[IAUC] CBET 3151: 20120620 : SUPERNOVA 2012cz = PSN J15574636+1622274

Mie Jun 20 16:58:47 ART 2012

                                                  Electronic Telegram No. 3151
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 2012cz = PSN J15574636+1622274
     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; 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 Catalina Sky Survey (CSS).

 SN       2012 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2012cz   May 25.28   15 57 46.36  +16 22 27.4   18.9    2" W, 3" N

The variable was designated PSN J15574636+1622274 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012cz based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2012cz:  Mar. 17.40 UT, 18.1 (CSS); Apr. 18.39, 18.4 (CSS); Apr. 29.30, 18.6
(CSS); May 15.44, 18.9 (CSS); 27.258, 17.6 (J. Brimacombe, Cairns, Australia;
luminance filter assumed; position end figures 46s.36, 28".1; image posted at
website URL http://www.flickr.com/photos/43846774@N02/7286069916/); June 10.29,
18.9 (CSS); June 16.37, 19.1 (CSS).  Federica Luppi and Luca Buzzi (Varese,
Italy) obtained unfiltered images with a 0.38-m f/6.8 reflector on May 29.998
that yield position end figures 46s.44, 28".7 for 2012cz (reference stars
from the CMC-14 catalogue); they have posted their image at the following
website URL:  http://www.astrogeo.va.it/pub/TOCP/PSN_J15574636+1622274.jpg.

     D. Milisavljevic, Harvard-Smithsonian Center for Astrophysics, reports
that an optical spectrogram (resolution 0.3 nm; range 410-690 nm) of PSN
J15574636+1622274 = SN 2012cz, obtained on May 29.3 UT with the 2.4-m Hiltner
telescope (+ OSMOS) at MDM Observatory, indicates that it is a type-IIn
supernova.  The spectrum is dominated by strong H-alpha emission with a
complex profile exhibiting a broad component (FWHM around 5000 km/s) and a
narrow component with P-Cyg absorption.  Weaker H-beta emission shows a
similar profile.  A redshift of z = 0.036 is estimated from narrow H-alpha
and [N II] 654.8- and 658.3-nm nebular emission lines, which is consistent
with the redshift of the host galaxy, KUG 1555+165 (Haynes et al. 1997, A.J.
113, 1197).

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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 June 20                     (CBET 3151)              Daniel W. E. Green