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            pcfabs, zpcfabs:  partial covering fraction absorption

A partial covering fraction absorption. The relative abundances are set by the abund command.

M(E) = f*exp(-n_H*sigma(E)) + (1-f)

where s(E) is the photo-electric cross-section (NOT including Thomson scattering) (see phabs) and:

par1= nH

equivalent hydrogen column (in units of 1022 atoms cm–2)

par2= f

covering fraction 0 < par2 < 1 (dimensionless)

The redshifted variant zpcfabs is given by:

M(E) = n_H*exp[-f*sigma(E[1+z])] + 1 - f

where s(E) is the photo-electric cross-section (NOT including Thomson scattering) (see phabs). Relative abundances are as for pcfabs. Parameters are:

par1= nH

equivalent hydrogen column (in units of 1022 atoms cm–2)

par2= f

dimensionless covering fraction (0 < f <= 1)

par3= z

redshift