J/A+A/437/1135ivo://CDS.VizieR/J/A+A/437/1135doi:10.26093/cds/vizier.34371135CDSCamargo I.B.Daigne G.Ducourant C.Charlot P.2018-01-04T08:21:35Z2005-08-21T15:06:40ZCDS support team

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

cds-question@unistra.frquasarsinfrared-sourcesastrometryWe present high quality astrometry, along with J, H, and Ks photometry, for 30 southern International Celestial Reference Frame (ICRF) quasars observed with the ESO NTT/SOFI at La Silla. Our main purpose is to document the optical counterpart of ICRF quasars, by reporting their position in a stellar reference frame and their near-infrared photometry. Our investigation lies within the scope of extending the (radio) extragalactic reference frame into the optical range. An internal precision generally better than 10mas was obtained in positioning the near-infrared counterpart of these quasars within their stellar surroundings. The actual astrometric accuracy is estimated from the departure between the observed and the radio (VLBI) positions of quasars, and is about 35mas, mainly due to the statistical uncertainties of the stellar reference catalogue (UCAC2, Cat. <I/289>). The positional accuracy was improved to 25mas for a subset of 14 quasars observed with extended fields of view, as obtained from mosaics of overlapping images. The 3-band photometry was achieved with a precision most often better than 0.04mag, based on calibration with the 2MASS magnitudes.2005A&A...437.1135Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/437/1135CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/251 : VLBI International Celestial Reference Frame (ICRF) (Ma+, 1997)J/A+A/375/308 : Extension of ICRF for SA down to V=15 (Camargo+ 2001)J/A+A/409/361 : Extension of ICRF for SA down to V=16 (Camargo+, 2003)J/AJ/127/3587 : VLBI ICRF. II (Fey+, 2004)J/AJ/125/2728 : Optical positions of ICRF sources (Assafin+, 2003)I/289 : UCAC2 Catalogue (Zacharias+ 2004)VII/235 : Quasars and Active Galactic Nuclei (11th Ed.) (Veron+, 2003)I/284 : The USNO-B1.0 Catalog (Monet+ 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/437/1135https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/437/1135http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/437/1135https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/437/1135https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/437/1135http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/437/1135GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/437/1135/position (Positions, from Ma et al., Cat. <I/251>)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/437/1135/position?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/437/1135/position?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/437/1135/position?GETtext/xml+votable180.050000true47.98020972917-76.864124563890.0055555555555555566/20503 20657 21012 21049 24608 32961 33043 33973 34264 37064 37217 37385 37474 37819 37919 37994 38189 38277 38383 38579 38734 39181 39489 39557 39577 39848 40060 40344 40479 40527https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/437/1135?format=asciiInfrareddefaultJ/A+A/437/1135/table2Photometric datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIERSIERS designationcharc[CDO] Defining/Candidate/Other category of sourcecharl_zLimit flag on zcharz? Redshift (1)floatnullablen_z[*] *: Redshift from Cat. <VII/235>charS6cm? Flux density at 6cm, from literatureJyfloatnullablen_S6cm[*] *: 6cm flux density from Cat. <VII/235>charalphaR? Radio spectral index (1)floatnullableTypeObject type (1)charBMAG? Absolute B magnitude, from Cat. <VII/235>magfloatnullableBmag? B magnitude, from USNO-B1, Cat. <I/284>magfloatnullableVmag? V magnitude, from literature (1)magfloatnullablen_Vmag[*] *: Vmag from Cat. <VII/235>charRmag? R magnitude, from USNO-B1, Cat. <I/284>magfloatnullableIntIdInternal identification (p: photometry mode, a: astrometry mode)charMJDJulian date of the observationddoubleJmagObserved J magnitudemagfloatHmagObserved H magnitudemagfloatKsmagObserved Ks magnitudemagfloatJFluxObserved J-band fluxmJyfloatHFluxObserved H-band fluxmJyfloatKsFluxObserved Ks-band fluxmJyfloatSp+IndexNear-IR spectral indexfloate_Sp+Indexrms uncertainty on Sp+IndexfloatVVSimbad column added by the CDScharJ/A+A/437/1135/table3*Astrometric datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIERSIERS quasar identificationcharMJDJulian Date of the observationddoubleORA*Offset in RAcosDE, in the sense near-IR minus ICRF (1)masinte_ORA*Precision of the observed near-IR position, in RAcosDE (2)masintODEOffset in declination, in the sense near-IR minus ICRF (1)masinte_ODEPrecision of the observed near-IR position, in declination (2)masintdRA*Standard deviations of the positional measurements in the J, H, and Ks filters in RAcosDEmasintdDEStandard deviations of the positional measurements in the J, H, and Ks filters in declinationmasinteRA*Mean of the standard deviation, in RAcosDE (3)masinteDEMean of the standard deviation, in declination (3)masintNNumber of reference (UCAC2) stars used in the astrometric analysis of the observations made in the photometry modeintJ/A+A/437/1135/table4*Astrometric data, Results in the F filterrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIERSIERS quasar identificationcharMJDJulian Date of the observationddoubleORA*SOffset in RAcosDE, in the sense near-IR minus ICRF (1)masinte_ORA*SPrecision of the observed near-IR position, in RAcosDE (2)masintODESOffset in declination, in the sense near-IR minus ICRF (1)masinte_ODESPrecision of the observed near-IR position, in declination (2)masintNSNumber of reference (UCAC2) stars used in the astrometric analysis of the single central imageintORA*MOffset in RAcosDE, in the sense near-IR minus ICRF (3)masinte_ORA*MPrecision of the observed near-IR position, in RAcosDE (4)masintODEMOffset in declination, in the sense near-IR minus ICRF (3)masinte_ODEMPrecision of the observed near-IR position, in declination (4)masintNMNumber of reference (UCAC2) stars used in the astrometry modeintcRA*Internal precision as obtained from the positions of stars in overlapping regions, in RAcosDEmasintcDE*Internal precision as obtained from the positions of stars in overlapping regions, in declinationmasintRA*rms of the differences observed minus calculated, in RAcosDE (5)masintDErms of the differences observed minus calculated, in declination (5)masintrRARatio between the values and the respective nominal for right ascensionfloatrDERatio between the values and the respective nominal for declinationfloatJ/A+A/437/1135/positionPositions, from Ma et al., Cat. <I/251>recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIERSIERS designationcharprimaryICRFICRF designationcharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainIERSdataDisplay the details from the VLBI-*ICRF (Mat et al., Cat. I/251)char