A Systematic Study of the X-ray Cyclotron-Line Sources Observed by BeppoSAX

Abstract

X-ray pulsars are neutron stars in binary systems in which the compact object accretes plasma from a non-degenerate primary stellar companions. The observed phenomenology of accreting pulsars is rather complex. We observe light curves, spin and orbital periods and their variability, energy dependent pulse profiles, as well as pulse and time dependent energy spectra. It is through the understanding of these phenomena, and their comparison with theoretical models, that mechanisms for the formation and transport of radiation in accreting pulsars can be studied and understood. This work presents a systematic study of a sample of X-ray pulsars observed with the BeppoSAX mission. Most of these data were analysed for the first time in this work. The sample includes all observed sources that show a cyclotron line feature in their energy spectra. Through this study general properties of the accreting pulsars sample have been obtained, including several correlations between the cyclotron line parameters and the spectral continuum.