J/MNRAS/406/1583ivo://CDS.VizieR/J/MNRAS/406/1583doi:10.26093/cds/vizier.74061583CDSWu X.-B.Jia Z.2024-07-11T20:17:01Z2011-03-04T13:32:24ZCDS support team

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

cds-question@unistra.frsurveysquasarsredshiftedvisible-astronomysloan-photometryinfrared-photometryWe present a sample of 8498 quasars with both Sloan Digital Sky Survey (SDSS) ugriz optical and United Kingdom Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS) YJHK near-infrared (near-IR) photometric data. With this sample, we obtain the median colour-z relations based on 7400 quasars with magnitude uncertainties less than 0.1mag in all bands. By analysing the quasar colours, we propose an empirical criterion in the Y-K versus g-z colour-colour diagram to separate stars and quasars with redshift z<4, and two other criteria for selecting high-redshift quasars. Using the SDSS-UKIDSS colour-z relations, we estimate the photometric redshifts of 8498 SDSS-UKIDSS quasars, and find that 85.0 per cent of them are consistent with the spectroscopic redshifts within |{Delta}z|<0.2, which leads to a significant increase of the photometric redshift accuracy from that based on the SDSS colour-z relations only. As two tests, we compare our colour-selection criterion with a small UKIDSS/EDR quasar/star sample and a sample of 4671 variable sources in the SDSS Stripe 82 region with both SDSS and UKIDSS data. We find that they can be clearly divided into two classes (quasars and stars) by our criterion in the Y-K versus g-z plot.2010MNRAS.406.1583Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/406/1583CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-tohttp://www.sdss.org : SDSS Home Pagehttp://www.ukidss.org : UKIDSS Home Pagehttp://surveys.roe.ac.uk/wsa/theSurveys.html : UKIDSShttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/406/1583https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/406/1583http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/406/1583https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/406/1583https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/406/1583http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/406/1583GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/406/1583/table1 (Parameters of 8498 SDSS-UKIDSS quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/406/1583/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/406/1583/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/406/1583/table1?GETtext/xml+votable180.050000true0.049839440.040358610.0055555555555555564/259 261-262 516 518 521-523 1647 1653-1654 1657 1722 1732-1733 1735 1967 5/1024 1031 1034-1035 1041-1043 1052 1056-1057 1059-1062 1064 1088 2052 2061-2063 2068-2070 2076 2078 2083 2096-2098 2176-2178 4438 4441-4442 4453-4454 4457-4458 4505-4506 4517-4518 4522 4693-4694 4697-4698 4709-4710 4713-4714 5461-5463 5469 5493 5501 5786 5797-5798 6489-6490 6501 6505-6506 6525 6527 6553 6582-6583 6585-6587 6607 6611 6620-6622 6632-6634 6636-6638 6640-6642 6741-6742 6745 6762 6805-6807 6809-6812 6822 6825-6826 6845-6847 6883-6884 6886 6892 6918 6927 6937-6938 6965 6976 6978-6979 6982-6986 7823 7855 7859 7867 7912 7914 11261 6/0-2 4104-4106 4119 4121 4123 4128 4131 4134-4135 4160 4162-4163 4212 4216 4233-4235 4252-4254 4260-4262 4264 4288-4290 4292 4356 4360 8212 8221-8223 8237 8239 8241-8243 8325-8327 8329-8331 8396 8398 8416-8418 8448-8450 8716 8718 8720-8721 8723-8724 8736-8738 17405-17407 17661-17663 17725 17727 17741 17743 17745-17748 17751 17756-17758 17761-17763 17772-17774 17776-17778 17805 17807 17810-17811 17820-17822 17826-17827 17836-17838 17840-17842 17856-17858 17860 17981-17983 17997-17999 18001-18005 18007-18008 18010 18012-18014 18017-18019 18028 18061 18063 18065-18067 18076 18081-18086 18092 18096 18112 18176-18178 18685-18687 18749-18751 18765-18767 18769-18771 18780-18781 18785-18787 18796 18800 18829-18831 18833-18835 18844 18849-18851 18860-18862 18864-18866 18880 19025 19027-19029 19031 19200-19202 19458 21843 21873 21884-21885 21887 21971 21976-21977 21981-21983 22001 22012-22013 23102-23103 23138 23150 23181-23183 23186-23187 23196-23198 23201-23204 23207 23209-23214 23216-23218 23232-23234 25599 25855 25935 25945-25947 25955 25964 25968 25999 26003 26009-26010 26012 26019 26028 26032 26048 26105-26107 26175 26191 26195-26198 26200-26202 26204 26211 26217-26218 26220 26224 26255 26260-26261 26263 26266-26267 26277 26288 26301-26303 26317-26319 26321 26324 26327 26337-26339 26423 26427 26437 26439 26492-26494 26503-26504 26506-26509 26511 26541-26543 26556-26558 26572-26574 26576-26578 26592-26594 26879 26959 26963 26972 26979 26985 26988 26992 27043 27045-27047 27052 27197-27199 27213-27215 27219 27233-27235 27252-27254 27256 27258 27277 27279 27281-27286 27292-27294 27299 27308-27310 27312-27314 27328-27329 27373-27375 27377-27379 27392 27439 27523 27525-27527 27529-27531 27550 27572 27648 27661 27663 27665-27670 27676 27678 27685 27696 27699 27701-27703 27705 27744-27746 27756-27757 27797-27799 27804 27840 27857-27859 27865 27867-27868 27908 27910-27911 27921-27923 27927 27948 27952 27976 28032 31336 31369-31370 31381 31392 31400 31402 31419 31425-31426 31430-31431 31442 31448 31451 31454-31455 31463 31467 31626 31654 36861-36863 40959 45023 45053 450558.305533028865447e-20 2.0230500264803382e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/406/1583?format=asciiOpticalInfrareddefaultJ/MNRAS/406/1583/table1Parameters of 8498 SDSS-UKIDSS quasarszRedshift (from SDSS)src.redshiftfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOffsetSDSS-UKIDSS offsetarcsecpos.angDistancefloatumag? SDSS u magnitude (Vega system)magphot.mag;em.opt.Ufloatnullablegmag? SDSS g magnitude (Vega system)magphot.mag;em.opt.BfloatnullablermagSDSS r magnitude (Vega system)magphot.mag;em.opt.RfloatimagSDSS i magnitude (Vega system)magphot.mag;em.opt.Ifloatzmag? SDSS z magnitude (Vega system)magphot.mag;em.opt.IfloatnullableYmagUKIDSS Y magnitude (Vega system)magphot.magfloatJmagUKIDSS J magnitude (Vega system)magphot.mag;em.IR.JfloatHmagUKIDSS H magnitude (Vega system)magphot.mag;em.IR.HfloatKmagUKIDSS K magnitude (Vega system)magphot.mag;em.IR.KfloatDR7Details from the SDSS-DR7 Photometric Catalog (Cat. II/294)meta.ref.urlcharSDSSDisplay the SDSS data for this quasarmeta.ref.urlcharRAJ2000SDSS right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000SDSS declination (J2000)degpos.eq.dec;meta.main