Detailed Multiwavelength Study of the Late-Time Evolution of SN 1978K

SN 1978K is a remarkable Type IIn supernova that remains bright at X-ray through radio wavelengths 35 years after its explosion. Our ongoing multiwavelength observations probe the dense medium that was ejected by the progenitor star, possibly a Luminous Blue Variable. While the radio flux has dropped steadily, the X-ray and UV/optical fluxes remained surprisingly constant for a decade. However, our most recent XMM observation in 2013 June reveals a significant fading. Here we request a 100 ksec observation to continue the detailed spectral evolution study. This will serve as a pathfinder for younger Type IIn supernovae. As secondary science, we will obtain data on the ULXs X-1 and X-2, and the other luminous sources in NGC 1313.