pwab: power-law distribution of neutral absorbers

An extension of partial covering fraction absorption into a power-law distribution of covering fraction as a function of column density, built from the wabs code.  See Done & Magdziarz 1998 (MNRAS 298, 737) for details.

 

 par1   = minimum equivalent hydrogen column (in units of 10**22 atoms/cm**2)

 par2   = maximum equivalent hydrogen column (in units of 10**22 atoms/cm**2)

 par3   = power law index for covering fraction.