J/A+A/673/A165ivo://CDS.VizieR/J/A+A/673/A165doi:10.26093/cds/vizier.36730165CDSde Gasperin F.Edler H.Williams W.L.Callingham J.R.Asabere B.,Bruggen M.Brunetti G.Dijkema T.J.Hardcastle M.J.Iacobelli M.,Offringa A.Norden M.J.Rottgering H.Shimwell T.van Weeren R.,Tasse C.Bomans D.J.Bonafede A.Botteon A.Cassano R.Chyzy K.T.,Cuciti V.Emig K.L.Kadler M.Miley G.Mingo B.Oei M.S.S.L.,Prandoni I.Schwarz D.J.Zarka P.2023-10-16T12:09:44Z2023-08-11T12:20:15ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsurveysradio-continuum-emissionThe Low Frequency Array (LOFAR) is the only existing radio interferometer able to observe at ultra-low frequencies (<100MHz) with high resolution (<15-arcsec) and high sensitivity (<1mJy/beam). To exploit these capabilities, the LOFAR Surveys Key Science Project is using the LOFAR Low Band Antenna (LBA) to carry out a sensitive wide-area survey at 41-66MHz named the LOFAR LBA Sky Survey (LoLSS). LoLSS is covering the whole northern sky above declination 24 deg with a resolution of 15-arcsec and a sensitivity of 1-2mJy/beam (1 {sigma}) depending on declination, field properties, and observing conditions. Here we present the first data release, including a discussion of the calibration strategy and the properties of the released images and catalogues. A fully automated pipeline was used to reduce the 95 fields included in this data release. The data reduction procedures developed for this project have a general application and are currently being used to process almost all LOFAR LBA interferometric observations. Compared to the preliminary release, direction-dependent errors have been derived and corrected for during the calibration process. This results in a typical sensitivity of 1.55mJy/beam, which is four times better than for the preliminary release, at the target resolution of 15 arcsec. The first data release of the LOFAR LBA Sky Survey covers 650 sqdeg in the HETDEX spring field. The resultant data products released to the community include mosaic images (I and V Stokes) of the region, and a catalogue of 42463 detected sources and related Gaussian components used to describe the sources' morphologies. Separate catalogues for the six in-band frequencies of 44, 48, 52, 56, 60, and 64MHz are also released. The first data release of LoLSS shows that, despite the influences of the ionosphere and radio frequency interference, LOFAR can conduct large-scale surveys in the frequency window 42-66MHz with unprecedentedly high sensitivity and resolution. The data can be used to derive unique information on the low-frequency spectral properties of many thousands of sources with a wide range of applications in extragalactic and galactic astronomy.2023A&A...673A.165Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/673/A165CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/659/A1 : LOFAR Two-metre Sky Survey (LoTSS) DR2 (Shimwell+, 2022)http://www.lofar-surveys.org : LoLSS Home Pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/673/A165https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/673/A165http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/673/A165https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/673/A165https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/673/A165http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/673/A165GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/673/A165/lolss1s (LoLSS DR1 v1.1 catalogue (LoLSS]\_DR1_v1.1.srl))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/673/A165/lolss1s?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/673/A165/lolss1s?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/673/A165/lolss1s?GETtext/xml+votable180.050000true161.737662250474348.45628119030860.005555555555555556Cone search capability for table J/A+A/673/A165/lolss1g (LoLSS DR1 v1.1 catalogue with Gaussians (LoLSS]\_DR1_v1.1.gaus))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/673/A165/lolss1g?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/673/A165/lolss1g?