[IAUC] CBET 2928: 20111202 : SUPERNOVA 2011im IN NGC 7364 = PSN J22442522-0010020

Vie Dic 2 03:25:24 ART 2011

                                                  Electronic Telegram No. 2928
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 2011im IN NGC 7364 = PSN J22442522-0010020
     Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent
supernova (mag 18.5) on unfiltered CCD images (limiting magnitude 19.5)
obtained on Nov. 26.426 UT with a 0.60-m f/5.7 reflector.  The new object is
located at R.A. = 22h44m25s.22, Decl. = -0d10'02".0 (equinox 2000.0), which is
13".0 east and 18".8 south of the nucleus of the presumed host galaxy, NGC
7364 (whose position end figures are measured as 24s.35, 09'43".2).  The
discovery image is posted at URL http://www.k-itagaki.jp:80/images/psn7364.jpg.
The variable was designated PSN J22442522-0010020 when it was posted on the
Central Bureau's TOCP webpage and is here designated SN 2011im based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2011im (unfiltered unless noted otherwise):  Aug. 7.623, [19.5 (Itagaki);
Nov. 10.449, [19.5 (Itagaki); 27.058, 17.3 (J. Brimacombe, Cairns, Australia;
remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter at
the New Mexico Skies Observatory near Mayhill, New Mexico; position end
figures 25s.19, 02".1); 27.072, 17.0 (R. A. Koff, Bennett, CO, USA; Meade
0.25-m f/10 reflector + Apogee AP-47p camera; limiting magnitude 19.0;
position end figures 25s.14, 02".0; UCAC3 reference stars); 27.383, 16.9 (T.
Yusa, Osaki, Japan; 0.30-m f/7 Cassegrain reflector + SBIG STL-1001E camera;
limiting magnitude 19.0; position end figures 25s.20, 02".0; UCAC3 reference
stars); 27.470, 17.2 (T. Noguchi, Katori, Chiba-ken, Japan; 0.23-m f/6.3
Schmidt-Cassegrain reflector + BITRAN BT-11E camera; limiting mag 18.0;
position end figures 25s.23, 01'.7; galaxy center at position end figures
24s.35, 09'43".1; communicated by S. Nakano).  Brimacombe's image is posted
at website URL http://www.flickr.com/photos/43846774@N02/6413938181/.
Supernovae 2006lc and 2009fk also appeared in NGC 7364.

     L. Tomasella, A. Pastorello, S. Valenti, and S. Benetti, Istituto
Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a
larger collaboration, report that a spectrogram of PSN J22442522-0010020 =
SN 2011im, obtained on Nov. 27.71 UT with the Asiago 1.82-m Copernico Telescope
(+ AFOSC; range 350-820 nm; resolution 2.4 nm), shows it to be a type-Ia
supernova.  The best fit to this spectrum found by GELATO (Harutyunyan et al.
2008, A.Ap. 488, 383; available at URL https://gelato.tng.iac.es/login.cgi)
suggests that 2011im is similar to SN 1994D (Patat et al. 1996, MNRAS 278, 111)
about ten days before maximum light.  Adopting for the host galaxy (NGC 7364)
a redshift of z = 0.01623 (Catinella et al 2005, A.J. 130, 1037; via NED), the
ejecta velocity as deduced from the position of the minimum of the Si II
635.5-nm line is about 13600 km/s.


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

                         (C) Copyright 2011 CBAT
2011 December 2                  (CBET 2928)              Daniel W. E. Green