2010CBET.2293....1M

N. Morrell, Las Campanas Observatory, on behalf of the Carnegie Supernova Project, reports spectroscopic observations (range 330-950 nm) of 2010bv (cf. CBET 2255) and 2010co (cf. CBET 2271), obtained on May 20 UT with the Boller and Chivens spectrograph attached to the 2.5-m du Pont telescope at Las Campanas Observatory. The spectrum of 2010bv is that of an evolved type-Ia supernova; cross-correlation with a library of supernova spectra via the Supernova Identification tool (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) yields very good matches with a number of normal type-Ia supernovae around three months past maximum light.

The data for 2010co show that this is a young type-II supernova. The minimum of the H-beta absorption is blueshifted by approximately 5000 km/s, if the NED recession velocity of 4205 km/s (Lauberts and Valentijn 1989, The Surface Photometry Catalogue of the ESO-Uppsala Galaxies) is adopted for NGC 6862. Significant Na I interstellar absorption (EW approximately 0.13 nm) at the velocity of the host galaxy is observed in the spectrum of 2010co. SNID provides good matches for 2010co with many type-II-P supernovae between 10 and 30 days after maximum.