Electronic Telegram No. 3168
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 2012dk IN PGC 926 = PSN J00135630-7001407
     Greg Bock, Windaroo, Queensland, Australia, reports the discovery of a
possible supernova (mag 14.4) by Stuart Parker (Oxford, Canterbury, New
Zealand) on a 30-s unfiltered CCD image taken on June 26.60 UT with a 28-cm
Celestron C11 reflector (+ ST10 camera); Bock measures the position of the
new object as R.A. = 0h13m56s.30, Decl = -70d01'40".7 (equinox 2000.0;
measured by Bock using stars from the USNO-B and UCAC3 catalogues), with the
offset given as 14' [sic] west and 19' [sic] south (though it is presumed
that Bock meant 14" west and 19" south) of the nucleus of the galaxy PGC 926.
Nothing is visible at this position on red and infrared images from the
Digitized Sky Survey (limiting red mag > 19) or on Parker's image taken on
2012 June 9 (limiting red magnitude > 18.0).  The variable was designated
PSN J00135630-7001407 when it was posted at the Central Bureau's TOCP webpage
and is here designated SN 2012dk based on the spectroscopic confirmation
reported below.  Joseph Brimacombe, Cairns, Australia, reports magnitude
15.7 and position end figures 56s.47, 41".3 for PSN J00135630-7001407 = 2012??
from CCD images taken using an infrared filter (bandpass > 700 nm) with a
41-cm RCOS telescope (+ STL6K camera) on June 29.823; his image is posted at
website URL http://www.flickr.com/photos/43846774@N02/7471310214/.

     J. T. Parrent and D. A. Howell report that a CCD spectrogram (range
350-900 nm) of PSN J00135630-7001407 = 2012dk, taken with the "Gemini South"
telescope on July 1 UT, shows that it is a type-Ia supernova.  Using the
host-galaxy emission lines, a redshift of z = 0.0137 is inferred.  Correcting
for this redshift, the minimum of the Si 635.5-nm absorption feature is
found to be blue-shifted by about 11200 km/s.  Comparisons to other spectra
with "Superfit" (Howell et al. 2005, Ap.J. 634, 1190) show similar overlap
with SN 1990N at three days post-maximum-light.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 July 8                      (CBET 3168)              Daniel W. E. Green