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Register a new userThe Rapid ASKAP Continuum Survey Paper II: First Stokes I Source Catalogue Data Release
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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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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.
We present the first data release of the James Clerk Maxwell Telescope (JCMT) Plane Survey (JPS), the JPS Public Release 1 (JPSPR1). JPS is an 850-um continuum survey of six fields in the northern inner Galactic Plane in a longitude range of l=7-63, made with the Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2). This first data release consists of emission maps of the six JPS regions with an average pixel-to-pixel noise of 7.19 mJy beam^-1, when smoothed over the beam, and a compact-source catalogue containing 7,813 sources. The 95 per cent completeness limits of the catalogue are estimated at 0.04 Jy beam^-1 and 0.3 Jy for the peak and integrated flux densities, respectively. The emission contained in the compact-source catalogue is 42 +- 5 per cent of the total and, apart from the large-scale (greater than 8) emission, there is excellent correspondence with features in the 500-um Herschel maps. We find that, with two-dimensional matching, 98 +- 2 per cent of sources within the fields centred at l=20, 30, 40 and 50 are associated with molecular clouds, with 91 +- 3 per cent of the l=30 and 40 sources associated with dense molecular clumps. Matching the JPS catalogue to Herschel 70-um sources, we find that 38 +- 1 per cent of sources show evidence of ongoing star formation. The images and catalogue will be a valuable resource for studies of star formation in the Galaxy and the role of environment and spiral arms in the star formation process.
The LOFAR Two-metre Sky Survey (LoTSS) is an ongoing sensitive, high-resolution 120-168MHz survey of the entire northern sky for which observations are now 20% complete. We present our first full-quality public data release. For this data release 424 square degrees, or 2% of the eventual coverage, in the region of the HETDEX Spring Field (right ascension 10h45m00s to 15h30m00s and declination 45$^circ$00$$00$$ to 57$^circ$00$$00$$) were mapped using a fully automated direction-dependent calibration and imaging pipeline that we developed. A total of 325,694 sources are detected with a signal of at least five times the noise, and the source density is a factor of $sim 10$ higher than the most sensitive existing very wide-area radio-continuum surveys. The median sensitivity is S$_{rm 144 MHz} = 71,mu$Jy beam$^{-1}$ and the point-source completeness is 90% at an integrated flux density of 0.45mJy. The resolution of the images is 6$$ and the positional accuracy is within 0.2$$. This data release consists of a catalogue containing location, flux, and shape estimates together with 58 mosaic images that cover the catalogued area. In this paper we provide an overview of the data release with a focus on the processing of the LOFAR data and the characteristics of the resulting images. In two accompanying papers we provide the radio source associations and deblending and, where possible, the optical identifications of the radio sources together with the photometric redshifts and properties of the host galaxies. These data release papers are published together with a further $sim$20 articles that highlight the scientific potential of LoTSS.
We present the completed KMOS$^mathrm{3D}$ survey $-$ an integral field spectroscopic survey of 739, $log(M_{star}/M_{odot})>9$, galaxies at $0.6<z<2.7$ using the K-band Multi Object Spectrograph (KMOS) at the Very Large Telescope (VLT). KMOS$^mathrm{3D}$ provides a population-wide census of kinematics, star formation, outflows, and nebular gas conditions both on and off the star-forming galaxy main sequence through the spatially resolved and integrated properties of H$alpha$, [N II], and [S II] emission lines. We detect H$alpha$ emission for 91% of galaxies on the main sequence of star-formation and 79% overall. The depth of the survey has allowed us to detect galaxies with star-formation rates below 1 M$_{odot}$/ yr$^{-1}$, as well as to resolve 81% of detected galaxies with $geq3$ resolution elements along the kinematic major axis. The detection fraction of H$alpha$ is a strong function of both color and offset from the main sequence, with the detected and non-detected samples exhibiting different SED shapes. Comparison of H$alpha$ and UV+IR star formation rates (SFRs) reveal that dust attenuation corrections may be underestimated by 0.5 dex at the highest masses ($log(M_{star}/M_{odot})>10.5$). We confirm our first year results of a high rotation dominated fraction (monotonic velocity gradient and $v_mathrm{rot}$/$sigma_0 > sqrt{3.36}$) of 77% for the full KMOS$^mathrm{3D}$ H$alpha$sample. The rotation-dominated fraction is a function of both stellar mass and redshift with the strongest evolution measured over the redshift range of the survey for galaxies with $log(M_{star}/M_{odot})<10.5$. With this paper we include a final data release of all 739 observed objects.
We present chemical elemental abundances for $36,561$ stars observed by the RAdial Velocity Experiment (RAVE), an ambitious spectroscopic survey of our Galaxy at Galactic latitudes $|$b$|>25^{circ}$ and with magnitudes in the range 9$<I_{DENIS}<$13. RAVE spectra cover the Ca-triplet region at 8410--8795AA with resolving power R$sim$7500. This first data release of the RAVE chemical catalogue is complementary to the third RAVE data release of radial velocities and stellar parameters, and it contains chemical abundances for the elements Mg, Al, Si, Ca, Ti, Fe and Ni, with a mean error of $sim$0.2 dex, as judged from accuracy tests performed on synthetic and real spectra. Abundances are estimated through a dedicated processing pipeline in which the curve of growth of individual lines is obtained from a library of absorption-line equivalent widths to construct a model spectrum that is then matched to the observed spectrum via a $chi^2$-minimization technique. We plan to extend this pipeline to include estimates for other elements, such as oxygen and sulfur, in future data releases.
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