J/MNRAS/501/2848ivo://CDS.VizieR/J/MNRAS/501/2848doi:10.26093/cds/vizier.75012848CDSAltavilla G.Marinoni S.Pancino E.Galleti S.Bellazzini M.Sanna N.,Rainer M.Tessicini G.Carrasco J.M.Bragaglia A.Schuster W.J.,Cocozza G.Gebran M.Voss H.Federici L.Masana E.Jordi C.,Monguio M.Castro A.Pena-Guerrero M.A.Perez-Villegas A.2024-08-21T20:17:04Z2021-01-18T15:11:08ZCDS support team

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

cds-question@unistra.frstandard-starsinfrared-photometryvisible-astronomybroad-band-photometryccd-photometryWe present Johnson-Kron-Cousins BVRI photometry of 228 candidate spectrophotometric standard stars for the external (absolute) flux calibration of Gaia data. The data were gathered as part of a 10-yr observing campaign with the goal of building the external grid of flux standards for Gaia and we obtained absolute photometry, relative photometry for constancy monitoring, and spectrophotometry. Preliminary releases of the flux tables were used to calibrate the first two Gaia releases. This paper focuses on the imaging frames observed in good sky conditions (about 9100). The photometry will be used to validate the ground-based flux tables of the Gaia spectrophotometric standard stars and to correct the spectra obtained in non-perfectly photometric observing conditions for small zero-point variations. The absolute photometry presented here is tied to the Landolt standard stars system to ~1 per cent or better, depending on the photometric band. Extensive comparisons with various literature sources show an overall ~1 per cent agreement, which appears to be the current limit in the accuracy of flux calibrations across various samples and techniques in the literature. The Gaia photometric precision is presently of the order of 0.1 per cent or better, thus various ideas for the improvement of photometric calibration accuracy are discussed.2021MNRAS.501.2848Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/501/2848CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/426/1767 : Gaia spectrophotometric standard stars I. (Pancino+, 2012)J/MNRAS/462/3616 : Gaia SPSS variability monitoring (Marinoni+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/501/2848https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/501/2848http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/501/2848https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/501/2848https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/501/2848http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/501/2848GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/501/2848/table4 (BVRI program stars magnitudes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/501/2848/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/501/2848/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/501/2848/table4?GETtext/xml+votable180.050000true76.377541752.83111110.0055555555555555566/1890 1908 2263 2536 2973 3169 3258 3313 3693 3781 4067 5550 5555 5827 6009 6040 6070 6118 6705 7019 7036 7267 7476 7678 8093 8135 9040 9071 9154 9322 9424 9458 9747 9788 9840 9944 9992 10149 10464 10471 10504 10571 10683 10969 11020 11113 11176 11605 11607 11612 11652 11984 12068 12621 12738 12746 12791 13013 13085 13133 13295 13652 13668 13689 14289 14533 14667 15353 15355 15359 15391 15462 16042-16043 16078 16089 16344 16508 17039 17094 17879 18061 18139 18195 18712 18790 19141 19306 19970 20423 20680 20760 20904 21479 21953 22211 22638 23101 23286 23476 23789 24204 25018 25988 26025 26175 26187 26261 26678 26808 26916 27049 27128 27380 27693 27844 27963 28018 28026 28134 28494 28559 29855 30040 30042 30406 30528 30694 30754 31227 31354 31382 31416 32115 32149 32468 32783 32847 33015 33109 33792 34502 34652 34676 34975 35490 35570 35670 35702 35767 35790 37248 37546 37890 38036 38164 38324 38682 38912 39353 39612 39880 40070 40908 40944 41638 42091 42760 43130 43513 44125 45017 45110 45433 45506 45649 45782 45802 45815 45909 45921 45962 45979 46385 46612 47122 47676 47957 487282.367228618189496e-19 4.920466254354166e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/501/2848?format=asciiOpticalInfrareddefaultJ/MNRAS/501/2848/table4BVRI program stars magnitudesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSPSSID[1/355] SPSS internal IDmeta.idintNameSPSS namemeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainBmagJohnson B magnitudemagphot.mag;em.opt.BfloatVmagJohnson V magnitudemagphot.mag;em.opt.VfloatRmagCousins R magnitudemagphot.mag;em.opt.RfloatImag? Cousins I magnitudemagphot.mag;em.opt.Ifloatnullablee_BmagBmag uncertaintymagstat.error;phot.magfloate_VmagVmag uncertaintymagstat.error;phot.magfloate_RmagRmag uncertaintymagstat.error;phot.magfloate_Imag? Imag uncertaintymagstat.error;phot.magfloatnullableNBNumber of nights for Bmeta.numberintNVNumber of nights for Vmeta.numberintNRNumber of nights for Rmeta.numberintNINumber of nights for Imeta.numberinto_BmagNumber of measurements for Bmeta.numberinto_VmagNumber of measurements for Vmeta.numberinto_RmagNumber of measurements for Rmeta.numberinto_ImagNumber of measurements for Imeta.numberintf_Bmag[0/1] 1 if no fully photometric nightsmeta.codeintf_Vmag[0/1] 1 if no fully photometric nightsmeta.codeintf_Rmag[0/1] 1 if no fully photometric nightsmeta.codeintf_Imag? [0,1] 1 if no fully photometric nightsmeta.codeintnullableNote[1/36]? Individual notes, see (1)meta.noteintnullable