Electronic Telegram No. 1173 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 2007sr IN NGC 4038 H. Naito, Nishi-Harima Astronomical Observatory (NHAO); and Y. Sakane, T. Anan, S. Kouzuma, and H. Yamaoka, Kyushu University, report that a low- resolution (R about 400) spectrum of 2007sr (cf. CBET 1172) was obtained on Dec. 19.87 UT with the 2.0-m NAYUTA telescope at NHAO, showing a somewhat-blue continuum with broad absorption features (Si II and Fe II are prominent), which suggests that it is a type-Ia supernova a few days before maximum. The expansion velocity, derived from the Si II 635.5-nm absorption minimum, is 12300 km/s. Preliminary magnitudes from the images taken with the same instrument are as follows: Dec. 19.81, B = 13.42; 19.78, V = 12.86. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 December 20 (CBET 1173) Daniel W. E. Green