2009CBET.1689....1S

M. Stritzinger, N. Morrell, and G. Folatelli, on behalf of the Carnegie Supernova Project and the Millennium Center for Supernova Studies, report that they obtained spectra (range 380-940 nm) of supernovae 2009U, 2009W, and 2009aa on Feb. 8.1-8.2 UT with the 6.5-m Magellan II (Clay) telecope (+ LDSS3). The spectrum of 2009U (cf. CBET 1679) reveals it to be a subluminous 1991bg-like type-Ia-supernova event at two to three weeks past maximum light.

SN 2009W (cf. CBET 1683) appears to be a type-IIP supernova around a month-and-a-half past explosion. Cross correlation with a library of supernovae spectra (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) reveals that 2009W is most similar to supernova 2004dj at 51 days past explosion.

A spectrum of 2009aa (cf. CBET 1685) appears to be that of a young type-Ia supernova. With the aid of SNID, they find an excellent match to SN 2002er at one week before maximum. Adopting a host-galaxy recession velocity of 8187 km/s (Theureau et al. 2007, A.Ap. 465, 71) for the host galaxy (ESO 570-G20), Si II is measured to be blue-shifted by roughly 10000 km/s.