Extension of the coordinate parameterization of radio sources observed by VLBI (ECORAS)

• Applicants: Dr.-Ing. Robert Heinkelmann; Professor Dr.-Ing. Harald Schuh
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography ; Astrophysics and Astronomy
• Term: from 2014 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 249935073

The optical astrometric satellite mission Gaia (ESA) is going to provide positions and proper motions of radio sources at a level of precision comparable to current VLBI (Very Long Baseline Interferometry) or even better. In the 2nd phase of the project ECORAS, the comparison of the Gaia and VLBI celestial coordinates will be exploited for the determination of systematic reference frame effects, such as the Galactic aberration, primordial gravitational waves, gravitational lensing and comparable deformations due to inter-stellar mater. The comparison will also reveal important details about possible technique-dependent systematic errors of the VLBI and Gaia coordinates. Steps towards these important scientific goals are the detection, modelling and correction of radio source structure effects on celestial coordinates and observables. The evolution of intrinsic structure caused by astrophysical processes can cause very large apparent proper motions and hence, it needs to be considered to enable the precise comparisons. Likewise, the comparison requires an accurate orientation of the VLBI and Gaia reference frames. In the focus of the second part of project ECORAS is the alignment of the two radio and optical wavelengths-based frames. The same celestial object is very likely to appear at different positions depending on the observed frequency, an effect that needs to be considered for the precise tie of radio and optical reference frames.

• DFG Programme: Research Grants