Data Combination: Interferometry and Single-dish Imaging in Radio Astronomy

Abstract

Modern interferometers routinely provide radio-astronomical images down to subarcsecond resolution.However, interferometers filter out spatial scales larger than those sampled by the shortest baselines, which affects the measurement of both spatial and spectral features. Complementary single dish data is vital for recovering the true flux distribution of spatially resolved astronomical sources with such extended emission. In this work, we provide an overview of the prominent available methods to combine single dish and interferometric observations. We test each of these methods in the framework of the CASA data analysis software package on both synthetic continuum and observed spectral datasets. We develop a set of new assessment tools which are generally applicable to all radio-astronomical cases of data combination. Applying these new assessment diagnostics we evaluate the methods' performance and demonstrate the