Electronic Telegram No. 3562

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 2013di IN NGC 7321 = PSN J22362746+2136543

     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 (CSS).

 SN       2013 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2013di   June 12.38   22 36 27.46  +21 36 54.3   18.2    7".8 W, 24".2 S

The variable was designated PSN J22362746+2136543 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013di based on the
spectroscopic confirmation reported below.  Additional magnitudes for 2013di:
June 4.37 UT, [19.5 (CSS); June 13.760, 17.5 (Joseph Brimacombe, Cairns,
Australia; 41-cm telescope + infrared filter; bandpass > 700 nm; position end
figures 27s.56, 54".9); 16.092, 16.6 (Xavier Bros, Ager, Spain, 35-cm f/4.6
telescope; position end figures 27s.56, 54".7; image posted at website URL
http://anysllum.com/PSN_NGC7321.jpg).  Brimacombe's image is posted at the
following website URL:  http://www.flickr.com/photos/43846774@N02/9038677758/.

     S. B. Cenko, Goddard Space Flight Center, NASA; B. E. Tucker, Australian
National University; and I. Shivvers, K. I. Clubb, and A. V. Filippenko,
University of California, Berkeley, report that inspection of a CCD spectrum
(range 350-1000 nm), obtained on June 14.5 UT with the Shane 3-m reflector (+
Kast spectrograph) at Lick Observatory, shows that PSN J22362746+2136543 = SN
2013di is a type-Ia supernova.  Cross-correlation with a library of supernova
spectra using the "SuperNova Identification" code (SNID; Blondin and Tonry
2007, Ap.J. 666, 1024) indicates that 2013di is a normal type-Ia supernova
shortly before maximum light.  After removal of the host-galaxy recession
velocity of 7145 km/s (Huchra et al. 1999, Ap.J. Suppl. 121, 287), the
absorption minimum of the Si II 635.5-nm line is found to be blue-shifted by
about 19000 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 June 16                     (CBET 3562)              Daniel W. E. Green