Electronic Telegram No. 2777 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 2011ei IN NGC 6925 = PSN J20342262-3158236 Peter Marples, Loganholme Observatory, Queensland, Australia, reports the discovery by Stuart Parker (Oxford, Canterbury, New Zealand) of an apparent supernova (red mag 18.0) on a 30-s unfiltered CCD image taken on July 25.434 UT with a Celestron C14 35-cm f/6.3 Schmidt-Cassegrain reflector (+ ST10 CCD camera). Colin Drescher (Calamvale, Queensland, Australia) measured the magnitude and the position of the new object to be R.A. = 20h34m22s.62, Decl. = -31d58'23".6 (equinox 2000.0), which is 26" east and 28" north of the nucleus of the galaxy NGC 6925. Nothing is visible at this position on a red Digitized Sky Survey image from 1990 Sept. 24 (no limiting magnitude provided). The variable was designated as PSN J20342262-3158236 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011ei based on the spectroscopic reports below. Additional magnitudes for 2011ei: 2011 June 23.58, [19.1 (Parker; red magnitude); July 26.43, 18.3 (Greg Bock, Leyburn, Queensland, Australia; Meade 35-cm LX200 ACF Schmidt-Cassegrain telescope + ST10 CCD camera; unfiltered red mag measured by Marples; limiting red mag 18.6); 27.322, 18.7 (Joseph Brimacombe, Cairns, Australia; remotely using a 51-cm RCOS telescope + unfiltered STL11K camera at the New Mexico Skies observatory near Mayhill, NM, U.S.A.; position end figures 22s.63, 22".9 image posted at URL http://www.flickr.com/photos/43846774@N02/5982678302/); 27.508, 17.8 (Brimacombe, Coral Towers Observatory, Cairns; 30-cm telescope + red filter; position end figures 22s.52, 24".1; 27.515, 17.7 (Brimacombe; 40-cm RCOS telescope + STL6K camera + infrared filter; position end figures 22s.60, 22".4; http://www.flickr.com/photos/43846774@N02/5983785346/); Aug. 2.330, 16.9 (Brimacombe; red filter; image posted at website URL http://www.flickr.com/photos/43846774@N02/6002976621/). M. Stritzinger, Stockholm University; N. Morrell, Las Campanas Observatory; and G. Pignata, Universidad Andres Bello, report that they obtained a spectrum (range 373-945 nm) of PSN J20342262-3158236 = SN 2011ei on July 29.2 UT with the Magellan II Clay 6.5-m telescope (+ LDSS3) at Las Campanas Observatory. The spectrum is consistent with a type-II supernova. Comparison with a library of supernova spectra (Blondin and Tonry 2007, Ap.J. 666, 1024) suggests that 2011ei is most similar to the type-IIb supernovae 1993J and 1996cb prior to maximum light, although a comparison to SN 1987A at early phases cannot be ruled out. D. Milisavljevic and R. Fesen, Dartmouth College; K. Nordsieck, University of Wisconsin; and T. Pickering, A. Gulbis, and D. O'Donoghue, South African Astronomical Observatory, on behalf of a larger SALT Commissioning Team, report that low-dispersion spectra (range 320-900 nm), obtained July 29.8 UT with the 10-m SALT telescope (+ RSS), show PSN J20342262-3158236 = SN 2011ei to be a type-II supernova. Comparison with spectra retrieved from the Supernova Spectrum Archive (SUSPECT; see the following website URL: http://bruford.nhn.ou.edu/~suspect/index.html) shows a good match to the energetic type-IIb 'hypernova' 2003bg at approximately 7 days before maximum light (Hamuy et al. 2009, Ap.J. 703, 1612). Assuming a redshift of z = 0.0093 for the host galaxy, NGC 6925 (Koribalski et al. 2004, A.J. 128, 16), the H-alpha P-Cyg profile shows broad emission spanning 622-700 nm with a relatively shallow absorption minimum blueshifted around -15700 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2011 CBAT 2011 August 3 (CBET 2777) Daniel W. E. Green