Sedov model with separate ion and electron temperatures. This model is slow. par1 provides a measure of the average energy per particle (ions+electrons) and is constant throughout the postshock flow in plane shock models (Borkowski et al., 2001, ApJ, 548, 820). par2 should always be less than par1. If par2 exceeds par1 then their interpretations are switched (ie the larger of par1 and par2 is always the mean temperature). Additional references can be found under the help for the equil model. Several versions are available. To switch between them use the xset neivers command. xset neivers 1.0 gives the version from xspec v11.1, xset neivers 1.1 uses updated calculations of ionization fractions using dielectronic recombination rates from Mazzotta et al (1988), xset neivers 2.0 uses the same ionization fractions as 1.1 but uses APED to calculate the resulting spectrum, and xset neivers 3.0 uses the beta release from AtomDB 3.0. Note that versions 1.x have no emission from Ar. The default is version 3.0.
The vsedov variant allows the user to set the abundances of the most common elements and vvsedov allows the user to set the abundances of all elements with Z<=30..
Parameters for sedov are:
|
par1 |
mean shock temperature (keV) |
|
par2 |
electron temperature immediately behind the shock front (keV) |
|
par3 |
Metal abundances (He fixed at cosmic). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Relative abundances are defined by the abund command |
|
par4 |
ionization age (s cm–3) of the remnant (= electron density immediately behind the shock front multiplied by the age of the remnant) |
|
par5 |
redshift z |
|
norm |
|
For vsedov the parameters are:
|
par1 |
mean shock temperature (keV) |
|
par2 |
electron temperature immediately behind the shock front (keV) |
|
par3 |
H density in cm-3 |
|
par4-par15 |
Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) |
|
par4 |
ionization age (s cm–3) of the remnant (= electron density immediately behind the shock front multiplied by the age of the remnant) |
|
par5 |
redshift z |
|
norm |
|
For vvsedov the parameters are:
|
par1 |
mean shock temperature (keV) |
|
par2 |
electron temperature immediately behind the shock front (keV) |
|
par3 |
H density in cm-3 |
|
par4-par33 |
Abundances for all elements with Z <= 30 wrt Solar (defined by the abund command) |
|
par34 |
ionization age (s cm–3) of the remnant (= electron density immediately behind the shock front multiplied by the age of the remnant) |
|
par35 |
redshift z |
|
norm |
|
where DA
is the angular diameter distance to the source (cm) , and ne ,
nH (cm-3) are the electron and hydrogen
densities respectively.