Principal Investigator
Nuno C. Santos

Abstract

The present project has the goal of supporting the national participation in the project of a new high resolution super-stable spectrograph for the European Southern Observatory (ESO) Very Large Telescope (VLT): ESPRESSO. It will focus on our scientific contribution, and in the design of one of the instrumental components, the "Coude Train". This component will make the VLT the first equivalent 16-m telescope in the world.

The development of different high resolution spectrographs over the last 10 years allowed a considerable development of a number of different domains in Astrophysics. Areas such as the detection of extra-solar planets, the study of stellar oscillations, the discovery that the fundamental constants of physics may have varied in the past, or the analysis of chemical abundances and isotopic ratios in distant stars, have seen an unprecedented success. New questions have been raised, and new solutions are being sought.

Motivated by these premises, a new generation of instruments and telescopes is being conceived by different teams around the world. This includes a new generation of Extremely Large Telescopes (ELTs). In parallel, a number of new instruments for current 8 to 10-m class facilities is being planned.

With this in mind, ESO opened in March 2008 a call-for-proposals to build a new high-resolution ultra stable spectrograph for the VLT telescopes. In reply to this call (see attached files "HRUSS_Scientific_Report" and "HRUSS_Management_Plan"), a consortium was created that includes the Centro de Astrofisica da Universidade do Porto (leading a national consortium also including SIM and INETI/LAER - DOL), the Geneva Observatory (Switzerland), the Instituto de Astrofisica de Canarias (Spain), and the Trieste Observatory (Italy). The project was recently named ESPRESSO (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations). The PI of the present project is one of the 4 Co-PIs of the consortium.

The consortium proposed the construction of a high-efficiency, high-resolution, fiber-fed spectrograph of high mechanical and thermal stability located at the VLT incoherent Coude Focus. The goal is to combine and improve the stability of instruments like HARPS with the efficiency of UVES (http://www.eso.org/sci/facilities). ESPRESSO is an innovative instrument to fully exploit the VLT potentiality. In particular, it will offer the possibility of combining the light of the 4 VLT-Unit Telescopes, making of it a 16-m equivalent telescope several years before the E-ELT is available to the community.

This project has been accepted by ESO for Phase A study. If there are no major difficulties, this spectrograph will be mounted at the VLT site in 2014.

The unprecedented accuracy in the radial velocities determination together with the largest photon collecting area will certainly provide breakthroughs on many areas of astronomical research (as those mentioned above). Particular attention should be given to the two main science cases of ESPRESSO: the search for Earth-like planets, and the measurement of the variations of physics fundamental constants. ESPRESSO will effectively change our current knowledge in these two high impact domains.

The proposed Portuguese participation in ESPRESSO is in this respect crucial. On the one side, all the scientific areas mentioned above are particularly fond to the national astronomical community. This is particularly true to some of our team members, that have a strong international recognition for their research. Furthermore, and based on the previous successful experience of our team with other ESO instrumentation (e.g. CAMCAO IR camera for the VLT, working in the context of the MCAO Multi-Conjugate Adaptive Optics System), in the context of the ESPRESSO project our team ís responsible for the design and construction of the "Coude Train" for the VLT. This component will bring the light from the 4 UT telescopes to the Combined Coude Room, where the instrument will be positioned.

The goal of the present project ís to give to the national team all the necessary means to pursue the first phases of the project:

-> Define the science case to be developed in the guaranteed time available to the consortium, as well as the instrumental requirements for the scientific success of the project (responsibility of the CAUP team).

-> Design of the optical system of the Coude Train (responsibility of the INETl/LAER (DOl) team).

-> Design of the mechanical system of the Coude Train (responsibility of the SIM team).

These phases of the project will finish in the end of 2011 with the Final Design Review (FDR), after which the construction should start.

Our participation in this project perfectly fits into one of the recommendations of the evaluation panel of CAUP, who recently proposed in their report that " ... some funding be provided specifically to the enhancement of the group' s contributions to instrumentation" .

Institutions & Research Units involved in the project:
- Centro de Astrofísica da Universidade do Porto (CAUP/UP)
- Fundação da Faculdade de Ciências (FFC/FC/UL)
- Laboratório de Sistemas, Instrumentação e Modelação em Ciências e Tecnologias da Terra e do Espaço (SIM)

Project members in CAUP:
- Carlos Martins
- Nuno Santos
- Manuel Monteiro
- Mário João Monteiro
- Pedro Figueira
- Sérgio Sousa

Start
1 June 2010
End
31 December 2012

Funding Institution
Fundação para a Ciência e a Tecnologia