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##

equil, vequil: collisional plasma, ionization equilibrium

Ionization equilibrium collisional plasma model. This is the
equilibrium version of Kazik Borkowski's NEI models. 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. For versions 3.x and
later additional xset options are available and are listed
under the documentation for nei.

For the equil 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 |
redshift |

norm |
, where is
the angular diameter distance to the source (cm), is the
electron density (cm), and is the hydrogen density
(cm). |

For the vequil model, the parameters are:

par1 |
plasma temperature (keV) |

par2-par13 |
Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe,
Ni wrt Solar (defined by the abund command) |

par14 |
Redshift, z |

norm |
, where is
the angular diameter distance to the source (cm), is the
electron density (cm), and is the hydrogen density
(cm). |

The references for this model are as follows:

Borkowski, Lyerly & Reynolds (2001)

Hamilton, Sarazin & Chevalier (1983)

Borkowski, Sarazin & Blondin (1994)

Liedahl, Osterheld & Goldstein (1995)

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