BeppoSAX studies of cyclotron features in the spectrum of binary pulsars

The detection of Cyclotron Resonance Scattering Features (CRSFs) in the hig h energy spectra of highly magnetized X-ray binary pulsars provide the only direct method for determining the magnetic field strength close to the sur face of the neutron star. Moreover, variation of the spectral parameters wi th the phase of the pulse provide new information on the constraints that m odels for those sources must satisfy. Using the broad band coverage (from 0 .1 up to 200 keV) of the Narrow Field Instruments, BeppoSAX has enabled the continuum as well as the CRSFs studies in many sources of that class. In t his work we report results on the pulse phase averaged spectra of X-ray pul sars with the main emphasis on overall properties of the cyclotron features . We also show results on pulse phase resolved spectroscopy for some of the sources of the class.