EWOCS projects: X-ray sources catalog
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The catalog of X-ray sources will be compiled adopting a complex procedure that requires the definition of extraction regions around all putative sources, the extraction of source photons, and the calculations of a statistical parameter defining sources reliability.
The position of photons extraction regions were defined by running all available source detection methods:
- PWDetect in five bands (broad, soft, medium, hard, very hard) across the central part of the merged event file produced setting BIN=1. The threshold is set in order to have about 50 spurious detections in each band. The merged list of sources detected with pwdetect counts 2307 candidate sources
- Wavdetect in five bands (broad, soft, medium, hard, very hard) across both the whole event file (BIN=2) and a central part (BIN=1), setting the sigmathresh parameter equal to 10-4 and adopting only two small detection scales. The merged list of sources detected with wavdetect counts 1841 candidate sources
- A novel method developed by E. Flaccomio, which is aimed at detecting transient sources by running pwdetect in overlapping slices of 10ksec, and then merging the results. The resulting list contains 1147 candidate sources.
- The Image Reconstruction method described by Broos et al. 2010 in four bands (broad, soft, hard, veryhard). The method resulted in 7585 candidate detections. The large number of detections is justified by the fact that the method is more efficient than the other methods in detecting faint sources in bright and irregular background, such as in the cluster core. However, a large number of these detections are expected to be spurious or not significant.
The final list of detections was merged by eye, and it contains 8845 candidate sources.
The figure shows the positions of all the extraction regions colored according to the methods used to define them (pwdetect: red; wavdetect: yellow; pink: variability; green: image reconstruction)