3 juin - 6 juin 2014


Atelier de préparation à l’exploitation scientifique de l’instrument GRAVITY

GRAVITY Instrument Science Operation Preparation Workshop

Room 227C

The GRAVITY instrument will see its first light in spring 2015. This two half days workshop will be an opportunity to gather together French consortium participants and members of the community willing to get familiar with the astrophysical potential of the instrument or who are planning to propose observations.

The objective of this workshop is to inform French astronomers about GRAVITY capabilities, to present the consortium-established science cases, and to discuss ideas proposed by the French community. Invited talks and spontaneous contributions are foreseen. The goal is to prepare France for scientific operation of GRAVITY, which should start in 2015.

The GRAVITY Instrument

GRAVITY is a second-generation instrument for the VLTI. It is a four-telescope interferometer operating at K-band (2.2 µm), able to simultaneously observe two fields in order to perform phase-referenced imaging with a spacial resolution of 4 mas or precision astrometry to an accuracy of 10 µas. It has been dimensioned for observing the Galactic Centre black-hole and its environment. GRAVITY is going to be the most sensitive and accurate near-infrared interferometer that has ever been built, making it able to tackle a wide variety of scientific studies ranging from strong-field gravitation to stellar physics. French teams are deeply involved in building the instrument. They are responsible for several sub-systems (integrated optics, fibered functions, fringe tracker, data reduction software) and participating in other sub-systems (adaptive optics, system study, astrometry). The instrument is currently being integrated and will be shipped to Paranal end of 2014.


GRAVITY has been designed specifically for for studying the Galactic Centre: it will enable studies of relativistic stellar orbits around the central black-hole candidate Sgr A* as well as astrometric studies of matter swirling down to its event horizon.

However, GRAVITY is a general purpose instrument. The consortium science group has studied a wide variety of science cases: spectro-imaging of active galactic nuclei or young stellar objects, evolved star surfaces, astrometric detection of exo-planets... and the French and international community are expected to propose yet other topics.

Tuesday 3, June
Instrument Presentation
2-2:10pm Workshop Introduction (Guy Perrin, LESIA, GRAVITY)
2:10-2:40pm GRAVITY: getting ready for ESO's VLT Interferometer (Frank Eisenhauer, MPE, GRAVITY PI)
The Galactic Centre and Strong Field Gravity
2:40-3pm Black Holes and Tests of Gravitation (Éric Gourgoulhon, LUTh)
3-3:20pm An Alternative to the Galactic Centre Black hole: the Boson Star (Claire Somé, LUTh)
3:20-3:40pm Constraining Galactic center flare models with the GRAVITY instrument (Frédéric Vincent, CAMK, Warsaw)
3:40-4pm The Galactic Centre Stellar Population and Relativistic Dynamics (Thibaut Paumard, LESIA)
4-4:30pm Coffee break
The Universe In Motion
4:30-4:50pm Active Galactic Nuclei (Yann Clénet, LESIA)
4:50-5:10pm Exoplanets (Fabien Malbet, IPAG)
5:10-5:40pm General Discussion
Wednesday 4, June
The Universe in Motion
2-2:25pm Evolved Star Surfaces (Pierre Kervella, LESIA)
2:25-2:50pm The innermost astronomical unit of protoplanetary disks as probed by GRAVITY (Myriam Benisty, IPAG)
2:50-3:15pm Planet Formation in Multiple Stellar Systems: the Example of GG Tau (Emmanuel Di Folco, LAB/OASU Université de Bordeaux)
3:15-3:40pm Physical Properties of Solar System Small Bodies Determination with GRAVITY (Alexis Matter, IPAG)
3:40-4:10pm Coffee break
Observational Techniques and Data Processing
4:10-4:35pm Multi-Spectral Image Reconstruction (Ferréol Soulez, CRAL)
4:35-5:10pm "Wide field" imaging with GRAVITY (Stéphane Guilloteau, LAB/OASU Université de Bordeaux)
5:10-5:35pm Astrometry (Sylvestre Lacour, LESIA)
5:35-6pm General Discussion

e-posters in this session