2010CBET.2461....2C

S. B. Cenko, M. T. Kandrashoff, J. M. Silverman, and A. V. Filippenko, University of California, Berkeley, report that inspection of CCD spectra (range 340-1000 nm), obtained on Sept. 16 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that 2010hy is a supernova, perhaps of type Ic near maximum brightness, but the possibility that 2010hy is actually a type-Ia supernova cannot be ruled out. The observed brightness, together with the derived redshift of about 0.2 (from the supernova features), implies an absolute visual magnitude of roughly -21, which is highly overluminous for type-Ia and type-Ic supernovae. Higher quality spectra, as well as continued photometry, should be obtained. Inspection of similar CCD spectra shows that 2010hs (CBET 2454) is a type-Ia supernova; cross-correlation with a library of supernova spectra using the "SuperNova IDentification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) indicates that 2010hs is near maximum brightness. A noisy spectrum of 2010hw (CBET 2458) shows that it is a type-II supernova.