Electronic Telegram No. 3705
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 2013gg IN UGC 4958 = PSN J09210825+4935338
     Zhangwei Jin, Ningbo, Zhejiang, China; and Xing Gao, Urumqi, Xinjiang,
China, report the discovery of a possible supernova (mag approximately 17.9)
on two 40-s unfiltered CCD survey images (limiting mag about 19.5) taken by
Gao in the course of the Xingming Sky Survey around Nov. 5.870 and 6.898 UT
using a 0.35-m Celestron C14 reflector at Mt. Nanshan.  The new object is
approximately located at R.A. = 9h21m08s.25, Decl. = +49d35'33".8 (equinox
2000.0), which is about 63".7 east and 34".2 south of the center of UGC 4958.
Nothing is visible at this position on a Digitized Sky Survey image from 1995
Mar. 30 (limiting red mag about 19.8).  The discovery images are posted at
website URL http://www.xjltp.com/XOSS/XM47ZJ/XM47ZJ.htm.  The variable was
designated PSN J09210825+4935338 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2013gg based on the spectroscopic
confirmation reported below.  Additional CCD magnitudes for 2013gg:  2013 Oct.
22, [19.2 (Jin and Gao); Nov. 7.118, 17.7 (Gianluca Masi, Francesca Nocentini,
and Patrick Schmeer; remotely using a 36-cm robotic telescope near Ceccano,
Italy; position end figures 08s.22, 33".8); 7.188, 18.1 (Federica Luppi and
Luca Buzzi, Varese, Italy; 0.36-m f/7.1 reflector; position end figures 08s.26,
33".2; reference stars from CMC-14 catalogue; image posted at website URL
http://www.astrogeo.va.it/pub/TOCP/PSN_U04958.jpg); 7.380, 18.4 (Joseph
Brimacombe, Cairns, Australia; remotely with a 51-cm RCOS telescope +
STXL-6303 camera located at the New Mexico Skies observatory near Mayhill,
NM, USA; position end figures 08s.31, 33".7; image posted at website URL
http://www.flickr.com/photos/43846774@N02/10741553623/).

     D. Milisavljevic, Harvard-Smithsonian Center for Astrophysics; and S.
Gottilla, MMT Observatory, report that a low-dispersion spectrogram (range
335-855 nm), obtained on Nov. 8.4 UT with the 6.5-m MMT telescope (+ Blue
Channel), shows PSN J09210825+4935338 = SN 2013gg to be a young type-II
supernova.  Cross-correlation with a library of supernova spectra using the
"Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666,
1024) shows a reasonable match with the type-IIP event 2006bp at four days
after maximum light.  Using a redshift of z = 0.0274 for the host galaxy, UGC
4958 (from the Sloan Digital Sky Survey, DR2, 2004; via NED), they estimate
the minimum of the H_alpha P-Cyg absorption to be blueshifted by approximately
13000 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 November 11                 (CBET 3705)              Daniel W. E. Green