J/ApJS/217/5ivo://CDS.VizieR/J/ApJS/217/5doi:10.26093/cds/vizier.22170005CDSKrogager J.-K.Geier S.Fynbo J.P.U.Venemans B.P.Ledoux C.,Moller P.Noterdaeme P.Vestergaard M.Kangas T.Pursimo T.,Saturni F.G.Smirnova O.2017-06-13T11:08:52Z2015-04-30T08:28:17ZCDS support team

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

cds-question@unistra.frquasarsredshiftedspectroscopyextinctionvisible-astronomysloan-photometrysurveysQuasi-stellar objects (QSOs) whose spectral energy distributions (SEDs) are reddened by dust either in their host galaxies or in intervening absorber galaxies are to a large degree missed by optical color selection criteria like the ones used by the Sloan Digital Sky Survey (SDSS). To overcome this bias against red QSOs, we employ a combined optical and near-infrared (near-IR) color selection. In this paper, we present a spectroscopic follow-up campaign of a sample of red candidate QSOs which were selected from the SDSS and the UKIRT Infrared Deep Sky Survey (UKIDSS). The spectroscopic data and SDSS/UKIDSS photometry are supplemented by mid-infrared photometry from the Wide-field Infrared Survey Explorer. In our sample of 159 candidates, 154 (97%) are confirmed to be QSOs. We use a statistical algorithm to identify sightlines with plausible intervening absorption systems and identify nine such cases assuming dust in the absorber similar to Large Magellanic Cloud sightlines. We find absorption systems toward 30 QSOs, 2 of which are consistent with the best-fit absorber redshift from the statistical modeling. Furthermore, we observe a broad range in SED properties of the QSOs as probed by the rest-frame 2{mu}m flux. We find QSOs with a strong excess as well as QSOs with a large deficit at rest-frame 2{mu}m relative to a QSO template. Potential solutions to these discrepancies are discussed. Overall, our study demonstrates the high efficiency of the optical/near-IR selection of red QSOs.2015ApJS..217....5Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/217/5CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/311 : WISE All-Sky Data Release (Cutri+ 2012)VIII/90 : The FIRST Survey Catalog, Version 12Feb16 (Becker+ 2012)VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)J/A+A/572/A12 : GRB 140506A spectra (Fynbo+, 2014)J/AJ/145/157 : Reddening curve of IRAS 14026+4341 (Jiang+, 2013)J/ApJ/757/51 : FIRST-2MASS dust-reddened QSO spectra (Glikman+, 2012)J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)J/MNRAS/424/2876 : Large area KX quasar catalogue (Maddox+, 2012)J/A+A/541/A77 : Kohonen-selected unusual SDSS quasars (Meusinger+, 2012)J/ApJS/199/3 : The quasars MMT-BOSS pilot survey (Ross+, 2012)J/AJ/141/105 : NIR-matched quasar catalog (Peth+, 2011)J/A+A/505/1087 : DLAs in SDSS-DR7 (Noterdaeme+, 2009)J/ApJ/698/1095 : The FIRST-2MASS red QSO survey. II. (Urrutia+, 2009)J/MNRAS/386/1605 : Luminous K-band selected QSOs from UKIDSS (Maddox+, 2008)J/A+A/478/701 : Color excess of SDSS quasars with DLA systems (Vladilo+, 2008)J/ApJ/667/673 : FIRST-2MASS red quasar survey (Glikman+, 2007)J/AJ/133/186 : Optical spectroscopy of luminous AGNs and QSOs (Lacy+, 2007)J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)J/ApJ/640/579 : Near-infrared spectra of 27 SDSS quasars (Glikman+, 2006)J/AJ/121/2308 : Sloan Digital Sky Survey quasar photometry (Richards+, 2001)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/ApJS/217/5https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/217/5http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/217/5https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/217/5https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/217/5http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/217/5GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/217/5/tablef1 (Remaining candidate QSOs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/217/5/tablef1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/217/5/tablef1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/217/5/tablef1?GETtext/xml+votable180.050000true0.0353458312.842633330.005555555555555556Cone search capability for table J/ApJS/217/5/redQSOc (Spectroscopic results of red QSO candidates observed with NOT)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/217/5/redQSOc?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/217/5/redQSOc?