[IAUC] CBET 898: 20070319 : SUPERNOVAE 2007at AND 2007au

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                                                  Electronic Telegram No. 898
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 2007at AND 2007au
     S. Blondin, M. Hicken, M. Modjaz, R. Kirshner, and P. Challis,
Harvard-Smithsonian Center for Astrophysics, report that spectra (range
350-740 nm) of 2007at (cf. CBET 893) and 2007au (cf. CBET 895),
obtained on Mar. 19.45 and 19.27 UT by P. Berlind with the F. L.
Whipple Observatory 1.5-m telescope (+ FAST), shows them to be both
type-Ia supernovae.  Cross-correlation with a library of supernova
spectra shows that 2007at is most similar to SN 1989B at 9.5 days past
maximum light, and that 2007au is most similar to SN 1992A (Kirshner et
al. 1993, Ap.J. 415, 589) at one day before maximum.  Adopting a
recession velocity of 16262 km/s for the host galaxy of 2007at (from
Fouque et al. 1992, Catalogue of Optical Radial Velocities, vol. 1),
the maximum absorption in the Si II line (rest 635.5 nm) is blueshifted
by roughly 11500 km/s.  Adopting a recession velocity of 6164 km/s for
the host galaxy of 2007au (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 roughly 13000 km/s.


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                         (C) Copyright 2007 CBAT
2007 March 19                    (CBET 898)               Daniel W. E. Green