[IAUC] CBET 487: 20060427 : SUPERNOVAE 2006br AND 2006bs

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                                                  Electronic Telegram No. 487
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 2006br AND 2006bs
     S. Blondin, M. Modjaz, R. Kirshner, and P. Challis,
Harvard-Smithsonian Center for Astrophysics, report that a spectrogram
(range 350-740 nm) of SN 2006br (cf. CBET 482), obtained by W. Brown
on Apr. 27.36 UT with the F. L. Whipple Observatory 1.5-m telescope (+
FAST), shows it to be a reddened type-Ia supernova with a
spectral-feature age (Riess et al. 1997, A.J. 114, 722) of about 1
week before maximum brightness.  Adopting a recession velocity of 7353
km/s for the host galaxy (from "The Updated Zwicky Catalog",
http://tdc-www.harvard.edu/uzc/), the maximum absorption in the Si II
line (rest 635.5 nm) is blueshifted by 13500 km/s.  Also, interstellar
Na I D absorption at the redshift of the host galaxy is visible in the
spectrum with an equivalent width of 0.3 nm.
    Blondin et al. add that a spectrogram (range 350-740 nm) of SN 2006bs
(cf. CBET 484), obtained by Brown on Apr. 27.18 UT, shows it to be a
type-II supernova roughly 2-3 weeks past maximum, confirming the
classification given in CBET 484 by Filippenko and Foley.  The spectrum
consists of a blue continuum with P-Cyg lines of hydrogen, sodium, and
iron, consistent with the plateau phase of a normal type-II supernova.
The spectrum is similar to the type-II-plateau supernova 2004et at
17 days past maximum.  Adopting a recession velocity of 9007 km/s for
the host galaxy (Beers et al. 1995, A.J. 109, 874), the maximum
absorption in the H_beta line (rest 486.1 nm) is blueshifted by 12000
km/s.


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                         (C) Copyright 2006 CBAT
2006 April 27                    (CBET 487)               Daniel W. E. Green