Electronic Telegram No. 2091 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2009mu IN ESO 374-3 G. Pignata, Universidad Andres Bello; J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, P. Lopez, S. Silva, G. Folatelli, R. Cartier, F. Forster, S. Marchi, and A. Rojas, Universidad de Chile; B. Conuel, Wesleyan University; 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, report the discovery of an apparent supernova (mag approximately 18.2 +/- 0.4) on an unfiltered image taken on Dec. 21.3 UT with the 0.41-m 'PROMPT 5' telescope located at Cerro Tololo. The new object, which is also present in an image taken on Dec. 23.28 at mag approximately 18.3, is located at R.A. = 9h51m57s.75 +/- 0".1, Decl. = -33o04'42".4 +/- 0".1 (equinox 2000.0), which is about 4".0 east and 17".6 south of the center of the galaxy ESO 374-3. Nothing is visible at this position in a stack of fifteen 40-s archival images taken with the same instrument between 2008 Oct. 13.35 and 2009 May 7.15 (limiting mag 20.0). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 December 24 (CBET 2091) Daniel W. E. Green