disko: accretion disk, inner, radiation pressure viscosity

A modified blackbody disk model. The spectrum from the inner region of an accretion disk where the viscosity is dominated by radiation pressure.

par1 accretion rate in Eddington Luminosities
par2 central mass in solar mass units
par3 inner disk radius in gravitational (= 3 Schwarzschild radii)
par4 viscosity
norm $2 \cos(i)/d^2$ where $i$ is the inclination of the disk and $d$ is the distance in units of 10 kpc