SIMBAD references

R. Chornock, A. A. Miller, D. A. Perley, and J. S. Bloom, University of California, Berkeley, report on further spectroscopic observations of the 2008es, observing the object for 840 s using the Low-Resolution Imaging Spectrometer (Oke et al. 1995, PASP 107, 375) on the Keck I 10-m telescope on Aug. 3.25 UT. The initial observations of this object (reported at the following website URL: http://www.astronomerstelegram.org/?read=1576) showed a blue and largely featureless spectrum, but at later epochs several unidentified weak spectral features appeared (ibid.,/?read=1576, 1593). The object now has developed a prominent broad (FWHM about 10000 km/s) emission feature centered near 790 nm, which is identified as H-alpha near redshift 0.2. The spectrum shows several other P-Cyg absorption features consistent with higher-order Balmer lines and Fe II at a similar redshift, leading to the conclusion that the object is a type-II supernova. Application of the "SuperNova IDentification" code (Blondin and Tonry 2007, Ap.J. 666, 1024) to this spectrum confirms the identification as a type-II supernova and gives a best-fit redshift of z = 0.206 ± 0.005. At this redshift, the peak apparent optical magnitude of around 17.8 (see text by Yuan et al., above) corresponds to an absolute magnitude of M_V less-than- or-equal-to -22.2, making this object one of the most luminous supernovae ever observed, comparable to, if not brighter than, the extreme supernova 2006gy (Smith et al. 2007, Ap.J. 666, 1116; Ofek et al. 2007, Ap.J. 659, L13). Chornock et al. thank M. Malkan (UCLA) for the exchange of observing time.