Electronic Telegram No. 3413
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
CBAT Director:  Daniel W. E. Green; Hoffman Lab 209; Harvard University;
 20 Oxford St.; Cambridge, MA  02138; U.S.A.
e-mail:  cbatiau@eps.harvard.edu (alternate cbat@iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2013X
     F. V. Ferrante, Southern Methodist University; J. M. Silverman,
University of Texas; J. Vinko, University of Szeged; G. Dhungana, Southern
Methodist University; R. Quimby, Kavli IPMU, University of Tokyo; W. Zheng,
University of California at Berkeley; A. Romadan and C. Akerlof, University of
Michigan; F. Yuan, Australian National University; J. C. Wheeler and E.
Chatzopoulos, University of Texas; R. Kehoe, Southern Methodist University;
and G. H. Marion, Harvard-Smithsonian Center for Astrophysics, on behalf of
the ROTSE collaboration, report the discovery of a new supernova (mag about
17.9) in unfiltered images taken on Feb. 6.23 UT with the 0.45-m ROTSE-IIIb
telescope at McDonald Observatory.  The transient was observed again at similar
brightness on Feb. 7.22 and 8.23, with no detection before Jan. 20 down to a
limiting magnitude of about 18.2.  The new object is located at R.A. =
12h17m15s.19, Decl. = +46o43'35".9 (equinox 2000.0; uncertainty about 1"),
which is 4".9 east and 3".8 south of the prosumed host galaxy (SDSS
J121714.86+464339.7, whose SDSS spectroscopic redshift is z = 0.03260 +/-
0.00001); a finding chart is posted at the following website URL:
http://www.rotse.net/rsvp/j121715.2+464336/ROTSE3_J121715.2+464336.jpg.
     A spectrogram, obtained on Feb. 10.51 UT with the 9.2-m Hobby-Eberly
Telescope (+ Marcario Low-Resolution Spectrograph) by S. Odewahn, shows that
2013X is a type-Ia supernova.  Correlation with a library of supernova spectra
using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J.
666, 1024) indicates that 2013X is a 1991T-like supernova about 10 days after
maximum brightness.  After removal of the host-galaxy recession velocity of
9642 km/s (from narrow emission lines), the absorption minimum of the Si II
635.5-nm line is found to be blueshifted by about 11300 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 February 12                 (CBET 3413)              Daniel W. E. Green