Corrected neutral Hydrogen HI flux: m21c
The HI line magnitude m21 has been corrected for self-absorption effect
following
Heidmann et al (1972), with parameter kappa=0.031.
The inclination needed to compute this correction is given as
parameter incl.
If inclination is higher than 89 deg the maximum correction is limited
to -0.82 mag.
Corrected flux at other wavelengths are given in the parameters:
bt, it.
The measured HI flux is m21.