Electronic Telegram No. 3519 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 2013ci = PSN J17045368+0907596 Denis Vida communicates that Miguel Hurtado, on behalf of the "La Sagra Sky Survey (LSSS) Supernova Search Team" (which also includes Filip Novoselnik, Ivica Skokic, David Gostinski, Salvador Sanchez, Jaime Nomen, Reiner Stoss, Bill Yeung, and Juan Rodriguez), reports the discovery of an apparent supernova (magnitude 17.1) on three unfiltered CCD images (limiting mag about 20.0) taken on May 4.07, 4.076, and 4.083 UT with a 0.45-m telescope. The new object is located at R.A. = 17h04m53s.68, Decl = +09d07'59".6 (equinox 2000.0), which is 6" east and 10" north of the nucleus of the presumed host galaxy. Nothing is visible at this position on a red Digitized Sky Survey plate from 1987 June 22.266 to limiting mag 22. The LSSS image from May 4 has been posted (with the red DSS image on the right) at the following website URL: http://i.imgur.com/39kqG7c.png. The variable was designated PSN J17045368+0907596 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2013ci based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2013ci: 2013 Apr. 6.010, [18.7 (D. Denisenko, E. Gorbovskoy, and V. Lipunov, Sternberg Astronomical Institute; 0.40-m f/2.5 MASTER-Kislovodsk robotic telescope); 15.022, 16.1 (Denisenko et al.; pre-discovery; limiting mag 19.3; position end figures 53s.51, 59".3; MASTER-Kislovodsk); May 1.707, 16.7 (Denisenko et al.; pre-discovery; limiting mag 18.1; position end figures 53s.64, 58".6; MASTER-Amur); 5.346, 17.1 (J. Brimacombe, Cairns, Australia; remotely with a 51-cm RCOS telescope + luminance filter located at the New Mexico Skies observatory near Mayhill, NM, U.S.A.; position end figures 53s.58, 59".9; image posted at website URL http://www.flickr.com/photos/43846774@N02/8713622476/). The MASTER pre-discovery and reference images are available at the following website URL: URL http://master.sai.msu.ru/static/OT/PSNJ17045368+0907596-MASTER.jpg. L. Tomasella, A. Pastorello, P. Ochner, S. Benetti, E. Cappellaro, and M. Turatto, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report that optical spectroscopy (range 340-820 nm; resolution 1.3 nm), obtained on May 5.06 UT with the Asiago 1.82-m Copernico Telescope (+ AFOSC), shows that PSN J17045368+0907596 = SN 2013ci is a type-Ia supernova at a redshift of about 0.036. A good match is found with several normal type-Ia supernovae two weeks after maximum light. The expansion velocity, as deduced from the position of the minimum of the Si II 635.5-nm absorption, is about 11200 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). D. D. Balam, Dominion Astrophysical Observatory, National Research Council of Canada; M. L. Graham, Las Cumbres Observatory Global Telescope, University of California at Santa Barbara; and E. Y. Hsiao, Las Campanas Observatory, report that a spectrogram (range 368-700 nm, resolution 0.3 nm) of PSN J17045368+0907596 = SN 2013ci, obtained on May 8.35 UT with the 1.82-m Plaskett Telescope of the National Research Council of Canada, shows it to be a type-Ia supernova several weeks past maximum light. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2013ci is similar to the type-Ia supernova 1998bu at 21 days post-maximum. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2013 CBAT 2013 May 12 (CBET 3519) Daniel W. E. Green