HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.

Search:

[Advanced Search]



next up previous contents Xspec Home Page
Next: pexriv: reflected powerlaw, ionized Up: Additive Model Components Previous: pexmon: neutral Compton reflection


pexrav: reflected powerlaw, neutral medium

Exponentially cut off power law spectrum reflected from neutral material (Magdziarz & Zdziarski 1995). The output spectrum is the sum of the cut-off power law and the reflection component. The reflection component alone can be obtained for $rel_{refl} < 0$. Then the actual reflection normalization is $\vert rel_{refl}\vert$. Note that you need to then change the limits of $rel_{refl}$ to exclude zero (as then the direct component appears). If $E_c$ = 0 there is no cutoff in the power law. The metal and iron abundance are variable with respect to those defined by the command abund. The opacities are those set by the command xsect. As expected in AGNs, H and He are assumed to be fully ionized

The core of this model is a Greens' function integration with one numerical integral performed for each model energy. The numerical integration is done using an adaptive method which continues until a given estimated fractional precision is reached. The precision can be changed by setting PEXRAV_PRECISION eg xset PEXRAV_PRECISION 0.05. The default precision is 0.01 (ie 1%).

par1 $\Gamma$, first power law photon index, $N_E \propto E^{\Gamma}$
par2 $E_c$, cutoff energy (keV) (if $E_c$ = 0 there is no cutoff)
par3 $rel_{refl}$, reflection scaling factor (0 = no reflected component, <0 reflection component only)
par4 redshift, z
par5 abundance of elements heavier than He relative to the solar abundances
par6 iron abundance relative to that defined by abund
par7 cosine of inclination angle
norm photon flux at 1 keV (photons/keV/cm$^2$/s) of the cutoff broken power-law only (no reflection) in the observed frame.
next up previous contents Xspec Home Page
Next: pexriv: reflected powerlaw, ionized Up: Additive Model Components Previous: pexmon: neutral Compton reflection
HEASARC Home | Observatories | Archive | Calibration | Software | Tools | Students/Teachers/Public
Last modified: Friday, 23-Aug-2024 13:20:40 EDT

HEASARC Staff Scientist Position - Applications are now being accepted for a Staff Scientist with significant experience and interest in the technical aspects of astrophysics research, to work in the High Energy Astrophysics Science Archive Research Center (HEASARC) at NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. Refer to the AAS Job register for full details.