[IAUC] CBET 1157: 20071208 : SUPERNOVA 2007rx

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                                                  Electronic Telegram No. 1157
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 2007rx
     F. Yuan, University of Michigan; R. Quimby, California Institute of
Technology; C. Akerlof, University of Michigan; and J. C. Wheeler, University
of Texas -- on behalf of the ROTSE collaboration -- report the discovery of a
supernova (mag about 17.2) in unfiltered CCD images taken with the 0.45-m
ROTSE-IIIb telescope at McDonald Observatory on Nov. 28.11 UT.  The new object
was also detected at mag about 18.2 on Nov. 24.06 and was observed to rise to
mag about 16.3 by Dec. 5.11.  SN 2007rx is located at R.A. = 23h40m11s.74,
Decl. = +27o25'16".5 (equinox 2000.0; uncertainty < 1"), which is 2".2 east
and 5".9 north of a possibly extended object (USNO-B1.0 catalogued magnitude
R = 19.59) seen in the Digitized Sky Survey.  A finding chart of the supernova
can be found at the following WWW URL:
http://www.rotse.net/transients/j2340+2725/j234011.7+272516.jpg
     A spectrum (range 420-890 nm) of 2007rx, obtained on Dec. 6.16 with the
9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S.
Odewahn and A. Westfall, shows it to be a type-Ia supernova.  The spectra are
similar to those of SN 1994D just prior to maximum light (Patat et al. 1996,
MNRAS 278, 111).  Using the 1994D spectra as a template, Yuan et al. find an
approximate redshift of z = 0.03 for 2007rx, which is compatible with the
nearby Abell 2634 galaxy cluster (z = 0.031; Oegerle and Hill 2001, A.J.
122, 2858).


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                         (C) Copyright 2007 CBAT
2007 December 8                  (CBET 1157)              Daniel W. E. Green