2011CBET.2721....3S

J. M. Silverman, A. V. Filippenko, and W. Li, University of California, Berkeley, report that inspection of a CCD spectrum (range 340-1000 nm), obtained by K. Hiner (University of California, Riverside) and A. Diamond- Stanic (University of California, San Diego) on May 11 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that PSN J14325381+1135493 = SN 2011cj is a very young type-II supernova. The broad H-alpha emission component has a substantially blueshifted centroid and greatly dominates over the absorption component, and the continuum is quite blue. There appears to be broad, weak emission in the range 450-470 nm (blending with H-beta emission around 480 nm), probably corresponding to C III/N III and He II, as is commonly seen in Wolf-Rayet stars and in some other very young type-II supernovae (e.g., SN 1998S; Leonard et al. 2000, Ap.J. 536, 239). However, unlike the case of SN 1998S, there is no clear evidence for an intermediate- width or narrow component, so the object is not a type-IIn evemt at this stage. After removal of the host-galaxy recession velocity of 2300 km/s, determined from narrow emission lines, the absorption minimum of the H-alpha line is found to be blueshifted by 16000 km/s.