[IAUC] CBET 3698: 20131110 : SUPERNOVA 2013gb IN UGC 4700 = PSN J08585252+4135001

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                                                  Electronic Telegram No. 3698
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 en eps.harvard.edu (alternate cbat en iau.org)
URL http://www.cbat.eps.harvard.edu/index.html
Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2013gb IN UGC 4700 = PSN J08585252+4135001
     [Editor's note:  this text replaces that on CBET 3697 (discovery date)]
     Bin Wang, Shaoxing, Zhejiang, China; and Xing Gao, Urumqi, Xinjiang,
China, report the discovery of a possible supernova (mag approximately 16.7)
on a 40-s unfiltered CCD survey image (limiting mag about 19.5) taken by Xing
Gao in the course of the Xingming Sky Survey around Oct. 31.85 UT using a
0.36-m f/6.9 Celestron C14 Schmidt-Cassegrain telescope at Mt. Nanshan.  The
new object is approximately located at R.A. = 8h58m52s.52, Decl. =
+41d35'00".1 (equinox 2000.0), which is about 25".9 east and 11".7 north of
the center of UGC 4700 = PGC 25224.  Nothing is visible at this position on
a Digitized Sky Survey plate taken on 1989 Dec. 8 (limiting mag about 19.8,
but nothing stated about the plate emulsion type).  The discoverers' images
have been posted at URL http://www.xjltp.com/XOSS/XM08BW/XM08BW.htm.  The
variable was designated PSN J08585252+4135001 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013gb based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013gb:  2013 Oct. 21, [19.0 (Wang and Gao); Nov. 1.989, 16.5 (Gianluca Masi,
Francesca Nocentini, and Patrick Schmeer; remotely using a 43-cm f/6.8 robotic
telescope near Ceccano, Italy; position end figures 52s.48, 34'59".9); 2.478,
17.7 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS
telescope at the New Mexico Skies observatory near Mayhill, NM, USA; image
posted at URL http://www.flickr.com/photos/43846774@N02/10638247463/); 7.169,
16.1 (Federica Luppi and Luca Buzzi, Varese, Italy; 0.36-m f/7.1 reflector;
position end figures 52s.51, 59".7; reference stars from CMC-14 catalogue;
image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_P25224.jpg).

     M. Yamanaka, Kyoto University; and Y. Moritani, R. Itoh, and K. S.
Kawabata, Hiroshima University, obtained a low-resolution optical spectrogram
(range 480-900 nm) of PSN J08585252+4135001 = SN 2013gb on Nov. 5.8 UT with
the 1.5-m Kanata telescope (+ HOWPol) at Higashi-Hiroshima Observatory.  A
comparison with a library of supernova spectra using GELATO (Harutyunyan et
al. 2008, A.Ap. 488, 383) suggests that the spectrum of 2013gb is consistent
with that of the type-Ia supernova 1999ac at two days before B-band maximum.
After the correction of the recession velocity of the host galaxy, 2013gb
exhibits absorption lines at 486, 532, 547, and 613 nm, which are identified
as an Fe II multiplet, S II 545.4- and 564.0 nm, and Si II 635.5-nm,
respectively.  The line velocities of Si II 635.5-nm reach 10000 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 10                 (CBET 3698)              Daniel W. E. Green