Electronic Telegram No. 3546
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 2013cy IN ESO 532-25 = PSN J22103421-2239480
     L. A. G. Monard, Calitzdorp, Western Cape, South Africa, reports his
discovery of an apparent supernova (mag 16.8) on several unfiltered CCD images
taken at his Klein Karoo Observatory with a 30-cm RCX400 telescope on May
31.167, June 1.080, and June 3.095 UT.  The new object is located at R.A. =
22h10m34s.21, Decl. = -22d39'48".0 (equinox 2000.0; UCAC2 reference stars),
which is 3" east and 26" south of the core of the SBbc-type galaxy ESO 532-25.
The variable was designated PSN J22103421-2239480 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013cy based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013cy:  May 12.120, [18.5 (Monard); June 2.711, 17.3 (Joseph Brimacombe,
Cairns, Australia; 41-cm telescope + infrared filter; bandpass > 700 nm;
position end figures 34s.27, 47".6; images posted at website URL
http://www.flickr.com/photos/43846774@N02/8954897582/).

     M. Childress, R. Scalzo, B. Tucker, F. Yuan, and B. Schmidt, Australian
National University (ANU); E. Hadjiyska, E. S. Walker, D. Rabinowitz, C.
Baltay, N. Ellman, and R. McKinnon, Yale University; P. Nugent, Lawrence
Berkeley Laboratory; and U. Feindt and M. Kowalski, University of Bonn, report
spectroscopy of PSN J22103421-2239480 = SN 2013cy with the Wide Field
Spectrograph (WiFeS; Dopita et al. 2007, Ap. Space Sci. 310, 255) on the ANU
2.3-m telescope (+ B3000/R3000 gratings; range 350-980 nm, 0.1-nm resolution)
at Siding Spring Observatory.  A 40-min spectrum of the variable shows clear
signatures of a type-Ia supernova, with Si II 635.5-nm; Ca II H and K, and
the infrared triplet; and Fe II lines near 500.0 nm.  Classification with
SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) shows good matches to normal
type-Ia supernovae at maximum light at a mean redshift of 0.034 +/- 0.006,
consistent with the redshift of the apparent host galaxy (ESO 532-25; z =
0.031465 via Da Costa et al. 1991, Ap.J. Suppl. 75, 935).  Given this host
redshift, they calculate the velocity of the absorption minimum of the
Si II 635.5-nm line to be at 10300 km/s.  The authors add that 2013cy was
discovered independently on May 29 by the La Silla Quest Survey.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 June 9                      (CBET 3546)              Daniel W. E. Green