Supernovae 2010ej and 2010em

Abstract

J. M. Silverman, S. B. Cenko, D. Perley, A. Cucchiara, J. S. Bloom, and A. V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 350-1000 nm), obtained on July 7 UT with the 10-m Keck I telescope (+ LRIS), shows that 2010ej (CBET 2329) is a type-II supernova. After removal of the host-galaxy recession velocity of 15700 km/s, determined by narrow emission lines, it is found that the absorption minimum of the H-alpha line is blueshifted by about 13000 km/s. Cross- correlation with a library of supernova spectra using the ``SuperNova IDentification’’ code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010ej is possibly a type-IIb supernova near maximum brightness (which means that the supernova was discovered shortly after explosion). SN 2010em (CBET 2335) is also a type-II supernova; after removal of the host-galaxy recession velocity of 8300 km/s, determined by narrow emission lines, it is found that the absorption minimum of the H-alpha line is blueshifted by about 7500 km/s. SNID indicates that 2010em is 1 to 2 months past maximum brightness.

Publication
Central Bureau Electronic Telegrams