Duchesne et al. present a new data release from the Rapid ASKAP Continuum Survey (RACS), a widefield snapshot radio survey conducted with the Australian SKA Pathfinder. This data release contains the second RACS epoch to make use of ASKAP’s low-frequency band, centred on 887.5 MHz with a bandwidth of 288 MHz, referred to as RACS-low2. This RACS-low2 data release includes both Stokes I (total intensity) and V (circular polarisation) imaging and catalogue data products covering the whole sky up to a declination of +48 degrees. The Stokes I and V catalogues are derived from images with a median point-spread function (PSF) of 14.2 × 11.8 arcseconds, and have median root-mean-square noise properties of 195 and 163 micro-jansky per beam for the Stokes I and V images, respectively.  The consolidated Stokes I catalogue contains 3,922,151 sources.  A catalogue of Stokes V sources was also constructed by measuring Stokes V images at the Stokes I source positions. For the 221 Stokes V measurements above the estimated leakage and detection thresholds likely identifications are provided, including detections of 61 radio stars, 85 pulsars, 43 AGN (many likely to be residual leakage), and one source that is not associated with a known astronomical object.  These data products, including calibrated visibilities, images, source lists, and consolidated catalogues, are made publicly available through the CSIRO ASKAP Science Data Archive (CASDA).

The image above shows example cutouts of the giant radio galaxy associated with the galaxy ESO 505−G014 highlighting the differences in the available RACS-low1 and RACS-low2 images.  The left and centre-left panels show the original RACS-low1 images (before and after mosaicking and convolution to 25 × 25 arcsecond angular resolution) and the remaining three images show cutouts from the same field from RACS-low2 (original image, full-sensitivity mosaic image, and the full-sensitivity mosaic image convolved to 25 × 25 arcsecond angular resolution).

This particular field saw a dramatic improvement to the angular resolution and root-mean-square (rms) noise in the RACS-low2 observation, going from 18.3 × 17.3 arcseconds (with an rms noise of 342 micro-jansky per beam) in the RACS-low1 observation to 13.1 × 11.1 arcseconds (with rms noise of 214 micro-jansky per beam) in the equivalent RACS-low2 field.  Part of the improvement in rms noise follows from the improvement in angular resolution, although there is also a reduction in the rms noise for the full-sensitivity mosaic 25 arcssecond images as well, highlighting the general data quality improvement with this second RACS-low epoch.