[IAUC] CBET 3077: 20120329 : SUPERNOVA 2012bm IN UGC 8189 = PSN J13054566+4627529

Jue Mar 29 11:57:05 ART 2012

                                                  Electronic Telegram No. 3077
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 2012bm IN UGC 8189 = PSN J13054566+4627529
     T. Puckett and J. Newton report the discovery of an apparent supernova
(mag 17.1) on an unfiltered CCD image (limiting mag 19.1) taken with a 0.40-m
reflector at Portal, AZ, U.S.A., on Mar. 27.245 UT in the course of the
Puckett Observatory Supernova Search.  The new object, which was confirmed at
mag 17.0 on Mar. 28.429 by Puckett with the same instrumentation at Portal, is
located at R.A. = 13h05m45s.66, Decl. = +46o27'52".9 (equinox 2000.0), which
is 11".0 west and 10".4 north of the center of UGC 8189.  Nothing is visible
at this position on images taken by Puckett on Mar. 11 (limiting mag 19.0).
An image is posted at URL http://www.possdata.com/PSNJ13054566+4627529.jpg.
The variable was designated PSN J13054566+4627529 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012bm based on the
spectroscopic confirmation reported below.  Additional CCD magnitudes for
2012bm:  Mar. 27.809, 16.5 (Nick James, Chelmsford, Essex, England; Celestron
11 telescope + ST9XE camera; red magnitude cited; position end figures 45s.64,
52".2); 28.018, 17.0 (Massimiliano Martignoni, Magnago, Italy; 25-cm f/10
Schmidt-Cassegrain telescope; V bandpass cited).

     E. Cappellaro, A. Pastorello, L. Tomasella, S. Benetti, M. Fiaschi, P.
Ochner, M. Turatto, and S. Valenti, Osservatorio Astronomico di Padova,
Istituto Nazionale di Astrofisica, report that a spectrogram of PSN
J13054566+4627529 = SN 2012bm, obtained on Mar. 28.05 UT with the Asiago
1.82-m Copernico Telescope (+ AFOSC; range 340-820 nm; resolution 2.4 nm),
suggests that it is a reddened type-Ia supernova.  Adopting for the host
galaxy a redshift z = 0.0248 (SDSS 2005, via NED), and assuming a color
excess E(B-V) = 0.5 mag, the comparison with a library of supernovae spectra
via GELATO (Harutyuyan et al. 2008, A.Ap. 488, 383) shows that 2012bm is a
type-Ia event similar to SN 1994D (Patat et al. 1996, MNRAS 278, 111) at
about one week before the B-band maximum light.  The expansion velocity,
deduced from the Si II 635.5-nm minimum, is about 11200 km/s.


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      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2012 CBAT
2012 March 29                    (CBET 3077)              Daniel W. E. Green