Electronic Telegram No. 3517
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 2013cg IN NGC 2891 = PSN J09265677-2446596
     G. Pignata, Y. Apostolovski, E. Paillas, and S. Varela, Universidad
Andres Bello; M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster, S.
Silva, F. Carrasco, P. Sanchez, and R. Ramirez, Universidad de Chile; F. Aros,
Pontificia Universidad Catolica de Chile; B. Conuel, Wesleyan University; G.
Folatelli, IPMU, University of Tokyo; and D. E. Reichart, J. B. Haislip, J. P.
Moore, and A. P. LaCluyze, University of North Carolina at Chapel Hill, on
behalf of the CHASE project (which is part of the Millennium Center for
Supernova Science collaboration), report the discovery of an apparent supernova
(mag approximately 13.3) on an unfiltered image taken on May 6.03 UT with the
0.41-m 'PROMPT 3' telescope located at Cerro Tololo.  The new object is located
at R.A. = 9h26m56s.77 +/- 0".2, Decl. = -24o46'59".6 +/- 0".2 (equinox 2000.0),
which is about 1".7 east and 1".0 south of the center of the galaxy NGC 2891.
The variable is also barely visible in an image taken under poor weather
conditions on Apr. 22.99.  The variable was designated PSN J09265677-2446596
when it was posted at the Central Bureau's TOCP webpage and is here designated
SN 2013cg based on the spectroscopic confirmation reported below.  Additional
CCD magnitudes for 2013cg:  Apr. 4.04, [18.5 (CHASE); May 8.519, V = 13.98 and
I_c = 13.92 (Seiichiro Kiyota, Tsukuba, Japan; iTelescope.net 0.50-m f/6.8
astrograph + FLI-PL6303E camera located at Siding Spring, NSW; measurements
very difficult, with the variable very close to the nucleus of NGC 2891; image
posted at URL http://meineko.sakura.ne.jp/ccd/PSN_J09265677-2446596.jpg).

     K. Takaki, K. Kawaguchi, and K. S. Kawabata, Hiroshima University; and M.
Yamanaka, Kyoto University; report that they obtained low-resolution (R = 400)
optical spectra of PSN J09265677-2446596 = SN 2013cg on May 11.5 UT at the
Higashi-Hiroshima Observatory, Hiroshima University.  After the recession
velocity of the host galaxy (NGC 2891) is corrected, the spectra show the
absorption feature of Si II at 610 nm; this line seems to have a relatively
flat-bottomed profile, and the line velocity reaches 12000 km/s.  The
absorption line of S II around 540 nm is relatively broad and shallow.  The
absorption line of Si II is seen at 572 nm.  These profiles are similar to
that of a normal type-Ia supernova at around a week before maximum (Garavini
et al. 2007, A.Ap. 471, 527).


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

                         (C) Copyright 2013 CBAT
2013 May 12                      (CBET 3517)              Daniel W. E. Green