaxy
contamination.


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                         (C) Copyright 2008 CBAT
2008 April 29                    (CBET 1358)              Daniel W. E. Green