Electronic Telegram No. 3737
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 2013gt IN PGC 20784 = PSN J07213165+5545321
     Peiyuan Sun, Weifang, Shandong, China; Zhangwei Jin, Ningbo, Zhejiang,
China; and Xing Gao, Urumqi, Xinjiang, China, report the discovery of an
apparent supernova (mag approximately 17.6) on an unfiltered CCD 40-s survey
image (limiting mag about 19.5) taken by Gao in the course of the Xingming Sky
Survey (XSS) around Nov. 16.844 UT with a 0.36-m Celestron C14 telescope at
Mt. Nanshan.  The new object is approximately located at R.A. = 7h21m31s.66
+/- 0s.02, Decl. = +55d45'32".3 +/- 0".2 (equinox 2000.0), which is about 3".6
west and 7".5 north of the center of PGC 20784.  Nothing is visible at this
position on a red Digitized Sky Survey plate taken on 1989 Dec. 5 (limiting
mag about 19.8).  The discovery images have been posted at the following
website URL:  http://www.xjltp.com/XOSS/XM01PS/XM01PS.htm.  The variable was
designated PSN J07213165+5545321 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2013gt based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2013gt:  2013 Nov.
5, [19.0 (XSS); 7, [19.2 (XSS); 26.957, 17.1 (XSS); 29.897, 17.7 (G. Masi, F.
Nocentini, and P. Schmeer; remotely using a 43-cm telescope near Ceccano,
Italy; position end figures 31s.58, 32".2);  Dec. 1.056, 17.2 (F. Luppi and L.
Buzzi, Varese, Italy; position end figures 31s.65, 31".8; image posted at URL
http://www.astrogeo.va.it/pub/TOCP/PSN_P20784.jpg); 2.995, 17.4 (Massimiliano
Martignoni, Magnago, Italy; 0.25-m Schmidt-Cassegrain reflector; position end
figures 31s.69, 32".0; PPMXL reference stars).

     L. Tartaglia, P. Ochner, S. Benetti, L. Tomasella, E. Cappellaro, N.
Elias-Rosa, A. Pastorello, and M. Turatto, Istituto Nazionale di Astrofisica,
Osservatorio Astronomico di Padova, report that optical spectroscopy (range
340-820 nm; resolution 1.3 nm), obtained on Dec. 6.01 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC), shows that PSN J07213165+5545321 = SN
2013gt is a type-Ia supernova at a recessional velocity of 11430 km/s (Russell
et al. 2000, MNRAS 313, 469; via NED).  The best match was found with the
type-Ia supernova 1994D (Patat et al. 1996, MNRAS 278, 111) about 13 days
after maximum light.  The expansion velocity, as deduced from the position of
the Si II 635.5-nm absorption, is about 10300 km/s.  The Asiago classification
spectra are posted at website URL http://graspa.oapd.inaf.it.  The
classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383)
and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).


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

                         (C) Copyright 2013 CBAT
2013 December 8                  (CBET 3737)              Daniel W. E. Green