Removing the Effect of Source Structure From Correlated VLBI Data
Abstract
Recent studies suggest that in geodetic very long baseline interferometry (VLBI) the assumption of sources being point‐like results in a significant residual error introduced by the effect of source structure. Our aim is to remove the impact of source structure from geodetic VLBI data right after the correlation step. For this purpose, we have developed a dedicated software tool that takes models of the brightness distribution to correct the interferometric phases of the correlator output. The corrected data are then further processed following conventional procedures. Images obtained from corrected visibilities appear more compact, by up to 43%, compared to the original ones. The distribution of closure delays is significantly improved, by up to 27 ps, for the structure‐corrected data, provided that the image information is accurate. The WRMS of post‐fit‐delay residuals is reduced by up to 5 ps per corrected source. The positive effect of the correction is greatly reduced when applied to data with a large temporal offset to the images used for its configuration. We conclude that the images used for any structure correction should have a time difference of not more than a few weeks to the data to which they are applied.
Related
- Modified Corn Straw Hydrogel Adsorbent Fabricated via Embedding for Removing Cu2+ and Pb2+ from Wastewater
- The concept of quasi-correlated absorption spectra and its application in atmospheric remote sensing
- A novel integrated objective-subjective weighting method using principal component analysis to correct overrepresentation of correlated criteria in sustainability decision-making
- Separation of Source, Site, and Path Effects Based on Elastic Radiative Transfer Theory, Part 2: Generalized Inversion of Source and Site Parameters and Application to Metropolitan France
- A 400 Myr subduction memory in the mid-ocean ridge source
BibTeX
@article{jaron2026removing,
title = {{Removing the Effect of Source Structure From Correlated VLBI Data}},
author = {Frédéric Jaron and Víctor Pérez-Díez and Hana Krásná and Johannes Böhm and Patrick Charlot and Arnaud Collioud and Jakob Gruber and Iván Martí-Vidal and Axel Nothnagel},
journal = {Radio Science},
year = {2026},
month = oct,
doi = {10.1029/2025rs008500},
url = {https://hal.science/hal-05858198v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Removing the Effect of Source Structure From Correlated VLBI Data
AU - Frédéric Jaron
AU - Víctor Pérez-Díez
AU - Hana Krásná
AU - Johannes Böhm
AU - Patrick Charlot
AU - Arnaud Collioud
AU - Jakob Gruber
AU - Iván Martí-Vidal
AU - Axel Nothnagel
PY - 2026
DA - 2026/10/15
JO - Radio Science
DO - 10.1029/2025rs008500
UR - https://hal.science/hal-05858198v1
AB - Recent studies suggest that in geodetic very long baseline interferometry (VLBI) the assumption of sources being point‐like results in a significant residual error introduced by the effect of source structure. Our aim is to remove the impact of source structure from geodetic VLBI data right after the correlation step. For this purpose, we have developed a dedicated software tool that takes models of the brightness distribution to correct the interferometric phases of the correlator output. The corrected data are then further processed following conventional procedures. Images obtained from corrected visibilities appear more compact, by up to 43%, compared to the original ones. The distribution of closure delays is significantly improved, by up to 27 ps, for the structure‐corrected data, provided that the image information is accurate. The WRMS of post‐fit‐delay residuals is reduced by up to 5 ps per corrected source. The positive effect of the correction is greatly reduced when applied to data with a large temporal offset to the images used for its configuration. We conclude that the images used for any structure correction should have a time difference of not more than a few weeks to the data to which they are applied.
SN - 0048-6604
ER -