4MOST Policies

  1. Calls for public surveys, proposal submission and evaluation proces
  2. Participating and Non-Participating Surveys
  3. Targets duplication policy
  4. Survey Management Plan

Application and Selection Process.

ESO will issue a Call for Letters of Intent (LoI) for 4MOST Public Surveys every five years. During the initial five years period of 4MOST operations, guaranteed time for the instrument consortium will be 70% of the total observing time. The LoIs will be reviewed by ESO’s Public Survey Panel (PSP), composed of experts from the community. The PSP will select the successful teams that will be invited to submit a detailed proposal. The PSP prime mandate is to review the Public Survey Proposals and elaborate a scientifically and observationally well coordinated set of 4MOST Public Surveys covering five years. After evaluating the feasibility of different combinations of proposed surveys, the PSP will review all proposals and issue a recommendation. Based on this recommendation, the survey plan for the combined recommended Community and Consortium Surveys will be optimised and its implications in terms of predicted success and efficiency analysed. The resulting report and the PSP recommendation will form the basis for the recommendation of ESO’s Observing Programmes Committee (OPC) for the final 4MOST survey programme.


Participating and Non-Participating Surveys.

Proposers will have the choice of whether to propose a Participating or a Non-Participating Community Survey. 

Participating Surveys will join the Consortium Surveys in the 4MOST Science Team immediately after their selection, and should therefore adhere to the Science Team Policies. All Participating Surveys will be planned and executed jointly as a single science programme. They will pool their targets such that in any given observation 4MOST will typically obtain spectra for many different science cases simultaneously. Parallel observing enables efficient use of 4MOST for surveys that have compatible observing conditions requirements and/or a target density lower than the 4MOST multiplexing capability. Each Participating Survey will only be “charged” the observing time for the fibres actually used by that survey (including fractional overheads and any residual inefficiencies). This mode does imply, however, that all Participating Surveys will have to agree on a common survey strategy and prepare Observation Blocks (OBs) jointly. As a consequence, all Participating Surveys will have to fully share the raw data as well as the calibrated spectra in order to be able to assess selection functions and mitigate the impact of any cross-talk effect on their science. The description of the operations model provides further details on the policies and data-flow for Participating Surveys.

Community Surveys wishing to use 4MOST in single survey mode are called Non-Participating Surveys. These will not pool their targets with any other survey, and their observing time will be allocated in named nights or half nights  during which they will be the only survey using the facility. Accordingly, these surveys will be “charged” the full equivalent in fibre-hours, regardless of how many fibres they actually use. Although these surveys will not join the 4MOST Science Team, the Consortium’s Operations System will nevertheless provide these surveys with the software necessary to produce OBs, which, however, they will need to run themselves. In addition, the Consortium’s Data Management System will reduce the data of Non-Participating Surveys and provide them with calibrated, science-ready spectra (i.e. Level 1 data). However, Non-Participating Surveys will not have access to the advanced data analysis pipelines developed by the IWGs, i.e. the 4MOST Science Team. Non-Participating Surveys will have to produce their own advanced data products and deliver them to ESO.


Targets duplication policy.

The Science Team Policies (Sec. 10) stipulate some restrictions regarding the overlap between the target list of a Participating Community Survey and those of the Consortium Surveys. The number of targets that a Participating Community Survey has in common with a Consortium Survey shall not exceed 20% of the number of the Consortium Survey’s targets, and the number of targets in common with all Consortium Surveys shall not exceed 20% of the number of the Participating Community Survey’s targets. 

Non-Participating Community Surveys shall not have more than 30% of their targets in common with those of the Consortium Surveys. The duplicated targets between approved Non-Participating Surveys and Participating (Community and Consortium) Surveys will be observed twice. 


Survey Management Plan.

The ESO Director General will select the public spectroscopic surveys for 4MOST based on the recommendations of the OPC and taking into account the statement from the 4MOST Consortium executive board. All surveys will then be invited to submit their individual (for Non-Participating Surveys) or collective (for Participating Surveys) survey management plan, whose approval by the ESO DG is mandatory before final acceptance of a public spectroscopic survey. The survey management plan shall contain a detailed list and timeline for the release of science data products.

For Consortium and Participating Community Surveys a coherent and unique survey management plan will be delivered. The 4MOST PI will represent the full Science Team towards ESO and is responsible for the delivery of the 4MOST survey programme. The Survey Management Plan should capture the full details of the delivery of1 dimensional, calibrated, science-ready spectra extracted from the raw data, which are in common to all surveys, as well the delivery of the additional science products that may differ from survey to survey.

For Non-Participating Community Surveys, each PI will be responsible for the delivery of a Survey Management Plan which includes the full details of the delivery of 1 dimensional, calibrated, science-ready spectra extracted from the raw data, which are in common to all surveys, as well the delivery of the additional science products that may differ from survey to survey.

Note that all surveys executed by 4MOST (irrespective of whether they are Participating or Non-Participating, Consortium or Community Surveys) will be ESO Public Surveys. That means that all raw data will become public immediately (through ESO’s Science Archive Facility), and that all surveys will have to deliver a set of data products back to ESO for publication (Phase 3), where both the contents of the data set and the schedule of the delivery will have been previously agreed upon by ESO and the surveys.