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/673/A165/lolss1g?GETtext/xml+votable180.050000true161.737662250474348.45628119030860.0055555555555555563/93 173-174 178 4/349-351 369 622 669-671 685-687 689-691 700 705-710 716 736 5/1375 1391 1395 1521 1523-1526 1529 2479 2483 2492 2494 2655 2671 2675 2719 2735 2739 2755 2804-2806 2808-2810 2819 2844 2846 2872-2874 2948-2950 2952-2954 6/5493-5495 5498-5499 5557-5559 5561-5563 5573-5575 5577-5579 5940-5941 5943 6080-6081 6083 6089 6091 6108-6110 6124-6125 6128-6130 9911 9915 9927 9931 9944 9946-9947 9980 9982-9983 10615 10619 10679 10683 10695 10699 10870-10871 10874-10875 10933-10935 10939 10949 10951 10953-10955 11014-11015 11017 11019 11228-11230 11244-11246 11248-11250 11271 11275 11380-11381 11472-11474 11480 11482 11500-11502 11504-11506 11520 11522 11528 11804-11806 11820-11822 11824-11825 11840-11842 11904-119063.5780776607782883e-26 3.5780776607782883e-26https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/673/A165?format=asciiRadiodefaultJ/A+A/673/A165/lolss1sLoLSS DR1 v1.1 catalogue (LoLSS]\_DR1_v1.1.srl)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSourceThe source ID (LOL1JHHMMSS.s+DDMMSS) (G1)meta.id;meta.maincharRAJ2000Centroid right ascension (J2000)degpos.eq.ra;meta.mainindexede_RAJ2000Uncertainty on right ascension (1 sigma)arcsecstat.error;pos.eq.rafloatDEJ2000Centroid declination (J2000)degpos.eq.dec;meta.mainindexede_DEJ2000Uncertainty on declination (1 sigma)arcsecstat.error;pos.eq.decfloatFtotIntegrated flux density at 54MHzmJyphot.flux.density;em.radio.20-100MHzdoublee_FtotUncertainty on flux density at 54MHz (1 sigma)mJystat.errordoubleFpeakPeak brightness at 54MHzmJy/beamphot.flux.density;em.radio.20-100MHzdoublee_FpeakUncertainty on peak brightness at 54MHz (1 sigma)mJy/beamstat.errordoubleMajMajor axisarcsecphys.angSizefloate_MajUncertainty on major axis (1 sigma)arcsecstat.errorfloatMinMinor axisarcsecphys.angSize;srcfloatE_MinUncertainty on minor axis (1 sigma)arcsecstat.error;stat.maxdoublePAPosition angledegpos.posAngfloate_PAUncertainty on position angle (1 sigma)degstat.errordoubleDCMajDeconvolved Major axisarcsecphys.angSizefloate_DCMajUncertainty on deconvolved major axis (1 sigma)arcsecstat.errorfloatDCMinDeconvolved Minor axisarcsecphys.angSize;srcfloate_DCMinUncertainty on deconvolved minor axis (1 sigma)arcsecstat.errorfloatDCPADeconvolved position angledegpos.posAngfloate_DCPAUncertainty on deconvolved position angle (1 sigma)degstat.errorfloatIslrmsLocal rms noise at the source locationmJy/beamstat.errordoubleSCode[CMS] Source code (G2)meta.codecharMosaicMosaic identifier (G3)meta.idcharJ/A+A/673/A165/lolss1gLoLSS DR1 v1.1 catalogue with Gaussians (LoLSS]\_DR1_v1.1.gaus)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSourceThe source ID (LOL1JHHMMSS.s+DDMMSS) (G1)meta.id;meta.maincharGausIdGaussian identifiermeta.idintRAJ2000Centroid right ascension (J2000)degpos.eq.ra;meta.mainindexede_RAJ2000Uncertainty on right ascension (1 sigma)arcsecstat.error;pos.eq.rafloatDEJ2000Centroid declination (J2000)degpos.eq.dec;meta.mainindexede_DEJ2000Uncertainty on declination (1 sigma)arcsecstat.error;pos.eq.decfloatFtotIntegrated flux density at 54MHzmJyphot.flux.density;em.radio.20-100MHzdoublee_FtotUncertainty on flux density at 54MHz (1 sigma)mJystat.errordoubleFpeakPeak brightness at 54MHzmJy/beamphot.flux.density;em.radio.20-100MHzdoublee_FpeakUncertainty on peak brightness at 54MHz (1 sigma)mJy/beamstat.errordoubleMajMajor axisarcsecphys.angSizefloate_MajUncertainty on major axis (1 sigma)arcsecstat.errorfloatMinMinor axisarcsecphys.angSize;srcfloate_MinUncertainty on minor axis (1 sigma)arcsecstat.error;stat.minfloatPAPosition angledegpos.posAngfloatE_PAUncertainty on position angle (1 sigma)degstat.error;stat.maxfloatDCMajDeconvolved Major axisarcsecphys.angSizefloate_DCMajUncertainty on deconvolved major axis (1 sigma)arcsecstat.errorfloatDCMinDeconvolved Minor axisarcsecphys.angSize;srcfloate_DCMinUncertainty on deconvolved minor axis (1 sigma)arcsecstat.errorfloatDCPADeconvolved position angledegpos.posAngfloate_DCPAUncertainty on deconvolved position angle (1 sigma)degstat.errorfloatIslrmsLocal rms noise at the source locationmJy/beamstat.errordoubleSCode[CMS] Source code (G2)meta.codecharMosaicMosaic identifier (G3)meta.idchar