[IAUC] CBET 3337: 20121212 : SUPERNOVA 2012hn IN NGC 2272 = PSN J06424255-2726498

Mar Dic 11 20:45:35 ART 2012

                                                  Electronic Telegram No. 3337
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 2012hn IN NGC 2272 = PSN J06424255-2726498
     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, Australian National University; and E. C.
Beshore, S. M. Larson, and E. Christensen, Lunar and Planetary Laboratory,
University of Arizona, report the discovery of an apparent supernova in public
images from the Siding Spring Survey (SSS):

 SN       2012 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2012hn   Apr. 4.41    6 42 42.55  -27 26 49.8   16.5    16".6 E, 44".4 N

The variable was designated PSN J06424255-2726498 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012hn based on the
spectroscopic confirmation reported below.  Additional magnitudes for 2012hn:
2011 Apr. 7.46 UT, [19.5 (SSS); 2012 Apr. 16.127, 18.6 (Joseph Brimacombe,
Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera +
luminance filter at the New Mexico Skies Observatory near Mayhill, NM, U.S.A.;
position end figures 42s.56, 50".3; image posted at the following website URL:
http://www.flickr.com/photos/43846774@N02/7083122477/); May 16.42, 17.3 (SSS).

     S. Benitez-Herrera and S. Taubenberger, Max-Planck-Institut fuer
Astrophysik; and S. Valenti, S. Benetti, and A. Pastorello, Istituto Nazionale
di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a larger
collaboration, report that a spectrogram of PSN J06424255-2726498 = SN 2012hn,
obtained on Apr. 14.02 UT with the European Southern Observatory's New
Technology Telescope (+ EFOSC2; range 365-930 nm; resolution 1.8 nm), shows it
to be a peculiar type-Ic supernova.  The best matches to this spectrum found
by GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383; available at website URL
https://gelato.tng.iac.es/login.cgi) suggest that 2012hn was then a few weeks
after maximum light.  There are prominent O I and Ca II lines, but also
several unidentified features.  There is no clear evidence for the presence of
H or He lines.  The redshift of the host galaxy, NGC 2272, is z = 0.007
(Wegner et al. 2003, A.J. 126, 2268; via NED).

     S. Valenti, University of California at Santa Barbara and Las Cumbres
Observatory Global Telescope; S. Benitez-Herrera and S. Taubenberger,
Max-Planck-Institute fuer Astrophysik, Garching; A. Pastorello and S. Benetti,
Istituto Nazionale di Astrofisica, Padova; S. J. Smartt, D. Young, and K.
Smith, Queen's University, Belfast; M. Sullivan, University of Southampton;
and I. Arcavi, A. Gal-Yam, and O. Yaron, Weizmann Institute of Science, on
behalf of the PESSTO collaboration (see Valenti et al., posted at website URL
http://www.astronomerstelegram.org/?read=4037), report that a spectrogram of
PSN J06424255-2726498 = SN 2012hn, obtained on Apr. 14.02 UT with the European
Southern Observatory's New Technology Telescope (+ EFOSC2; range 365-930 nm;
resolution 1.8 nm), shows it to be a faint, peculiar type-I supernova (see
Benitez-Herrera et al., at URL http://www.astronomerstelegram.org/?read=4047).
Subsequent spectroscopic monitoring (Apr. 20, 22, and 29, May 11 and 18, and
Sept. 13 and 14) confirms the initial classification.  Lines of Ti II, Ca II,
and Fe II are clearly visible, while H and He I have never been detected.  In
addition, the faint peak absolute magnitude supports the idea that 2012hn is
photometrically similar to the peculiar, stripped-envelope supernova 2005E
(Peretz et al. 2010, Nature 465, 322).

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

                         (C) Copyright 2012 CBAT
2012 December 12                 (CBET 3337)              Daniel W. E. Green