Electronic Telegram No. 3648
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 2013fg IN NGC 2578 = PSN J08212244-1318370
     Stuart Parker, Canterbury, New Zealand, reports the discovery of an
apparent supernova (red mag 15.4) on a 30-s unfiltered CCD image (limiting mag
18.5) taken by himself on Sept. 2.726 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. = 8h21m22s.44, Decl. = -13d18'37".0 (equinox 2000.0; reference
stars from USNO-B and UCAC4 catalogues), which is 27" west and 27" north of
the nucleus of the galaxy NGC 2578.  Nothing is visible at this position on
Digitized Sky Survey red and infrared images (limiting red magnitude > 19).
The variable was designated PSN J08212244-1318370 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2013fg based on the
spectroscopic confirmation reported below.

     N. Morrell, Las Campanas Observatory, Carnegie Supernova Project; and
P. Lira, Universidad de Chile, report that on Sept. 4.42 UT, during morning
twilight, they obtained an optical spectrogram (range 365-950 nm) of PSN
J08212244-1318370 = SN 2013fg with the Las Campanas 2.5-m du Pont telescope
(+ WFCCD).  Inspection of the data shows that this is a type-Ia supernova,
roughly ten days after maximum light.  An expansion velocity of approximately
10900 km/s is derived from the minimum of the Si II 635.5-nm absorption, after
correcting for the recession velocity of NGC 2578 (i.e., 4601 km/s, after
Theureau et al. 1998, A.Ap. Suppl. 130, 333; via NED).  Na I D absorption with
equivalent width 0.60 nm at the redshift of the host galaxy is also present in
the supernova's spectrum.  Cross-correlation with a library of supernova
spectra using the Supernova Identification tool (SNID; Blondin and Tonry 2007,
Ap.J. 666, 1024) indicates that 2013fg is a normal type-Ia supernova, most
similar to SN 2003du at 13 days after maximum brightness.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2013 CBAT
2013 September 9                 (CBET 3648)              Daniel W. E. Green