Two-dimensional probability contours between the fitted parameters of the fundamental cyclotron line (a depth, τ_CRSF, 0 (CYCLABS) and D_CRSF, 0 (GABS); b energy, E_CRSF, 0) and the centroid energy, E_10 keV, of the 10 keV feature calculated by a MCMC method for epoch II and both CRSF models (CYCLABS, red; GABS, blue). The contours correspond to the 68% (solid line), 90% (dashed line), and 99% confidence levels (dotted line) according to the MCMC walker distribution. The crosses are our best-fit parameters and their uncertainties using χ²-minimization (see Table 1).