2009CBET.1710....2V

J. Vinko, H. Marion, and J. C. Wheeler, University of Texas; P. Garnavich, University of Notre Dame; and C. Gerardy, Florida State University, report that a spectrum (range 430-1000 nm) of 2009am (cf. CBET 1707), obtained on Mar. 1.34 UT with the 9.2-m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) by J. Caldwell, shows it to be a type II-P supernova at least one month after the explosion. The spectrum shows strong Balmer-alpha and Ca II infrared-triplet lines with P-Cyg profiles. Na I (590 nm) and other metallic lines (mostly Fe II) appear toward the blue end of the spectrum. Comparison of the spectrum of SN 2009am to other supernovae spectra using SNID (Blondin and Tonry 2007, Ap.J. 666, 1024) provides a close match for two spectra: that of SN 2005cs at 27 ± 3 days after maximum and 1999em at about 60 days after maximum. Spectra of SN 2009an were obtained on Mar. 1.37 with the Hobby-Eberly Telescope (HET), using the same configuration as above, and on Mar. 1.52 with the Infrared Telescope Facility (+ SpeX in low-dispersion mode, range 0.7-2.4 microns); the data show it to be a young type-Ia supernova. SNID finds the best match for the HET spectrum to be to that of SN 2002bo at 6 ± 2 days before maximum. Adopting the host-galaxy (NGC 4332) recession velocity of 2768 km/s listed in NED, the Si II (635.5 nm) feature is blueshifted by 14000 ± 2000 km/s. The near-infrared spectrum reveals a strong high-velocity component for the Ca II infrared triplet and lines from O I and Mg II, consistent with the age above.