Electronic Telegram No. 2727 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 2011dd IN NGC 3178 = PSN J10160965-1547351 J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster, S. Silva, F. Carrasco, P. Sanchez, C. Hervias, D. Iturra, and R. Ramirez, Universidad de Chile;G. Pignata, M. Cifuentes, Universidad Andres Bello; C. Farias, 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 15.8) on an unfiltered image taken on May 15.98 UT with the 0.41-m 'PROMPT 3' telescope located at Cerro Tololo. The new object, was was designated PSN J10160965-1547351 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011dd based on the spectroscopic report below, is located at R.A. = 10h16m09s.65 +/- 0".2, Decl. = -15o47'35".1 +/- 0".2 (equinox 2000.0), which is about 6".9 east and 6".6 south of center of the galaxy NGC 3178. Additional magnitudes for 2011dd: Apr. 30.01, [18.0 (CHASE); May 7.99, [18.0 (CHASE); 17.96, 14.7 (CHASE); 21.186, 16.0 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 09s.64, 36".0). Brimacombe's image is posted at the following website URL: http://www.flickr.com/photos/43846774@N02/5742847522/. J. Anderson and C. Gutierrez, Universidad de Chile; and G. Pignata, Universidad Andres Bello, on behalf of the Millennium Center for Supernova Science, report on optical spectroscopy (range 3500-8800 nm) of PSN J10160965-1547351 = 2011dd, obtained on May 26.9 UT with the SOAR telescope (+ Goodman). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) gives good matches to type-IIP supernovae about two weeks after explosion. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 May 29 (CBET 2727) Daniel W. E. Green