Electronic Telegram No. 2653 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 2011aa IN UGC 3906 = PSN J07364263+7426348 T. Puckett, and J. Newton report the discovery of a supernova (mag 16.1) on an unfiltered CCD image (limiting mag 19.0) taken with a 0.40-m reflector at Portal, AZ, U.S.A., on Feb. 6.335 UT in the course of the Puckett Observatory Supernova Search. The new object, which was confirmed at mag 16.0 on Feb. 7.076 by Puckett with the same instrumentation at Portal, is located at R.A. = 7h36m42s.63, Decl. = +74o26'34".8 (equinox 2000.0), which is 20".4 east and 10".2 south of the center of UGC 3906. Nothing is visible at this position on images taken by Puckett on Jan. 26 (limiting mag 19.6). The object was automatically designated PSN J07364263+7426348 when posted on the Central Bureau's TOCP webpage. D. D. Balam, D. Bohlender, D. Monin, and E. Chisholm, Dominion Astrophysical Observatory, National Research Council of Canada; and D. W. E. Green, CBAT, Harvard University, report that CCD exposures yield the following R-band magnitudes for PSN J07364263+7426348 = 2011aa from differential photometry using a nearby star of similar brightness (USNO-A2.0 1575-02747274): Feb. 8.23 UT, 15.6; 9.24, 15.5. Uday K. Gurugubelli, D. K. Sahu, G. C. Anupama, P. Anto, and S. Arora, Indian Institute of Astrophysics, Bangalore, report that a low-resolution spectrogram (range 350-930 nm) of PSN J07364263+7426348 = 2011aa, obtained on Feb. 8.87 UT with the Indian Astronomical Observatory's 2-m Himalayan Chandra Telescope (+ HFOSC), shows it to be a type-Ia supernova, a few days before maximum light. Using the SNID code of Blondin and Tonry (2007, Ap.J. 666, 1024), the spectrum of 2011aa is found to best match that of SN 1998aq at about a week before maximum light. Adopting a recession velocity of 3704 km/s for the host galaxy, UGC 3906 (de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies), the velocity corresponding to the Si II 635.5-nm absorption line is 13000 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars.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 February 11 (CBET 2653) Daniel W. E. Green