SIMBAD references

Blondin et al. add that their spectrum is not consistent with the description given by Soderberg et al. in GCN 1765, who report on a "smooth, featureless continuum" with "some suggestion of a broad bump near 5500 Angstroms". However, based on other spectra of familiar objects fully reduced from the same night, Blondin et al. are confident that their flux and wavelength calibrations are accurate. The separation in time between the MMT spectrum and the one described in GCN 1765 is only 0.1 day. Blondin et al. clearly detect narrow emission lines at the supernova position, consistent with the NED redshift of 1934 km/s for NGC 2770 (from The Updated Zwicky Catalog, http://tdc-www.harvard.edu/uzc/). Adopting this recession velocity, the maximum absorption in the Si II line (rest 635.5 nm) is blueshifted by roughly 23000 km/s. Also, interstellar Na I D absorption at that redshift is visible in the spectrum with an equivalent width of 0.2 nm. A comparison plot can be seen at the following URL: http://www.cfa.harvard.edu/supernova/spectra/sn2008D_comp.gif; note that, in this plot, the spectrum of SN 1990aa had to be blueshifted by 5500 km/s in order for prominent spectroscopic features to match up with those present in SN 2008D, while that of SN 1998bw has been redshifted by 13000 km/s for the same reason. S. Valenti, Universita di Ferrara; D. Fugazza and E. Maiorano, Istituto Nazionale di Astrofisica (INAF), Osservatorio Astronomico di Bologna; V. D'Elia and L. A. Antonelli, INAF, Ossevatorio Astronomico di Roma; S. Covino, INAF, Osservatorio Astronomico di Brera; A. Magazzu and N. Pinilla-Alonso, INAF, Telescopio Nazionele Galileo (TNG); M. Della Valle, INAF, Osservatorio Astrofisico di Arcetri; G. Chincarini, Universita' degli Studi di Milano Bicocca; E. Pian and P. A. Mazzali, INAF, Osservatorio Astronomico di Trieste; and A. Harutyunyan and S. Benetti, INAF, Osservatorio Astronomico di Padova, report that preliminary reduction of a spectrogram of 2008D, taken with the TNG (+ LRS; range 350-780 nm) on Jan. 11.1 UT, shows that the spectrum resembles that of the energetic type-Ic supernova 2006aj (cf. IAUC 8674) at three days after explosion (Pian et al. 2006, Nature 442, 1011). The Si II 635.5-nm feature shows a higher expansion velocity than in the spectrum of 2006aj. The bluer bumps seen in the 2006aj spectrum, centered at about 440 and 500 nm, are not yet well developed, also suggesting a higher expansion velocity.