The present work investigates the calculation of absorption and emission
cyclotron line profiles in the non-relativistic and trans-relativistic regimes.
We provide fits for the ten first harmonics with synthetic functions down to
10^(-4) of the maximum flux with an accuracy of 20 per cent at worst. The lines
at a given particle energy are calculated from the integration of the Schott
formula over the photon and the particle solid angles relative to the magnetic
field direction. The method can easily be extended to a larger number of
harmonics. We also derive spectral fits of thermal emission line plasmas at
non-relativistic and trans-relativistic temperatures extending previous
parameterisations.Comment: 11 pages, 11 figures, accepted for publication in Astronomy &
Astrophysic