[IAUC] CBET 3232: 20120917 : SUPERNOVA 2012ev = PSN J22030299-2231010

Dom Sep 16 20:40:57 ART 2012

                                                  Electronic Telegram No. 3232
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 2012ev = PSN J22030299-2231010
     G. Pignata, M. Cifuentes, and Y. Apostolovski, Universidad Andres Bello;
J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster, S. Silva,
F. Carrasco, P. Sanchez, C. Hervias, and R. Ramirez, Universidad de Chile; F.
Aros, Pontificia Universidad Catolica de Chile; B. Conuel, Wesleyan
University; G. Folatelli, IPMU, University of Tokyo; and D. Reichart, K.
Ivarsen, J. Haislip, A. Crain, D. Foster, M. Nysewander, and A. LaCluyze,
University of North Carolina at Chapel Hill, on behalf of the CHASE project
(which is part of the Millennium Center for Supernova Science collaboration),
report the discovery of an apparent supernova (mag approximately 17.8) on an
unfiltered image taken on Sept. 5.08 UT with the 0.41-m 'PROMPT 3' telescope
located at Cerro Tololo.  The new object is located at R.A. = 22h03m02s.99
+/- 0".2, Decl. = -22o31'01".0 +/- 0".2 (equinox 2000.0), which is about 4".9
west and 0".5 south of center of the presumed host galaxy.  The variable was
designated PSN J22030299-2231010 when it was posted at the Central Bureau's
TOCP webpage and is here designated SN 2012ev based on the spectroscopic
confirmation reported below.  Additional unfiltered CCD magnitudes for 2012ev:
2011 July 24-2012 Aug. 28, [20.5 (stack of twenty-two 40-s CHASE images); 2012
Aug. 28.10, [18.5 (CHASE); Sept. 6.05, 17.7 (CHASE); 8.945, 18.2 (Federica
Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8 reflector; position end
figures 03s.05, 00".6; reference stars from CMC-14 catalogue; image posted at
website URL http://www.astrogeo.va.it/pub/TOCP/PSN_J22030299-2231010.jpg).
Joseph Brimacombe, Cairns, Australia, reports that four 15-min CCD images
taken with a 41-cm RCOS telescope (+ STL6K camera + infrared filter) yields
position end figures 02s.97, 00".0 (photometry was too difficult due to the
background light of the presumed host galaxy); his image is posted at website
URL http://www.flickr.com/photos/43846774@N02/7974278686/.

     N. Morrell, Las Campanas Observatory; and G. Pignata, Universidad Andres
Bello, on behalf of the Millenium Center for Supernova Science and the
Carnegie Supernova Project collaboration, write that on Sept. 13.07 UT they
obtained an optical spectrogram (range 380-920 nm) of PSN J22030299-2231010 =
SN 2012ev with the du Pont telescope (+ WFCCD) at Las Campanas Observatory,
which reveals this is a type-Ia supernova approximately one week after
maximum brightness.  Cross-correlation with a library of supernova spectra
using the Supernova Identification tool (SNID; Blondin and Tonry 2007, Ap.J.
666, 1024) suggests that 2012ev is a normal type-Ia supernova, very similar
to SN 1998co at seven days after maximum light.  Adopting for the host galaxy
(2MASX J22030334-2231004) a recession velocity of 21952 km/s (Jones et al.
2009, The 6dF Galaxy Survey Data Release 3; via NED), the minimum of the Si
II 635.5-nm absorption appears to be blueshifted by 10450 km/s.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
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                         (C) Copyright 2012 CBAT
2012 September 17                (CBET 3232)              Daniel W. E. Green