J/A+A/574/A73ivo://CDS.VizieR/J/A+A/574/A73doi:10.26093/cds/vizier.35740073CDSMoldon J.Deller A.T.Wucknitz O.Jackson N.Drabent A.Carozzi T.,Conway J.Kapinska A.D.McKean J.P.Morabito L.Varenius E.Zarka P.,Anderson J.Asgekar A.Avruch I.M.Bell M.E.Bentum M.J.Bernardi G.,Best P.Birzan L.Bregman J.Breitling F.Broderick J.W.Bruggen M.,Butcher H.R.Carbone D.Ciardi B.de Gasperin F.de Geus E.Duscha S.,Eislooffel J.Engels D.Falcke H.Fallows R.A.Fender R.Ferrari C.,Frieswijk W.Garrett M.A.Griessmeier J.Gunst A.W.Hamaker J.P.,Hassall T.E.Heald G.Hoeft M.Juette E.Karastergiou A.,Kondratiev V.I.Kramer M.Kuniyoshi M.Kuper G.Maat P.Mann G.,Markoff S.McFadden R.McKay-Bukowski D.Morganti R.Munk H.,Norden M.J.Offringa A.R.Orru E.Paas H.Pandey-Pommier M.Pizzo R.,Polatidis A.G.Reich W.Roottgering H.Rowlinson A.Scaife A.M.M.,Schwarz D.Sluman J.Smirnov O.Stappers B.W.Steinmetz M.Tagger M.,Tang Y.Tasse C.Thoudam S.Toribio M.C.Vermeulen R.Vocks C.,van Weeren R.J.White S.Wise M.W.Yatawatta S.Zensus A.2015-07-08T13:00:23Z2015-01-28T08:23:28ZCDS support team

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

cds-question@unistra.frinterferometryastrometryradio-continuum-emissionradio-sourcessurveysvery-long-baseline-interferometryAn efficient means of locating calibrator sources for international LOw Frequency ARray (LOFAR) is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140MHz. We used the multi-beaming capability of LOFAR to conduct a fast and computationally inexpensive survey with the full international LOFAR array. Sources were preselected on the basis of 325MHz arcminute-scale flux density using existing catalogues. By observing 30 different sources in each of the 12 sets of pointings per hour, we were able to inspect 630 sources in two hours to determine if they possess a sufficiently bright compact component to be usable as LOFAR delay calibrators.2015A&A...574A..73Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/574/A73CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)VIII/62 : The Westerbork Northern Sky Survey (Leiden, 1998)VIII/97 : 74MHz VLA Low-frequency Sky Survey Redux (VLSSr) (Lane+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/574/A73https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/574/A73http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/574/A73https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/574/A73https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/574/A73http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/574/A73GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/574/A73/lofarlb (LOFAR sources observed)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/574/A73/lofarlb?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/574/A73/lofarlb?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/574/A73/lofarlb?GETtext/xml+votable180.050000true219.97587572.63147220.0055555555555555565/2527 2922-2924 2926 2934 2967 2973 3008-3010 3012 3014 3016-3018 3020 3836-3837 3980 3983 3994-3995 4005 4012 4016 4026 6/10102 10107 10189 10191-10192 10195 10200-10202 10213 10224 11518-11519 11638-11639 11643 11645 11647 11683-11684 11686-11687 11702 11708 11710 11725 11728-11729 11731 11733-11735 11740-11742 11761 11859-11862 11865 11867 11888-11889 11891 11897 11900-11901 12044 12046-12047 12052 12054-12055 12060-12062 12076-12078 12084 12088 15215 15225-15227 15230 15261 15263 15281-15283 15285-15288 15293 15301 15305-15308 15310-15312 15316-15317 15323 15326-15327 15329 15333-15336 15352 15906-15909 15911-15913 15915-15917 15924-15925 15929-15930 15968-15970 15974 15998 16000 16002-16004 16010 16026-16027 16029 16032-16033 16035-16037 16039 16041 16043-16044 16046-16047 16052 16054 16061 16063 16068-16070 16076 16081-16083 16085-16088 16090-16091 16093-16095 16098-16100 16102-16103 16110-16112 161144.903291545219051e-26 9.276497240453405e-25https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/574/A73?format=asciiRadiodefaultJ/A+A/574/A73/lofarlbLOFAR sources observedrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (WNBHHMM.m+DDMMA or JHHMM+DDMM)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainFwenss? Peak flux density in the WENSS catalogue (330MHz, VIII/62)mJyphot.flux.density;em.radio.200-400MHzfloatnullablee_Fwenss? Error of peak flux density in the WENSS cataloguemJystat.errorfloatnullableFnvss? Flux density in the NVSS catalogue (1.4GHz, VIII/65)mJyphot.flux.density;em.radio.750-1500MHzfloatnullablee_Fnvss? Error of flux density in the NVSS cataloguemJystat.errorfloatnullableFvlss? Flux density of VLSS catalogue (74MHz, VIII/97)Jyphot.flux.density;em.radio.20-100MHzfloatnullableq[1/3] Quality factor, 3=good calibrator (1)arith.factorintSEDPlot the spectrum with SPECFIND (Vollmer et al. 2009, Cat. VIII/85)meta.ref.urlchar