Electronic Telegram No. 3717
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 2013gk IN ESO 230-G6 = PSN J18421303-4944370
     Stuart Parker, Canterbury, New Zealand, reports the discovery of an
apparent supernova (red mag 16.8) on a 30-s unfiltered CCD image (limiting mag
18.5) taken on Oct. 28.372 UT with a 30-cm Astro-Tech AT12RC Ritchey-Chretien
astrograph (+ ST10 camera) at his Parkdale Observatory in the course of the
Backyard Observatory Supernova Search.  The new object is located at R.A. =
18h42m13s.03, Decl. = -49d44'37".0 (equinox 2000.0; reference stars from
USNO-B and UCAC3 catalogues), which is 11" east and 6" north of the nucleus of
the galaxy ESO 230-G6.  Nothing is visible at this position on Digitized Sky
Survey red and infrared images (limiting red magnitude > 19).  The variable
was designated PSN J18421303-4944370 when it was posted at the Central
Bureau's TOCP webpage and is here designated SN 2013gk based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2013gk:  Sept. 15.385, [19 (Parker); Nov. 4.420, 17.5 (Joseph Brimacombe,
Cairns, Australia; 41-cm RCOS telescope + STL6K camera + infrared filter;
bandpass > 700 nm; position end figures 12s.97, 37".2; image posted at URL
http://www.flickr.com/photos/43846774@N02/10698811695/).

     E. Y. Hsiao, N. Morrell, and Mark M. Phillips, Las Campanas Observatory;
G. H. Marion, University of Texas, Austin; J. Vinko, University of Szeged; and
T. Diamond, Florida State University, report that a near-infrared spectrogram
(range 800-2400 nm) of PSN J18421303-4944370 = SN 2013gk was obtained on Nov.
14.02 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the
6.5-m Magellan Baade Telescope.  The spectrum indicates that 2013gk is a
type-IIb supernova. The near-infrared spectrum is similar to that of SN
2001bq.  P-Cyg lines of the hydrogen Paschen series and He I 1.083-micron are
present.  Using the redshift from the presumed host galaxy (ESO 230-G6) of z
= 0.0177 (via the H I Parkes All Sky Survey Final Catalogue, 2006; via NED),
the He I 1.083-micron absorption yields an expansion velocity of approximately
7000 km/s.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 November 20                 (CBET 3717)              Daniel W. E. Green