The Long-Lived UV "Plateau" of SN 2012aw
  Observations with the Swift UVOT have unambiguously uncovered for the first time a long-lived, UV "plateau" in a Type II-P supernova (SN).   Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band lightcurves initially declined rapidly, but 27 days after explosion the light curves flattened. Some possible sources of the UV plateau are: the same thermal process that cause the optical plateau, heating from radioactive decay, or a combination of both processes. 
Amanda J. Bayless, Tyler Pritchard, Peter W. A. Roming, Paul Kuin,   Peter J. Brown, Maria Teresa Botticella, Massimo Dall'O...
astro-ph.HE