The Long-Lived UV "Plateau" of SN 2012aw

TL;DR

This paper reports the first clear observation of a long-lived ultraviolet plateau in a Type II-P supernova, SN 2012aw, revealing new insights into supernova UV emission behavior and underlying physical processes.

Contribution

It provides the first unambiguous detection of a UV plateau in a Type II-P supernova, enhancing understanding of supernova UV lightcurve evolution.

Findings

UV plateau observed 27 days after explosion

UV and u-band lightcurves initially declined rapidly

UV plateau may result from thermal processes or radioactive decay heating

Abstract

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.