[IAUC] CBET 3353: 20121224 : SUPERNOVA 2012hw IN MCG +08-18-23 = PSN J09413802+4840255

Lun Dic 24 16:24:07 ART 2012

                                                  Electronic Telegram No. 3353
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 2012hw IN MCG +08-18-23 = PSN J09413802+4840255
     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, 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 Catalina Sky Survey (CSS).

 SN       2012 UT       R.A. (2000.0) Decl.      Mag.      Offset
 2012hw   Dec. 11.48   9 41 38.02  +48 40 25.5   17.5    2".0 E, 11".5 N

The variable was designated PSN J09413802+4840255 when it was posted at the
Central Bureau's TOCP webpage and is here designated SN 2012hw based on the
spectroscopic confirmation reported below.  Further CCD magnitudes for 2012hw
(unfiltered unless noted otherwise):  June 23.36 UT, [18.5 (CSS); Dec. 12.432,
16.8 (L. Elenin, Lyubertsy, Russia; and I. Molotov, Moscow; remotely taken
with a 0.45-m f/2.8 telescope at the ISON-NM Observatory near Mayhill, NM,
USA; limiting mag about 19.8; position end figures 38s.08 +/- 0".06, 23".8
+/- 0".05; UCAC-4 reference stars; image posted at website URL
http://spaceobs.org/images/TOCP/PSNJ09413802+4840255-20121212.png);
12.510, 18.4 (Joseph Brimacombe, Cairns, Australia; remotely uisng a 51-cm
RCOS telescope + luminance filter at the New Mexico Skies Observatory near
Mayhill; position end figures 38s.12, 24".9; image posted at website URL
http://www.flickr.com/photos/43846774@N02/8276547098/); 19.156, 18.1 (F.
Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8 reflector; position end
figures 38s.08, 25".2; reference stars from NOMAD catalogue; image posted at
URL http://www.astrogeo.va.it/pub/TOCP/PSN_M08-18-023.jpg); 22.86, 17.9
(Tianmeng Zhang and Xu Zhou, National Astronomical Observatories of China;
and Li Zhou, Juncheng Chen, and Xiaofeng Wang, Tsinghua University; 0.6-m
NAOC Schmidt telescope; reported as independent discovery; position end
figures 38s.05, 25".0; offset 4" east, 11" north); 23.90, 17.7 (Zhang et
al.).  Zhang et al. add that nothing was visible at the position of 2012hw
on their archival search images obtained in the course of THU-NAOC Transient
Survey on Dec. 3 (limiting mag about 19.5).

     M. Turatto, S. Benetti, L. Tomasella, E. Cappellaro, A. Pastorello, and
P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di
Astrofisica, report that a spectrogram of PSN J09413802+4840255 = 2012hw,
obtained on Dec. 19.12 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC;
range 350-820 nm; resolution 1.3 nm), suggests that this is a type-II
supernova.  Together with Balmer lines showing P-Cyg profiles, Fe II lines and
the Na I doublet feature are detected.  Adopting for the host galaxy (MCG
+08-18-23) the redshift z = 0.038054 (from SDSS 2004 Data Release 3, via NED),
the best fit is obtained with the type-IIP supernova 1999gi (Leonard et al.
2002, A.J. 124, 2490; Smartt et al. 2001, Ap.J. Lett. 556, 29) at maximum
light.  The Asiago classification spectra are posted at website URL
http://graspa.oapd.inaf.it; classification was made via GELATO (Harutyunyan
et al. 2008, A.Ap. 488, 383) and SNID (Blondin and Tonry 2007, Ap.J. 666,
1024).


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

                         (C) Copyright 2012 CBAT
2012 December 24                 (CBET 3353)              Daniel W. E. Green