Emission Measures and Emission-measure-weighted Temperatures of Shocked
  ISM and Ejecta in Supernova Remnants
  A goal of supernova remnant (SNR) evolution models is to relate fundamental
parameters of a supernova (SN) explosion and progenitor star to the current
state of its SNR. The SNR hot plasma is characterized by its observed X-ray
spectrum, which yields electron temperature, emission measure and abundances.
Depending on their brightness, the properties of the plasmas heated by the SNR
forward shock, reverse shock or both can be measured. The current work utilizes
models which are spherically symmetric. One dimensional hydrodynamic
simulations are carried out for SNR evolution prior to onset of radiative
losses. From these, we derive dimensionless emission measures and
emission-measure-weighted temperatures, and we present fitting formulae for
these quantities as functions of scaled SNR time. These models allow one to
infer SNR explosion energy, circumstellar medium density, age, ejecta mass and
ejecta density profile from SNR observations. The new results are incorporated
into the SNR modelling code SNRPy. The code is demonstrated with application to
three historical SNRs: Kepler, Tycho and SN1006.
