Electronic Telegram No. 907 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://cfa-www.harvard.edu/iau/cbat.html SUPERNOVA 2007ax IN NGC 2577 S. Blondin, M. Modjaz, R. Kirshner, and P. Challis, Harvard-Smithsonian Center for Astrophysics; and T. Matheson, National Optical Astronomy Observatory, report that a spectrogram (range 350-740 nm) of 2007ax (cf. CBET 904), obtained by M. Calkins on Mar. 26.21 UT with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), shows it to be a type-Ia supernova around maximum light. Cross-correlation with a library of supernova spectra indicates that 2007ax is most similar to the subluminous type-Ia supernova 1991bg at 3 days past maximum. Adopting a recession velocity of 2074 km/s for the host galaxy (from "The Updated Zwicky Catalog", available online at http://tdc-www.harvard.edu/uzc/), the maximum absorption in the Si II line (rest 635.5 nm) is blueshifted by roughly 10000 km/s. Assuming that the galaxy is in the Hubble flow and that the supernova suffers negligible extinction, the discovery magnitude of 17.2 corresponds to an absolute magnitude of roughly -15, which is roughly 2 magnitudes fainter than SN 1991bg at the same phase. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2007 CBAT 2007 March 26 (CBET 907) Daniel W. E. Green