2011CBET.2745....2M

D. Milisavljevic, J. Thorstensen, and R. Fesen, Dartmouth College, report that low-dispersion optical spectra (range 470-670 nm) of PSN J21564159+7317489 = SN 2011dm, obtained on June 22.5 UT with the 2.4-m Hiltner telescope (+ Modspec) at MDM Observatory, show it to be a type-Ia supernova. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows matches with normal type-Ia events at 3-6 days before maximum light. After correcting for the recessional velocity of its host galaxy (UGC 11861) of 1481 km/s, the velocity of the Si II 635.5-nm feature is estimated to be approximately 13000 km/s. Suppressed blue flux and a relatively strong Na D line suggest a significant amount of extinction toward the supernova. Weak C II 658.0-nm absorption is also visible.