J/MNRAS/380/1608ivo://CDS.VizieR/J/MNRAS/380/1608doi:10.26093/cds/vizier.73801608CDSLopes P.A.A.2024-07-05T20:15:23Z2008-09-25T05:42:27ZCDS support team

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

cds-question@unistra.frgalaxy-clustersgalaxiescatalogsredshiftedvisible-astronomysloan-photometryIn this work I discuss the necessary steps for deriving photometric redshifts for luminous red galaxies (LRGs) and galaxy clusters through simple empirical methods. The data used are from the Sloan Digital Sky Survey (SDSS). I show that with three bands only (gri) it is possible to achieve results as accurate as the ones obtained by other techniques, generally based on more filters. In particular, the use of the (g-i) colour helps improving the final redshifts (especially for clusters), as this colour monotonically increases up to z~0.8. For the LRGs I generate a catalogue of ~1.5 million objects at z<0.70. The accuracy of this catalogue is sigma=0.027 for z<=0.55 and sigma=0.049 for 0.55<z<=0.70. The photometric redshift technique employed for clusters is independent of a cluster selection algorithm. Thus, it can be applied to systems selected by any method or wavelength, as long as the proper optical photometry is available. When comparing the redshift listed in literature to the photometric estimate, the accuracy achieved for clusters is sigma=0.024 for z<=0.30 and sigma=0.037 for 0.30<z<=0.55. However, when considering the spectroscopic redshift as the mean value of SDSS galaxies on each cluster region, the accuracy is at the same level as found by other authors: sigma=0.011 for z<=0.30 and sigma=0.016 for 0.30<z<=0.55. The photometric redshift relation derived here is applied to thousands of cluster candidates selected elsewhere. I have also used galaxy photometric redshifts available in SDSS to identify groups in redshift space and then compare the redshift peak of the nearest group to each cluster redshift. This procedure provides an alternative approach for cluster selection, especially at high redshifts, as the cluster red sequence may be poorly defined.2007MNRAS.380.1608Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/380/1608CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/276 : The SDSS Photometric Catalog, Release 5 (Adelman-McCarthy+, 2007)http://www.sdss.org : SDSS Home Pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/380/1608https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/380/1608http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/380/1608https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/380/1608https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/380/1608http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/380/1608GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/380/1608/catalog (The LRG catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/380/1608/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/380/1608/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/380/1608/catalog?GETtext/xml+votable180.050000true0.0015711114.982668890.0055555555555555561/5 10 2/19 25 28 32 34-36 38 103 108-109 111 3/64 71 73 75 97 116 132 134-135 176-178 184 407 409-410 421 423 427-428 430 440-441 443 494 4/260-262 264 278-279 281-283 290-291 296-297 299 385 399 469 472 532 535 600 602 624 716 718 724 740 744-746 1114 1126 1130 1178 1194 1367 1373 1399 1450 1599 1621-1623 1625-1627 1635 1644-1645 1647 1691 1703 1707 1717-1719 1724 1768-1769 1771 1958 1962 1965-1967 1980 1982-1983 2025 2027 2031 3063 5/131 136-138 1052 1060-1062 1064 1071 1081-1083 1085-1090 1102-1103 1107 1109-1111 1121 1123 1152-1154 1158-1159 1192-1193 1195 1548-1549 1551 1585 1588-1589 1593 1684-1685 1728-1729 1732-1733 1872-1873 1875 1880-1882 1884 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6584-6585 