[IAUC] CBET 3233: 20120918 : SUPERNOVA 2012ew = PSN J02452841-6207214

Mar Sep 18 08:41:36 ART 2012

                                                  Electronic Telegram No. 3233
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 2012ew = PSN J02452841-6207214
     Colin Drescher, Calamvale, Queensland, Australia, reports the discovery
of an apparent supernova (red mag 18.5) by Stuart Parker (Oxford, Canterbury,
New Zealand) on a 30-s unfiltered image taken on Sept. 12.535 UT with a 35-cm
Celestron C14 f/6.3 reflector (+ ST10 CCD camera) in the course of the
"Backyard Observatory Supernova Search" (BOSS) program.  The new object is
located at R.A. = 2h45m28s.36, Decl. = -62d07'21".0 (equinox 2000.0; measured
by Drescher), which is 10" west and 9" north of the nucleus of the galaxy
PGC 127935 = IRAS 02443-6220.  Parker subsequently found the variable to be
present on earlier images that he took on July 17.672 (at red mag 17.7 and
position end figures 28s.41, 21".4, as measured by Drescher), July 27, and
Aug. 29.  Nothing is visible at this position on an image by Parker taken
on Apr. 24.293, to limiting red mag 18.4.  The variable was designated PSN
J02452841-6207214 when it was posted at the Central Bureau's TOCP webpage
and is here designated SN 2012ew based on the spectroscopic confirmation
reported below.

     N. Morrell, Las Campanas Observatory, on behalf of the Carnegie Supernova
Project, reports on an optical spectrogram (range 370-920 nm) obtained of PSN
J02452841-6207214 = SN 2012ew on Sept. 14.25 UT with the 2.5-m du Pont
telescope at Las Campanas Observatory.  Inspection of the data reveals that
this is an evolved type-II supernova.  Comparison with a library of supernova
spectra via the Supernova Identification tool (SNID; Blondin and Tonry 2007,
Ap.J. 666, 1024) yields good comparisons with a number of type II-p supernovae
with no clear indication of age, though the best comparison is to that of SN
2004et at 83 days past maximum brightness, which is consistent with both the
early detection by the BOSS team on July 17 and their last non-detection on
Apr. 24.  H-alpha and [O III] nebular emission from an underlying H II region
at the redshift quoted by NED for the host galaxy (2MASX J02452974-6207300;
z = 0.025700, Colless et al. 2003, The 2dF Galaxy Redshift Survey Final
Data Release) is also present on the supernova spectrum.  Adopting this
redshift, the minimum of the H-beta absorption appears to be blueshifted
by 2700 km/s.


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

                         (C) Copyright 2012 CBAT
2012 September 18                (CBET 3233)              Daniel W. E. Green