Electronic Telegram No. 3041 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 2012ar = PSN J16203602-1027383 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 2012 UT R.A. (2000.0) Decl. Mag. Offset 2012ar Mar. 1.49 16 20 36.02 -10 27 38.3 16.6 7".1 W, 27".8 N The variable was designated PSN J16203602-1027383 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2012ar based on the spectroscopic confirmation reported below. Additional CCD magnitudes for 2012ar (unfiltered unless noted otherwise): Jan. 25.56, [19.4 (CSS); Mar. 3.191, 16.9 (Federica Luppi and Luca Buzzi, Varese, Italy; 0.38-m f/6.8 reflector; position end figures 36s.05, 38".1; reference stars from CMC-14 catalogue); 3.523, 16.9 (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 36s.02, 38".1; image posted at URL http://www.flickr.com/photos/43846774@N02/6805881064/). The image from Luppi and Buzzi is posted at the following website URL: http://www.astrogeo.va.it/pub/TOCP/PSN_J16203602-1027383.jpg. E. Y. Hsiao, M. M. Phillips, and N. Morrell, Las Campanas Observatory; G. H. Marion, Harvard-Smithsonian Center for Astrophysics; and M. Stritzinger, Aarhus University, report that a near-infrared spectrum (range 800-2400 nm) of PSN J16203602-1027383 = 2012ar was obtained on Mar. 3.39 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan Baade Telescope. The spectrum shows that 2012ar is a type-Ia supernova a few days before maximum light. The near-infrared spectrum is similar to that of SN 2002cr at five days before maximum (Marion et al. 2009, A.J. 138, 727). The velocity of the Mg II 1092.7-nm absorption feature is measured to be approximately 11800 km/s, using an estimated redshift of z = 0.028 for the presumed host galaxy (2MASX J16203650-1028061). NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 March 5 (CBET 3041) Daniel W. E. Green