Electronic Telegram No. 2693 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 2011bk = PSN J16203475+2112082 Miguel Hurtado and Denis Vida, on behalf of the "La Sagra Sky Survey" (LSSS) Supernova Search Team (which also includes Filip Novoselnik, Ivica Skokic, David Gostinski, Robert Gregic, Salvador Sanchez, Jaime Nomen, Reiner Stoss, Bill Yeung, and Juan Rodriguez), report the discovery of an apparent supernova (red magnitude 15.8) on three CCD images (limiting mag about 20.0) taken on 2011 Mar. 7.088, 7.099, and 7.109 UT with a 0.45-m telescope. The new object is located at R.A. = 16h20m34s.75, Decl. = +21d12'08".2 (equinox 2000.0), which is 7".6 east and 0".7 south of the nucleus of the presumed host galaxy (PGC 3089915). The variable was designated PSN J16203475+2112082 when posted on the Central Bureau's TOCP webpage and is here designated SN 2011bk based on the spectroscopic report below. Additional approximate magnitudes for 2011bk, from unfiltered CCD images unless otherwise noted): 1991 June 7.288, [22 (Digitized Sky Survey, red plate; via the LSSS group); 2010 May 21.962, [20 (LSSS); 2011 Apr. 1.420, 18.9 (Joseph Brimacombe, Cairns, Australia, remotely using a 51-cm RCOS telescope + STL11K camera at New Mexico Skies Observatory, Mayhill, NM, U.S.A.; position end figures 34s.79, 09".2). The LSSS images have been posted (with the red Digitized Sky Survey image on the right) at website URL http://img814.imageshack.us/img814/6943/pgc3089915.png. Brimacombe has posted his image at http://www.flickr.com/photos/43846774@N02/5580864140/. G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, reports that a spectrum (range 340-740 nm) of PSN J16203475+2112082 = 2011bk was obtained on Apr. 3 UT by Marion with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011bk is a type-Ia supernova about one month past maximum light. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 April 12 (CBET 2693) Daniel W. E. Green