Electronic Telegram No. 2871 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 2011gy IN UGC 2756 = J03293530+4052029 Zhangwei Jin (Ningbo, Zhejiang, China) and Xing Gao (Urumqi, Xinjiang, China) report the discovery of a possible supernova (mag approximately 15.8) on a 40-s unfiltered CCD survey image (limiting mag about 19.5) taken by Xing Gao in the course of the Xingming Observation Sky Survey around Oct. 22.795 UT using a 0.35-m f/6.9 Celestron C14 Schmidt-Cassegrain telescope. The new object is approximately located at R.A. = 3h29m35s.30, Decl. = +40d52'02".9 (equinox 2000.0), which is about 2".3 east and 5".1 south of the center of the galaxy UGC 2756 = MCG +7-8-15 = PGC 12982. Nothing is visible at this position on archival images taken at Mt. Nanshan on Oct. 6 (limiting mag 19.0) and 8 (limiting mag 19.5) or on a Digitized Sky Survey red plate from 1989 Sept. 29 (limiting mag about 19.8). Their images have been posted at the following website URL: http://www.xjltp.com/XOSS/XM24ZJ/XM24ZJ.htm. The variable was designated as PSN J03293530+4052029 when it was posted on the Central Bureau's TOCP webpage and is here designated SN 2011gy based on the spectroscopic confirmation reported below. Additional unfiltered CCD magnitudes for 2011gy: Oct. 23.211 UT, 15.5 (R. A. Koff, Bennett, CO, USA; Meade 0.25-m f/10 reflector + Apogee AP-47p CCD camera; position end figures 35s.30, 03".4; UCAC3 reference stars; limiting magnitude 18.2); 23.287, 16.1 (Joseph Brimacombe, Cairns, Australia; position end figures 35s.27, 03".8); 23.500, 15.4 (C. Jacques and E. Pimentel, Belo Horizonte, Brazil; remotely using the GRAS G11 telescope in New Mexico, USA; position end figures 35s.34, 03".0; UCAC2 reference stars; limiting magnitude 18.5; image posted at website URL http://ceamig-rea.net/tocp/P12982_tocp.jpg). S. Taubenberger and M. Klauser, Max-Planck-Institut fuer Astrophysik; S. Hachinger, S. Benetti, and S. Valenti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and M. Fiaschi, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrum of PSN J03293530+4052029 = SN 2011gy, obtained on Oct. 23.92 UT with the Ekar-Copernico 1.82-m Telescope (+ AFOSC; range 350-810 nm, resolution 2.4 nm) shows it to be a normal type-Ia supernova a few days before maximum light. Cross-correlation with a library of supernova spectra using GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383; publicly available at https://gelato.tng.iac.es) yields a best match with spectra of SN 1998bu at half a week to one week before maximum light. Adopting a recession velocity 5061 km/s for MCG +7-8-15 (Emilio et al. 1999, PASP 111, 438; via NED), the expansion velocity measured from the Si II 635.5-nm line is about 12000 km/s. T. Zhang, National Astronomical Observatories of China (NAOC); J. Chen, and X. Wang, Tsinghua Center for Astrophysics, Tsinghua University; and L. Lin and X. Kong, University of Science and Technology of China, report on an optical spectrogram (range 350-820 nm) of PSN J03293530+4052029 = SN 2011gy that was obtained on Oct. 24.73 UT with the 2.16-m telescope (+ OMR) at the Xinglong Station of the NAOC. The spectrum is consistent with a type-Ia supernova at about one week before maximum light. After removal of the host- galaxy recession velocity of about 5061 km/s (from NED), they find the absorption minimum of the Si II 635.5-nm line to be blueshifted by about 12000 km/s. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011gy matches with SN 2002er at -6 days. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 October 25 (CBET 2871) Daniel W. E. Green