Roger A. Chevalier, Christopher M. Irwin
Type IIn and related supernovae show evidence for an interaction with a dense
circumstellar medium that produces most of the supernova luminosity. X-ray
emission from shock heated gas is crucial for the energetics of the interaction
and can provide diagnostics on the shock interaction. Provided that the shock
is at an optical depth tau_w\la c/v_s in the wind, where c is the speed of
light and v_s is the shock velocity, a viscous shock is expected that heats the
gas to a high temperature. For tau_w\ga 1, the shock wave is in the cooling
regime; inverse Compton cooling dominates bremsstrahlung at higher densities
and shock velocities. Although tau_w\ga 1, the optical depth through the
emission zone is \la 1 so that inverse Compton effects do not give rise to
significant X-ray emission. The electrons may not reach energy equipartition
with the protons at higher shock velocities. As X-rays move out through the
cool wind, the higher energy photons are lost to Compton degradation. If
bremsstrahlung dominates the cooling and Compton losses are small, the
energetic radiation can completely photoionize the preshock gas. However,
inverse Compton cooling in the hot region and Compton degradation in the wind
reduce the ionizing flux, so that complete photoionization is not obtained and
photoabsorption by the wind further reduces the escaping X-ray flux. We
conjecture that the combination of these effects led to the low observed X-ray
flux from the optically luminous SN 2006gy.
View original:
http://arxiv.org/abs/1201.5581
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