[IAUC] CBET 3301: 20121119 : SUPERNOVA 2012gk IN ESO 305-21 = PSN J05224150-3903443

[quai en eps.harvard.edu]

                                                  Electronic Telegram No. 3301
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 2012gk IN ESO 305-21 = PSN J05224150-3903443
     Stuart Parker, Oxford, Canterbury, New Zealand, reports his discovery
of an apparent supernova (red mag 18.0) on a 30-s unfiltered CCD image
(limiting mag 19.5) taken with a 35-cm Celestron C14 reflector (+ ST10 camera)
at his Parkdale Observatory on Nov. 13.57 UT in the course his participation
with the Backyard Observatory Supernova Search.  The new object is located at
R.A. = 5h22m41s.50, Decl. = -39d03'44".3 (equinox 2000.0), which is 11" west
and 5" north of the center of nucleus of the galaxy ESO 305-21.  Nothing is
visible at this position on Digitized Sky Survey red and infrared plates
(limiting red mag > 19).  The variable was designated PSN J05224150-3903443
when it was posted at the Central Bureau's TOCP webpage and is here
designated SN 2012gk based on the spectroscopic confirmation reported below.
Additional unfiltered CCD magnitudes for 2012gk:  Oct. 22.679, [18.5 (Parker);
Nov. 4.582, 17.9 (Parker; apparent pre-discovery image; limiting mag 18.5);
15.60, 18.0 (Greg Bock, Windaroo Lakes Observatory, Queensland, Australia;
Meade 350F7 ACF telescope + ST10XE camera; limiting mag > 19.0).

     D. Milisavljevic, M. R. Drout, and G. H. Marion, Harvard-Smithsonian
Center for Astrophysics, report that an optical spectrum (range 410-935 nm;
resolution 0.4 nm) of PSN J05224150-3903443 = SN 2012gk, obtained on Nov. 17.3
UT with the 6.5-m Magellan Baade telescope (+ IMACS), shows it to be a type-II
supernova.  Cross-correlation with a library of supernova spectra using the
"Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666,
1024) shows matches with normal type-IIP events approximately three weeks
after maximum light.  The best match is with SN 2004et at 23 days post-maximum.
After correcting for the host galaxy (ESO 305-21) redshift of z = 0.050415
(de Souza et al. 1997, A.Ap. Suppl. 125, 329; via NED), the velocity of the
minimum of the H_alpha feature is estimated to be approximately 10500 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2012 CBAT
2012 November 19                 (CBET 3301)              Daniel W. E. Green