J/A+AS/108/79ivo://CDS.VizieR/J/A+AS/108/79CDSRoettgering H.J.A.Lacy M.Miley G.K.Chambers K.C.Saunders R.1997-12-09T17:35:15Z1997-12-09T18:35:04ZCDS support team

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

cds-question@unistra.frradio-sourcesRadio sources with ultra-steep spectra (USS; spectral index <~ -1.0) have been found to be excellent tracers of galaxies at redshifts z>~2. The samples are selected from the set of catalogues referenced below, in a range of frequencies from 38 to 408MHz; they are are fainter by a factor of three than the previously well-studied samples of USS sources from 4C. Snapshot observations of sources from these samples have been made with the VLA at 1.5arcsec resolution and are presented in the printed paper. The list of the sources (Appendix A of the paper) includes positions, flux densities and radio structures for a total number of 605 sources derived from these observations.1994A&AS..108...79Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+AS/108/79CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+AS/108/79https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+AS/108/79http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+AS/108/79https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+AS/108/79https://vizier.iucaa.in/viz-bin/votable?-source=J/A+AS/108/79http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+AS/108/79GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+AS/108/79/source (Source list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+AS/108/79/source?https://vizier.iucaa.in/viz-bin/conesearch/J/A+AS/108/79/source?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+AS/108/79/source?GETtext/xml+votable180.050000true1.54625-1.69758330.005555555555555556https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+AS/108/79?format=asciiRadiodefaultJ/A+AS/108/79/sourceSource listl_SizeLimit flag on Sizemeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSamplesName of the samples to which the source belongs (1)meta.id;meta.datasetcharNameSource name in IAU B1950.0 formatmeta.id;meta.maincharm_Name[1-5ABc ] Component designator (2)meta.code.multipcharRAJ2000[]? Right ascension J2000pos.eq.ra;meta.mainDEJ2000Declination signpos.eq.dec;meta.mainnullableSpeakPeak brightnessmJyphot.flux.density;em.radio.20-100MHzintSint[]? Integrated flux densitymJyphot.flux.density;em.radio.750-1500MHzintR[]? Ratio of the integrated VLA flux density to the flux density obtained from the NRAO Green Bank 1400 MHzphot.flux;arith.ratiofloatalpha(l)[]? Low frequency spectral indexspect.indexfloate_alpha(l)[]? Rms uncertainty on alpha(l)stat.errorfloatalpha(h)[]? High frequency spectral indexspect.indexfloate_alpha(h)[]? Rms uncertainty on alpha(h)stat.errorfloatCat[a-r ] Radio catalogues that have been used in the spectral index calculations (3)meta.notecharn_CatNotes on catalogues (4)meta.notecharMul[DPMTF ] D = double, P = point source, T = triple DF = diffuse, M = complexmeta.code.multipcharSize[]? Angular size measured from VLA mapsarcsecphys.angSize;srcfloatPA[]? Position angle measured from VLA mapsdegpos.posAngint