swind1: absorption by partially ionized material with large velocity shear

A model to fit the soft excess in AGN by partially ionized absorbing material with large velocity shear. It approximates this by using XSTAR kn5 photoionization absorption model grids (calculated assuming a microturbulent velocity of 100km/s), and then convolving this with Gaussian smearing. This is the model used by Gierlinski & Done (2006), Sobolewska & Done (2007) and Done et al (2006). It is an update (uses a newer version of XSTAR) of the original model of Gierlinski & Done (2004).

par1 column density ($10^{22}$ cm$^{-2}$)
par2 log(xi) where xi = $L/nr^2$
par3 sigma : Gaussian sigma for velocity smearing (v/c)
par4 redshift