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wndabs, zwndabs: photo-electric absorption, warm absorber

Photo-electric absorption from approximation to a warm absorber using Balucinska-Church & McCammon (1992) cross-sections. Relative abundances are set by the abund command.

$\displaystyle M(E) = \begin{array}{ll} 1 & E > E_w \\ [.2cm]\exp[-\eta_H\sigma(E)] & E \leq E_w \end{array}$

where $\sigma(E)$ is the photo-electric cross-section (NOT including Thomson scattering) and

par1=$\eta_H$ equivalent hydrogen column (in units of $10^{22}$ atoms cm$^{-2}$)
par2=$E_w$ window energy (keV)

The zwndabs variant allows the user to specify a (fixed) redshift and uses the corresponding formula:

$\displaystyle M(E) = \begin{array}{ll} 1 & E > E_w \\ [.2cm]\exp[-\eta_H\sigma(E[1+z])] & E \leq E_w \end{array}$

with parameters:

par1=$\eta_H$ equivalent hydrogen column (in units of $10^{22}$ atoms cm$^{-2}$)
par2=$E_w$ window energy (keV)
par3=z redshift