Electronic Telegram No. 3494
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 2013bs IN NGC 6343 = PSN J17172203+4104002
     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; S. M. Larson and E.
Christensen, Lunar and Planetary Laboratory, University of Arizona; and R. H.
McNaught, Australian National University, report the Catalina Real-time
Transient Survey discovery of an apparent supernova in unfiltered CCD images:

 SN       2013 UT         R.A. (2000.0) Decl.      Mag.      Offset
 2013bs   Apr. 18.48   17 17 22.03  +41 04 00.2    17.0    65".1 E, 50".3 N

The variable was designated PSN J17172203+4104002 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013bs based on the
spectroscopic confirmation reported below.  Joseph Brimacombe, Cairns,
Australia, reports that he obtained magnitude 16.0 and position end figures
22s.05, 00".2 for 2013bs from images obtained remotely on Apr. 19.256 UT with
a 51-cm RCOS telescope (+ red filter) at the New Mexico Skies observatory near
Mayhill, NM, U.S.A.; he also obtained mag 16.7 using a luminance filter and
V magnitudes for reference stars.  Brimacombe has posted his images at
website URL http://www.flickr.com/photos/43846774@N02/8665084006/.

     L. Tomasella, A. Pastorello, S. Benetti, E. Cappellaro, M. Turatto, and
P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di
Astrofisica, report that optical spectroscopy (range 340-820 nm; resolution
1.3 nm), obtained on Apr. 19.04 UT with the Asiago 1.82-m Copernico Telescope
(+ AFOSC), shows that PSN J17172203+4104002 = SN 2013bs is a type-Ia
supernova.  Adopting for the host galaxy, NGC 6343, the redshift z = 0.027612
(Marzke et al. 1996, A.J. 112, 1803; via NED), the best fit is obtained with
several type-Ia supernovae at a few days before maximum light.  The expansion
velocity, as deduced from the position of the Si II 635.5-nm absorption, is
about 11200 km/s.  The Asiago classification spectra are posted at website
URL http://graspa.oapd.inaf.it; 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 April 25                    (CBET 3494)              Daniel W. E. Green