Electronic Telegram No. 863 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2007af IN NGC 5584 S. Nakano, Sumoto, Japan, reports the discovery by K. Itagaki (Teppo-cho, Yamagata, Japan) of an apparent supernova (mag 15.4) on numerous unfiltered CCD 15-s frames taken around Mar. 1.84 UT using a 0.60-m f/5.7 reflector (limiting mag 19.0). The new object is located at R.A. = 14h22m21s.03, Decl. = -0o23'37".6 (equinox 2000.0), which is 40" west and 22" south of the center of NGC 5584. Nothing is visible on Itagaki's reference frames of this galaxy taken on Feb. 24.81 (limiting mag 19.0) and 25.73 ((limiting mag 18.5) or on the Digitized Sky Survey. A confirming image of 2007af at mag 15.3 was obtained by Itagaki on Mar. 2.576. The type-Ic supernova 1996aq also appeared in NGC 5584 (cf. IAUC 6454). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 March 2 (CBET 863) Daniel W. E. Green