Figure 5.3
Figure 5.3: Sky area as a function of net exposure time (based on vignetted exposure maps) for 3XMM-DR4 catalogue fields. The blue curve shows the total sky area without corrections for field overlaps, while the red line shows the 'actual' sky area, corrected for field overlap. The blue and red arrows indicate the corresponding total sky areas and corrected sky areas, respectively, for the observations in the 2XMMi-DR3 catalogue for exposures ≥ 1ksec.