The progenitor of SN 2011ja: Clues from circumstellar interaction. (arXiv:1302.7067v1 [astro-ph.HE])

The progenitor of SN 2011ja: Clues from circumstellar interaction. (arXiv:1302.7067v1 [astro-ph.HE]):
Massive stars, possibly red supergiants, which retain extended hydrogen
envelopes until the time of core collapse produce Type IIP (Plateau)
supernovae. The ejecta from these explosions shock the circumstellar matter
originating from the mass loss of the progenitor during the final phases of its
life. This interaction accelerates particles to relativistic energies which
then lose energy via synchrotron radiation in the shock-amplified magnetic
fields and inverse Compton scattering against optical photons from the
supernova. These processes produce different signatures in the radio and X-ray
part of the electromagnetic spectrum. Observed together, they allow us to break
the degeneracy between shock acceleration and magnetic field amplification. In
this work we use X-rays observations from the Chandra and radio observations
from the ATCA to study the relative importance of particle acceleration and
magnetic fields in producing the non-thermal radiation from SN 2011ja. We use
radio observations to constrain the explosion date. Multiple Chandra
observations allow us to probe the history of variable mass loss from the
progenitor. The ejecta expands into a low density bubble followed by
interaction with a higher density wind from a red supergiant consistent with
M>16 solar masses. Our results suggest that a fraction of type IIP supernovae
may interact with circumstellar media set up by non-steady winds.