Electronic Telegram No. 2988 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 2011jy Vladimir Lipunov, Sternberg Astronomical Institute, on behalf of the MASTER Robotic Net team, reports the discovery of an apparent supernova (mag V = 16.5 +/- 0.3) via the MASTER-Amur auto-detection system on two images (limiting mag 17.9) taken on 2011 Dec. 30.792 UT. The new object is located at R.A. = 10h53m57s.03, Decl. = +23d22'34".5 (equinox 2000.0); while a faint galaxy of red mag 20 is seen on Sloan Digital Sky Survey images, it is not present on the MASTER images (given the SDSS position for the galaxy, the variable would be about 0".8 southwest of the galaxy center). Nothing is visible at this position on a MASTER reference image from 2011 Nov. 22.894 (limiting V magnitude 18.1). The discovery image has been posted at URL http://observ.pereplet.ru/images/105357.03+232234.5/105357.03+232234.5.png. L. Tomasella, E. Cappellaro, P. Ochner, S. Benetti, A. Pastorello, and S. Valenti, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, report that a spectrum (range 360-810 nm; resolution 2.2 nm) of 2011jy was obtained on Jan. 17.92 UT with the Ekar-Copernico 1.82-m telescope (+ AFOSC). The spectrum is dominated by broad Balmer emissions. Using a library of supernova spectra via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383; available via https://gelato.tng.iac.es/login.cgi), they found a best match with typical type-II supernovae at 1-2 weeks after maximum at a redshift z = 0.04. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2012 CBAT 2012 January 21 (CBET 2988) Daniel W. E. Green