New methods for ALMA angular-scale based observation scheduling, quality assessment, and beam shaping II: refinements

TL;DR

This paper refines methods for ALMA observation scheduling and quality assessment, focusing on uv coverage evaluation, maximum recoverable scale measurement, and improving imaging robustness, applicable to large radio interferometers.

Contribution

It introduces improved techniques for uv coverage assessment, maximum recoverable scale measurement, and integrates these into observation scheduling for enhanced image quality.

Findings

Efficient uv coverage assessment methods developed.

New metrics for maximum recoverable angular scale proposed.

Enhanced robustness of deconvolution against uv coverage defects.

Abstract

The Atacama Large Millimeter/submillimeter Array remains the largest mm radio interferometer observatory world-wide. It is now conducting its 11th observing cycle. In our previous paper presented at this conference series in 2020, we outlined a number of possible improvements to the ALMA end-to-end observing and data processing procedures which could further optimize the uv coverage and thus the image quality while at the same time improving the observing efficiency. Here we report an update of our results refining our proposed adjustments to the scheduling and quality assurance processes. In particular we present new results on ways to assess the uv coverage of a given observation efficiently, methods to define and measure the maximum recoverable angular scale, and on the robustness of the deconvolution in the final interferometric imaging process w.r.t. defects in the uv coverage. Finally we present the outline of a design for integrating uv coverage assessment into the control and processing loop of observation scheduling. The results are applicable to all radio interferometers with more than approx. 10 antennas.