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Future Options

There are a number of problem areas for which action has been deferred. Perhaps the most obvious of these arises when an observation is 'deferred' by setting the field flag D=T. The two most common causes for invoking D=T are (a) the target is a cluster of galaxies or a supernova remnant, and the detect algorithm went wild with an excessive number of detections throughout the extended emission, and (b) HRI observations of the same type of target, but for which the SASS detect algorithm aborted. This was built into the SASS whenever there were more than 200 detections per detect cell size.

Another option would be the merging of sequences which cover the same field in the sky (or are overlapping). An example for this is the many deep pointings to the Lockman hole. A third possibility concerns the combination of adjacent pointings for sources of very large angular extent, like the mosaic-observations of M31. Also all extended sources need to be re-examined with new algorithms because the original SASS software was optimized for unresolved sources. Therefore both positions and intensities of extended sources are not reliably measured. Another natural extension of our current effort would be the collection of source information from other wave bands.

Since all of these problems would involve a substantial investment in new software and since all of the contributing sites have experienced reductions in ROSAT  funding and hence manpower, there are no current plans to implement solutions.

The work at SAO was supported by NASA contract 5-30934.

Wed Jun 3 11:20:57 EDT 1998