2011CBET.2651....1C

Further to CBET 2634, S. B. Cenko, W. Li, and A. V. Filippenko report the LOSS discovery of an apparent supernova on unfiltered KAIT images:

------------------------------------------------------------------------— SN 2011 UT R.A. (2000.0) Decl. Mag. Offset ------------------------------------------------------------------------— 2011W Jan. 16.12 0 32 51.24 +11 44 07.5 18.6 12".0 E, 4".8 S ------------------------------------------------------------------------—

Additional KAIT magnitudes for 2011W in UGC 323: a co-added image from 2010 Sept.-Dec, [19.8; 2011 Jan. 18.11 UT, 18.5. This object was designated PSN J00325124+1144075 on the Central Bureau's TOCP webpage.

J. M. Silverman, M. T. Kandrashoff, J. Rex, and A. V. Filippenko, University of California, Berkeley, report that inspection of a low-signal-to-noise-ratio CCD spectrum (range 350-1000 nm), obtained on Feb. 2 UT with the 3-m Shane reflector (+ Kast) at Lick Observatory, shows that PSN J00325124+1144075 = SN 2011W is likely a type-II supernova. The spectrum is heavily contaminated by host-galaxy light, but broad H-alpha emission and the Ca II near-infrared triplet (the latter having a clear P-Cyg profile) are detected. Silverman et al. add that SN 2011U (cf. CBET 2649) is a relatively reddened type-Ia supernova. After removal of the host-galaxy recession velocity of 3970 km/s (measured from narrow host-galaxy emission lines), they find the absorption minimum of the Si II 635.5-nm line to be blueshifted by about 11700 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 2011U is a normal type-Ia supernova near maximum brightness. Na I D absorption at the redshift of the host galaxy is detected with an equivalent width of approximately 0.2 nm.