Electronic Telegram No. 520 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 SUPERNOVAE 2006bw AND 2006cl The 'Nearby Supernova Factory' group (P. Antilogus, S. Gilles, R. Pain, and R. Pereira, Laboratoire de Physique Nucleaire et de Haute Energies de Paris; G. Aldering, S. Bailey, S. Bongard, D. Kocevski, S. Loken, P. Nugent, S. Perlmutter, R. Scalzo, R. C. Thomas, L. Wang, and B. A. Weaver, Lawrence Berkeley National Laboratory, Berkeley; N. Blanc, Y. Copin, E. Gangler, and G. Smadja, Institut de Physique Nucleaire de Lyon; E. Pecontal and G. Rigaudier, Centre de Recherche Astronomique de Lyon; R. Kessler, Kavli Institute for Cosmological Physics, Chicago; and C. Baltay, D. Rabinowitz, and A. Bauer, Yale University) reports the discovery of a supernova (approximate calibrated R mag 19.2) in NEAT images (cf. CBET 263) obtained on May 20.4 UT with the Palomar 1.2-m Schmidt telescope: SN 2006cl is located at R.A. = 16h19m48s.80, Decl. = -10d03'25".2 (equinox 2000.0). Spectroscopy (range 320-1000 nm), obtained on May 24.5 with the Supernova Integral Field Spectrograph (SNIFS) on the University of Hawaii 2.2-m telescope, shows 2006cl to be a type-II supernova. H-alpha in net emission, with a maximum expansion velocity of 4000 km/s, is detected, along with H-beta and the Ca II infrared triplet. A redshift derived from the peak of the H-alpha feature indicates z = 0.025. A SNIFS spectrum of 2006bw (cf. CBET 497, 499; IAUC 8705) obtained on May 24.5 confirms that it is a type-Ia supernova about 3 weeks after maximum light; comparison to a library of supernova spectra suggests an approximate redshift of z = 0.03. SN 2006bw had an approximate calibrated R magnitude of 18.0 on May 20.3, from a NEAT image; its position was measured as R.A. = 14h33m56s.76, Decl. = +3d47'55".6. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2006 CBAT 2006 May 25 (CBET 520) Daniel W. E. Green