XMM-Newton Science Analysis System: User Guide

6.2.2 Handling of tracking data

Two output datasets related to tracking data are distributed as pipeline products, namely the TSHPLT.PDF and the TSTRT.FIT file. They are created as follows.

• omprep (step1). The task omprep does not generate final data products but only intermediate files. OM images, tracking history files and fast mode files if any, are copied into temporary files. Further information is added via keywords. Intermediate products are generated, which carry information extracted from the tracking history file. If no tracking history file was produced, these are generated on the fly assuming perfect stable pointing. Tracking history data can be missing if no suitable tracking stars were available during the observation. This can also occur when certain instrument modes (full frame, engineering modes) or when some filter elements (e.g. grisms) are used.

• omdrifthist (step2). This task creates the TSHPLT.ps file (TSHPLT.PDF in the pipeline processing), which provides an overview of the pointing stability during an exposure. The file contains diagrams illustrating the absolute and incremental OM drift.

• omthconv (step3). This task creates the TSTRTS.FIT file, which contains the tracking star time series, i.e the average count rate (cts/s) per tracking frame for each tracking star.