Electronic Telegram No. 1704 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 2009aj IN ESO 221-18 G. Pignata, J. Maza, M. Hamuy, R. Antezana, L. Gonzalez, P. Gonzalez, P. Lopez, S. Silva, G. Folatelli, D. Iturra, R. Cartier, F. Forster, and S. Marchi, Universidad de Chile; B. Conuel, Wesleyan University; and D. Reichart, K. Ivarsen, 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 14.5) on unfiltered images taken on Feb. 24.26 and 26.22 UT with the 0.41-m 'PROMPT 4' telescope located at Cerro Tololo. The new object is located at R.A. = 13h56m45s.33 +/- 0".1, Decl. = -48o29'36".2 +/- 0".1 (equinox 2000), which is about 3".6 east and 13".8 north of the center of the galaxy ESO 221-18. Nothing is visible at this position on archival images taken on Jan. 17.25 and Feb. 11.20 (limiting mag 18.5). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 February 26 (CBET 1704) Daniel W. E. Green