XMM-Newton Phase II RPS Users Manual

3.1.2.3 For a bright point source

7.

Science mode of all instruments

For both MOS and pn, when using the ''Full Frame'' imaging mode, it must be decided if any given part of the source is bright enough to give rise to local photon pile-up that would degrade the calibration beyond that demanded by the science goals (see XMM-Newton Users Handbook section on EPIC pile-up ). In the case of a bright point source, pile-up is likely to be a concern. If so, the user should choose the partial window mode with the largest FOV that minimises pile-up or, for the very brightest sources, use the ''Timing'' or ''Burst'' modes.

Pile-up in individual emission lines in RGS data of bright targets is possible and should be assessed. In the case where 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 RGS ''Small Window'' mode should be used (see XMM-Newton Users Handbook section 3.4.5 on RGS modes ).

For an optically bright point source the user might consider using the ''Science User Defined'' mode with a large ''Image mode'' window plus a ''Fast mode'' window centered on the target, if high time-resolution photometry is required.

8.

Observation duration

If the observation is long compared with the visibility window (as reported by the online XMM-Newton Target Visibility Tool), the user must consider how best to split the observation, e.g., into multiple observations that fit into continuous visibility periods.

9.

Selection of EPIC optical blocking filters

Users must check the visible magnitude of in-field or nearby optical sources and the science target itself. If the soft X-ray response is important, one should choose the thinnest filter compatible with the brightest visible objects, as described in the XMM-Newton Users Handbook section on EPIC filters .

10.

RGS readout sequence

In case of observations of a target with particularly strong emission lines, observers might want to read out individual CCDs more often than others (see § 5.2.4.4).

11.

Choice of OM filter sequence

For OM, it must be decided if a specific filter coverage is necessary to achieve the science, or if the recommended filter sequence is adequate (see XMM-Newton Users Handbook section on OM modes and OM optical elements ).

12.

Exposure duration

Telemetry and onboard memory limits place upper and lower boundaries on the duration of single OM exposures as listed in § 5.2.4.5.