XMM-Newton Phase II RPS Users Manual

A..1 Observation of a faint extended source

As an example for a faint extended X-ray source one might consider observing a cluster of galaxies, at relatively low redshift, $z$. The input of standard information (target name, catalogued position etc.) in XRPS is trivial. Other input parameters require some more thought:

Choice of prime instrument

Chose the XMM-Newton prime instrument according to your main scientific goal. If moderate resolution spectroscopy is most important for the proposed science, the observer might want to select the EPIC pn camera. Alternatively, if high-resolution spectroscopy is intended, they may want to chose the RGS instrument.

Science mode of the prime instrument

If the source is weak, all EPIC cameras can be assumed to have no problems with photon pile-up. In that case, they can all be used in the standard FULL FRAME imaging mode. RGS could be used in its standard SPECTROSCOPY mode.

X-ray properties of the source

Based on PIMMS observers can convert ROSAT, ASCA or other known flux and band data into the XMM-Newton band (0.1-15 keV), and enter these, together with an X-ray spectral model, e.g. Raymond-Smith, kT = 6 keV, N(H) = 3e20 cm$^{-2}$ and the lower and upper limit of the energy band over which the X-ray flux was observed into XRPS.

Duration of observation vs. visibility constraints

Users must check that the requested observation fits into a continuous visibility period of the XMM-Newton orbit by using the XMM-Newton Target Visibility Tool. In case that the required total integration time is longer than the longest possible visibility window, the observation must be split into an adequate number of individual observations.

Pointing coordinates

Assuming that the cooling flow is located at the core of the cluster, no boresight coordinates need to be entered, and thus the target coordinates will automatically be propagated into the boresight fields. Otherwise, the boresight would be chosen to be directed towards the location of the brightest/most important X-ray feature to be observed. The best data quality will be achieved in the aim point of the prime instrument.

Avoidance of nearby bright sources

Optical and X-ray catalogues should be searched for nearby bright sources which might lead to contamination of either the X-ray (e.g., RGS spectral overlaps) and/or optical/UV observations. Such sources must be avoided, which might require a Position Angle (PA) constraint.

Science modes of the other instruments

The expected RGS count rates are lower than those for EPIC. There will thus be no need for fast readouts and RGS would be used in its standard SPECTROSCOPY mode.

Assuming that the cluster fits into the OM's $17'$ FOV, the standard configuration would be chosen (''EPIC Image'' or ''RGS Image'').

EPIC filters

Since the source is assumed to be weak (both in X-rays and the optical/UV) the ''THIN'' optical blocking filter can be used.

RGS readout sequence

For the case of standard spectroscopy observations there is no need to change anything in the RGS readout sequence. CCDs will then be read out sequentially.

OM brightness limit

Before planning the details of OM observations, users should check for the presence of bright optical/UV sources within the OM's FOV. There should be no source in the FOV that violates the brightness constraints tabulated in UHB Table 25 . If such sources exist, no OM exposure should be included.

OM filters and modes

OM filters and modes have to be chosen according to the optical characteristics of the target (see 5.2.4.5).

Duration of exposures

All X-ray observations of faint sources can be obtained in a single exposure covering the entire duration of the observation.

The OM exposure times should be chosen according to the explanations in § 5.2.4.5 and the OM chapter of the XMM-Newton Users Handbook.