2005IAUC.8639....3F

Filippenko, Foley, and Matheson add that inspection of a CCD spectrogram (range 400-900 nm), obtained by J. Cooke and J. C. Berrier (University of California, Irvine) on Dec. 3 UT with the Keck II 10-m telescope (+ DEIMOS), shows that SN 2005la is a peculiar type-II/Ib supernova: "In addition to relatively weak, narrow hydrogen Balmer lines having P-Cyg profiles, the spectrum exhibits narrow He I lines with P-Cyg profiles dominated by the emission component. The recession velocity of the host galaxy is 5570 km/s, based on narrow H_alpha from nearby H II regions. The supernova expansion velocity, determined from the minima in the absorption components, is about 1700 km/s. The FWHM of the emission components is about 1800 km/s. We have previously not encountered a supernova spectrum having these characteristics. Further monitoring of the object is encouraged."