Electronic Telegram No. 3468
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 2013bc IN IC 4209 = PSN J13102131-0710241
     S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski, A.
Mahabal, M. J. Graham, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; R. H. McNaught, Australian National University; and E.
Christensen and S. M. Larson, Lunar and Planetary Laboratory, University of
Arizona, report the Catalina Real-time Transient Survey discovery of an
apparent supernova in public images from the Catalina Sky Survey:

 SN       2013 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2013bc   Mar. 31.37   13 10 21.31  - 7 10 24.1   18.1    17".6 W, 9".6 S

The variable was designated PSN J13102131-0710241 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013bc based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013bc:  Apr. 1.416, 17.5 (L. Elenin, Lyubertsy, Russia; and I. Molotov,
Moscow, Russia; remotely taken with a 0.45-m f/2.8 telescope at the ISON-NM
Observatory near Mayhill, NM, USA; position end figures 21s.49 +/- 0".07,
22".2 +/- 0".08; UCAC-4 reference stars; limiting mag about 18.7; image
posted at http://spaceobs.org/images/TOCP/PSNJ13102131-0710241-20130401.png);
1.600, 17.5 (Joseph Brimacombe, Cairns, Australia; 41-cm RCOS telescope +
infrared filter; bandpass > 700 nm; position end figures 21s.44, 23".4;
image posted at URL http://www.flickr.com/photos/43846774@N02/8611730632/).

     E. Y. Hsiao and N. Morrell, Las Campanas Observatory; F. Forster,
Universidad de Chile; and G. H. Marion, Harvard-Smithsonian Center for
Astrophysics, report that a near-infrared spectrogram (range 800-2400 nm) of
PSN J13102131-0710241 = SN 2013bc was obtained on Apr. 3.31 UT with the
FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan
Baade Telescope.  The spectrum shows that 2013bc is a type-Ia supernova a
few days before maximum light.  The near-infrared spectrum is similar to that
of SN 2005am at four days before maximum (Marion et al. 2009, A.J. 138, 727).
The supernova redshift approximately matches the redshift of the presumed
host galaxy (IC 4209) at z = 0.022.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 April 13                    (CBET 3468)              Daniel W. E. Green