XMM-Newton Science Analysis System


ommosaic (ommosaic-2.11) [xmmsas_20230412_1735-21.0.0]

Stacking of sky-images from differeent observations

Figure 1 shows the image from the stacking of each of the V-band full-frame sky images from 4 SA-95 observations. The command-line to produce the image was,

ommosaic imagesets=”P0134921001OMS001FSIMAGV000.FIT P0134921101OMS001FSIMAGV000.FIT P0154150201OMS001FSIMAGV000.FIT P0410780201OMS008FSIMAGV000.FIT" mosaicedset=testimage.fits mincorr=0”. Setting mincorr to 0.0 resulted in the images being stacked without being aligned. Omdetect was also run on the image, and the detected source-regions are shown overlaid on the image.

Figure 1: V-band sky-image produced from stacking the V-band full-frame sky-image from 4 SA-95 observations. The detected source regions are shown.

A careful inspection of the image shows the following features

1. Three read out streaks associated with the bright source near the lower left-hand side of the image, each one having a different orientation.

Figure 2 shows the stacked exposure image. The central region has an exposure about 5 times greater than that of a single image.

Figure 2: V-band exposure-image (seconds) produced from stacking the V-band full-frame sky-image from 4 SA-95 observations. The exposure varies from 1791 (light-brown) to 7224 (blue) and the area outside the image is white

Figure 3 shows the stacked quality image. The central-enhancement regions (large circles near the centre), read-out streaks, bright-sources and edges are clearly seen.

Figure 3: V-band quality-image produced from stacking the V-band full-frame sky-image from 4 SA-95 observations