DISCO: a Spatio-Spectral Recombiner for Pupil Remapping Interferometry

Pupil-remapping is a new high-dynamic range imaging technique that has recently demonstrated feasibility on sky. The current prototypes present however deceiving limiting magnitude, restricting the current use to the brightest stars in the sky. We propose to combine pupil-remapping with spatio-spectral encoding, a technique first applied to the VEGA/CHARA interferometer. The result is an instrument proposal, called "Dividing Interferometer for Stars Characterizations and Observations" (DISCO). The idea is to take profit of wavelength multiplexing when using a spectrograph in order to pack as much as possible the available information, yet providing a potential boost of 1.5 magnitude if used in existing prototypes. We detail in this paper the potential of such a concept.Comment: Improving the performances of current optical interferometers \& future designs, France (2013

AMBER : a near infrared focal instrument for the VLTI

10 pagesInternational audienceAMBER is the General User near-infrared focal instrument of the Very Large Telescope interferometer. Its specifications are based on three key programs on Young Stellar Objects, Active Galactic Nuclei central regions, masses and spectra of hot Extra Solar Planets. It has an imaging capacity because it combines up to three beams and very high accuracy measurement are expected from the spatial filtering of beams by single mode fibers and the comparison of measurements made simultaneously in different spectral channels

The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI

The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.Comment: Published in the ESO Messenge

Entretiens avec Rossana Dalmonte

À travers ses entretiens avec Rossana Dalmonte et ses essais sur la musique, Luciano Berio (1925-2004) fait apparaître la profondeur et la générosité d'une pensée qui s'est développée indépendamment de celle de sa propre génération, et qui embrasse la totalité des formes musicales, au-delà des oppositions entre l'ancien et le nouveau, le savant et le populaire, la musique avant-gardiste et la musique de masse. C'est que Berio vise moins la dimension théorique en soi, se méfiant des formulations trop rigides ou des positions fondées sur des a priori idéologiques, qu'il n'accompagne son travail de compositeur d'une réflexion en actes, puisant à des sources telles que l'anthropologie, l'ethnomusicologie, la linguistique ou la musicologie. Sa lecture des œuvres et des différentes musiques abordées se fait toujours de l'intérieur, mais sans jamais oublier que la musique est un fait social. Elle est parfois violemment critique, voire polémique, mais toujours éclairante, grâce à son ampleur et à sa justesse. Comme l'indique Martin Kaltenecker, traducteur des entretiens, les textes ici rassemblés constituent un document essentiel pour l'histoire de la musique du xxe siècle

Global optimization of core station networks for space geodesy: application to the referencing of the SLR EOP with respect to ITRF

International audienc

OCA/GEMINI-GRGS BECOMING AN OFFICIAL ILRS ANALYSIS CENTER

National audienceOCA/GEMINI-GRGS is currently moving from its status of an associate ILRS analysis center to an official ILRS analysis center. The ILRS (International Laser Ranging System) is one of the nine services of the International Association of Geodesy (IAG). This new status should permit to GRGS to validate and, especially, enlighten in an easy way its scientific results coming from SLR data, within this international organization

AMBER data simulator

International audienceWe present the design and realization of the AMBER data simulator. This tool provides the AMBER team with: (1) a way to test the performance and sensitivity of AMBER wrt. external parameters (e.g., observed source magnitude, AO correction); (2) a means to validate proposed visibility retrieval algorithms; and (3) a mean to obtain realistic data flows to test and implement the AMBER data reduction software