Electronic Telegram No. 1724 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 2009av [This text replaces that on CBET 1720] S. Kulkarni and R. Quimby, California Institute of Technology, on behalf of a large collaboration called the "Palomar Transient Factory" (PTF; including also N. Law, M. Kasliwal, E. Ofek, P. Nugent, I. Arcavi, L. Bildsten, J. Bloom, J. Brewer, T. Brown, S. B. Cenko, D. Ciardi, E. Croner, R. Dekany, G. Djorgovski, A. V. Filippenko, D. Fox, A. Gal-Yam, C. Grillmair, D. Hale, N. Hamam, D. Helfand, G. Helou, I. Hook, A. Howell, J. Jacobsen, M. Kiewe, R. Laher, A. Mahabal, S. Mattingly, J. Patterson, H. Perets, S. Perlmutter, A. Pickles, D. Poznanski, A. Rau, G. Rahmer, W. Reach, W. Rosing, M. Shara, R. Smith, D. Starr, M. Sullivan, J. Surace, R. Thomas, and V. Velur), reports the discovery of a normal type-Ia supernova (mag 18.62 +/- 0.04) in g-band images taken with the 1.2-m Oschin Schmidt telescope (+ CFH12K camera) at Palomar on Mar. 2.347 UT; the discovery image was subtracted from a reference template made from PTF images acquired on Feb. 25, 26, and 28 (which may contain some light from the rising transient). The new object is located at R.A. = 14h23m55s.82, Decl. = +35o11'05".2 (equinox 2000.0; uncertainty < 1"), which is 0".9 west and 2".7 south of the core of a galaxy (listed in the Sloan Digital Sky Survey with magnitude g = 17.78 and redshift z = 0.0555). Spectra (range 330-870 nm) of 2009av, obtained on Mar. 8.388 with the 5-m Palomar Hale telescope (+ Double Beam Spectrograph), reveal a redshift that is consistent with the apparent SDSS host galaxy; the expansion velocity derived from the minimum of the Si II (rest 635.5 nm) line is about 10700 km/s. The best match of the spectra of 2009av, found with the "Superfit" supernova spectral-identification code (Howell et al. 2005, Ap.J. 634, 1190), is to that of SN 1994D around one week prior to maximum light. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 March 16 (CBET 1724) Daniel W. E. Green