Data processing

The source catalogue from overlapping observations is based on archival XMM-Newton attitude files and event lists which were processed with the XMM-Newton Science Analysis Software. The 2XMM User Guide describes the catalogue pipeline in details, the User Guides to 3XMM-DR4 and 3XMM-DR7 list the updates for the 3XMM catalogue series and 4XMM-DR9 for the 4XMM catalogue series. For the stacked catalogue, the data handling has been adjusted to the needs of source detection on multiple observations, using the same parameters as in the 4XMM pipeline wherever applicable. The new standardised approach to perform stacked source detection on multiple observations is available as SAS tasks edetect_stack. Input data to source detection are prepared for each observation individually, and source detection is run on all input data in parallel, namely: images, exposure maps, and background maps for each observation, instrument, and energy band, and detection masks for each observation and instrument. The final source parameters are calculated by edetect_stack.