Electronic Telegram No. 1185 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) CBAT@CFA.HARVARD.EDU (science) URL http://www.cfa.harvard.edu/iau/cbat.html SUPERNOVA 2007sw IN UGC 7228 R. Quimby, California Institute of Technology; F. Yuan and C. Akerlof, University of Michigan; and J. C. Wheeler, University of Texas, report the discovery of a supernova (mag about 16.0) in unfiltered CCD images taken on Dec. 29.49 UT using the 0.45-m ROTSE-IIIb telescope at the McDonald Observatory. The new object is located at R.A. = 12h13m36s.88, Decl. = +46o29'36".1 (equinox 2000.0), which is 0".7 east and 2".2 south of the center of UGC 7228. SN 2007sw was found by subtracting a co-addition of images taken between 2005 April and 2006 June (limiting mag about 18.7). A spectrum (range 420-890 nm) of 2007sw, obtained on Dec. 30.39 with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by S. Odewahn and E. Terrazas, shows it to be a type-Ia supernova. The spectra are similar to that of SN 2005ir (cf. CBET 277; IAUC 8629) a few days prior to maximum light. Adopting the redshift of the apparent host (z = 0.025; Updated Zwicky Catalog, via NED), the expansion velocity derived from the minimum of the Si II (rest 635.5 nm) line is about 14000 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 December 31 (CBET 1185) Daniel W. E. Green