  We present accurate analytic fitting formulae which summarize the results of
the recent calculation by Nozawa, Itoh and Kohyama on the relativistic thermal
bremsstrahlung Gaunt factor for the intracluster plasma. The fitting is carried
out for Z = 1 to 28, 6.0 < log T < 8.5, -4.0 < log (omega/kT) < 1.0, where Z is
the charge number of the ion, T is the temperature, and omega is the angular
frequency of the emitted photon. The present analytic fitting formulae will be
useful for the analysis of the X-ray emission which comes from the intracluster
plasma as well as the other X-ray sources.
