[IAUC] CBET 3500: 20130426 : SUPERNOVA 2013bw IN UGC 5886 = PSN J10505237-0123269

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                                                  Electronic Telegram No. 3500
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)
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Prepared using the Tamkin Foundation Computer Network


SUPERNOVA 2013bw IN UGC 5886 = PSN J10505237-0123269
     S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; and E. Christensen and S. M. Larson, Lunar and Planetary
Laboratory, University, report the Catalina Real-time Transient Survey
discovery of an apparent supernova in public images from the Catalina Sky
Survey (CSS):

 SN       2013 UT        R.A. (2000.0) Decl.       Mag.      Offset
 2013bw   Apr. 14.24   10 46 52.37 -01 23 26.9    18.4    13".3 E, 2".1 N

Note that the right ascension has been corrected; the variable was designated
PSN J10505237-0123269 (based on an erroneous R.A. that was 4 min to the east)
when it was posted at the Central Bureau's TOCP webpage and is here designated
SN 2013bw based on the spectroscopic confirmation reported below.  Additional
CCD magnitudes for 2013bw:  Mar. 2.26 [20.3 (CSS); 14.26, 19.6 (CSS); Apr.
3.21, 17.9 (CSS); 15.343, 17.2 (Joseph Brimacombe, Cairns, Australia; remotely
with a 51-cm RCOS telescope + luminance filter located at the New Mexico Skies
observatory near Mayhill, NM, U.S.A.; position end figures 52s.35, 28".2 (he
also noted the 50-min discrepancy in R.A.); image posted at website URL
http://www.flickr.com/photos/43846774@N02/8653981218/); 16.222, 17.0
(Brimacombe; position end figures 52s.35, 28".6; image posted at website URL
http://www.flickr.com/photos/43846774@N02/8657091328/); 18.52, 18.6 (Federica
Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8 reflector position end
figures 52s.26, 27".4; reference stars from CMC-14 catalogue; a knot, or H II
region is visible at the position of 2013bw in Digitized Sky Survey images;
image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_U5886.jpg).

     N. Morrell and E. Hsiao, Las Campanas Observatory, on behalf of the
Carnegie Supernova Project, report optical spectroscopy (range 370-960 nm) of
PSN J10505237-0123269 = SN 2013bw, obtained on Apr. 16 UT with the Las
Campanas 2.5-m du Pont telescope (+ WFCCD).  Inspection of the data reveals
that 2013bw is a young type-II supernova.  Cross-correlation with a library of
supernova spectra via the Supernova Identification tool (SNID, Blondin and
Tonry 2007, Ap.J., 666, 1024) yields best matches with SN 1999em at +9 days
for 2013bw.  Strong nebular emission from surrounding H II regions is present
in the supernova spectra, allowing determination of redshift 0.03889 +/-
0.00009 for 2013bw, in very good agreement with the redshift of 0.0383 quoted
in NED for the host galaxy, UGC 5886 (after Jones et al. 2009, The 6dF Galaxy
Survey Data Release 3).  The authors also note the incorrect R.A. given on
the TOCP (and corrected above).


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

                         (C) Copyright 2013 CBAT
2013 April 26                    (CBET 3500)              Daniel W. E. Green