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/217/5/redQSOc?GETtext/xml+votable180.050000true0.141579175.964936110.0055555555555555566/8 20 21 34 40 51 66 130 131 160 521 558 640 648 8199 8212 8217 8219 8223 8234 8236 8237 8249 8259 8263 8268 8270 8274 8281 8324 8327 8329 8344 8354 8389 8450 8663 8714 8737 8889 8936 8942 9153 9162 9255 9258 9271 9277 9318 9319 9325 9327 9329 9347 9359 9366 9380 10247 10252 10255 10257 10260 10261 10270 10275 10280 10281 10286 10293 10305 10319 10338 10351 10362 10363 10365 10376 10377 10383 10384 10389 10393 10399 10401 10407 10410 10412 10416 10419 10432 10435 10448 10467 10468 10539 10758 10765 17838 17844 17845 17846 17850 17867 17889 17895 17898 17901 18036 18043 18044 18045 18095 18099 18102 18108 18117 18132 18155 18162 18169 18173 18174 18196 18208 18209 18214 18223 18229 18230 18232 18243 18244 18248 18265 18277 18279 18306 18308 18310 18316 18318 18320 18326 18337 18341 18350 18351 18355 18362 18363 18372 18387 18389 18392 18396 18407 18416 18781 18792 18801 18802 18807 18811 18845 18869 18872 18875 18879 18887 18891 18894 18900 18902 18911 18912 18920 18922 18924 18927 18928 18932 18943 19044 19066 19203 19204 19208 19212 19215 19217 19222 19230 19235 19239 19245 19248 19255 19267 19271 19274 19282 19289 19294 19297 19299 19315 19318 19458 19462 19464 19470 19471 19478 19482 19492 19501 19503 19504 19505 19518 19523 19524 19526 19529 19530 19531 19539 19544 19547 19548 19553 19554 19558 19569 19574 19575 19576 19578 19580 19581 19584 19587 19588 19592 19594 19600 19602 19612 19616 19623 19629 19633 19638 19644 19646 19647 19650 19660 19663 19668 19670 19677 19685 19686 19712 19715 19719 19721 19722 19724 19725 19732 19742 19746 19750 19754 19761 19968 19974 19976 19978 19980 19982 19989 19990 20005 20032 23139 23142 23145 23146 23183 23187 23212 23216 23233 23245 23268 23277 23278 25918 25931 25935 25944 25962 25963 25980 26008 26020 26021 26023 26026 26031 26034 26037 26049 26054 26061 26062 26069 26071 26082 26083 26084 26093 26100 26101 26103 26183 26196 26202 26212 26223 26226 26246 26253 26255 26261 26268 26283 26302 26303 26308 26318 26319 26321 26323 26329 26349 26356 26358 26363 26367 26369 26375 26404 26409 26423 26431 26437 26439 26453 26482 26485 26487 26490 26502 26507 26509 26511 26521 26522 26527 26538 26548 26552 26554 26561 26564 26580 26582 26595 26956 26960 26986 26987 27006 27061 27074 27085 27104 27113 27118 27131 27135 27461 27478 27648 27659 27661 27674 27679 27690 27693 27700 27704 27735 27738 27741 27755 27760 27783 27786 27796 27808 27836 27839 27846 27851 27858 27907 27916 27919 27925 27936 27946 28034 28108 28112 28114 28116 28119 28122 28123 28144 28146 28153 28168 28175 28178 28179 28186 28195 28210 28211 31289 31292 31337 31338 31366 31373 31380 31382 31389 31390 31394 31396 31398 31409 31415 31420 31434 31458 31463 31468 31470 450509.276497240453405e-25 3.5010283109654867e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/217/5?format=asciiOpticaldefaultJ/ApJS/217/5/table5Intervening absorption systemsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHAQTarget designation (HHMM+DDMM; J2000)meta.id;meta.maincharz[0.8/3.8] QSO redshiftsrc.redshiftfloatzsp[0.2/3.3] Spectroscopic redshift of the absorption systemsrc.redshiftfloatu_zspTentative detections due to low S/Nmeta.code.errorcharzabs[1.1/2.4]? The absorber redshift (1)src.redshiftfloatnullablee_zabs[0.03/0.1]? zabs uncertaintystat.errorfloatnullableA(V)a[0.2/0.5]? V-band extinction at the absorber redshift (1)magphys.absorptionfloatnullablee_A(V)a[0.02/0.07]? A(V)a uncertaintymagstat.errorfloatnullableA(V)q[-0.05/0.8] V-band extinction at the QSO redshiftmagphys.absorptionfloate_A(V)q[0.01/0.03]? A(V)q uncertaintymagstat.errorfloatnullableNotesNotesmeta.noteJ/ApJS/217/5/tablef1Remaining candidate QSOsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHAQTarget designation (HHMM+DDMM; J2000)meta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainrmag[17.4/21.2] SDSS r-band AB magnitudemagphot.mag;em.opt.RfloatUKIDSSSources within 1" of UKIDSS-DR9 LAS, GCS and DXS surveys (II/319)meta.ref.urlintnullableDR9Display the SDSS-DR9 photometric data (V/139) within 2"meta.ref.urlcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharJ/ApJS/217/5/redQSOcSpectroscopic results of red QSO candidates observed with NOTrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAbsnumber of absorption systems detected (table5)meta.ref.urlintnullableRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainrmag[16/20.2] SDSS r-band AB magnitudemagphot.mag;em.opt.RfloatTelTelescope(s) (NOT and/or BOSS)instr.telcharExpExposure time(s)stime.duration;obs.exposurecharHAQTarget designation (HHMM+DDMM; J2000)meta.id;meta.maincharf_HAQ[b] Flag on HAQ (1)meta.codecharTypeType of object (2)src.classcharu_z[~] Uncertainty flag on zmeta.code.error;src.redshiftcharz[0/3.8]? QSO redshiftsrc.redshiftfloatnullableu_A(V)[~] Uncertainty flag on A(V)meta.code.errorcharA(V)[-0.05/1.3]? V-band extinction (3)magphys.absorption;em.opt.Vfloatnullablef_A(V)[a] Flag on A(V) (1)meta.codecharl_FradLimit flag on Fradmeta.code.errorcharFrad[0.2/882.6] FIRST 1.4GHz flux densitymJyphot.flux.density;em.radio.750-1500MHzfloate_Frad[0.08/0.3]? Frad uncertaintymJystat.errorfloatnullableNotesNotesmeta.notecharUKIDSSSources within 1" of UKIDSS-DR9 LAS, GCS and DXS surveys (II/319)meta.ref.urlintnullableDR9Display the SDSS-DR9 photometric data (V/139) within 2"meta.ref.urlcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlchar