Electronic Telegram No. 3525
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 2013cm
     A. J. Drake, S. G. Djorgovski, M. J. Graham, A. Mahabal, and R. Williams,
California Institute of Technology; J. L. Prieto, Princeton University; M.
Catelan, Pontificia Universidad Catolica de Chile; and S. M. Larson and E.
Christensen, Lunar and Planetary Laboratory, University of Arizona, report the
Catalina Real-time Transient Survey discovery of an apparent supernova in
unfiltered Catalina Sky Survey (CSS) images:

 SN       2013 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2013cm   May 10.39   17 20 01.94  +23 44 51.3   18.3    7".7 E, 10".3 S

Nothing was visible at this position on a CSS image from Apr. 21.43 UT
(limiting mag 20.0).

     C. McCully and S. W. Jha, Rutgers University, report that a spectrogram
(range 460-980 nm) of 2013cm, taken on May 11.6 UT with the Keck II 10-m
telescope (+ DEIMOS), shows it to be a subluminous type-Ia supernova near
maximum light.  Cross-correlation of these data with a library of supernova
spectra using the "Supernova Identification" code (SNID; Blondin and Tonry
2007, Ap.J. 666, 1024) yields good matches to SN 1986G and the 1991bg-like
supernova 1999by, approximately one day before maximum light.  The supernova
spectral features suggest a redshift of about 0.04 for the host galaxy, 2MASX
J17200138+2345018.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 May 13                      (CBET 3525)              Daniel W. E. Green