6587 6727 6757-6759 6761-6763 6805-6807 6809-6811 6821-6823 6825-6827 6864-6866 6900-6902 6904 7081-7083 7508-7510 7516 7786 7823 7829-7830 7838-7839 7841-7846 7855 7857 7859 7882-7883 7886-7887 7898-7899 7902 7924 7926 8097 8099 8105 8107 8114-8115 8118-8120 8122-8123 8170 8172 8174 9179 9181-9183 9191 9193-9197 9200-9202 11261-11263 12247 12271 12273-12276 12280 12282 12287 6/0-2 8 521-523 538 556 640 642 4212-4214 4216-4217 4252 4260-4261 4270-4271 4279 4281-4283 4288-4290 4319 4321-4323 4337-4339 4364-4366 4368-4370 4372 4384 4398-4399 4403 4405-4407 4427 4433-4435 4481 4483 4489-4491 4621-4625 4628 4630-4631 4776-4777 4779 6145 6148-6149 6151 6157 6181 6183 6200-6201 6337 6339 6350-6351 6362-6363 6365-6367 6380-6381 6383 6725 6727 6976-6977 6980-6981 6992-6993 6996-6997 7496 7498-7499 7532-7533 7540 7568-7570 7572-7573 7576 7578-7579 7582-7583 7596-7598 7608-7609 7612-7613 7680-7681 7684-7685 7696-7697 7700-7701 7744 8529 8531 8548 8550-8551 9486 9488-9489 9491-9492 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19681-19683 19700 19704 19725-19727 19729-19731 19745-19747 19764 19768 19780 19784 19844 19848 19979 19985-19987 20012-20014 20016-20018 20036 20040 20096-20098 21823 21838-21839 21841-21843 21857-21859 21868-21869 21871 21917 21919 21941 21952 21955 21984 21988 21990-21991 21993 21995 22012-22013 22337 22340-22342 22349-22352 22358-22359 22372-22373 22480-22481 22483 22491 22524-22525 22710-22711 22713-22715 22760 22762-22763 23043 23064-23066 23068 23076-23078 23080 23095 23099 23104 23137-23139 23142 23175 23179 23185-23187 23196-23198 23220 23224 25563 25575 25579 25821-25823 25831 25835 25837-25839 25841-25843 25885-25887 25901-25903 25905-25907 25922-25923 25985-25987 26135 26139 26151 26155 26157-26159 26344-26345 26347 26877-26879 26903 26932-26933 26941-26943 27021-27023 27025-27027 27041-27043 27197-27199 27213-27215 27217-27219 27233-27235 27277-27279 27281-27283 27297-27299 27468-27470 27612-27613 27615 27620-27622 27624-27625 27647 28320-28321 28323 29973 30016 30023 30029-30031 30044-30046 30053 30068 30975 31139 31148 31279 31285-31287 31289-31291 31310-31311 31315 31324-31326 31344-31346 31351 31363 31388-31390 31408-31410 31413-31415 31417-31419 31424-31426 31433-31435 31488 31522-31523 31526-31527 31538-31539 31542 31586-31587 31614 31700 31710 32302-32303 32314-32315 32387 32393 32395 32417 32419 32425-32427 32448 32450-32451 32454 32467 32470 32484 32486 32650 32672 32674 32700 32702 36607 36701-36703 36715 36721-36723 36758-36759 36761-36763 36771 36792-36794 36796 36812-36814 36816-36818 36820 36832 36855 36859 36861-36863 40957-40959 45023 45038-45039 45043 48981 48983 48987 49005-49007 49055 49077-49079 49081 49091 49108 49112 49114 49124-49126 491472.040811542443644e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/380/1608?format=asciiOpticaldefaultJ/MNRAS/380/1608/catalogThe LRG catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedumagSDSS u magnitudemagphot.mag;em.opt.Ufloate_umag? rms uncertainty on umagmagstat.error;phot.mag;em.opt.UfloatnullablegmagSDSS g magnitudemagphot.mag;em.opt.Bfloate_gmagrms uncertainty on gmagmagstat.error;phot.mag;em.opt.BfloatrmagSDSS r magnitudemagphot.mag;em.opt.Rfloate_rmagrms uncertainty on rmagmagstat.error;phot.mag;em.opt.RfloatimagSDSS i magnitudemagphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.mag;em.opt.IfloatzmagSDSS z magnitudemagphot.mag;em.opt.Ifloate_zmag? rms uncertainty on zmagmagstat.error;phot.mag;em.opt.IfloatnullablezphotPhotometric redshiftsrc.redshiftdoublee_zphot? rms uncertainty on zphotstat.errordoublenullableobjIDSDSS identification numbermeta.idcharDR5Display the SDSS-DR5 photometric data for this galaxymeta.ref.urlcharSDSSDisplay the SDSS data for this galaxymeta.ref.urlchar