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تسجيل مستخدم جديدThe Rapid ASKAP Continuum Survey I: Design and First Results
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The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia, and will cover the full ASKAP band of $700-1800$ MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey (NVSS) and Sydney University Molonglo Sky Survey (SUMSS) radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with $sim 15$ arcsecond resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination $+41^circ$ made over a 288 MHz band centred at 887.5 MHz.
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The Rapid ASKAP Continuum Survey (RACS) is the first large sky survey using the Australian Square Kilometre Array Pathfinder (ASKAP), covering the sky south of +41$^circ$ declination. With ASKAPs large, instantaneous field of view, $sim 31$ deg$^2$,
RACS observed the entire sky at a central frequency of 887.5 MHz using 903 individual pointings with 15 minute observations. This has resulted in the deepest radio survey of the full Southern sky to date at these frequencies. In this paper, we present the first Stokes I catalogue derived from the RACS survey. This catalogue was assembled from 799 tiles that could be convolved to a common resolution of 25$^{primeprime}$, covering a large contiguous region in the declination range $delta=-$80$^circ$ to +30$^circ$. The catalogue provides an important tool for both the preparation of future ASKAP surveys and for scientific research. It consists of $sim$2.1 million sources and excludes the $|b|<5^circ$ region around the Galactic plane. This provides a first extragalactic catalogue with ASKAP covering the majority of the sky ($delta<+30^circ$). We describe the methods to obtain this catalogue from the initial RACS observations and discuss the verification of the data, to highlight its quality. Using simulations, we find this catalogue detects 95% of point sources at an integrated flux density of $sim$5 mJy. Assuming a typical sky source distribution model, this suggests an overall 95% point source completeness at an integrated flux density $sim$3 mJy. The catalogue will be available through the CSIRO ASKAP Science Data Archive (CASDA).
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