Electronic Telegram No. 2651 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 2011U AND 2011W Further to CBET 2634, S. B. Cenko, W. Li, and A. V. Filippenko report the LOSS discovery of an apparent supernova on unfiltered KAIT images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011W Jan. 16.12 0 32 51.24 +11 44 07.5 18.6 12".0 E, 4".8 S Additional KAIT magnitudes for 2011W in UGC 323: a co-added image from 2010 Sept.-Dec, [19.8; 2011 Jan. 18.11 UT, 18.5. This object was designated PSN J00325124+1144075 on the Central Bureau's TOCP webpage. J. M. Silverman, M. T. Kandrashoff, J. Rex, and A. V. Filippenko, University of California, Berkeley, report that inspection of a low-signal-to- noise-ratio CCD spectrum (range 350-1000 nm), obtained on Feb. 2 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that PSN J00325124+1144075 = SN 2011W is likely a type-II supernova. The spectrum is heavily contaminated by host-galaxy light, but broad H-alpha emission and the Ca II near-infrared triplet (the latter having a clear P-Cyg profile) are detected. Silverman et al. add that SN 2011U (cf. CBET 2649) is a relatively reddened type-Ia supernova. After removal of the host-galaxy recession velocity of 3970 km/s (measured from narrow host-galaxy emission lines), they find the absorption minimum of the Si II 635.5-nm line to be blueshifted by about 11700 km/s. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2011U is a normal type-Ia supernova near maximum brightness. Na I D absorption at the redshift of the host galaxy is detected with an equivalent width of approximately 0.2 nm. S. Valenti and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a larger collaboration, report that a spectrogram (range 380-820 nm, resolution 1.1 nm) of SN 2011U (cf. CBET 2649), obtained on Feb. 4.82 UT with the Ekar-Copernicus 1.82-m telescope (+ AFOSC), shows the new object to be a type-Ia supernova at maximum. Comparison of the observed spectrum with a library of supernova spectra via the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383; available at website URL https://gelato.tng.iac.es/login.cgi) shows 2011U to be similar to SN 1990N at two days after maximum. The expansion velocity, obtained from the Si II 635.5-nm feature, is about 10500 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 February 5 (CBET 2651) Daniel W. E. Green