Multi scale multi wavelength analysis of AGN

Applications are solicited for a post-doctoral position in astrophysics at J.-L. Lagrange laboratory in Nice, France. The position is for one year, renewable for at least one more year.

J.-L. Lagrange laboratory is a joint research unit of Côte d’Azur University, Côte d’Azur Observatory and CNRS. It has teams in Galaxies and Cosmology, Instrumental Astrophysics, Stellar and solar Physics, Signal and Image processing, Theory and Observation in Planetology and Turbulence, Fluids and Plasma. It is the birthplace and remains a world leader in multi telescopes optical interferometry with the PI ship of the VLTI instruments AMBER and MATISSE and strong contributions to the VLTI upgrade GRAVITY+ and to the visitor instrument ASGARD. The fellowship is funded by the French Agence Nationale de la Recherche (ANR) grant AGN_MELBa (Multi Scale Multi Wavelength study of AGN) for the 1st year. 

General science goal :

Active Galactic Nuclei are a key component of Galactic evolution through AGN feedback. They are a tracer of the coevolution of super massive black holes (SMBH) and galaxies and they can be used as cosmological probes. The Very Large Telescope Interferometer (VLTI) offers major breakthroughs on the inner structure of AGN. The GRAVITY instrument resolves Broad Line Regions (BLR) by spectro-astrometry (SA) and provides dynamical measures of SMBH masses. Combined with Reverberation Mapping, SA yields a direct geometrical distance that should eventually contribute to the Hubble tension problem. The GRAVITY and MATISSE VLTI instruments give images of the AGN dust torus and dusty wind in the 1-10 pc range. The JWST and Advanced Adaptive Optics (AO) Instruments on unit telescopes, such as ERIS on the VLT, provide images of the circum nuclear disk (CND) and shocks created by in- and outflowing material, in the 10-100 pc range. All these structures are interacting and cannot be accurately modeled independently. The observational data for each of these instrumental techniques is affected by structures that can be only accurately analyzed at the different scales by the other instruments. The science goal of ANR project AGN_MELBa is to analyze these physical interactions and mutual observational constraints, in the unique instrumental context of the very strong development of the VLTI sensitivity, spectral coverage and resolution.

Main task :

The fellow will work with Drs. Romain Petrov and Pierre Vermot in interaction with the MATISSE and ANR AGN_MELBa AGN science groups. Her/His first main task will be to combine existing image reconstruction codes for interferometry and deconvolution codes for single aperture Adaptive Optics, in a global image reconstruction or model fitting at all these scales. Several options are possible but the preferred one, which would be the continuation of previous work, would use machine learning on a simulated data base to define the tools, followed by an application to data from MATISSE, GRAVITY and ERIS. A second step would analyze how the large scale structures can constrain and improve the modeling of differential interferometry of BLR.