2011CBET.2746....1L

Simone Leonini, Siena, Italy, reports the discovery of an apparent supernova (mag about 16.8) on an unfiltered CCD image (limiting mag about 19.2) taken on June 21.931 UT during the Montarrenti Observatory Supernovae Search program (part of the Italian Supernovae Project) using a 0.53-m f/7.8 Ritchey-Chretien telescope (+ Apogee Alta U47 CCD camera). The new object is located at R.A. = 19:58:35.53, Decl. = +2:36:16.3 (equinox 2000.0), which is 26" west of the nucleus of the galaxy UGC 11501. No stellar source is visible at this position in their past images from 2009 June 16 to 2011 May 30 (limiting mag about 19.0) or on Palomar Sky Survey infrared, red, and blue plates (1995 August 16, F plate; 1992 July 1, J plate; 1990 June 20, N plate, limiting mag 20.0). Confirmation images were obtained on 2011 June 22.93 by L. M. Tinjaca Ramirez using the discovery telescope, with the variable then at (mag about 17.1; limiting mag about 19.2). The new object was designated PSN J19583553+0236163 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011dn based on the spectroscopic report below. The discovery image is posted at the following website URL: http://www.jacopobaldi.it/dati/PSN%20in%20UGC11501.jpg, and the confirmation at http://www.jacopobaldi.it/dati/confirmation%20PSN%20in%20UGC11501.jpg.

Additional unfiltered CCD magnitudes for SN 2011dn: June 23.23-23.30 UT, 16.5 (R. A. Koff, Bennett, CO, U.S.A.; Celestron 0.20-m f/10 reflector + SBIG ST-6 CCD camera; multiple co-added images); 23.354, 16.1 (Joseph Brimacombe, Cairns, Australia; three co-added 60-s images; position end figures 35s.56, 11".3). Brimacombe's image is posted at the following website URL: http://www.flickr.com/photos/43846774@N02/5865118910/.