Relation between magnetic field strength and intersection energy. Top panel: cyclotron line energies from literature versus intersection energies as obtained in this work. Black data points: sources with magnetic fields known from CRSF observations. Red line: linear regression taking uncertainties of E_CRSF and E_int into account that is based on the four data points, with the relation is given in the lower right corner of the panel. Bottom panel: Residual of the best fit in units of the individual ratio uncertainty, σ_i.