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Fig. 1


Sky exposure with SPI for the data set analysed. The units of the map are given in cm2s. The equivalent exposure time is calculated for 19 detectors with an effective area of ~ 75 cm2 for photon energies around 511 keV. The contours, starting from the innermost, correspond to exposures of 22 Ms, 16 Ms, 9 Ms, 4 Ms, 2 Ms, 1 Ms, 0.5 Ms, and 0.1 Ms, respectively. The total exposure time is 160 Ms.

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