Non-equilibrium ionization collisional plasma model. This assumes a constant temperature and single ionization parameter. It provides a characterization of the spectrum but is not a physical model. The references for this model can be found under the description of the equil model. Several versions are available. To switch between them use the xset neivers command. The versions available are:
1.0 | the version from xspec v11.1 |
1.1 | as 1.0 but with updated ionization fractions using dielectronic recombination rates from Mazzotta et al (1998) |
2.0 | same ionization fractions as 1.1 but uses AtomDB v2 to calculate the resulting spectrum |
3.x | ionization fractions and spectrum calculation uses AtomDB v3.x |
Note that versions 1.x have no emission from Ar. Versions 3.x and later can have their behaviour changed using a number of options with the xset command.
NEIAPECROOT | |
By default this model reads atomic physics continuum and line data from the files apec_v[version]_nei_comp.fits and apec_v[version]_nei_line.fits in $HEADAS/../spectral/modelData. There are several options to specify different files. NEIAPECROOT can be set to a version number (eg 3.0.3, 3.0.7). In this case the value of NEIAPECROOT will be used to replace the default version number in the name of the standard files and the resulting files will be assumed to be in the modelData directory. Alternatively, a filename root (eg apec_v3.0.3) can be given. This root will be used as a prefix for the _nei_comp.fits and _nei_line.fits files. Finally, if neither of these work then the model will assume that the NEIAPECROOT value gives the complete directory path (eg /foo/bar/apec_v3.0.3 will use the input files /foo/bar/apec_v3.0.3_nei_comp.fits and /foo/bar/apec_v3.0.3_nei_line.fits). | |
APECTHERMAL | |
Setting this option to yes thermally broadens lines. This runs significantly slower than the option without thermal broadening so should only be used when necessary. | |
APECVELOCITY | |
Setting this option to a number velocity broadens lines using the given number as the line sigma in km/s. This is added in Gaussian quadrature with any thermal broadening in use. | |
APECMINFLUX | |
Setting this option to some flux will ensure that all lines below this flux are not broadened. | |
APECBROADPSEUDO | |
Setting this option to yes changes the default behaviour not to broaden the pseudo-continuum (low-flux lines which are not individually stored in the AtomDB output files) even if the stronger lines are being broadened. | |
APECNOLINES | |
Setting this option to yes producesa continuum-only spectrum. This will turn off lines for all models using the apec files. Note that a line-free version of a single apec model is available as nlapec. | |
APEC_TRACE_ABUND | |
This option can be used to set the abundances of the trace elements (ie Li, Be, B, F, Na, P, Cl, K, Sc, Ti, V, Cr, Mn, Co, Cu, Zn) when vv variants of models are not being used. These trace element abundances can be set either to the abundance of one of the main elements (give a string argument such as Fe) or to a numerical value (relative to Solar). | |
APECLOGINTERP | |
Setting this option to yes uses logarithmic interpolation between tabulated temperatures. | |
APECMULTITHREAD | |
Setting this option to yes parallelizes over temperatures for the calculation of the lines in the spectrum. For the basic model, for which only two temperatures are calculated, this does not provide a speed advantage unless line broadening is selected. However, for models which combine multiple temperatures such as cooling flow or NEI models multithreading can provide a significant speed increase. | |
APECEEBREMSS | |
Setting this option to yes includes calculation of the e-e bremsstrahlung. |
For the nei model the parameters are:
par1 | plasma temperature (keV) |
par2 | Metal abundances (He fixed at that defined by the abund command). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are defined by the abund command |
par3 | Ionization timescale in units of s/cm. |
par4 | redshift |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |
For the vnei model, the parameters are:
par1 | plasma temperature (keV) |
par2 | H abundance (set to 0 for no free-free continuum, otherwise 1) |
par3-par14 | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) |
par15 | Ionization timescale in units of s/cm. |
par16 | Redshift, z |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |
For the vvnei model, the parameters are:
par1 | plasma temperature (keV) |
par2 | H abundance (set to 0 for no free-free continuum, otherwise 1) |
par3-par31 | Abundances for all elements with 2 Z 30 wrt Solar (defined by the abund command) |
par32 | Ionization timescale in units of s/cm. |
par33 | Redshift, z |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |
For the bnei model the parameters are:
par1 | plasma temperature (keV) |
par2 | Metal abundances (He fixed at that defined by the abund command). The elements included are C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni. Abundances are defined by the abund command |
par3 | Ionization timescale in units of s/cm. |
par4 | redshift |
par5 | gaussian velocity broadening (sigma in km/s) |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |
For the bvnei model, the parameters are:
par1 | plasma temperature (keV) |
par2 | H abundance (set to 0 for no free-free continuum, otherwise 1) |
par3-par14 | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) |
par15 | Ionization timescale in units of s/cm. |
par16 | Redshift, z |
par17 | gaussian velocity broadening (sigma in km/s) |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |
Finally, for the bvvnei model, the parameters are:
par1 | plasma temperature (keV) |
par2 | H abundance (set to 0 for no free-free continuum, otherwise 1) |
par3-par31 | Abundances for all elements with 2 Z 30 wrt Solar (defined by the abund command) |
par32 | Ionization timescale in units of s/cm. |
par33 | Redshift, z |
par34 | gaussian velocity broadening (sigma in km/s) |
norm | , where is the angular diameter distance to the source (cm), is the volume element (cm), and and are the electron and H densities (cm), respectively |