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 are 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 data sets. We develop a set of new assessment tools that are generally applicable to all radio-astronomical cases of data combination. Applying these new assessment diagnostics, we evaluate the methods' performance and demonstrate the significant improvement of the combined results in comparison to purely interferometric reductions. We provide combination and assessment scripts as add-on material. Our results highlight the advantage of using data combination to ensure high-quality science images of spatially resolved objects.

29 pages, 20 figures. Accepted for publication in PASP. Code repository available at: github.com/teuben/DataComb

References in corpus (13)

• Array Programming with NumPy
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• Multi-Scale CLEAN deconvolution of radio synthesis images
• AUTO-MULTITHRESH: A General Purpose Automasking Algorithm
• The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview
• Assessing molecular outflows and turbulence in the protostellar cluster Serpens South
• GASKAP-HI Pilot Survey Science I: ASKAP Zoom Observations of HI Emission in the Small Magellanic Cloud
• Fourier Plane Image Combination by Feathering
• Total Power Map to Visibilities (TP2VIS): Joint Deconvolution of ALMA 12m, 7m, and Total Power Array Data
• J-comb: An image fusion algorithm to combine observations covering different spatial frequency ranges
• A joint deconvolution algorithm to combine single dish and interferometer data for wideband multi-term and mosaic imaging
• The Cygnus Allscale Survey of Chemistry and Dynamical Environments: CASCADE: Overview and first results toward DR20 from the Max Planck IRAM Observatory program (MIOP)