Electronic Telegram No. 1747 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 SUPERNOVAE 2009bp, 2009bs, AND 2009bt J. M. Silverman, S. B. Cenko, X. Wang, and A. V. Filippenko, University of California, Berkeley, report that inspection of a CCD spectrum (range 340-1020 nm), obtained on Mar. 29 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2009bp (CBET 1733) is a type-Ia supernova, possibly the SN-1999aa subtype (Li et al. 2001, Ap.J., 546, 734; Garavini et al. 2004, A.J., 128, 387). Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2009bp is about 17 days past maximum light. SN 2009bs (CBET 1736) is a SN-1991bg-like (e.g., Filippenko et al. 1992, A.J., 104, 1543) type-Ia supernova; after removing the host-galaxy recession velocity (8922 km/s; Falco et al. 1999, The Updated Zwicky Catalog), the absorption minimum of the Si II 635.5-nm feature is found to be blue- shifted by about 10500 km/s. Cross-correlation with SNID indicates that 2009bs is about two days past maximum light. SN 2009bt (CBET 1737) is a type-Ia supernova; cross-correlation with SNID indicates that it is 2-3 weeks past maximum light. Red CCD magnitudes for 2009bt: Mar. 27.832 UT, 17.2 (J. Nicolas, Vallauris, France, 0.28-m f/6.5 reflector; R.A. = 3h08m57s.11, Decl. = +70o33'34".1, equinox 2000.0); 27.856, 17.1 (C. Rinner and F. Kugel, Banon, France, 0.5-m f/3 reflector; position end figures 57s.14, 35".1). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 March 30 (CBET 1747) Daniel W. E. Green