During the initial 5-year period of 4MOST operations, 30% of the total available observing time will be available to the ESO community. The following provides a high-level description of the process that led to the selection of the Community Surveys to be executed in this time.
4MOST was designed as a survey facility, and for a period of at least 5 years, 4MOST will be entirely dedicated to executing a comprehensive survey programme, to the exclusion of all other types of observing programmes. Furthermore, all 4MOST surveys will be ESO Public Surveys (meaning that their science case and scope need to be comprehensive enough to be of significant legacy value to the astronomical community at large). Therefore, it will not be possible to apply for time on 4MOST in response to the usual biannual Call for Proposals issued by ESO. Instead, ESO issued a single Call for Proposals for Public Surveys with 4MOST that covered the entire initial 5-year period of 4MOST operations.
Application and Selection Process
The process by which the final, complete 4MOST Survey Programme was defined is governed by ESO’s 4MOST Policies. In particular, these policies govern the application and selection procedure for Community Surveys, a process which is managed by ESO.
In brief, this process was set in motion with the 4MOST consortium publishing a set of 13 articles in the March 2019 issue of the ESO Messenger, providing extensive information on the 4MOST project, the facility, the operations scheme, the survey strategy and the Consortium Surveys. The consortium and ESO then further engaged with the community by jointly organising a workshop, entitled Preparing for 4MOST: A community workshop introducing ESO’s next-generation spectroscopic survey facility, which was held in Garching in May 2019. This workshop again provided interested members of the community with information about 4MOST, as well as with an opportunity to ask questions and discuss ideas and tentative plans for surveys. The workshop’s programme provides links to the videos and PDFs of the presentations. A summary of the workshop is provided by Liske & Mainieri (2019).
Following this period of information dissemination, ESO issued a Call for Letters of Intent (LoI) for public spectroscopic surveys with 4MOST in November 2019, with a submission deadline on 28 February 2020. The LoIs were reviewed by ESO’s Public Survey Panel (PSP), and the successful teams were invited to submit a detailed proposal by 15 December 2020. ESO and the 4MOST consortium then supported the preparation of proposals by organising a 2nd 4MOST community workshop, entitled Planning for 4MOST: toward the 4MOST survey programme, in July 2020, and by providing access to the 4MOST Facility Simulator. After evaluating the feasibility of different combinations of proposed surveys, the PSP reviewed all proposals and issued a recommendation. Based on this recommendation, the survey plan for the combined recommended Community and Consortium Surveys was optimised and its implications in terms of predicted success and efficiency analysed. The resulting report and the PSP recommendation formed the basis for the recommendation of ESO’s Observing Programmes Committee (OPC) for the final 4MOST survey programme.
The selection process was concluded in February 2022 with ESO announcing the selection of 15 Galactic and extragalactic Community Surveys. These were then integrated into the 4MOST Science Team and joined the existing 10 Consortium Surveys to form the final 4MOST survey programme.