2006CBET..554....1I

S. Immler, Goddard Space Flight Center, NASA, and Universities Space Research Association; P. Milne, Steward Observatory, University of Arizona; and P. J. Brown, Pennsylvania State University – on behalf of the Swift-satellite team – report on Swift Ultraviolet/Optical Telescope (UVOT) and X-Ray Telescope (XRT) observations of SN 2006dd (cf. CBET 553) obtained on June 20.71 UT. They confirm, via comparison to Digitized Sky Survey images, the detection of a new object at R.A. = 03h22m41s.64, Decl. = -37o12'13".2 (equinox 2000.0), consistent with the position reported by Monard on CBET 553; the following UVOT magnitudes were measured for 2006dd (statistical and systematic errors are 0.1 mag each): V = 14.0 (167-s exposure), B = 14.5 (259 s), U = 13.7 (258 s), UVW1 [181-321 nm] = 15.5 (520 s), UVM2 [166-268 nm] = 17.9 (881 s), and UVW2 [112-264 nm] = 18.1 (881 s). Comparison to the photometry obtained on June 20.158 (B = 14.66, V = 14.41, from CBET 553) shows that the supernova is still pre-maximum. The B-V and U-B colors are similar to those of SN 2006bp (type II-P) before maximum (Immler and Brown, http://www.astronomerstelegram.org/?read=793). Furthermore, comparison of the colors with other supernovae from Poznanski et al. (2002, PASP 114, 833) indicates that 2006dd is a young type-II supernova before or around maximum.