XMM-Newton Phase II RPS Users Manual

5.2.4.3 Filling in RGS details

Similarly to the EPIC exposures, a few details must be defined for each RGS exposure. Fig. 15 provides an example for an RGS exposure form sheet.

Figure 15: Screen shot of an RGS exposure form sheet for a 123034s exposure and an offset with respect to the previous exposure of 0s of RGS1 in the recommended mode for standard ''Spectroscopy''.

''Exposure Time (secs)''

The valid range is between 0 and 124000s.

''Exposure Offset (secs)''

The exposure offset should be left at its default value of 0s to ensure continuous operation of the instrument. Only under special circumstances, in which one would not want the instrument to operate for a certain amount of time, should an offset with respect to the previous instrument exposure, if any, be defined here. The valid range is between 0 and 1000s.

''Instrument''

When first entering this page, the ''Instrument'' query will have two options, ''RGS 1'' and ''RGS 2''. Users must choose one or the other since ''RGS 1'' and ''RGS 2'' exposures are defined independently for each other. Once specified, and once all entries have been made and successfully committed to memory, this will not be a selectable parameter anymore, and the fixed entry will appear in red in the form sheet as displayed in Fig. 15. Therefore, it is not possible to change a RGS 1 exposure to a RGS 2 exposure without making a copy.

''Instrument Mode'', RGS modes of operation

If photon pile-up is not a problem, the RGS should be left in the normal ''Spectroscopy'' mode. If a high count rate is expected, the ''Small Window'' mode should be used. For a more detailed description of allowed RGS modes see Table 4 and consult the XMM-Newton Users Handbook details.

Table 4: RGS mode names

RGS mode name

Spectroscopy

Small Window

''Order (ins. based)''

In this field one can define the order of multiple exposures using the same instrument within an observation.

''Edit Details''

Calls the RGS settings form to specify the RGS CCD readout sequence. This is only necessary if a non-standard readout sequence is required. Otherwise the following default sequences are used:

RGS 1

1,2,3,4,5,6,8,9

RGS 2

1,2,3,5,6,7,8,9