XMM-Newton Science Analysis System: User Guide

4.8.4 Generating spectra from RGS multi-pointing mode data

In an observation that has been taken in RGS multi-pointing mode, the position of the source on the EPIC detector changes with each exposure (typically the shift between exposures is 15 or 30 arcseconds). This is illustrated in Figure 27.

Figure 27: Example of a source observed in RGS multi-pointing mode in the EPIC-pn small window.

In order to analyse the EPIC data gathered under the RGS multi-pointing mode, SAS needs to know the satellite pointing in each exposure. The procedure to analyse EPIC-pn or EPIC-MOS data changes slightly, mainly, in the way event files for each sub-pointing are derived. Once event files exist for each sub-pointing and EPIC camera, the task arfgen needs to be able to handle the different sub-pointings. This is done by using the attitude history file. In particular, the task arfgen, needs to convert from sky coordinates into detector coordinates by using this file, which is achieved by setting the task parameter useodfatt=yes.

Details on how to proceed in order to analyse EPIC data under the RGS multi-pointing mode can be found in a dedicated thread: https://www.cosmos.esa.int/web/xmm-newton/sas-thread-epic-spectrum)