XMM-Newton Announcement of Opportunity: Policies and Procedures

8.4 Success of Observations

The Project Scientist is responsible for declaring a particular observation successful.

Observations are declared successful based on the accumulated observation time according to the following rules:

1. The accumulated exposure time of the prime instrument is greater ($\ge$) than 80% of the requested observing time.
2. The accumulated exposure time of non-prime instruments is greater ($\ge$) than 60% of the requested exposure time.
3. For structural identically instruments all calculations are performed for all instruments together.
   RGS-1 and RGS-2 are evaluated together and have the same weight. MOS-1, MOS-2 and pn are evaluated together for EPIC and the two MOSs have the same weight. The higher effective area of pn relative to MOS-1 and MOS-2 is reflected through a weighting factor of two for pn exposure times.
4. Exposure time of non-prime instruments lost for operational or safety reasons (e.g. radiation alert) is only counted if the exposure is crucial for the science originally addressed in the proposal.
5. Radiation induced background is not taken into account.

All observations for which no compensation time is allocated are considered as successfully observed.

The SOC automatically allocates compensation time for observations which have not been successfully performed or which have not been completed fulfilling the above rules. The compensation time is calculated through comparison between the accumulated and allocated observing time. The requested observing time is given by the exposure time requested by the PI in the original proposal, but not exceeding the total time allocated by OTAC, for those observing modes which are not violating security or technical constraints of the instruments or the spacecraft.

The compensation time should significantly increase the signal-to-noise ratio of the data already obtained and is crucial for the science originally addressed in the proposal, e.g. the compensation time should exceed 5 ks.

These rules may be illustrated with the following examples:

• Taking rule 3 into account, 60% of the requested observing time accumulated for RGS-1 and 105% obtained for RGS-2 fulfills rule 1 for RGS prime
  ( $60\%+105\%=165\%>160\%=80\%+80\%$)
• Taking rule 3 into account, 50% of the requested observing time accumulated for pn, 80% obtained for MOS-1 and MOS-2 fulfills rule 2 for EPIC secondary.
  ( $2.0 * 50\% + 80\% + 80\% = 260.0\% > 240 \% = 2.0 * 60\% + 60\% + 60\%$)
• Taking rule 4 into account, 0% of the requested observing time accumulated for RGS fulfills a proposal which aims at the detection of a weak source with EPIC (RGS not prime).
• Taking the rule of compensation time into account, 3 ks missing observing time fulfills an observation aiming at a long (140 ks) variability study.

The Project Scientist can grant a complete repetition of a partly performed observation if the collected data are insufficient. In this case the Project Scientist decides about the data rights of the data taken during the partly performed observation.

Observations that are performed in instrument modes, which are supported by the SOC on a best effort basis, compare 5.6, are declared successful by the Project Scientist independently of the rules established above.