[IAUC] CBET 3194: 20120728 : SUPERNOVA 2012dw = PSN J21223528-3333546

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                                                  Electronic Telegram No. 3194
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 2012dw = PSN J21223528-3333546
     R. H. McNaught, Australian National University; 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; and E. Christensen and S. M. Larson, Lunar and
Planetary Laboratory, University of Arizona, report the discovery of an
apparent supernova in unfiltered Siding Spring Survey (SSS) images:

 SN       2012 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2012dw   July 23.72   21 22 35.28  -33 33 54.6   17.5    8".8 W, 2".5 S

The variable was designated PSN J21223528-3333546 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012dw based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2012dw:  July 7.77, [19.0 (SSS); July 24.78, 17.5 (SSS); July 25.349, 16.6
(L. Elenin, Lyubertsy, Russia, and I. Molotov, Moscow, Russia; images remotely
taken at the ISON-NM Observatory near Mayhill, NM, USA, with a 0.45-m f/2.8
telescope; limiting mag about 19.6; position end figures 35s.42 +/- 0".14,
54".5 +/- 0".17; NOMAD reference stars; image posted at website URL
http://spaceobs.org/images/TOCP/PSNJ21223528-3333546-20120725.png); July
25.585, 17.9 (J. Brimacombe, Cairns, Australia; 43-cm CDK Planewave telescope
+ STL6K + infrared filter; bandpass > 700 nm; position end figures 35s.30,
55".0; image posted at http://www.flickr.com/photos/43846774@N02/7647121482/).

     M. McCrum, M. Fraser, and R. Kotak, Queens University, Belfast, report
that they obtained a spectrum of PSN J21223528-3333546 = 2012dw with the
Telescopio Nazionale Galileo (+ DOLORES + LRB; range 400-800 nm) on July 25.1
UT.  Cross-correlation with a range of template supernova spectra using the
SuperNova IDentification code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024)
gives a good match to a number of normal type-Ia supernovae within a few days
of maximum light, at a redshift of z about 0.05.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2012 CBAT
2012 July 28                     (CBET 3194)              Daniel W. E. Green