J/AJ/131/1872ivo://CDS.VizieR/J/AJ/131/1872doi:10.26093/cds/vizier.51311872CDSPetrov L.Kovalev Y.Y.Fomalont E.B.Gordon D.2013-07-14T12:14:18Z2007-11-14T22:00:48ZCDS support team

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

cds-question@unistra.frsurveysradio-sourcesastrometryThis paper presents the fourth extension to the VLBA Calibrator Survey, containing 258 new sources not previously observed with very long baseline interferometry (VLBI). This survey, based on three 24hr Very Long Baseline Array observing sessions, fills remaining areas on the sky above declination -40{deg} where the calibrator density is less than one source within a 4{deg} radius disk in any given direction. The share of these areas was reduced from 4.6% to 1.9%. Source positions were derived from astrometric analysis of group delays determined at 2.3 and 8.6GHz frequency bands using the Calc/Solve software package. The VCS4 catalog of source positions, plots of correlated flux density versus projected baseline length, contour plots, and fits files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available online at http://vlbi.gsfc.nasa.gov/vcs4 .2006AJ....131.1872Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/131/1872CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/141/13 : VLBA calibrator Survey - VCS1 catalog (Beasley+, 2002)J/AJ/126/2562 : Second VLBA calibrator survey: VCS2 (Fomalont+, 2003)J/AJ/129/1163 : Third VLBA calibrator survey: VCS3 (Petrov+, 2005)http://vlbi.gsfc.nasa.gov/vcs4 : VCS4 Home Pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/131/1872https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/131/1872http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/131/1872https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/131/1872https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/131/1872http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/131/1872GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/131/1872/table2 (The VCS4 catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/131/1872/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/131/1872/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/131/1872/table2?GETtext/xml+votable180.050000true2.14025587917-36.023625591670.0055555555555555566/28 597 882 968 1093 1228 1914 2028 2548 3057 3074 3165 3208 3237 4194 4303 4487 5156 5984 5988 6469 7873 8106 8440 8641 9618 9762 9786 9805 11649 11757 11759 13198 14792 14794 15067 15260 15629 15870 16409 16635 16739 16863 17094 17148 17186 17223 17245 17265 17388 17418 17529 17545 17672 18349 18490 19341 19694 19824 20344 20377 20433 20485 20503 20541 20594 20596 20677 20770 20781 20830 20836 20841 20873 20908 20929 20941 20969 20976 21020 21055 21060 21228 21348 21374 21403 21411 21503 21625 21675 21718 21767 22034 22049 22057 22080 22152 22157 22184 22232 22233 22256 22265 22271 22541 22719 22729 22768 22799 22856 22993 23069 23092 23197 23306 23397 23469 23601 23637 23697 23817 24252 24402 24476 24526 24718 25083 25409 25568 25647 25841 25939 25969 26195 26529 26569 26755 27080 27138 27196 28299 28763 28781 28822 28866 28948 28959 28982 29138 29151 29153 29215 29244 29271 29275 29336 29401 29402 29414 29467 29480 29520 29522 29617 29636 29653 29658 29730 29736 29772 29823 29833 29895 29907 29946 30091 30094 30305 30366 30388 30857 30941 30975 30990 31001 31002 31101 31276 32101 32181 32210 32227 34168 34302 34461 34665 34740 35741 35865 35952 36225 36304 36580 36620 36665 36674 36735 38303 38351 38352 38353 38355 38399 38519 38614 38663 39326 39350 39354 39356 39622 39633 39858 39883 39997 40106 40162 40164 40193 40281 40354 40360 40412 40494 40542 40635 40637 40727 40766 40831 40858 40873 40885 40902 40919 40955 42433 42481 42482 42696 43005 43633 43753 43980 44099 44113 44335 44441 44513 44597 44699 44937 46529 46562 46801 46868 46887 47478 47847 47882 47912 47969 47971 47978 47980 48120 48300 48392 48398 48708 48716 48761 48878 48901 48918 49019 49069 490841.5239959695752804e-24 5.6984200832293834e-24https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/131/1872?format=asciiRadiodefaultJ/AJ/131/1872/table2The VCS4 catalogl_T8.6GHzUpper limit flag on T8.6GHzmeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCat[-C] Category (where C = calibrator)meta.codecharIVSThe IVS name (B1950), BHHMM-DDdmeta.idcharVCS4The IAU name (J2000), JHHMM-DDMMmeta.id;meta.maincharRAJ2000Hour of Right ascension (J2000)pos.eq.ra;meta.maine_RAJ2000Inflated error in Right Ascensionmasstat.error;pos.eq.rafloatDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.maine_DEJ2000Inflated error in Declinationmasstat.error;pos.eq.decfloatCorrCorrelation between Right Ascension and Declination errorsstat.correlationfloatNobsNumber of group delays used for position determinationmeta.numberintT8.6GHz? X-band (8.6GHz) total flux density integrated over entire map (1)Jyphot.flux.density;em.radio.6-12GHzfloatnullablel_U8.6GHzUpper limit flag on U8.6GHzmeta.code.errorcharU8.6GHz? X-band (8.6GHz) unresolved flux density at longest VLBA baselines (1)Jyphot.flux.density;em.radio.6-12GHzfloatnullablel_T2.3GHzUpper limit flag on T2.3GHzmeta.code.errorcharT2.3GHz? S-band (2.3GHz) total flux density integrated over entire map (1)Jyphot.flux.density;em.radio.1500-3000MHzfloatnullablel_U2.3GHzUpper limit flag on U2.3GHzmeta.code.errorcharU2.3GHz? S-band (2.3GHz) unresolved flux density at longest VLBA baselines (1)Jyphot.flux.density;em.radio.1500-3000MHzfloatnullableBandUsed band for position estimation (2)em.freqchar