Electronic Telegram No. 3059 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 2012bb IN PGC 39723 = PSN J12195197-3627261 G. Pignata, M. Cifuentes, Y. Apostolovski, and M. Vidal, Universidad Andres Bello; J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, and 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 15.9) on an unfiltered image taken on Feb. 2.19 UT with the 0.41-m 'PROMPT 5' telescope located at Cerro Tololo. The new object is located at R.A. = 12h19m51s.97 +/- 0".2, Decl. = -36o27'26".1 +/- 0".2 (equinox 2000.0), which is about 11".4 east and 8".0 north of the center of the galaxy PGC 39723 (= ESO 380-14). The variable was designated PSN J12195197-3627261 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012bb based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2012bb: 2011 May 16.15, [18.5 (CHASE); 2012 Feb. 3.14, 15.6 (CHASE); 10.802, 15.7: (J. Brimacombe, Cairns, Australia; 41-cm RCOS telescope + STL6K camera + infrared filter, bandpass > 700 nm; poor seeing/transparency; position end figures 52s.02, 27".0; marginal, uncertain detection); 11.545, 15.8 (Brimacombe; position end figures 52s.01, 26".6; image posted at URL http://www.flickr.com/photos/43846774@N02/6860587117/). Brimacombe notes that there is an area of brightening at the approximate position of 2012bb in a Digitized Sky Survey image. N. Morrell, Las Campanas Observatory; J. Anderson, Universidad de Chile; G. Pignata, Universidad Andres Bello; and G. Folatelli, Kavli IPMU, University of Tokyo, on behalf of the Millenium Center for Supernova Science and Carnegie Supernova Project collaboration, report on optical spectroscopy (range 370-940 nm) obtained on Mar. 2 UT with the 6.5-m Magellan II Clay telescope (+ LDSS3). The data were cross-correlated with a library of supernova spectra using the Supernova Identification Code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024). PSN J12195197-3627261 = SN 2012bb is a type-IIP supernova at about 2-3 weeks after maximum light. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 March 21 (CBET 3059) Daniel W. E. Green