2011CBET.2683....1P

G. Pignata and M. Cifuentes, Universidad Andres Bello; J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, R. Cartier, F. Forster, S. Silva, F. Carrasco, P. Sanchez, and C. Hervias, Universidad 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 16.6) on an unfiltered image taken on Mar. 14.08 UT with the 0.41-m 'PROMPT 1' telescope located at Cerro Tololo. The new object, which is also present at mag approximately 17.0 in an image taken on Mar. 8.18, is located at R.A. = 11:35:27.09 ± 0".3, Decl. = -38:00:54.9 ± 0".3 (equinox 2000.0), which is about 2".6 east and 0".7 north of center of the presumed host galaxy. Nothing is visible at this position on archival images taken on Feb. 28.15 (limiting mag 17.5) and Feb. 20.15 (limiting mag 18.0). The variable was designated PSN J11352709-3800549 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011bb based on the spectroscopic report below.