bknpower, zbknpower: broken power law

bknpower is a broken power law and zbknpower a redshifted variant.

where:

par1 = | power law photon index for |

par2 = | break point for the energy in keV |

par3 = | power law photon index for |

norm = K | photons/keV/cm/s at 1 keV |

The formula and parameters for the redshifted variant are:

where:

par1 = | power law photon index for |

par2 = | break point for the energy in keV |

par3 = | power law photon index for |

par4 = | redshift |

norm = K | photons/keV/cm/s at 1 keV |

If POW_EMIN and POW_EMAX have been defined by the xset command then the norm becomes the flux in units of ergs/cm/s over the energy range (POW_EMIN, POW_EMAX) keV unless POW_EMIN = POW_EMAX in which case the norm becomes the flux density in micro-Jansky at POW_EMIN keV. In these cases it is important that POW_EMIN and POW_EMAX lie within the energy range on which the model is being evaluated.