Electronic Telegram No. 3377 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 2013D Vladimir Lipunov, Sternberg Astronomical Institute, reports the discovery by Pavel Balanutsa via the MASTER-Kislovodsk auto-detection system of a possible supernova (mag 17.5) on on four unfiltered images (limiting mag 19.8) taken on Jan. 3.82 UT. The new object is located at R.A. = 3h41m15s.13, Decl. = +15d23'03".9 (equinox 2000.0). Nothing is visible at this position on a MASTER image taken on 2010 Dec. 3.8 (limiting mag 20.5). The discovery and reference MASTER images have been posted at the following website URL: http://observ.pereplet.ru/images/034115.13152303.9.png. G. H. Marion and P. Challis, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrogram (range 340-740 nm) of 2013D was obtained on Jan. 6 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 2013D is a type-Ia supernova a few days after maximum light. A good fit is found to the template of the subluminous, 1991bg-like type-Ia supernova 1997cn at four days after maximum. The velocities of the Si II 635.5- and 597.2-nm absorption features are measured to be 9300 and 8900 km/s, respectively, using a redshift of z = 0.027119 for PGC 1483058 (2MASX J03411352+1522440; Smith et al. 2004, A.J. 128, 1558; via NED). The R(Si II) line-depth ratio (Nugent et al. 1995, Ap.J. Let. 455, 147) is about 0.63, which is consistent with 1991bg-like type-Ia events. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 January 8 (CBET 3377) Daniel W. E. Green