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npshock, vnpshock: shocked plasma, plane parallel, separate ion, electron temperatures.

Plane-parallel shock plasma 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 (1998), and 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 vnpshock variant allows the user to set the abundances of the most common elements and vvnpshock allows the user to set the abundances of all elements with Z<=30.

 

Parameters for npshock 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. Abundances are given by the Anders & Grevesse mixture.

par4

Lower limit on ionization timescale in units of s/cm3.

par5

Upper limit on ionization timescale in units of s/cm3.

par6

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.

 

For vnpshock the parameters are:

 

 

par1

Mean shock temperature (keV)

par2

electron temperature immediately behind the shock front (keV)

par3

H abundance (should take values of 0 or 1 to switch on and off free-free continuum).

par4-par15

Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (given by the Anders & Grevesse mixture)

par16

Lower limit on ionization timescale in units of s/cm3.

par17

Upper limit on ionization timescale in units of s/cm3.

par18

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.

 

For vvnpshock the parameters are:

 

 

par1

Mean shock temperature (keV)

par2

electron temperature immediately behind the shock front (keV)

par3

H abundance (should take values of 0 or 1 to switch on and off free-free continuum).

par4-par32

Abundances for all elements with 2 <= Z <= 30 wrt Solar (defined by the abund command)

par33

Lower limit on ionization timescale in units of s/cm3.

par34

Upper limit on ionization timescale in units of s/cm3.

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.

 

 

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Next: Nsa Up: Additive Model Components Previous: Nei