Call for Phase-A Proposals for 2nd generation VLTI instruments

A number of concepts for second generation VLTI instruments were received at the time of the workshop The power of optical/IR interferometry: recent scientific results and 2nd generation VLTI instrumentation held in Garching in the week of April 4-8, 2005. Some of them have been already discussed with ESO and presented at the recent STC meeting held on October 17-18, 2005. Following recommendations from STC, we are now pleased to announce here a formal "Call for Phase-A Proposals" which should address instruments for long-baseline interferometry at the VLTI in one or more of the available 1-20 microns spectral regions, and aim at combining a number of telescopes between 4 and 6.
Proposers are expected to be institutes, or consortia of institutes, with previous experience in the area of interferometric instrumentation. Proposals should be sent to J. Melnick and A. Richichi by January 30, 2006. Electronic submission is preferred (Word or PDF). A proposal should come from the potential P.I. and should be countersigned by the Director of the Institute potentially willing to invest the human resources needed to conduct the project. Associated Institutes should be identified, with the corresponding Co-I.s. Phase-A studies are expected to last about nine months. It is planned to hold final reviews at ESO and to transmit the results to the STC in time for its meeting of April 2007. On request, limited funding may be made available by ESO.

Proposals should be prepared in accordance with the guidelines provided in the document “Conditions Governing Calls for Proposals and Contracts for the VLT Instrumentation” (December 2004), which can be requested from the above ESO persons. In order to permit a homogeneous evaluation process, proposers should keep in mind the following points:

The projects should be conceived with the goal of developing end-to-end general use facilities, operated inside the ESO data flow system in place at Paranal & Garching (http://www.eso.org/outreach/ut1fl/whitebook/wb100.html) and based on the VLTI interface description (the current version is vlt-icd-eso-15000-1826_iss4.pdf, updates may be provided). As the total space inside the VLTI laboratory is limited, any new instrument would have in principle to replace one of the present 1st generation instruments.

The instrument concept, its capabilities and operating modes, with a basic description of calibration & data reduction strategy. Please also include a brief assessment of the concept standing with respect to related 1^st generation VLTI instrumentation capabilities (http://www.eso.org/projects/vlti/instru/) and, eventually, to similar scientific capabilities offered or planned by other Observatories. Obviously, a performance gain over present ESO and non-ESO facilities is highly desirable.

A compelling scientific case, spelling out the significant astronomical advance(s) that the proposed facility should permit. This is certainly one of the most important criteria on which the decision will be based.

A description of any technical area that would require significant R&D advances and/or prior prototyping, and the strategy to pursue it.

A preliminary implementation plan and cost estimate. Of particular importance is to establish the likely availability of an adequate team to carry out the project, and possible time scale including the earliest starting date. We expect that the human resources needed will be provided by the Consortia. At the moment, unfortunately ESO cannot guarantee coverage of the capital costs of the instruments.

In particular, the proposals should clearly outline the requirements on the VLTI infrastructure, observing strategies, telescope configurations and observing time requirements required to conduct the key scientific programs. The currently available and foreseen VLTI infrastracture is described in the Appendix.

Please indicate any significant direct involvement, apart from project monitoring, expected from ESO, especially in the detector system, instrument control and data flow areas, for which standardization is a must. Conversely, an eventual capacity of a Consortium to raise part of the funds necessary to develop the instrument would be received with keen interest.

Appendix: VLTI infrastracture

The Very Large Telescope Interferometer (VLTI) offers a facility with a collecting power significantly greater than any other interferometer available at present or being planned at visible and infrared wavelengths. It is based on an array of the four identical, 8.2-m VLT Unit Telescopes (UT) and four dedicated 1.8-m Auxiliary Telescopes (AT).

The main elements of the VLTI are:

· Four 8.2-m Unit Telescopes (UT), all with Adaptive Optics (AO) correction at their Coudé focus.

· Four 1.8-m Auxiliary Telescopes (AT). AO for ATs is being considered.

· Six Delay Lines (DL) installed. Variable Curvature Mirrors (VCM) in the cat’s eye of the DL are used to relay the pupil. VCMs are currently operational on 2DLs, and will be extended to all DLs.

· two Differential Delay Lines (DDL) units have been contracted and are under development.

· The Test instrument VINCI with an integrated optics beam combiner in the K-band (IONIC).

· The mid-infrared two beam combiner MIDI in regular science operation.

· The near-infrared three beam combiner AMBER in commissioning and offered in the Call for Proposals for science operations starting in October 2005.

· A Fringe Tracker with on-axis guide star (FINITO) under extensive testing at Paranal.

· A near-infrared tip-tilt sensor (IRIS) in the lab.

· PRIMA is a dual-feed system to perform accurate relative phase measurements between objects separated by up to 1 arcminute. Star Separators Systems (STS) for two ATs and two UTs are under development; a third STS/UT (and possibly a fourth one) are externally financed; Fringe Sensor Units A&B in development. Metrology in development.

If properly justified by the scientific case, proposers may consider extensions to the above VLTI infrastructure in the scenarios of their Phase-A studies.