J/ApJ/847/81ivo://CDS.VizieR/J/ApJ/847/81doi:10.26093/cds/vizier.18470081CDSSchmidt T.M.Worseck G.Hennawi J.F.Prochaska J.X.Crighton N.H.M.2020-02-03T08:45:25Z2018-06-29T09:42:39ZCDS support team

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

cds-question@unistra.frquasarsintergalactic-mediumredshiftedvisible-astronomyspectroscopyultraviolet-astronomysurveysThe HeII transverse proximity effect-enhanced HeII Ly{alpha} transmission in a background sightline caused by the ionizing radiation of a foreground quasar-offers a unique opportunity to probe the morphology of quasar-driven HeII reionization. We conduct a comprehensive spectroscopic survey to find z~3 quasars in the foreground of 22 background quasar sightlines with Hubble Space Telescope/COS HeII Ly{alpha} transmission spectra. With our two-tiered survey strategy, consisting of a deep pencil-beam survey and a shallow wide-field survey, we discover 131 new quasars, which we complement with known SDSS/BOSS quasars in our fields. Using a restricted sample of 66 foreground quasars with inferred HeII photoionization rates greater than the expected UV background at these redshifts ({Gamma}_QSO_^HeII^>5x10^-16^s^-1^) we perform the first statistical analysis of the HeII transverse proximity effect. Our results show qualitative evidence for a large object-to-object variance: among the four foreground quasars with the highest {Gamma}_QSO_^HeII^ only one (previously known) quasar is associated with a significant HeII transmission spike. We perform a stacking analysis to average down these fluctuations, and detect an excess in the average HeII transmission near the foreground quasars at 3{sigma} significance. This statistical evidence for the transverse proximity effect is corroborated by a clear dependence of the signal strength on {Gamma}_QSO_^HeII^. Our detection places a purely geometrical lower limit on the quasar lifetime of t_Q_>25Myr. Improved modeling would additionally constrain quasar obscuration and the mean free path of HeII-ionizing photons.2017ApJ...847...81Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/847/81CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)J/ApJ/592/728 : Lyman break galaxies at redshift z~3 (Steidel+, 2003)J/ApJ/651/61 : Optically thick absorbers near luminous QSO (Hennawi+, 2006)J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)J/AJ/133/2222 : Clustering of high-redshift QSOs from SDSS (Shen+, 2007)J/MNRAS/391/1457 : Lyman{alpha} forest in QSO pairs (Kirkman+, 2008)J/ApJ/690/20 : Models of AGN and black hole populations (Shankar+, 2009)J/ApJ/716/348 : The XMM-Newton survey of the COSMOS field (Brusa+, 2010)J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)J/ApJ/794/75 : HST-COS UV spectra observations of AGNs (Stevans+, 2014)J/MNRAS/445/1745 : Giant Gemini GMOS survey. I. (Worseck+, 2014)J/MNRAS/449/4204 : WFC3/UVIS quasar-stacked spectrum at z=~2.4 (Lusso+, 2015)J/ApJS/219/39 : QSOs selection from SDSS and WISE (Richards+, 2015)J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)J/ApJ/831/7 : SDSS-RM project: peak velocities of QSOs (Shen+, 2016)http://www.sdss3.org/ : SDSS-III home pagehttp://enigma.physics.ucsb.edu/ : ENIGMA home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/847/81https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/847/81http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/847/81https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/847/81https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/847/81http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/847/81GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/847/81/losqso (Overview of the FUV spectra, HeII sightlines and the number of foreground quasars for the 22 background quasar sightlines (tables 1 and 2))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/847/81/losqso?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/847/81/losqso?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/847/81/losqso?GETtext/xml+votable180.050000true15.24333332.52555560.005555555555555556Cone search capability for table J/ApJ/847/81/table3 (Quasars discovered within our survey)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/847/81/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/847/81/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/847/81/table3?GETtext/xml+votable180.050000true14.76371.87060.0055555555555555566/4436 4437 4884 4886 4950 6620 7190 7191 7232 10214 10219 10220 10221 11104 11529 11593 11595 11596 11598 11934 11935 12753 12754 12755 12756 17516 17518 17739 17740 18040 18042 18043 18544 18603 18606 18777 19046 23208 23210 26269 26312 27486 27646 27647 28040 28041 28610 28611 31503 31514 31536 46407 464182.85864675833786e-19 3.5010283109654867e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/847/81?format=asciiUVOpticaldefaultJ/ApJ/847/81/losqsoOverview of the FUV spectra, HeII sightlines and the number of foreground quasars for the 22 background quasar sightlines (tables 1 and 2)SimbadNameSimbad column added by the CDSmeta.idcharRefReference(s) (1)meta.ref;pos.framecharPIHST Program PIobs.observercharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHE2QSHe II-transparent quasar IDmeta.id;meta.maincharInstHST instrument +gratinginstrcharR[1000/18000] Dispersioninstr.dispersionintHST[9350/13013] HST Program Idmeta.id;obsintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainzBG[2.7/4] Spectroscopic redshift of HeII-transparent QSOsrc.redshift;pos.heliocentricfloatN-VLT[0/2]? Number of quasars detected with VLT/VIMOS+LBT/LBCmeta.numberintnullableN-NTT[0/2]? Number of quasars detected with NTT/EFOSC2meta.numberintnullableN-CAHA[0/5]? Number of quasars detected with CAHA/TWINmeta.numberintnullableN-SDSS[0/7]? Number of quasars used from SDSS (1)meta.numberintnullableN-Lit[1/2]? Number of quasars used from the Literature (2)meta.numberintnullableNfgNumber of foreground quasars in this field (link to table 3)meta.numberintnullableSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharJ/ApJ/847/81/table3Quasars discovered within our surveyHE2QSHe II-transparent quasar ID (1)obs.fieldcharzspec[0.6/4.2] Spectroscopic Redshiftsrc.redshiftfloatrmag[17/24.5]? SDSS r band AB magnitudemagphot.mag;em.opt.RfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension, foreground QSOs (J2000)degpos.eq.ra;meta.mainDEJ2000Declination, foreground QSOs (J2000)degpos.eq.dec;meta.mainM1450[-27.8/-20.5]? Absolute M1450 magnitudemagphys.magAbsfloatnullableSep[3.1/80.4] Angular separationarcsecpos.angDistancefloatDprop[1.5/39.8] Transverse separation in situation proper distances; in proper Mpc unitsMpcpos.distancefloatGamHeQSO[6.8e-17/1.1e-06] HeII photoionization rates**-1phys.ionizParam.raddoubleInstInstrument used (CAHA 3.5/TWIN, VLT/VIMOS, NTT/EFOSC2 or Keck/LRIS; see the "Description" section above)instr.setupcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar