First results of the GRAVITY, the near-infrared 2nd-generation instrument of the Very Large Telescope Interferometer (VLTI)

Séminaire IPAG de Karine Perraut (IPAG), jeudi 29 juin 2017 à 11h00, IPAG seminar room

GRAVITY is the second generation Very Large Telescope Interferometer (VLTI) instrument of ESO for precision narrow-angle astrometry and interferometric imaging. Designed to probe physics close to the event horizon of the Galactic Centre black hole, it operates in the near-infrared K band and takes benefit of the unique potential of the VLTI, with its four 8-meter Unit Telescopes (UTs) for high angular resolution imaging at high sensitivity, and with its 2-arcsecond field for providing simultaneous interferometry of two objects and narrow-angle astrometry with a precision of about 10 microarcseconds. Developed for about 10 years within a consortium led by the Max-Planck Insitute of Garching (MPE) and in which INSU (LESIA and IPAG) is a major partner, this instrument recorded its first-light in November 2015. Since then, GRAVITY has obtained several achievements as the first interferometric measurements on the S2 star of Kmag = 14.2, which is the closest known star around the Galactic Centre black hole, and the first interferometric observations of the Galactic Center during flares. We will quickly recall the principle of the instrument and besides focus our talk on the first scientific results.