XMM-Newton Science Analysis System


edetect_stack (edetect_stack-0.8.1) [xmmsas_20230412_1735-21.0.0]

General structure

General structure of edetect_stack, starting from event lists, attitude information and ODF summary files:

• sort input files and determine the number of different pointings
• set up the common coordinate system: choose reference coordinates and image size from the pointing coordinates and the position angles of the input files (if not explicitly given by the user)
• check whether all imput pointings are overlapping: If the field of view of an input pointing is not overlapping with any other field by at least 3 arcmin in radius, edetect_stack exits with an error. If the full fields of view are overlapping, but a pointing is not overlapping with the user-chosen area of interest (reference coordinates & image size), this pointing is ignored, and a warning ist thrown.
• project the input event lists onto the reference coordinate system
• prepare the input files to source detection per pointing (stages $2-7$, see below)
• perform stacked source detection on all pointings simultaneously
• create the final source list, which includes information on the detections in the individual pointings and all-EPIC, and a summary source list, which includes one all-EPIC row per valid detection.

Each input image is combined with its respective background image, exposure map, and detection mask. Within a cut-out radius about each tentative detection, the appropriate PSFs are chosen for all valid images, as illustrated in Fig. 1, and source position, counts, and extent are fit simultaneously.

Figure 1: Combining the PSFs of different instruments and observations (offset angles) within the source cut-out radius.