Electronic Telegram No. 2461 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION CBAT Director: Daniel W. E. Green; Hoffman Lab 209; Harvard University; 20 Oxford St.; Cambridge, MA 02138; U.S.A. e-mail: cbatiau@eps.harvard.edu (alternate cbat@iau.org) URL http://www.cbat.eps.harvard.edu/index.html Prepared using the Tamkin Foundation Computer Network SUPERNOVAE 2010hs, 2010hw, AND 2010hy Further to CBET 2458, J. Kodros, S. B. Cenko, W. Li, and A. V. Filippenko, University of California, report the LOSS discovery of an apparent supernova on unfiltered KAIT images: SN 2010 UT R.A. (2000.0) Decl. Mag. 2010hy Sept. 4.19 18 59 32.89 +19 24 25.9 19.1 Additional KAIT magnitudes for 2010hy: a co-added frame from May-July, [20.5; Sept. 5.22 UT, 19.1. SN 2010hy is located 50" west and 73" south of UGC 11385, but the spectrum (see below) appears to indicate that it is located in a background galaxy at significantly higher redshift. S. B. Cenko, M. T. Kandrashoff, J. M. Silverman, and A. V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 340-1000 nm), obtained on Sept. 16 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010hy is a supernova, perhaps of type Ic near maximum brightness, but the possibility that 2010hy is actually a type-Ia supernova cannot be ruled out. The observed brightness, together with the derived redshift of about 0.2 (from the supernova features), implies an absolute visual magnitude of roughly -21, which is highly overluminous for type-Ia and type-Ic supernovae. Higher quality spectra, as well as continued photometry, should be obtained. Inspection of similar CCD spectra shows that 2010hs (CBET 2454) is a type-Ia supernova; cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010hs is near maximum brightness. A noisy spectrum of 2010hw (CBET 2458) shows that it is a type-II supernova. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2010 CBAT 2010 September 19 (CBET 2461) Daniel W. E. Green