Electronic Telegram No. 2970 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 2011jt IN PGC 53208 = PSN J14532301+0257431 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; 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 2011jt Dec. 31.54 14 53 23.01 + 2 57 43.1 17.0 5".8 W, 16".4 S The variable was designated PSN J14532301+0257431 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011jt based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2011jt: 2011 June 23.25 UT, [20.3 (CSS); 2012 Jan. 1.526, 16.5 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + STL11K camera + luminance filter at the New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 23s.02, 42".9; image posted at website URL http://www.flickr.com/photos/43846774@N02/6618245617/). J. M. Silverman and A. V. Filippenko, University of California, Berkeley, report that inspection of a CCD spectrum (range 340-1000 nm), obtained on Jan. 3 UT with the Shane 3-m reflector (+ Kast spectrograph) at Lick Observatory, shows that PSN J14532301+0257431 = SN 2011jt is a type-Ia supernova. After removal of the host-galaxy recession velocity of 8334 km/s (from the Sloan Digital Sky Survey Data Release 1), they find the absorption minimum of the Si II 635.5-nm line to be blueshifted by about 14700 km/s. Cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that the object is a normal type-Ia supernova about six days before maximum brightness. J.-C. Chen and X.-F. Wang, Tsinghua Center for Astrophysics, Tsinghua University; X. Zhan, Beijing Planetarium; T.-M. Zhang, National Astronomical Observatory of China (NAOC), report on an optical spectrogram (range 400-8800 nm) of PSN J14532301+0257431 = SN 2011jt that was obtained on 2012 Jan. 3.9 UT with the 2.16-m telescope (+ OMR) at Xinglong Station of NAOC. The spectrum is consistent with a type-Ia supernova at about one week before maximum. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that it matches with SN 2002bo at -9 days. Adopting a recession velocity of 8334 km/s for the host galaxy from the NED, they measure a velocity of the Si II 635.5-nm absorption feature to be about 15000 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 January 7 (CBET 2970) Daniel W. E. Green