Xspec Redistribution Functions htsmooth: asymmetric broadening functionemcomp: empirical function that reproduces a Compton scattering profile Preface These two convolution models empirically reproduce asymmetrically broadened or Compton down-scattered spectra. They use the calcManyLines generic code in the Xspec spectral fitting software in HEASoft, which is used in the gsmooth function and other smoothing functions, and is provided as calcLinesLM.cxx in this distribution. Model: htsmooth The htsmooth (Half-Triangle SMOOTH) model redistributes the flux within each spectral bin (Ebin) to a half-triangular distribution. The model includes a single parameter, MaxVel, in units of km/s, which represents the maximum absolute radial velocity at the end of the half-triangle. A negative MaxVel value indicates a blueshift, while a positive value indicates a redshift, extending the triangle into the higher- or lower-energy range, respectively. Parameter Units Description MaxVel km/s maximum absolute radial velocity at the end of the half-triangle Model: emcomp The emcomp (EMpirical COMPton) model redistributes the flux within each spectral bin (Ebin) to a trapezoidal distribution, defined down to the 180-degree Compton backscattering energy ($E_{\rm BS}$) using the Smallest Scattering Cut (SSC), Smallest Scattering Fraction (SSF), Largest Scattering Cut (LSC), and Largest Scattering Fraction (LSF). The 180-degree Compton backscattering energy ($E_{\rm BS}$) is: $$E_{\rm BS} = \frac{E_{\rm bin}}{1+2(E_{\rm bin}/511~{\rm keV})}$$ The Compton Flux Ratio (CFR) parameter is the ratio of the Compton-scattering flux to the source flux. Parameter Description CompFluxR Compton Flux Ratio (CFR) - ratio of the Compton-scattering flux to the source flux. SmScatCut Smallest Scattering Cut (SSC) SmScatFrac Smallest Scattering Fraction (SSF) LgScatCut Largest Scattering Cut (LSC) LgScatFrac Largest Scattering Fraction (LSF) The CFR parameter controls the Compton scattering flux, and the CSF and LSF parameters only define the trapezoid shape. Therefore, either the CSF or the LSF parameter must be fixed to obtain a single solution. Meanwhile, the model breaks when LSC xspec XSPEC12>initpackage redistmodels /path/to//lmodel.dat /path/to/redistmodels/XSPEC12>lmod models /path/to/redistmodels/