Scientific Rationale

There is a great interest in the community for wide-field high-multiplex spectroscopic capabilities at ESO. For example, strong scientific cases for extragalactic spectroscopic surveys were presented by the ESO/ESA Working Group on Fundamental Cosmology ( and at the recent ESO workshop on Second Generation Instruments for the VLT (cf. 'Science with the VLT in the ELT era' ; Springer, 2008). These surveys will supplement and complement the many ground and space imaging surveys that are now underway or being planned for the short and medium term future, in particular using the ESO Survey telescopes VST and VISTA.

There is also a large interest in Galactic spectroscopic surveys notably as a follow-up of the GAIA mission detailed in the recent ESA/ESO Working Group report on 'Galactic populations, chemistry and dynamics' (, but also to follow-up the very comprehensive surveys of the Galactic plane that are due to start in 2009 with the ESO Survey Telescopes ( While a number of interesting proposals were presented at the Science with the VLT in the ELT era workshop, the workshop was mostly centered on the scientific aspects and therefore considered the technical designs only in a very general way. While this clearly underlied the strong interest of the community in high multiplex spectroscopic surveys, it also indicated the need of a more in-depth discussion dedicated entirely to spectroscopic surveys. This was immediately acknowledged by ESO's Scientific/Technical Committee (STC), which instructed the ESO executive to organize this workshop. Thus, the central aim of the workshop is to focus the needs of the community on high-multiplex spectroscopic instruments on the VLT on time scales coherent with the on-going efforts by the community to conduct imaging explorations, both for extragalactic and galactic science. The main topics of the workshop, therefore, will cover summaries of the science behind these on-going efforts, and of the corresponding requirements for complementary spectroscopic follow-ups. The list of topics is presented below.

Main topics include

  • Galactic Science: imaging surveys; astrometric surveys; and spectroscopic surveys from ground and space
  • Extragalactic Science: imaging surveys; photometric surveys; spectroscopic surveys from ground and space
  • Plans for high-multiplex spectroscopic instruments at ESO and elsewhere
  • The longer-term future