Electronic Telegram No. 2691 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 2011bi IN MCG +07-35-37 = PSN J17100581+4222201 T. Boles, Coddenham, England, reports the discovery of an apparent supernova (mag 17.1) on unfiltered CCD images taken on Apr. 4.041 UT with a 0.35-m reflector. The new object is located at R.A. = 17h10m05s.81, Decl. = +42o22'20".1 (equinox 2000.0), which is approximately 7".4 east and 2".1 north of the center of MCG +07-35-37. Boles also measured position end figures 05s.83, 20".3 and magnitude V = 17.1 on Apr. 5.116 using a 60-s unfiltered CCD image (limiting mag 20.5) taken with a 0.61-m Cassegrain reflector at the Sierra Stars Observatory, Alpine County, California. Nothing is present at this position on Boles' images from 2011 Feb. 7 and 2010 Oct. 20 (limiting mag 19.5) or on Digitized Sky Survey plates from 1992 July 21 (limiting red mag 20.5) and 1989 July 2 (limiting blue mag 21.0). The variable was designated PSN J17100581+4222201 when posted on the Central Bureau's TOCP webpage and is here designated SN 2011bi based on the spectroscopic reports below. G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, reports that a spectrum (range 340-740 nm) of PSN J17100581+4222201 = SN 2011bi was obtained on Apr. 4 UT by Marion with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011bi is a type-IIP supernova approximately three weeks after the explosion. J. Chen, J. Liang, and X. Wang, Tsinghua Center for Astrophysics, Tsinghua University; and T. Zhang and C. Wu, National Astronomical Observatories of China (NAOC), report on an optical spectrum (range 400-880 nm) of PSN J17100581+4222201 = SN 2011bi that was obtained on Apr. 8.80 UT with the 2.16-m telescope (+ OMR) at the Xinglong Station of the NAOC. The spectrum is consistent with that of a type-IIP supernova at about one month after maximum light. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011bi matches that of SN 2004et at 23 days after maximum. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 April 10 (CBET 2691) Daniel W. E. Green