Electronic Telegram No. 3563 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 2013dj V. Lipunov, Sternberg Astronomical Institute (SAI), reports the discovery by N. Tyurina of an apparent supernova (mag 16.6) in unfiltered CCD images (limiting mag 18.8) taken with the MASTER-Tunka auto-detection system (double 0.40-m f/2.5 reflector) on June 10.672 and 10.701 UT. The new object is located at R.A. = 16h46m01s.94, Decl. = +6d27'59".3 (equinox 2000.0), which is 6" east and 14" north of the center of the galaxy UGC 10535. D. Denisenko and E. Gorbovskoy (SAI) note that nothing was visible at this position on unfiltered MASTER-Tunka archival images from 2011 May 14.736 (limiting mag 18.6). The discovery and reference images are posted at the following website URL: http://master.sai.msu.ru/static/OT/164601.94062759.3.png. S. B. Cenko, Goddard Space Flight Center, NASA; B. E. Tucker, Australian National University, and I. Shivvers, K. I. Clubb, and A. V. Filippenko, University of California, Berkeley, report that inspection of a CCD spectrum (range 350-1000 nm), obtained on June 14.4 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that 2013dj 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 a similarity with pre-maximum-light spectra of SN 1991T (Filippenko et al. 1992, Ap.J. 384, L15), with a blue continuum and relatively weak Si II 635.5-nm absorption. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 June 16 (CBET 3563) Daniel W. E. Green