J/ApJ/690/1181ivo://CDS.VizieR/J/ApJ/690/1181doi:10.26093/cds/vizier.16901181CDSSyphers D.Anderson S.F.Zheng W.Haggard D.Meiksin A.Chiu K.,Hogan C.Schneider D.P.York D.G.2017-11-28T13:21:08Z2010-05-04T09:45:41ZCDS support team

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

cds-question@unistra.frquasarsultraviolet-photometryredshiftedsurveysInvestigations of HeII Ly{alpha} (304{AA} rest-frame) absorption toward a half-dozen quasars at z~3-4 have demonstrated the great potential of helium studies of the intergalactic medium, but the current critically small sample size of clean sightlines for the HeII Gunn-Peterson test limits confidence in cosmological inferences, and a larger sample is required. Although the unobscured quasar sightlines to high redshift are extremely rare, the Sloan Digital Sky Survey (SDSS) DR6 provides thousands of z>2.8 quasars. We have cross-correlated these SDSS quasars with the Galaxy Evolution Explorer (GALEX) GR2/GR3 to establish a catalog of 200 higher-confidence (~70% secure) cases of quasars at z=2.8-5.1 potentially having surviving far-UV (rest-frame) flux. We also catalog another 112 likely far-UV-bright quasars from GALEX cross-correlation with other (non-SDSS) quasar compilations. Reconnaissance UV prism observations with the Hubble Space Telescope (HST) of 24 of our SDSS/GALEX candidates confirm 12 as detected in the far-UV, with at least nine having flux extending to very near the HeII break; with refinements our success rate is even higher. Our SDSS/GALEX selection approach is thereby confirmed to be an order of magnitude more efficient than previous HeII quasar searches, more than doubles the number of spectroscopically confirmed clean sightlines to high redshift, and provides a resource list of hundreds of high-confidence sightlines for upcoming HeII and other far-UV studies from the HST. Our reconnaissance HST prism spectra suggest some far-UV diversity, confirming the need to obtain a large sample of independent quasar sightlines across a broad redshift range to assess such issues as the epoch(s) of helium reionization, while averaging over individual-object pathology and/or cosmic variance.2009ApJ...690.1181Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/690/1181CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)J/AJ/133/1780 : GALEX/SDSS quasar catalog (Trammell+, 2007)J/ApJ/664/53 : UV photometry of GALEX QSO candidates (Atlee+, 2007)J/ApJS/185/20 : Additional HeII quasar sightlines (Syphers+, 2009)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/690/1181https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/690/1181http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/690/1181https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/690/1181https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/690/1181http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/690/1181GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/690/1181/table2 (Catalog of candidate Far-UV-Bright (non-SDSS) VCV/GALEX quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/690/1181/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/690/1181/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/690/1181/table2?GETtext/xml+votable180.050000true1.739614.26280.005555555555555556Cone search capability for table J/ApJ/690/1181/table1 (Catalog of candidate Far-UV-Bright SDSS/GALEX quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/690/1181/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/690/1181/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/690/1181/table1?GETtext/xml+votable180.050000true0.76396306-10.864073890.0055555555555555566/0 419 2086 4096 4099 4124 4252 4299 4322 4343 4437 4576 4667 4686 4693 4814 4880 4925 4948 4950 4951 4960 4963 4965 4971 4976 5012 5202 5230 5282 5289 5352 5378 5400 5477 5524 5560 5698 5742 5783 5800 5844 6033 6042 6047 6069 6071 6073 6075 6120 6469 6604 6619 6620 6650 7232 7258 7262 7268 7380 7440 7445 8202 8234 8330 8344 8345 8521 8662 9195 9208 9343 9457 9463 9515 9609 9634 9749 9790 9869 9943 9989 9990 9997 10019 10113 10181 10214 10383 10394 10405 10434 10463 10567 10573 10577 10615 10688 10703 10718 10792 10853 10888 10911 10921 10954 10976 10992 11023 11037 11104 11106 11107 11125 11160 11230 11252 11318 11435 11454 11529 11906 12381 12399 16461 16467 16539 16643 16646 16652 16656 17032 17213 17294 17509 17517 17518 17564 17574 17662 17752 17772 17773 17809 17820 17825 18028 18042 18065 18069 18071 18087 18090 18124 18227 18387 18388 18389 18542 18544 18776 18777 18790 18791 18793 18800 18835 18839 18843 18845 18854 19007 19026 19046 19052 19053 19060 19412 19673 19688 19848 20005 21982 21990 23210 25917 25918 25946 26035 26064 26069 26080 26099 26167 26177 26181 26217 26247 26269 26270 26280 26291 26305 26382 26448 26870 26990 26992 27035 27036 27074 27199 27363 27369 27390 27429 27441 27486 27510 27561 27741 27761 27769 27799 27937 28153 28222 28414 28473 28609 28627 28632 28671 29718 30037 32442 33632 33635 33994 34287 34635 35027 35241 35243 35244 35246 35249 35252 35254 35309 35413 35418 35438 35439 35483 35505 35508 35512 35521 35537 35540 35547 35549 35551 35556 35557 35558 35571 35573 35580 35581 35583 35623 35646 35694 35744 35760 35772 35774 35778 36360 36767 36803 36805 38872 45621 46394 46418 46442 46587 46867 46995 47004 47485 48492 485062.040811542443644e-19 2.3647030891844645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/690/1181?format=asciiUVOpticaldefaultJ/ApJ/690/1181/table2Catalog of candidate Far-UV-Bright (non-SDSS) VCV/GALEX quasarsf_VmagFlag on Vmag (1)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameVeron-Cetty & Veron (VCV) name (Cat. <VII/258>)meta.id;meta.maincharzVCV redshift (spectroscopic)src.redshiftfloatVmagVCV V-band magnitudemagphot.mag;em.opt.VfloatNUV? GALEX NUV flux (177-300nm)1e-19W.m**-2.nm**-1phot.flux;em.UVfloatnullableFUV? GALEX FUV flux (120-177nm)1e-19W.m**-2.nm**-1phot.flux;em.UVfloatnullableObs[0/2] Prior observation flag (G2)meta.codeintVCVSimbad column added by the CDSmeta.ref.urlcharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainJ/ApJ/690/1181/table1Catalog of candidate Far-UV-Bright SDSS/GALEX quasarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS DR6 name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharzSDSS pipeline redshift (photometric)src.redshiftfloatzmagSDSS z-band magnitudemagphot.mag;em.opt.IfloatNUV? GALEX NUV flux (177-300nm)1e-19W.m**-2.nm**-1phot.flux;em.UVfloatnullableFUV? GALEX FUV flux (120-177nm)1e-19W.m**-2.nm**-1phot.flux;em.UVfloatnullableInsp[0/8] Inspection flag (1)src.classintObs[0/2] Prior observation flag (G2)meta.codeintSloanDisplay the SDSS data for this quasarmeta.ref.urlcharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.main