XMM-Newton Usage Scenarios

The usage scenarios (or prototype use-cases) listed below have been collected by Mike Watson. He canvassed potential users of the XMM-Newton SSC database since the first XMM-Newton source cataloge is about to be made public. I have edited the responses slightly to remove duplication and clarify some of them with my comments in italics

I have posted these here because although these are somewhat specific to the X-ray field, they provide a good indication of the types of basic data mining functionality that I think AstroGrid should eventually support (and posted them here because there didn't seem to be any other good place for them on the Wiki).

1. Compute Fx/Fopt (or something proportional to them) for associations within x arcsecs of the X-ray position; plot/tabulate Fx/Fopt versus optical magnitude sd s diagnostic of different source types. (Note: Fx/Fopt is X-ray to optical flux ratio)
2. Plot/tabulate HR2 vs HR1 and similar ratios, another diagnostic of different source types. (Note: HR means hardness ratio, ratio of flux in two bands)
3. Plot/tabulate XMM flux versus ROSAT flux to check for long-term variability (Note: this depends upon having a cross-identification with the ROSAT catalogue)
4. Find all XMM sources within x arcsecs of an entry in a specified star catalogue, such as the Bright Star Catalog, Catalog of Nearby Stars, etc.
5. Extract all sources with a specified galactic longitude/latitude box, e.g. 0<l<270, |b|<10.
6. Import own catalogue and perform cross-match with XMM catalogue. Output should be: correlated XMM catalogue object where there is a match, flux upper limits where there is not detection but the area was covered, a null indication where sky area was not included in the catalogue fields. (This needs not just an outer fuzzy join, but also a search of the list of the fields of view which contributed to the catalogue)
7. Compare fluxes measured with PN and MOS instruments to see if they are consistent or whether there were any calibration errors.
8. Plot/tabulate the ratio of flux to count-rate versus off-axis angle, to check whether the vignetting correction has been incorporated correctly.
9. Plot/tabulate mean hardness ratios as a function of off-axis angle to see if the instrument has any energy-dependence in its vignetting function.
10. Search catalogue by object-name (as in Simbad, NED) and list objects found sorted by distance from the position of the named object.
11. Browse the catalogue or the previously selected subset of it: it should be possible to select which parameters (columns) are shown, and the links to thumbnail images of the objects should be shown.
12. Download the selected subset of the catalogue to local storage in some suitable format.
13. Select objects by parameters other than by position or name, e.g. by flux, hardness ratio, or classification (possibly from cross-identifications).
14. Find objects with multiple observations (e.g. from different epochs)
15. For a given position in the sky, find the number of times it was observed, with exposure time, sensitivity, etc.

-- ClivePage - 11 Dec 2002