Generate SRCFIT table for stack merged source list

Create the basic merged source list file, with one row for each detection in the stack. At this stage, the file just contains the SRCFIT table. The same source may be detected multiple times and so have more than one row for the same source. We also estimate errors from the MLE draws:

• calculate the position error ellipse for each entry. Use the MLE draws.
• calculate the errors on the source amplitude and the extent parameters, also using the MLE draws.

Generate SRCLIST table in merged source list

For each source, calculate the largest likelihood value among the detections, according to the MLE recipe. Copy this entry to the SRCLIST table, which has one row per source. Tag each source as TRUE, MARGINAL, or FALSE depending on the likelihood.

Append other tables to merged source list

Take the WAVSRC table which was output by the wavdetect detection step and the MPNTSRC, MEXTSRC tables of point and extended sources created by the mkvtbkg step, and append them to the merged source list file for the record.

Set certain flags

Set flag in the SRCFIT table if the source lies on an ACIS bright source readout streak. Update the edge flags (src_edge_valid_〈band〉, ext_edge_valid_〈band〉); edge flags are TRUE if the source is close to the detector edge and FALSE if it is not. If the distance from the source to the edge is not calculated the value may be NULL.