Electronic Telegram No. 1174 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 G. Umbriaco, T. Pietrogrande, and F. Di Mille, Dipartimento di Astronomia, Universita' di Padova; and I. Agnoletto, A. Harutyunyan, and S. Benetti, Istituto Nazionale di Astrofisica and Osservatorio Astronomico di Padova, report that a spectrogram (range 335-770 nm, resolution 0.9 nm) of 2007sr (cf. CBET 1172, 1173), obtained on Dec. 20.22 UT at Asiago with the Galileo 1.22-m telescope (+ Boller & Chivens spectrograph), shows it to be a type-Ia supernova. Assuming a recession velocity of 1642 km/s (Lauberts and Valentijn 1989, The Surface Photometry Catalogue of the ESO-Uppsala Galaxies; via NED) for the host galaxy, the 'PASSparToo' spectrum-comparison code (Harutyunyan et al. 2005, ASP Conf. Ser. 342, 258) provides good fits to spectra of SNe 1996Z and 2002bo at five and four days after B-maximum light, respectively. The phase is confirmed by the high expansion velocity deduced from the Si II 635.5-nm absorption feature (about 12100 km/s) shown by the HVG class (Benetti et al. 2005, Ap.J. 623, 1011) during the photospheric phases. Visual magnitude estimate by P. Schmeer, Bischmisheim, Germany: Dec. 20.249 UT, 12.8. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars.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 1174) Daniel W. E. Green