[IAUC] CBET 849: 20070219 : SUPERNOVAE 2007X AND 2007Z

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                                                  Electronic Telegram No. 849
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 2007X AND 2007Z
     G. Folatelli, Las Campanas Observatory, La Serena, reports
spectroscopic observations of SN 2007X (cf. CBET 844) and SN 2007Z
(cf. CBET 847) obtained on Feb. 19.29 and 19.05 UT, respectively,
by N. Morrell in the course of the Carnegie Supernova Project with
the 2.5-m du Pont telescope (+ WFCCD spectrograph) at Las Campanas
Observatory.  The spectrum of 2007X shows this to be a young type-II
supernova, with a blue continuum and prominent P-Cyg Balmer lines.
Assuming the NED recession velocity of 2837 km/s for the host galaxy
(Theureau et al. 1998, A.Ap. Suppl. 130, 333), the 'superfit'
spectrum-comparison code (Howell et al. 2005, Ap.J. 634, 1190) provides
a very good match to SN 1999em at four days after explosion.  From the
absorption minimum of the H-beta line, an expansion velocity of 10700
km/s is derived.
     SN 2007Z is also a type-II supernova with prominent P-Cyg Balmer
lines.  The emission component of H-alpha is very strong as compared
with the absorption.  The overall slope of the continuum suggests that
this supernova suffers from significant reddening.  Adopting the NED
recession velocity of 5277 km/s for the host galaxy (Pantoja et al.
1997, A.J. 113, 905), 'superfit' provides a good match to the spectrum
of SN 1993W at four days after explosion.  An expansion velocity of
9700 km/s is measured from the absorption minimum of H-beta.


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                         (C) Copyright 2007 CBAT
2007 February 19                 (CBET 849)               Daniel W. E. Green