cutoffpl, zcutoffpl: power law, high energy exponential cutoff

A power law with high energy exponential rolloff.

where:

par1 | , power law photon index |

par2 | , e-folding energy of exponential rolloff (in keV) |

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

zcutoffpl is a variant which computes a redshifted spectrum using the parameters:

par1 | , power law photon index |

par2 | , e-folding energy of exponential rolloff (in keV) |

par3 | , redshift |

norm | K in photons/keV/cm/s at 1 keV in the source frame |

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.