Spectral parameter values as a function of phase. In each plot, black points are parameter values for Observation I and red points are for Observation II. The black points are connected with dashed black lines and the rotational cycle is plotted twice for clarity. 1σ errors are marked for each parameter. Top left panel: variation of 3–79 keV flux as a function of rotational phase. The error bars in flux are typically 0.4%, too small to be seen on this plot. Bottom left panel: variation of power-law index Γ. Top, middle, and bottom right panels: variation of CRSF central energy, width, and optical depth, respectively. The central energy peaks in phase with the luminosity, similar to observations in most other pulsars.