Faceted HyperSARA for RI wideband intensity imaging: Cygnus A wideband image at C band

Application of the wideband intensity imaging, dubbed Faceted HyperSARA to large scale radio interferometric (RI) observations of the celebrated radio galaxy Cygnus A from the VLA telescope. The dataset consists of wideband images of the celebrated radio galaxy Cygnus A obtained from 7.4 GB of VLA data, spanning the frequency range [4,8] GHz, using the Faceted HyperSARA approach (Thouvenin et al. 2022) and the benchmark methods. We investigate the scalability and precision of the proposed algorithm via two experiments. The first experiment consists in the reconstruction of a 15 GB image cube over the field of view 2.56 arcmin x 1.536 arcmin, and at the spatial resolution 0.06 arcsec and full spectral resolution (8 MHz). Wideband images are obtained with Faceted HyperSARA and the benchmark method SARA (Onose et al. 2017). The second experiment consists in the reconstruction of a 3.6 GB image cube over the field of view 2.1709 arcmin x 3.6181 arcmin and at the spatial resolution 0.0424 arcsec and the reduced spectral resolution (128 MHz), leveraging a joint image and data dimensionality reduction technique via visibility gridding. Wideband images are obtained with Faceted HyperSARA and the benchmark method of the WSClean software (Offringa and Smirnov 2017). All image cubes are provided in FITS format. GIF files for enhanced visual comparison of the different methods are also provided for both experiments.