Electronic Telegram No. 3490 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 2013bo A. J. Drake, S. G. Djorgovski, M. J. Graham, A. Mahabal, and R. Williams, California Institute of Technology; J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad Catolica de Chile; S. M. Larson and E. Christensen, Lunar and Planetary Laboratory, University of Arizona; and R. H. McNaught, Australian National University, report the Catalina Real-time Transient Survey discovery of an apparent supernova in unfiltered CCD images: SN 2013 UT R.A. (2000.0) Decl. Mag. 2013bo Apr. 15.36 13 17 29.19 +42 44 29.6 17.6 L. Tomasella, S. Benetti, A. Pastorello, E. Cappellaro, M. Turatto, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report that optical spectroscopy (range 340-820 nm; resolution 1.3 nm), obtained on Apr. 18.13 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC), shows that 2013bo is a type-Ia supernova at redshift z around 0.036. The best match was found with various type-Ia supernovae about one week after maximum light. The expansion velocity, as deduced from the position of the Si II 635.5-nm absorption, is about 10100 km/s. The Asiago classification spectra are posted at website URL http://graspa.oapd.inaf.it; classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 April 24 (CBET 3490) Daniel W. E. Green