Data reduction of the VLTI/GRAVITY interferometric instrument (Conference Presentation)

Vincent Lapeyrère; Pierre Kervella; Jean-Baptiste Le Bouquin; Sylvestre Lacour; Cesar Enrique Garcia-Dabó; Antoine Mérand; Julien Woillez; Guy Perrin; Frank Eisenhauer; Karine Perraut; Christian Straubmeier; António Amorim; Wolfgang Brandner

doi:10.1117/12.2314239

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10 July 2018 Data reduction of the VLTI/GRAVITY interferometric instrument (Conference Presentation)

Vincent Lapeyrère, Pierre Kervella, Jean-Baptiste Le Bouquin, Sylvestre Lacour, Cesar Enrique Garcia-Dabó, Antoine Mérand, Julien Woillez, Guy Perrin, Frank Eisenhauer, Karine Perraut, Christian Straubmeier, António Amorim, Wolfgang Brandner

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Proceedings Volume 10701, Optical and Infrared Interferometry and Imaging VI; 107011F (2018) https://doi.org/10.1117/12.2314239
Event: SPIE Astronomical Telescopes + Instrumentation, 2018, Austin, Texas, United States

Abstract

The new VLTI/GRAVITY instrument is a four telescope beam combiner installed at the VLT Interferometer. The principal novelty of this instrument is the availability of a dual field mode enabling narrow-angle relative astrometry at micro-arcsecond accuracy between two objects separated by several arcseconds. The fringe tracker (FT) stabilizes the interference fringes at up to 1 kHz frequency, allowing for long exposures with the science combiner (SC) as well as phase referenced imaging and differential astrometry (in dual field mode). The FT and SC beam combiners are integrated optics (IO) components, whose 24 outputs are (optionally) polarization-split and spectrally dispersed. The processing of the photometric signals from the IO components is based on the pixel-to-visibility matrix (P2VM) formalism, that translates them into complex visibilities. The retrieval of the relative phase of the two objects subsequently relies on the combination of the phases measured from the FT, SC and the laser metrology. We will present the adopted algorithms, and an overview of the structure of the developed software. The calibration of the wavelength scales of the FT and SC at the required accuracy presents specific difficulties that we will briefly discuss. Examples of the reduction of on-sky data obtained during the commissioning will also be presented.

Conference Presentation

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Vincent Lapeyrère, Pierre Kervella, Jean-Baptiste Le Bouquin, Sylvestre Lacour, Cesar Enrique Garcia-Dabó, Antoine Mérand, Julien Woillez, Guy Perrin, Frank Eisenhauer, Karine Perraut, Christian Straubmeier, António Amorim, and Wolfgang Brandner "Data reduction of the VLTI/GRAVITY interferometric instrument (Conference Presentation)", Proc. SPIE 10701, Optical and Infrared Interferometry and Imaging VI, 107011F (10 July 2018); https://doi.org/10.1117/12.2314239

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