[IAUC] CBET 2864: 20111018 : SUPERNOVA 2011gt IN IC 4913 = PSN J19564826-3719375

Mar Oct 18 00:55:30 ART 2011

                                                  Electronic Telegram No. 2864
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 2011gt IN IC 4913 = PSN J19564826-3719375
     S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology;
J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad
Catolica de Chile; R. H. McNaught and G. Garradd, Australian National
University; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory,
University of Arizona; and E. Christensen, Gemini Observatory, report the
discovery of an apparent supernova in public images from the Siding Spring
Survey (SSS).

 SN       2011 UT        R.A. (2000.0) Decl.      Mag.      Offset
 2011gt   Sep. 26.42   19 56 48.26  -37 19 37.5   16.0    7".6 E, 4".5 N

The new object was designated PSN J19564826-3719375 when it was posted on the
Central Bureau's TOCP webpage and is here designated SN 2011gt based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2011gt (unfiltered unless otherwise noted):  Aug. 22.48 UT, [18.5 (SSS);
Sept. 27.109, 15.7 (C. Jacques and E. Pimentel, Belo Horizonte, Brazil;
position end figures 48s.25, 37".9; UCAC2 reference stars; image posted at URL
http://ceamig-rea.net/SUPERNOVAE/CONFIRMATIONS/PSN_J19564826-3719375/I4913.jpg);
27.467, R = 15.6 (P. Miller, P. Roche, A. Tripp, R. Miles, R. Holmes, S.
Foglia, and L. Buzzi with the 2.0-m f/10 Faulkes Telescope South + Bessell R
filter at Siding Spring; position end figures 48s.28, 38".0; PPMXL catalogue;
image posted at URL http://www.astrogeo.va.it/pub/TOCP/PSN_I4913_FTS.jpg);
27.467, R = 17.5 (Joseph Brimacombe, Cairns, Australia; position end figures
48s.27, 37".3; image at http://www.flickr.com/photos/43846774@N02/6190491181/);
Oct. 1.560, R = 17.6 (Brimacombe; image posted at the following website URL:
http://www.flickr.com/photos/43846774@N02/6203147137/).

     J. Anderson, Universidad de Chile; and G. Pignata, Universidad Andres
Bello, on behalf of the Millennium Center for Supernova Science, report that
they obtained a spectrogram of PSN J19564826-3719375 = SN 2011gt on Sept. 30.1
UT with the Magellan II Clay 6.5-m telescope (+ LDSS3) at Las Campanas
Observatory, which shows it to be a type-Ia supernova.  Comparison with a
library of supernova spectra via the "Supernova Identification" tool (Blondin
and Tonry 2007, Ap.J. 666, 1024) provides very good matches with normal
type-Ia events around 3 weeks past maximum light.

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

                         (C) Copyright 2011 CBAT
2011 October 18                  (CBET 2864)              Daniel W. E. Green