J/ApJ/860/41ivo://CDS.VizieR/J/ApJ/860/41doi:10.26093/cds/vizier.18600041CDSLusso E.Fumagalli M.Rafelski M.Neeleman M.Prochaska J.X.,Hennawi J.F.O'Meara J.M.Theuns T.2020-05-13T07:25:36Z2019-07-11T12:44:14ZCDS support team

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

cds-question@unistra.frquasarsintergalactic-mediumvisible-astronomysloan-photometryredshiftedspectroscopyultraviolet-astronomyWe present the first results from our survey of intervening and proximate Lyman limit systems (LLSs) at z~2.0-2.5 using the Wide Field Camera 3 on board the Hubble Space Telescope. The quasars in our sample are projected pairs with proper transverse separations R_{perp}_<=150kpc and line-of- sight velocity separations <~11000km/s. We construct a stacked ultraviolet (rest-frame wavelengths 700-2000{AA}) spectrum of pairs corrected for the intervening Lyman forest and Lyman continuum absorption. The observed spectral composite presents a moderate flux excess for the most prominent broad emission lines, a ~30% decrease in flux at {lambda}=800-900{AA} compared to a stack of brighter quasars not in pairs at similar redshifts, and lower values of the mean free path of the HI ionizing radiation for pairs ({lambda}_mfp_^912^=140.7+/-20.2h_70_^-1^Mpc) compared to single quasars ({lambda}_mfp_^912^=213.8+/-28h_70_^-1^Mpc) at the average redshift z~2.44. From the modeling of LLS absorption in these pairs, we find a higher (~20%) incidence of proximate LLSs with logN_HI_>=17.2 at {delta}v<5000km/s compared to single quasars (~6%). These two rates are different at the 5{sigma} level. Moreover, we find that optically thick absorbers are equally shared between foreground and background quasars. Based on these pieces of evidence, we conclude that there is a moderate excess of gas-absorbing Lyman continuum photons in our closely projected quasar pairs compared to single quasars. We argue that this gas arises mostly within large-scale structures or partially neutral regions inside the dark matter halos where these close pairs reside.2018ApJ...860...41Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/860/41CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/ApJ/475/469 : Composite HST Spectrum of Quasars (Zheng+ 1997)J/A+A/417/515 : I Zw 1 unusual emission line spectrum (Veron-Cetty+, 2004)J/ApJ/651/61 : Opt. thick absorbers near luminous QSOs (Hennawi+, 2006)J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)J/ApJ/678/635 : Spectroscopy of quasar binary candidates (Myers+, 2008)J/ApJ/693/1554 : Double QSOs: merger scenarios (Foreman+, 2009)J/ApJ/719/1672 : SDSS binary quasars at high redshift. I. (Hennawi+, 2010)J/ApJ/718/392 : SDSS Lyman limit systems at z~3.5 (Prochaska+, 2010)J/ApJS/195/16 : HST survey for Lyman limit systems. I. (O'Meara+, 2011)J/ApJ/736/42 : HST QSO Catalog (Ribaudo+, 2011)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/ApJ/728/23 : GALEX UV-bright high-redshift quasars (Worseck+, 2011)J/ApJ/775/78 : Lyman limit absorption syst. in z~3 QSOs (Fumagalli+, 2013)J/ApJ/765/137 : HST survey for Lyman limit systems. II. (O'Meara+, 2013)J/ApJ/776/136 : QPQ VI. HI absorption of z~2 quasars (Prochaska+, 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/AJ/150/31 : Photometry & redshifts of gal. in the UDF (Rafelski+, 2015)J/ApJ/817/111 : HST/COS survey of z<0.9 AGNs. I. (Danforth+, 2016)J/MNRAS/464/3882 : Mergers and galaxy-galaxy interactions (Weston+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/860/41https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/860/41http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/860/41https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/860/41https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/860/41http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/860/41GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/860/41/table1 (Full WFC3 quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/860/41/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/860/41/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/860/41/table1?GETtext/xml+votable180.050000true6.09952-1.474346940.0055555555555555566/256 2074 2207 4222 4391 4469 4608 4997 5092 5203 5319 5466 5540 5653 6085 6250 6578 7501 8407 8701 8756 8795 9098 9268 9729 10288 10312 10463 10555 10584 11027 11148 11188 11228 12342 13328 18061 18641 18780 18875 19229 19426 26025 26381 26485 26578 27021 27686 28562 28628 31623 32479 32497 36427 402742.040811542443644e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/860/41?format=asciiUVOpticaldefaultJ/ApJ/860/41/table1Full WFC3 quasarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameIdentifiermeta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainumag[18.2/21.9]? SDSS u^*^ band model magnitudemagphot.mag;em.opt.Ufloatnullablegmag[18.2/21.6]? SDSS g^*^ band model magnitudemagphot.mag;em.opt.Bfloatnullablermag[18.1/21.7]? SDSS r^*^ band model magnitudemagphot.mag;em.opt.Rfloatnullableimag[17.9/22]? SDSS i^*^ band model magnitudemagphot.mag;em.opt.Ifloatnullablezmag[17.6/22]? SDSS z^*^ band model magnitudemagphot.mag;em.opt.IfloatnullableRperp[8.7/151.4]? Transverse proper separationkpcpos.distancefloatnullableASep[1/17.6]? Angular separationarcsecpos.angDistancefloatnullablez[1.8/2.7] Spectroscopic redshift estimatesrc.redshiftfloatsigma[0/1068] Uncertainty in zkm/sstat.error;src.redshiftintLineEmission line used to determine zmeta.id;spect.linecharInstSurvey/instrument/telescope used to determine z (1)instr.setupcharNoteAn additional notemeta.notecharf_NoteFlag on Note (2)meta.notecharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharJ/ApJ/860/41/table2WFC3 stacked spectrum corrected for IGM absorptionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[688.5/1994.7] Rest-frame wavelength; Angstroms0.1nmem.wldoubleFAll[0.6/4.5] Mean all WFC3 quasar flux per Angstrom (1)phot.fluxdoublee_FAll[0.0001/0.4] Uncertainty from bootstrap in FAllstat.errordoubleFPairs[0.6/4.5] Mean pair only quasar flux per Angstrom (1)phot.fluxdoublee_FPairs[0.0001/0.4] Uncertainty from bootstrap in FPairstat.errordouble