SIMBAD references

S. Blondin, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, reports that a spectrum (range 320-840 nm) of 2008cw (cf. CBET 1395), obtained on June 6.38 UT by P. Challis with the MMT 6.5-m telescope (+ Blue Channel spectrograph), shows it to be a type-IIb supernova around one week past maximum light. SN 2008cw was classified as a peculiar type-Ib supernova, similar to SN 2005bf, by Yuan et al. on CBET 1395. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2008cw is most similar to the type-IIb supernova 1993J at four days past maximum light. The top 50 comparison spectra that yield a good correlation with 2008cw all belong to type-IIb supernovae. Blueshifted absorption features due to H_alpha and H_beta are clearly seen in the spectrum, as are conspicuous lines of He I (rest 587.6, 667.8, 706.5 nm), characteristic of type-IIb supernovae. Specifically, a P-Cyg profile due to He I (rest 667.8 nm) overlaps with the H_alpha emission profile to create a broad, double- peaked emission feature. A recession velocity of cz = 9724 ± 38 km/s is derived using 12 emission lines in the host-galaxy spectrum, consistent with the redshift reported by Yuan et al. (z = 0.032; i.e., cz approximately 9590 km/s). Adopting this recession velocity for the host galaxy of 2008cw, the maximum absorption in the H_alpha line is blueshifted by roughly 11000 km/s. Furthermore, several other spectra (range 350-740 nm), obtained between June 4.29 and 11.23 UT by E. Falco, M. Calkins, and P. Berlind with the F. L. Whipple Observatory 1.5-m telescope (+ FAST), confirm the classification of 2008cw as a type-IIb supernova.