wsclean: an implementation of a fast, generic wide-field imager for radio astronomy

By A. Offringa, B. McKinley, N. Hurley-Walker, Frank H. Briggs, Randall B. Wayth, D. Kaplan, M. Bell, Lu Feng, A. Neben, J. Hughes and 43 more. 2014

562 citations recorded by the source corpus.

Astronomical widefield imaging of interferometric radio data is computationally expensive, especially for the large data volumes created by modern non-coplanar many-element arrays. We present a new widefield interferometric imager that uses the w-stacking algorithm and can make use of the w-snapshot algorithm. The performance dependencies of CASA's w-projection and our new imager are analysed and analytical functions are derived that describe the required computing cost for both imagers. On data from the Murchison Widefield Array, we find our new method to be an order of magnitude faster than w-projection, as well as being capable of full-sky imaging at full resolution and with correct polarisation correction. We predict the computing costs for several other arrays and estimate that our imager is a factor of 2-12 faster, depending on the array configuration. We estimate the computing cost for imaging the low-frequency Square-Kilometre Array observations to be 60 PetaFLOPS with current techniques. We find that combining w-stacking with the w-snapshot algorithm does not significantly improve computing requirements over pure w-stacking. The source code of our new imager is publicly released.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4676bbd55c0d6190178d893d4d4f81ecc670493d

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Citations in the corpus

Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR (2017, methodology): “We also have used WSClean (Offringa et al. 2014), and its image deconvolution features, for general verification of our images.”
GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey - I. A low-frequency extragalactic catalogue (2016, methodology): “Using chgcentre, part of the WSClean package, the peeled visibilities are phase-rotated to the minimum w-term direction, within 1◦ of zenith.”
Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR (2020, methodology): “Residual visibilities obtained after calibration and source subtraction are gridded and imaged independently for each sub-band using WSClean13 (Offringa et al. 2014), creating an (l,m, ν) image cube.”
LOFAR FACET CALIBRATION (2016, methodology): “One option that has recently been exploited is to make use of WSClean (Offringa et al. 2014) instead of the CASA imager.”
An optimized algorithm for multiscale wideband deconvolution of radio astronomical images (2017, methodology): “The WSCLEAN imager uses a w-stacking algorithm for the gridding, which is particularly advantageous for wide-field imaging (Offringa et al. 2014).”
PAPER-64 CONSTRAINTS ON REIONIZATION: THE 21 cm POWER SPECTRUM AT z = 8.4 (2015, methodology): “We account for the required threedimensional Fourier transform in wide field imaging by using the w-stacking algorithm implemented in WSclean (Offringa et al. 2014) although we note that the standard w-projection algorithm implemented in CASA18 gives similar performances as the PAPER array is…”