Compton neutral reflection with self-consistent Fe and Ni lines.

This model from Nandra et al. (2007) combines pexrav with self-consistently generated Fe Kα, Fe Kβ, Ni Kα and Fe Kα Compton shoulder.

Line strengths are based on Monte Carlo calculations by George and Fabian (1991) which are parametrized for 1.1 < Γ < 2.5 by :

EW = 9.66 EW0-2.8 - 0.56)
with inclination dependence for for i < 85 degrees :
EW = EW0 (2.20 cos i - 1.749 (cos i)2 + 0.541 (cos i)3)
and abundance dependence :
log EW = log EW0 (0.0641 log AFe - 0.172 (log AFe)2)
The Fe Kβ and Ni Kα line fluxes are 11.3% and 5% respectively of that for Fe Kα. The Fe Kα Compton shoulder is approximated as gaussian with E = 6.315 keV and σ = 0.035 keV. The inclination dependence is taken from Matt (2002) such that :
EWshoulder = EWFe Kα (0.1 + 0.1 cos i)

Model parameters are:

  • 1: Γ, power-law photon index, NE ∝ E.
  • 2: Ec, cutoff energy in keV (if Ec = 0 there is no cutoff; one needs to change the lower limit for that)
  • 3: scale, scaling factor for reflection; if <0, no direct component (scale=1 for isotropic source above disk)
  • 4: redshift, z
  • 5: abundance of elements heavier than He relative to the solar abundances
  • 6: iron abundance relative to the solar iron abundance
  • 7: inclination angle (degrees)
  • Normalization is the photon flux at 1 keV (photons keV-1 cm-2 s-1) of the cutoff power law only (without reflection) and in the earth frame.
To use this model download the source code, pexmon.f, and the model description file, pexmon_lmodel.dat and build as a local model. NB pexmon.f was updated on 2/23/2012 to fix a bug which caused the redshift correction to be applied twice to the reflected continuum.


Keith Arnaud, Lab. for High Energy Astrophysics, NASA/Goddard Space Flight Center

Xspec Xspec Home Page


HEASARC Home | Observatories | Archive | Calibration | Software | Tools | Students/Teachers/Public

Last modified: Thursday, 23-Feb-2012 11:42:18 EST