[IAUC] CBET 1666: 20090119 : SUPERNOVA 2009L IN NGC 4854

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                                                  Electronic Telegram No. 1666
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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SUPERNOVA 2009L IN NGC 4854
     F. Yuan, University of Michigan; J. Vinko, University of Texas; R.
Quimby, California Institute of Technology; D. Chamarro and M. D. Sisson,
University of Michigan; A. Uecker, Indiana University of Pennsylvania; C.
Akerlof, University of Michigan; and J. C. Wheeler and E. Chatzopoulos,
University of Texas, on behalf of the ROTSE collaboration, report the
discovery of a supernova (mag about 16.8) in unfiltered CCD images taken on
Jan. 13.44 UT with the 0.45-m ROTSE-IIIb telescope at McDonald Observatory.
The new object is located at R.A. = 12h58m48s.10, Decl. = +27o40'25".6
(equinox 2000.0), which is 8".4 east and 3".9 south of the center of its
apparent host galaxy, NGC 4854.  A finding chart FOR 2009L has been posted
at http://www.rotse.net/rsvp/j125848.1+274026/j125848.1+274026.jpg.  A
spectrum (range 340-1080 nm) of 2009L, obtained on Jan. 15.34 with the
9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by
J. Caldwell and A. Westfall, shows it to be a type-Ia supernova.  SNID
(Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that the spectra best
match the spectra of SNe 1999by and 1991bg at 3 days after maximum and at
a redshift consistent with that of NGC 4854.  The expansion velocity,
derived from the minimum of the Si II (rest 635.5 nm) line, is about 11000
km/s.  The (580 nm)/(615 nm) line-depth ratio (Nugent et al. 1995, Ap.J.
455, L147) for Si II is about 0.5, indicating a subluminous type-Ia event.
Strong, broad absorption features at 760 and 850 nm (attributed to O I and
Ca II) are also present, which strongly supports this classification
(Garnavich et al. 2004, Ap.J. 613, 1120).


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                         (C) Copyright 2009 CBAT
2009 January 19                  (CBET 1666)              Daniel W. E. Green