Procedure to implement GROND/ToO observations during MPIA time at the ESO/MPG 2.2m
Rules for GROND/ToO observations by MPE
MPE continues to use GROND for GRB/RRM, GRB/ToO, transient/ToO, and in the future, for ROSITA/ToO follow-up observations. The total amount of time spent on RRM and ToO observations during MPIA time (and time ceded by MPIA to third parties) shall not exceed 15% of the total shutter open time accumulated during a given semester for MPIA programs. The budgeted time for GROND/RRM and GROND/ToO observations shall include overheads that result from the interruption of regularly scheduled programs. Apart from GROND/RRM triggers and follow-up observations of a trigger, (see below), GROND/ToO observations shall not spend more than 20% of the available observing time during any given night. GROND/ToO observations exceeding 20% of the available time shall be scheduled only if a consensus is found between the GROND team and the PI of the affected, regularly scheduled program.
GROND/RRM observations (rapid response mode; immediate termination of on-going observations) shall be limited to 5 - 6 triggers per semester. Following a GROND/RRM trigger, MPE receives unlimited override permission for 100% of the remaining observing time during the night of the trigger. For 2 events per semester, MPE may use up to 50% of the available observing time during the rest of the first week, and up to 25% of the available time during the 2nd week, to follow up the trigger. Apart from the first night, the observations in nights 2 - 14 after a trigger shall not receive overriding priority over regularly scheduled programs, but shall be scheduled according to the rules layed out for GROND/ToO observations. In the event that more than 6 RRM triggers per semester shall be observed, consensus must be reached between MPIA and MPE before additional triggers are enabled.
GROND/ToO observations (including RRM follow-up observations) will be communicated to the observer at the telescope or to the TIO before the beginning of each night. The ToO observations will then be regularly scheduled during the night, in synthesis with the general observing plan as published on the MPIA website. GROND/ToO observations are performed in service mode by the MPIA observer or the TIO, in general, but without overriding priority over the regularly scheduled programs. It is expected that the GROND/RRM and GROND/ToO observations will sample the full spectrum of LaSilla atmospheric conditions and seeing statistics. Calibrations required for GROND/ToO observations that require observations during twilight are limited to a maximum of 15% of the available twilight time.
Rules for compensation of programs affected by GROND/ToO interrupts
In cases where a full compensation for GROND/ToO interrupts is not possible, due to constraints imposed by lunar phase, right ascencion, seeing or weather, the highest-ranked programmes should be served first. The rank of a programme is given in the observing plan.
During periods of lower than average trigger rates, the placeholders may also be used to compensate for weather losses. Again, the highest-ranked programmes should be served first, unless this is not possible from the various constriants such as lunar phase, seeing, etc.
Time accounting is based on the REMEDY ticket database containing all respective trigger information for the GROND/ToO observations. A final balancing reflecting actual losses incurred by GROND/ToO will be made after each year of operation between MPIA and MPE, based on detailed time accounting provided by the REMEDY database.
The use of twilight for GROND, WFI, and FEROS calibrations follows the rules outlined above. On average, 15% of the time available for twilight calibrations will be made available for calibrations required for the GROND/ToO programme.