Spectral model (in XSPEC atable format) of X-ray emission
from warm-hot intergalactic medium, calculated in Khabibullin \& Churazov 2019
(https://ui.adsabs.harvard.edu/abs/2019MNRAS.482.4972K/abstract)
as proposed earlier by Churazov et al. 2001
(https://ui.adsabs.harvard.edu/abs/2001MNRAS.323...93C/abstract).

Total emission is given by igmDTz03bct.fits,
contribution of the resonantly scattered CXB is in igmDTz03bcs.fits.
Purely thermal (CIE) emission from gas with the same parameters is presented
for comparison by igmDTz03bcth.fits.

Parameters of the model are:

1) logarithm of hydrogen number density $n_{H}$, 
2) logarithm of temperature T
3) redshift
4) normalisation defined as slab's hydrogen column density relative to $N_{H}=1.5\times10^{18}~cm^{-2}$
(corresponding to $\tau_T=10^{-6}$).

The model predicts surface brightness of X-ray emission from such a slab (in erg/s/cm$^2$/sr).
Corresponding gas emissivity $\epsilon$ can be calculated as $4\pi*M/n_{H}$,
so that luminosity of the volume element dV equals $L=\epsilon*n_{H}^2*dV$.

Assumed gas metallicity equals 0.3 in solar units (relative to Feldman 1992).
Incident radiation field is those of Haardt \& Madau 2010 at z$\sim$0. 

Examples of usage of these models in XSPEC are given by the corresponding *.xcm files.
