Opportunites for large public surveys with VST and VISTA

Please send any comments on this document to Alvio Renzini.

With the VLT Survey Telescope (VST) approaching its commissioning phase, and VISTA being under construction, time has come to set new procedures for the selection and implementation of Public Imaging Surveys to be conducted at ESO telescopes. In setting such procedures the following relevant agreements between ESO and Partners to ESO are taken into account.

• Over the first 10 years of VST operations 15-20% of the VST observing time is to be allocated to the Osservatorio Astronomico di Capodimonte (OAC) for having provided the VST, and 20% to the OmegaCam Consortium for having provided the OmegaCam instrument.
• As part of the agreements for the UK accession to ESO 75% of the VISTA observing time is to be dedicated to large surveys.

Public Imaging Surveys are to be conducted with the widest possible involvement of the community and will be selected according to the following guidelines:

• Ensure scientific excellence, enabling competitive research by ESO community on frontier scientific areas.
• Provide a continuous supply of scientific targets for the VLT/VLTI detailed investigation with their instrument complement.
• Ensure the set of implemented surveys cover the main scientific areas being actively investigated by the ESO community.
• Ensure the optimization of each survey for both primary and other possible scientific exploitations of the same data set.
• Ensure a balanced distribution of survey targets over right ascension, so as to avoid scheduling congestions at the survey telescopes and at the VLT/VLTI.
• Ensure optical/near-IR coverage to sky areas covered by complementary ground and/or space facilities at other wavelengths and which data are publicly accessible to the ESO community.
• Ensure coordination between optical and near-infrared surveys. To properly match UKIDSS and VISTA surveys it is anticipated that VST will have to dedicate to large surveys a fraction of its total time comparable to that dedicated by VISTA.

It is recognized that the normal procedure for ESO proposals with teams in the community directly submitting proposals for OPC evaluation would not ensure the scientific and scheduling coordination that is indispensable for a most efficient utilization of the telescopes. An intermediate step is then required in order to ensure that a given survey can serve a broader range of scientific applications than one individual group may conceive, that a proper balance is ensured among the various scientific areas, and that the resulting set of surveys is distributed as much uniformly as possible in right ascension.

The selection of Public Surveys will then proceed through the following steps:

1. ESO will periodically issue a "Call for Public Survey Concepts", for groups in the community to present concepts for dedicated surveys, including scientific rationale, observing strategy, estimated observing time and its distribution over observing Periods, and willingness and capability of the group to implement the proposed survey and to process its data into survey products. As part of the Call for Public Survey Concepts ESO will specify the support that could be provided to teams taking the responsibility of conducting the approved Public Surveys.
2. ESO will ask the OAC and the OmagaCam Consortium to provide detailed descriptions for the observing programmes they intend to conduct in their guaranteed time (GTO) at the VST over the first 4 semesters. A similar request will be repeated every two years.
3. ESO will establish a Public Survey Panel (PSP) with the mandate of reviewing the answers to the Call for Public Survey Concepts and to elaborate a coordinated set of surveys following the above guidelines and taking into account the planned GTO programmes. In doing so the PSP will have the faculty to merge, integrate, or expand upon the proposed surveys, thus defining new survey parameters such as filter set, depth, area, coordinates, etc.
4. The PSP will include scientists expert in a broad range of current astronomical research. The PSP may involve in its activities scientists having provided answers to the Call for Public Survey Concepts as well as representatives of the GTO Consortia.
5. The set of surveys recommended by the PSP will avoid duplications with respect to GTO programmes which will have priority over other surveys. However, ESO will not encourage GTO programmes aimed at complementing other databases (e.g., UKIDSS) publicly available to the ESO community, unless the GTO Consortia were to waive their proprietary time and made available to the ESO community the corresponding survey products in a timely fashion. In such case the GTO Consortia would be entitled to a compensation in the form of guaranteed time at other ESO telescopes.
6. The PSP will draft a Document commenting the answers to the Call for Public Survey Concepts, illustrating the criteria adopted for the optimization and coordination of the recommended set of surveys, and describing for each survey the scientific rationale, observational strategy, and specifications. Such specification shall include a detailed description of the survey products with their required accuracy and delivery time.
7. The PSP Document will be submitted to the STC and OPC for evaluation and recommendation, and the Chair of the PSP will be asked to illustrate this document. Following STC and OPC recommendations ESO will list the recommended set of Public Surveys in a dedicated section of the general Call for Proposals, with "Public Surveys" becoming a distinct category of ESO proposals. The PSP Document will be made available on the web.
8. For the Public Surveys so listed in the General Call for Proposals teams in the community could submit their proposals following the indicated deadline. Besides including all entries in ordinary proposals, such Public Survey Proposals will include a detailed description of the products the team takes responsibility to deliver and the timescale of delivery, and of the support - if any - requested from ESO. A Management Plan will also be attached to the proposal for ESO review. These Public Survey proposals will then be submitted for recommendations to the OPC.
9. For each approved Public Survey ESO will negotiate with the PI the final specifications of the survey products and their timeline, the amount of guaranteed time that could be granted following the successful delivery of the survey products, and the extent of ESO support that could be given.
10. For the surveys conducted by the GTO Consortia ESO will offer the opportunity of granting additional GTO time at other ESO telescopes in compensation for a prompt public delivery of survey products.
11. Proposals for Proprietary Surveys can be submitted as usual following the regular Calls for Proposals.
12. The ESO/STECF Science Archive Facility (SAF) will be the collection point for the survey products and the primary point of publication/availability of these products to the ESO community. ESO will assist the survey teams to define and package their data products in a manner consistent with SAF and VO standards and will integrate the products into the SAF.