The application of MultiView Methods for High Precision Astrometric Space VLBI at Low Frequencies

TL;DR

This paper demonstrates that MultiView methods enable high-precision low-frequency space VLBI astrometry by simulating challenging conditions, reducing infrastructure needs, and improving measurement accuracy for key astronomical targets.

Contribution

It introduces a MultiView approach for low-frequency S-VLBI that simplifies mission design and achieves high-precision astrometry under difficult technical conditions.

Findings

MultiView analysis achieves required astrometric precision in simulations.

The approach removes the need for beam switching and complex orbit reconstruction.

Simulations show robustness under poor ionospheric conditions.

Abstract

High precision astrometric Space Very Long Baseline Interferometry (S-VLBI) at the low end of the conventional frequency range, i.e. 20cm, is a requirement for a number of high priority science goals. These are headlined by obtaining trigonometric parallax distances to pulsars in Pulsar--Black Hole pairs and OH masers anywhere in the Milky Way Galaxy and the Magellanic Clouds. We propose a solution for the most difficult technical problems in S-VLBI by the MultiView approach where multiple sources, separated by several degrees on the sky, are observed simultaneously. We simulated a number of challenging S-VLBI configurations, with orbit errors up to 8m in size and with ionospheric atmospheres consistant with poor conditions. In these simulations we performed MultiView analysis to achieve the required science goals. This approach removes the need for beam switching requiring a Control Moment Gyro, and the space and ground infrastructure required for high quality orbit reconstruction of a space-based radio telescope. This will dramatically reduce the complexity of S-VLBI missions which implement the phase-referencing technique.