Electronic Telegram No. 2859 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 2011gs = PSN J04210999+1328044 A. J. Drake, S. G. Djorgovski, A. Mahabal, M. J. Graham, and R. Williams, California Institute of Technology; J. L. Prieto, Princeton University; M. Catelan, Pontificia Universidad Catolica de Chile; E. C. Beshore and S. M. Larson, Lunar and Planetary Laboratory, University of Arizona; and E. Christensen, Gemini Observatory, report the discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011gs Sep. 23.46 4 21 09.99 +13 28 04.4 17.4 10".1 E, 3".7 S This variable was designated PSN J04210999+1328044 when it was posted on the Central Bureau's TOCP webpage and is here designated SN 2011gs based on the spectroscopic report below. Further CCD magnitudes for 2011gs: Mar. 29.15 UT, [19.4 (CSS); Sept. 29.39, 17.6 (CSS); Oct. 2.131, R = 18.9 (Federica Luppi, Varese, Italy; 0.36-m f/7.9 reflector + Bessell R filter; position end figures 10s.03, 04".5; CMC-14 catalogue reference stars; image posted at website URL http://www.astrogeo.va.it/pub/TOCP/PSN_J04210999+1328044.jpg). F. Bufano, Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Catania; and S. Valenti and A. Pastorello, INAF, Osservatorio Astronomico di Padova, on behalf of a larger collaboration, report that a spectrum of PSN J04210999+1328044 = SN 2011gs, obtained on Oct. 1.95 UT with the Ekar-Copernico 1.82-m telescope (+ AFOSC), shows it to be 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) suggests a normal type-Ia supernova about 30 after its B-band maximum (the deduced redshift is 0.027). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 October 4 (CBET 2859) Daniel W. E. Green