How is the exposure map created? Is deadtime corrected?
The exposure map is created in SASS from the aspect histogram and the modified instrument map. In other words, the exposure map is the detector map projected by the attitude data, with a resolution of 15 arcsec per pixel. (The detector map comes from a flat field image created from all-sky survey data. The data in the pulse-height range 42-131 were used, and the vignetting function is therefore the weighted average derived from the "average" sky spectrum in that range. The map is normalized to the average value of the inner 10' diameter. NOTE: The exposure map does NOT include the mesh transmission fraction, but only the structure. The mesh transmission appears in the effective area.
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