Electronic Telegram No. 2103 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 SUPERNOVAE 2009mz AND 2009na D. K. Sahu, Indian Institute of Astrophysics, Bangalore, reports that a low-resolution spectrum of 2009mz (cf. CBET 2096), obtained on Dec. 29.9 UT with the Indian Astronomical Observatory's 2-m Himalayan Chandra Telescope (+ HFOSC), shows it to be a normal type-Ia supernova. Using the SNID code (Blondin and Tonry 2007, Ap.J. 666, 1024), the spectrum of 2009mz is found to be similar to that of SN 2002bo close to maximum light in the B band. Adopting a recession velocity of 2519 km/s for the host galaxy (de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies), the blue-shifted velocity of the Si II 635.5-nm absorption is estimated to be approximately 11850 km/s. Further, a low-resolution spectrum of 2009na (cf. CBET 2098), obtained on Dec. 29.8 UT with the same instrumental set-up, shows it to be a normal type-Ia supernova, similar to that of SN 2003du about six days before maximum light. Adopting a recession velocity of 6247 km/s for the host galaxy (de Vaucouleurs et al. 1991, ibid.), the blue-shifted velocity of the Si II 635.5-nm absorption is estimated to be approximately 11300 km/s. The Ca II near-infrared triplet shows a high-velocity feature, with velocity close to 22400 km/s. NOTE: These 'Central Bureau Electronic Telegrams' are sometimes superseded by text appearing later in the printed IAU Circulars. (C) Copyright 2009 CBAT 2009 December 30 (CBET 2103) Daniel W. E. Green