Electronic Telegram No. 2760 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 SUPERNOVA 2011dy IN UGC 12628 = PSN J23292013+0323086 E. Briggs, J. Newton, and T. Puckett report the discovery of an apparent supernova (mag 16.8) on an unfiltered CCD image (limiting mag 18.9) taken with a 0.40-m reflector at Portal, AZ, U.S.A., on June 28.4428 UT in the course of the Puckett Observatory Supernova Search. The new object, which was confirmed at mag 16.5 on June 29.3910 by E. Guido and G. Sostero with the GRAS Observatory 0.25-m reflector near Mayhill, NM, U.S.A., is located at R.A. = 23h29m20s.13, Decl. = +3o23'08".6 (equinox 2000.0), which is 28".8 west and 15".8 south of the center of UGC 12628. Nothing is visible at this position on images taken by Puckett on June 3 (limiting mag 18.6). The variable was designated PSN J23292013+0323086 when posted on the Central Bureau's TOCP webpage and is here designated SN 2011dy based on the spectroscopic confirmation reported below. A finder image is posted at the following website URL: http://possdata.com/PSNJ23292013+0323086.jpg. Additional CCD magnitudes for PSN J23292013+0323086 = SN 2011dy: June 30.428 UT, 16.0 (S. Baroni, L. Buzzi, P. Concari, S. Foglia, G. Galli, and M. Tombelli; remotely using a 0.21-m refractor + Bessel V filter at the Tzec Maun Observatory near Mayhill, NM, U.S.A.; position end figures 20s.16, 08".5); 30.431, 16.2 (Joseph Brimacombe, Cairns, Australia; unfiltered image; position end figures 20s.19, 08".7). Brimacombe has posted his image at the following website URL: http://www.flickr.com/photos/43846774@N02/5889670968/. J. L. Prieto, Carnegie Observatories, reports that a spectrogram (range 380-920 nm; resolution 0.7 nm) of 2011dy was obtained on July 3 UT with WFCCD mounted on the du Pont 2.5-m telescope at Las Campanas Observatory. The SNID cross-correlation software (Blondin and Tonry 2007, Ap.J. 666, 1024) was used to aid identification and age/redshift estimation. The spectrum of 2011dy shows a very blue continuum and broad Balmer lines with P-Cyg profiles, characteristic of young type-II supernovae. SNID gives an age of 1-2 weeks after explosion. After correcting for the recession velocity of the host galaxy, UGC 12628 (4679 km/s; Theureau et al. 1998, A.Ap. Suppl. 130, 333), a blueshift of the H-alpha P-Cyg profile of 8000 km/s is measured. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 July 5 (CBET 2760) Daniel W. E. Green