Emplois, stages

Paris Observatory-PSL is one of the largest astronomical centers in the world with 650 permanent staff out of a total of 1000 personnel, hosting LESIA (the Laboratory for Space Studies and Instrumentation in Astronomy, member of the GRAVITY/GRAVITY+ consortium). GRAVITY and the VLT Interferometer (VLTI) have transformed optical interferometry with groundbreaking results on the Galactic Center (see Nobel Prize in Physics 2020), active galactic nuclei, and exoplanets. Through its upgrades – off-axis fringe-tracking, extreme adaptive optics (AO) and laser guide stars for the four 8-m unit telescopes (UTs) – GRAVITY+ will open up the extragalactic sky for milli-arcsec resolution interferometric imaging, and give access to targets as faint as K = 22 mag. GRAVITY+ will measure the black hole masses of active galactic nuclei across cosmic time, and obtain high quality exoplanet spectra and orbits.

The French contribution, coordinated by LESIA, brings together the four French interferometric laboratories within a first-class international consortium, in an effort to implement and test the four units of the new high-order AO system. LESIA is responsible of several work packages, including (1) defining the calibration plan of the wide-field (≈ 20") off-axis FT mode (a.k.a. GRAVITY-wide) and (2) implementing the real-time computer (RTC) for this AO. IPAG (Grenoble) is responsible for the AO system work package, Lagrange (Nice) will host the integration optical bench and CRAL (Lyon) will participate in software developments. GRAVITY-wide is currently being implemented on Paranal and the new AO is scheduled to be deployed from 2022 to 2024, after integration and testing in Nice starting in fall 2021 for the first unit.

Applications featuring experience in adaptive optics and/or atmospheric simulations are solicited for a post-doctoral fellowship at Paris Observatory/LESIA in collaboration with the GRAVITY+ consortium. The post-doctoral research assistant (PDRA) will simulate the effect of atmospheric turbulence residuals on interferometric observables after adaptive optics (AO) and fringe-tracking (FT) correction, and participate in the integration of the new GRAVITY+ extreme adaptive optics system in Europe and on the Very Large Telescope (VLT) in Chile. He/she will be member of the consortium and be given the opportunity to participate in GRAVITY-wide early science. The successful candidate will be appointed initially for one year, with possibility for a second year on the basis of satisfactory performance.

In the context of GRAVITY-wide, residual atmospheric piston, tip/tilt and higher orders induce performance losses in the interferometric data, due to the cone effect, the isoplanetic angle and the isopistonic angle. The PDRA will study the Strehl and/or contrast losses as a function of reference star distance up to ≈ 30", based on theoretical arguments and numerical simulations to elaborate the calibration plan for such data. For this purpose, the PDRA will have access to experimental on-sky data and interact with other consortium members (MPE Garching – PI institute, University of Cologne) and partners (ESO).

In parallel to this study, the PDRA will join the AO system team lead by the IPAG laboratory in Grenoble with experts from LESIA, Lagrange, CRAL (Lyon), MPE and ESO. He/she will participate in the integration of the new AO system on the bench in Nice and on the VLT at Paranal, with ample flexibility for involvement in the various subsystems, in particular the RTC. The PDRA will be a member of the GRAVITY+ collaboration and participate to the preparation and early-use of the wide-field mode of the instrument.

The PDRA will be based at LESIA at Paris Observatory. He/she will work primarily together with :
–  Paris Observatory-PSL/LESIA : Thibaut Paumard, Yann Clénet, Éric Gendron
–  Grenoble Observatory/IPAG : Jean-Baptiste Le Bouquin
–  Côte d’Azur Observatory/Lagrange : Florentin Millour, Olivier Lai

The PDRA will also collaborate with the members of the GRAVITY+ consortium and ESO.

PhD involving atmospheric simulations or adaptive optics

Candidates should provide :
–  a CV ;
–  a letter of motivation ;
–  a complete list of publications and a separate list of first-author publications ;
–  the PhD certificate or, if not yet earned, the date of defense ;
–  two reference letters. apply on : https://emploi.cnrs.fr/Offres/CDD/UMR8109-SYLDES-029/Default.aspx