Electronic Telegram No. 2939 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 2011iu IN UGC 12809 = PSN J23510228+4643217 L. Cox, J. Newton, and T. Puckett report the discovery of an apparent supernova (mag 17.2) on an unfiltered CCD image (limiting mag 19.5) taken with a 0.40-m reflector at Portal, AZ, U.S.A., on Nov. 25.166 UT in the course of the Puckett Observatory Supernova Search. The new object is located at R.A. = 23h51m02s.28, Decl. = +46o43'21".7 (equinox 2000.0), which is 9".4 west and 4".1 south of the center of UGC 12809; an image is posted by the discoverers at website URL http://www.possdata.com/PSNJ23510228+4643217.jpg. The variable was designated PSN J23510228+4643217 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011iu based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2011iu (unfiltered unless noted otherwise): Oct. 25, [19.4 (Puckett); Nov. 28.168, 17.2 (Puckett; 40-cm reflector at Portal); 29.049, 17.1 (R. A. R. A. Koff, Bennett, CO, USA; Meade 0.25-m f/10 reflector + Apogee AP-47p camera; limiting magnitude 19.0; position end figures 02s.27, 21".3; UCAC3 reference stars); 29.083, 17.1 (J. Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 02s.37, 21".8; image posted at URL http://www.flickr.com/photos/43846774@N02/6428776279/). G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrum (range 340-740 nm) of PSN J23510228+4643217 = 2011iu was obtained on Dec. 1 UT by P. Berlind 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 2011iu is a type-Ia supernova soon after maximum light. A good fit is found to the template of SN 2006cf at 3 days post-maximum. The velocity of the Si II 635.5-nm absorption feature is measured to be approximately 10000 km/s, using an estimated redshift of z = 0.0460 that was measured from host-galaxy emission lines. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 December 6 (CBET 2939) Daniel W. E. Green