4.1.17. Euve: EUVE absorption model

This model calculates the transmission of gas with cosmic abundances as published first by Rumph et al. (1994). It is a widely used model for the transmission at wavelenghts covered by the EUVE satellite (\lambda > 70 Å). As it these wavelengths metals are relatively unimportant, it only takes into account hydrogen and helium, but for these elements it takes into account resonances. However it is not recommended to use the model for harder X-rays, due to the neglect of metals such as oxygen etc.

Otherwise the user is advised to use the absm model (Absm: Morrison & McCammon absorption model) or the hot model (Hot: collisional ionisation equilibrium absorption model) with low temperature in SPEX, which gives the transmission of a slab in collisional ionisation equilibrium.

The parameters of the model are:

nh : Hydrogen column density in 10^{28} \mathrm{m}^{-2}. Default value: 10^{-4} (corresponding to 10^{24} \mathrm{m}^{-2}, a typical value at low Galactic latitudes).
he1 : The He  / H  ratio. Default value: 0.1.
he2 : The He  / H  ratio. Default value: 0.01.
f : The covering factor of the absorber. Default value: 1 (full covering)

Recommended citation: Rumph et al. (1994).