Electronic Telegram No. 3146 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@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVA 2012cu IN NGC 4772 = PSN J12532935+0209390 Koichi Itagaki, Yamagata, Japan, reports his discovery of an apparent supernova (mag 16.3) on an unfiltered CCD image (limiting magnitude 19.5) taken on June 14.559 UT, apparently with a 0.60-m f/5.7 reflector. The new object is located at R.A. = 12h53m29s.35, Decl. = +2d09'39".0 (equinox 2000.0; UCAC3 reference stars), which is 3".1 east and 27".1 south of the nucleus of NGC 4772. Nothing was visible at this position on Itagaki's reference image from 2007 Feb. 25.648 (limiting mag 19.5). His discovery image is posted at website URL http://www.k-itagaki.jp/4772.jpg. The variable was designated PSN J12532935+0209390 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012cu based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2012cu: June 14.21, V = 16.4 (S. Howerton, Arkansas City, KS, U.S.A.; independent discovery; position end figures 29s.26, 36".4); 14.582, 16.2 (T. Noguchi, Chiba-ken, Japan; 0.23-m f/6.3 Schmidt-Cassegrain reflector + BITRAN BT-11E camera; limiting mag 17.5; position end figures 29s.36, 39".0; UCAC3 reference stars; communicated by S. Nakano, Sumoto, Japan); 15.177, 15.8 (L. Elenin, Lyubertsy, Russia; and I. Molotov, Moscow; taken remotely at the ISON-NM Observatory near Mayhill, NM, USA, with a 0.45-m f/2.8 telescope; position end figures 29s.36 +/- 0".13, 39".2 +/- 0".16; NOMAD reference stars; limiting mag about 20.3; image posted at http://spaceobs.org/images/TOCP/PSNJ12532935+0209390-20120615.png); 15.248, 16.5 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + luminance filter + STL11K camera at New Mexico Skies Observatory near Mayhill, NM; position end figures 29s.37, 39".4; image posted at website URL http://www.flickr.com/photos/43846774@N02/7377711798/). G. H. Marion and D. Milisavljevic, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrogram (range 340-740 nm) of PSN J12532935+0209390 = 2012cu was obtained on June 15 UT by K. Rines and S. Wilhelmy with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2012cu is a type-Ia supernova approaching maximum brightness. A good fit is found to the template of the 1999aa-like type-Ia supernova 2008ds at maximum. Reasonable fits are also found to templates from several normal type-Ia supernovae between 3 and 7 days before maximum. The spectrum is very red, which is attributed to extinction. Na I D is strong, with an equivalent width of 1.73 nm, and C II 658.0-nm is also strong. The velocity of Si II 635.5-nm is measured at the absorption minimum to be approximately 11900 km/s. An estimated redshift of z = 0.003469 for NGC 4771 was taken via NED (from de Vaucouleurs et al. 1991, RC3.9C). T.-M. Zhang and M.-Y. Lin, National Astronomical Observatories of China (NAOC); and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua University, report on an optical spectrogram (range 400-700 nm) of PSN J12532935+0209390 = 2012cu that was obtained on June 15.6 UT with the 2.16-m telescope (+ BFOSC) at the Xinglong Station of NAOC. The spectrum is consistent with a highly- reddened type-Ia supernova, at an age of about one week before maximum light. Adopting a recession velocity 1040 km/s (Tully et al. 2008, Ap.J. 676, 184) for the host galaxy (NGC 4772), the velocity of the Si II 635.5-nm absorption feature is measured to be about 11600 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 June 19 (CBET 3146) Daniel W. E. Green