rnei, vrnei, vvrnei: non-equilibrium recombining collisional plasma

Non-equilibrium ionization collisional plasma model. This is a model
for a recombining plasma where the plasma is
assumed to have started in collisional equilibrium with the initial
temperature given by the relevant input parameter. This model will
only work for xset **neivers 3.0** and above. Additional
xset options are available and are listed under the
documentation for nei.

For the rnei model the parameters are:

par1 | Plasma temperature (keV) |

par2 | Initial plasma temperature (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 defined by the abund command |

par4 | Ionization timescale in units of s/cm. |

par5 | 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 vrnei model, the parameters are:

par1 | Plasma temperature (keV) |

par2 | Initial plasma temperature (keV) |

par3 | H abundance (set to 0 for no free-free continuum, otherwise 1) |

par4-par15 | Abundances for He, C, N, O, Ne, Mg, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) |

par16 | Ionization timescale in units of s/cm. |

par17 | Redshift, z |

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

Finally, for the vvrnei model, the parameters are:

par1 | Plasma temperature (keV) |

par2 | Initial plasma temperature (keV) |

par3 | H abundance (set to 0 for no free-free continuum, otherwise 1) |

par4-par32 | Abundances for all elements with 2 Z 30 wrt Solar (defined by the abund command) |

par33 | Ionization timescale in units of s/cm. |

par34 | Redshift, z |

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