2010CBET.2120....1K

Rubab Khan, Ohio State University; and Jose Prieto, Carnegie Observatories, report that optical spectra (range 390-740 nm; resolution 1.4 nm) of 2009mx and 2009my (cf. CBET 2095) were obtained with the Hiltner 2.4-m telescope at MDM Observatory on Jan. 10.4 UT. Cross-correlation with a library of supernova spectra using SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) showS that the spectrum of 2009mx is most similar to the subluminous type-Ia supernova 1991bg at a couple weeks after maximum, and the spectrum of 2009my is of an old type-II supernova. After correcting the spectrum of 2009my for the recession velocity of its host galaxy (+3242 km/s; from de Vaucouleurs et al. 1991, Third Reference Catalogue of Bright Galaxies, ver. 3), an expansion velocity of 7400 km/s is measured from the blue-shifted absorption of the H-alpha profile.