2010CBET.2360....1S

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.