Supernova 2011dc = Psn 14585651+6554083

Report the Catalina Real-time Transient Survey's discovery of an apparent supernova in unfiltered Catalina Sky Survey images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011dc May 14.32 14 58 56.51 +65 54 08.3 17.0 9".5 W, 2".0 S This variable was designated PSN 14585651+6554083 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011dc based on the spectroscopic report below. Further magnitudes for 2011dc: Apr. 2.37 UT, [19.0 (Catalina Sky Survey); May 15.237, 17.1 (Joseph Brimacombe, Cairns, Australia; from four stacked 1200-s images taken remotely using a 51-cm RCOS telescope + red filter + STL11K camera at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 56s.5, 07".8). Brimacombe's image is posted at http://www.flickr.com/photos/43846774@N02/5729478332/. L. Tomasella, P. Ochner, S. Valenti, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a noisy spectrogram (range 390-810 nm; resolution 2.2 nm) of PSN 14585651+6554083 = SN 2011dc, obtained on May 26.03 UT under poor weather conditions by the Service Telescope Operator Team with the Ekar-Copernicus 1.82-m telescope (+ AFOSC), suggests that 2011dc is likely a type-I supernova; if a broad absorption measured at 644.0 nm is identified with Si II 635.5-nm, the redshift of 2011dc is between 0.04 and 0.05....