c6mekl, c6vmekl, c6pmekl, c6pvmkl: differential emission measure using Chebyshev representations with multi-temperature mekal

c6mekl is a multi-temperature mekal or
apec model using sixth-order Chebyshev polynomial for the
differential emission measure. The DEM is not constrained to be
positive.. The `switch` parameter determines whether spectrum is
calculated by running the mekal code, by interpolating on a
pre-calculated mekal table, or using the apec model. The final option
is now preferred. The reference for this model is Singh et al. (1996,
ApJ, 456, 766).

c6pmekl differs by using the exponential of the 6th order Chebyshev polynomial

c6mekl and c6pmekl use abundances relative to the Solar abundances set by the abund command.

The variants c6vmekl and c6pvmkl with polynomial and exponential polynomial respectively allow the user to specify 14 elemental abundance.

For c6mekl and c6pmekl the parameters are:

par1-6 | Chebyshev polynomial coefficients |

par7 | H density (cm) |

par8 | abundance wrt to Solar |

par9 | Redshift |

par10 | Switch (0 = calculate, 1 = interpolate, 2 = interpolate using APEC model). |

norm | Normalization |

While for c6vmekl and c6pvmkl the parameters are:

par1-6 | Chebyshev polynomial coefficients |

par7 | H density (cm) |

par8-21 | Abundances of He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, Ni wrt Solar (defined by the abund command) |

par22 | Redshift |

par23 | Switch (0 = calculate, 1 = interpolate, 2 = interpolate using APEC model). |

norm | Normalization |