SIMBAD references

N. Elias-Rosa and S. D. Van Dyk, Spitzer Science Center, California Institute of Technology; I. Agnoletto, Universita' di Padova; and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, report that a spectrogram (range 340-800 nm, resolution 1.8 nm) of 2009dd (cf. CBET 1764), obtained on Apr. 15.19 UT with the Nordic Optical Telescope (+ ALFOSC), shows it to be a young type-II supernova. Assuming a recession velocity of 757 km/s (Verheijen and Sancisi 2001, A.Ap. 370, 765; via NED) for the host galaxy, the "GELATO" spectrum-comparison code (Harutyunyan et al. 2008, A.Ap. 488, 383; available at https://gelato.tng.iac.es) provides good fits to spectra of type-II supernovae at several days after explosion. The expansion velocity deduced from the H-alpha absorption is about 9900 km/s. The spectrum shows an intense (equivalent width 0.28 nm) absorption due to the Na I D doublet, which might indicate a somewhat-high interstellar absorption suffered by the supernova light inside the parent galaxy.