A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometry

By U. Rau, Tim J. Cornwell. 2011

476 citations recorded by the source corpus.

Aims. We describe MS-MFS, a multi-scale multi-frequency deconvolution algorithm for wide-band synthesis-imaging, and present imaging results that illustrate the capabilities of the alg orithm and the conditions under which it is feasible and gives accurate results. Methods. The MS-MFS algorithm models the wide-band sky-brightness distribution as a linear combination of spatial and spectral basis functions, and performs image-reconstruction by combining a linear-least-squares approach with iterativeχ 2 minimization. This method extends and combines the ideas used in the MS-CLEAN and MF-CLEAN algorithms for multi-scale and multi-frequency deconvolution respectively, and can be used in conjunction with existing wide-field imaging algorithms. We also discus s a simpler hybrid of spectral-line and continuum imaging methods and point out situations where it may suffi ce. Results. We show via simulations and application to multi-frequency VLA data and wideband EVLA data, that it is possible to reconstruct both spatial and spectral structure of compact and extended emission at the continuum sensitivity level and at the angular resolution allowed by the highest sampled frequency.

Subfields: Astronomy and Astrophysics, Environmental Engineering

View Paper: https://www.semanticscholar.org/paper/f24752ed8a4e46ec76e7ff20939c92c648410000

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Citations in the corpus

LOFAR FACET CALIBRATION (2016, methodology): “At this time all the data (120–181 MHz) are imaged together using the MS-MFS clean algorithm (Rau & Cornwell 2011) as implemented in CASA with nterms=2.”
LOFAR 150-MHz observations of the Boötes field: catalogue and source counts (2016, methodology): “Multiscale CLEAN (MS-MFS; Rau & Cornwell 2011; Cornwell 2008) was used only in the case of a few complex extended sources.”
An optimized algorithm for multiscale wideband deconvolution of radio astronomical images (2017, methodology): “Rau & Cornwell (2011) mention this bias function is an empirical approximation of the inverse volume of the scale kernel, which normalizes the response to a given scale.”
EVIDENCE OF FAST PEBBLE GROWTH NEAR CONDENSATION FRONTS IN THE HL TAU PROTOPLANETARY DISK (2015, methodology): “This result is computed using the CLEAN task with nterms=2, based on the multi-frequency deconvolution algorithm developed by Rau & Cornwell (2011).”
wsclean: an implementation of a fast, generic wide-field imager for radio astronomy (2014, methodology): “Combining multi-scale with wideband deconvolution techniques is a possible further improvement (Rau & Cornwell 2011).”
CASA, the Common Astronomy Software Applications for Radio Astronomy (2022, methodology): “• mtmfs , multi-term multi-frequency synthesis imaging: Wideband image reconstruction that produces Taylor-coefficient maps, which represent smoothly varying spectral structure across the field-of-view of the image (Rau & Cornwell 2011, see also Sault & Wieringa 1994 Likhachev 2005).”
The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release (2017, methodology): “To image our data we used the multiscale multifrequency synthesis (MSMF) algorithm developed by Rau & Cornwell (2011) and implemented in CASA.”
FIRST RESULTS FROM HIGH ANGULAR RESOLUTION ALMA OBSERVATIO NS TOWARD THE HL TAU REGION (2015, background): “However, inclusion of the spectral slope requires good signal-to-noise ratio (S/N) at both frequency extrema of the calculation (Rau & Cornwell 2011), a condition the 2.9 mm data did not fulfill since four of the fiveavailable continuum spws were clustered at∼ 102 GHz.”
THE REPEATING FAST RADIO BURST FRB 121102: MULTI-WAVELENGTH OBSERVATIONS AND ADDITIONAL BURSTS (2016, methodology): “To account for the spectral shape of these sources, we used the multi-frequency synthesis mode of the CASA CLEAN implementation (Rau & Cornwell 2011) and approximated the sky brightness as a firstorder polynomial in frequency.”