XMM-Newton Users Handbook


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3.5.3.2 OM default configurations

To ease the use of the OM and to maximise the scientific yield of observations in cases when no particular instrument configuration is requested, OM default configurations have been defined. There is one type of default configuration per OM observing mode, thus one for the imaging mode and one for the Image plus Fast mode (§ 3.5.3.1). Default windows have also been predefined for the V and UV grisms exposures. Moreover, two additional full frame modes are available which allow imaging observation of the whole OM field of view.

The default configurations are as follows:

Figure 100: Setup of OM imaging mode default mode observations consisting of a sequence of 5 exposures. The science windows are indicated by solid lines, the detector windows by dashed lines. A 16 in-memory pixel margin around the science window is allocated to accommodate spacecraft drifts.
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  1. Imaging Mode default (named EPIC/RGS Image in the RPS, depending on the prime X-ray instrument)

    An example of the configuration corresponding to this mode is shown in Fig 101.

    Figure 101: Example of a field imaged with the default Image Mode configuration.
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  2. Fast Mode default (named EPIC/RGS Image Fast in the Remote Proposal System, RPS, depending on the prime X-ray instrument)

  3. Full-Frame imaging modes (Full Frame High/Low Resolution in the RPS)

    It is possible to obtain images of the whole OM field of view in full (high) or 2$\times $2 binned (low) resolution. These modes do not allow tracking, and have higher instrumental overheads than the Imaging Mode default. However, they allow homogeneous sampling of the whole OM field of view. They are therefore particularly well suited for survey studies or to obtain multiobject grism spectroscopy in a wide field. These modes have a single window, no other window can be defined (either in image or Fast mode) within the same exposure. Along an observation, Full-Frame imaging modes can be combined with modes using windows that require Field Acquisition (FAQ, see § 3.5.7), particularly Fast mode windows. In this case the Full-Frame exposures must be performed after all the exposures which need FAQ, because Full-Frame modes nullify the results of FAQ.

    The lack of tracking in Full Frame mode does not affect the quality of the image because, as experience has shown us, the drift of the XMM-Newton spacecraft is almost negligible (less than one arc sec per hour).

  4. Default grism configurations

    Two standard configurations are available for OM optical or UV grisms:


In addition to these default configurations it is also possible to define customised windows using the Science User Defined mode (see § 3.5.10.1).


Apart from the configuration of the OM exposures, exposure times and filters have to be specified.


next up previous contents
Next: 3.5.3.3 Integration time for exposures Up: 3.5.3 OM operating modes and filters configuration Previous: 3.5.3.1 OM operating modes
European Space Agency - XMM-Newton Science Operations Centre