Temperature Equilibration Behind the Shock Front: an Optical and X-ray Study of RCW 86

TL;DR

This study investigates electron-proton temperature equilibration behind shocks in the RCW 86 supernova remnant using optical and X-ray spectra, confirming equilibration in slow shocks but not supporting previous trends in temperature ratios.

Contribution

It provides new measurements of electron and proton temperatures at multiple locations in RCW 86, refining understanding of shock heating processes.

Findings

Electron and proton temperatures are consistent with equilibration in slow shocks.

Deviations from equilibration are observed in faster shocks.

The previously reported inverse square trend of temperature ratio is not confirmed.

Abstract

We study the electron-proton temperature equilibration behind several shocks of the RCW 86 supernova remnant. To measure the proton temperature, we use published and new optical spectra, all from different locations on the remnant. For each location, we determine the electron temperature from X-ray spectra, and correct for temperature equilibration between the shock front and the location of the X-ray spectrum. We confirm the result of previous studies that the electron and proton temperatures behind shock fronts are consistent with equilibration for slow shocks and deviate for faster shocks. However, we can not confirm the previously reported trend of the electron temperature to proton temperature ratio of 1/v^2.