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

TL;DR

This paper introduces new methods for ALMA observation scheduling and quality assessment based on angular scales, aiming to improve efficiency and image fidelity by analyzing data in visibility space.

Contribution

It proposes angular-scale-based scheduling, quality assessment, and visibility weighting methods, advancing beyond traditional beam shape and noise RMS criteria for better imaging outcomes.

Findings

Enhanced scheduling efficiency through angular-scale analysis.

Improved image fidelity by optimizing visibility weighting.

Method applicable to all radio interferometers with more than 10 antennas.

Abstract

Up to now, the completion of an ALMA interferometric observation is determined based on the achievement of a given shape and size of the synthesized beam and the noise RMS in the representative spectral range. This approach with respect to the angular resolution investigates mainly the longest baselines of the interferometer and says little about the sensitivity at larger angular scales. We are exploring the ideas of angular-scale-based scheduling and quality assessment, and of angular-scale-based visibility weighting as a step towards optimising both observation efficiency and image fidelity. This approach carries the imaging quality assurance into the visibility space where interferometers record the data, and therefore simplifies many aspects of the procedure. Similarly, during scheduling such detailed assessment of the expected imaging properties helps optimising the scheduling process. The methodology is applicable to all radio interferometers with more than ca. 10 antennas.