Coffee talks
Monday 19/02/2024 @ 14:30, Sala riunioni quarto piano e on-line (meet.google.com/sue-bwvk-axf)
Ezequiel Albentosa (Universitat de València, Spain), "Astronomical Analysis of Next-Generation Global Geodetic Observations"
The VLBI Global Observing System (VGOS) is a next generation VLBI system developed by the International VLBI Service for Geodesy and Astrometry (IVS) to achieve geodetic observations with ultra-wideband receivers, observing from 3 to 11 GHz. These receivers observe in linear polarization to achieve optimal polarization purity. In this talk, we explore the intricacies of VGOS data calibration, including the conversion from linear to circular polarization using PolConvert and the implementation of the Wideband Global Fringe-Fitting (GFF) algorithm. Distancing ourselves from the conventional geodetic approach of fringe-fitting separately for each baseline, we present the first results obtained by performing a Global Fringe-Fitting across a global IVS array, comprising 8 antennas with intercontinental baselines, operating within the complete VGOS bandwidth. This approach yields promising outcomes and allows us to preserve critical closure information, pivotal for reconstructing the full polarization brightness distribution structure of the observed sources, which we showcase as preliminary images for a selection of the observed sources.