[IAUC] CBET 2695: 20110412 : SUPERNOVA 2011bm IN IC 3917 = PSN J12565389+2222282

Mie Sep 14 16:18:58 ART 2011

                                                  Electronic Telegram No. 2695
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 2011bm IN IC 3917 = PSN J12565389+2222282
     Denis Vida, on behalf of the "La Sagra Sky Survey" (LSSS) Supernova
Search Team (which also includes Filip Novoselnik, Ivica Skokic, David
Gostinski, Robert Gregic, Salvador Sanchez, Jaime Nomen, Reiner Stoss, Bill
Yeung, Juan Rodriguez, and Miguel Hurtado), reports the discovery of an
apparent supernova (red magnitude 17.0) on three CCD images (limiting mag
about 20.0) taken on Apr. 4.98, 4.991, and 5.002 UT with a 0.45-m telescope.
The new object is located at R.A. = 12h56m53s.89, Decl = +22d22'28".2 (equinox
2000.0), which is 5".8 east and 3".1 north of the nucleus of the presumed host
galaxy (IC 3917 = IC 3918).  The variable was designated PSN J12565389+2222282
when posted on the Central Bureau's TOCP webpage and is here designated SN
2011bm based on the spectroscopic report below.  Additional approximate CCD
unfiltered magnitudes for 2011bm:  Jan. 13.133, [20 (LSSS); Feb. 3.06, [20
(LSSS); 4.092, [20 (LSSS); Apr. 10.072, 16.5 (D. Rich, Hampden, ME, U.S.A.,
0.41-m f/5.6 reflector; position end figures 53s.94, 27".9); 10.383, 16.1 (J.
Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope at
New Mexico Skies Observatory, Mayhill, NM, U.S.A.; position end figures 53s.89,
27".6).  The LSSS images (from Jan. 13 to April 4) have been posted (with a
red Digitized Sky Survey image on the right) at the following website URL:
http://img717.imageshack.us/img717/276/ic3917archive.png; also, three images
taken on the night of Apr. 4 have been posted at the following website URL:
http://img857.imageshack.us/img857/4702/ic3917confirmation.png.  Brimacombe's
image is posted at http://www.flickr.com/photos/43846774@N02/5605348297/.
The type-Ia supernova 2007bz also appeared in this galaxy (cf. CBETs 941, 943).

     E. Gall, S. Taubenberger, and I. Maurer, Max-Planck-Institut fuer
Astrophysik; R. Pakmor, Heidelberger Institut fuer Theoretische Studien; and
S. Valenti and S. Benetti, Instituto Nazionale di Astrofisica, Osservatorio
Astronomico di Padova, on behalf of a larger collaboration, report that an
optical spectrogram (range 380-820 nm; resolution 1.1 nm) of PSN
J12565389+2222282 = SN 2011bm was obtained with the Ekar-Copernicus 1.82-m
telescope (+ AFOSC) on Apr. 11.0 UT.  SN 2011bm shows a blue continuum with
a narrow H-alpha line that is possibly from the host galaxy.  After cross-
correlation with a library of supernova spectra via the "GELATO" code
(Harutyunyan et al. 2008, A.Ap. 488, 383; available at website URL
https://gelato.tng.iac.es/login.cgi), the best match is found to be with
type-Ic supernovae close to maximum.


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

                         (C) Copyright 2011 CBAT
2011 April 12                    (CBET 2695)              Daniel W. E. Green