J/ApJS/221/2ivo://CDS.VizieR/J/ApJS/221/2doi:10.26093/cds/vizier.22210002CDSProchaska J.X.O'Meara J.M.Fumagalli M.Bernstein R.A.Burles S.M.2017-06-12T08:25:28Z2016-02-04T12:19:19ZCDS support team

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

cds-question@unistra.frspectroscopyredshiftedsurveysinterstellar-mediumquasarsWe present an absorption-line survey of optically thick gas clouds --Lyman Limit Systems (LLSs)-- observed at high dispersion with spectrometers on the Keck and Magellan telescopes. We measure column densities of neutral hydrogen N_H1_ and associated metal-line transitions for 157 LLSs at z_LLS_=1.76-4.39 restricted to 10^17.3^cm^-2^<=N_HI_<10^20.3^cm^-2^. An empirical analysis of ionic ratios indicates an increasing ionization state of the gas with decreasing N_H1_ and that the majority of LLSs are highly ionized, confirming previous expectations. The Si^+^/H^0^ ratio spans nearly four orders of magnitude, implying a large dispersion in the gas metallicity. Fewer than 5% of these LLSs have no positive detection of a metal transition; by z~3 nearly all gas that is dense enough to exhibit a very high Lyman limit opacity has previously been polluted by heavy elements. We add new measurements to the small subset of LLS (~5%-10%) that may have super-solar abundances. High Si^+^/Fe^+^ ratios suggest an {alpha}-enhanced medium, whereas the Si^+^/C^+^ ratios do not exhibit the super-solar enhancement inferred previously for the Ly{alpha} forest.2015ApJS..221....2Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/221/2CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/445/1745 : Giant Gemini GMOS survey. I. (Worseck+, 2014)J/ApJ/776/136 : QPQ VI. HI absorption of z~2 quasars (Prochaska+, 2013)J/ApJ/775/78 : Lyman limit absorption systems in z~3 QSOs (Fumagalli+, 2013)J/ApJ/770/138 : Metallicities of Lyman limit systems and DLA (Lehner+, 2013)J/ApJ/769/54 : Spectroscopy of Damped Ly{alpha} systems (Neeleman+, 2013)J/ApJ/765/137 : HST survey for Lyman limit systems. II. (O'Meara+, 2013)J/ApJ/755/89 : Metallicities of damped Ly{alpha} systems (Rafelski+, 2012)J/ApJ/736/42 : HST QSO Catalog (Ribaudo+, 2011)J/ApJ/721/1 : Keck ESI observations of Ly{alpha} systems (Penprase+, 2010)J/ApJ/718/392 : SDSS Lyman limit systems at z~3.5 (Prochaska+, 2010)J/ApJ/714/1521 : Spectroscopy of galaxies around distant QSOs (Chen+, 2010)J/ApJ/700/1299 : Gas-phase element depletions in the ISM (Jenkins, 2009)J/ApJ/675/1002 : Proximate DLA systems in SDSS-DR5 (Prochaska+, 2008)J/ApJS/171/29 : UCSD/Keck DLA Abundance Database (Prochaska+, 2007)J/ApJ/649/L61 : SDSS J155810.16-003120.0 abundances (O'Meara+, 2006)J/ApJ/648/L97 : 2 SDSS supersolar super-Lyman limit systems (Prochaska+ 2006)J/ApJ/596/768 : Optical depths in 19 QSOs (Schaye+, 2003)http://www.ucolick.org/~xavier/HD-LLS/DR1/ : High dispersion-LLS samplehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/221/2https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/221/2http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/221/2https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/221/2https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/221/2http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/221/2GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/221/2/table1 (Journal of HIRES observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/221/2/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/221/2/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/221/2/table1?GETtext/xml+votable180.050000true20.483458314.80661110.005555555555555556Cone search capability for table J/ApJS/221/2/table6 (Ionic column densities for 130 unique quasars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/221/2/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/221/2/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/221/2/table6?GETtext/xml+votable180.050000true0.9375-23.396250.005555555555555556Cone search capability for table J/ApJS/221/2/table2 (Journal of MIKE observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/221/2/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/221/2/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/221/2/table2?GETtext/xml+votable180.050000true0.9375-23.39611110.0055555555555555566/2247 2348 4099 4125 4186 4259 5039 5639 5723 5731 5886 5975 6010 6030 6042 6070 6106 6205 6576 6582 6604 6617 6644 7168 7282 7741 8192 8218 8291 8303 8393 8657 9138 9946 10074 10188 10315 10753 11030 11036 11319 11321 11794 11854 16625 16752 17149 17187 17317 17511 17662 17743 17749 17805 17813 17895 18007 18032 18200 18406 18521 18537 18769 18777 18858 18859 19087 19099 19411 19458 19759 20016 20384 22594 23052 23076 23099 23190 23210 25120 25599 25953 25995 26015 26165 26167 26209 26239 26369 26373 26398 26479 26494 26574 26879 26882 26992 27083 27110 27237 27289 27341 27365 27416 27429 27441 27549 27550 27578 27649 27687 27748 27753 27855 27889 31313 31331 31451 31534 31622 31652 31656 32466 33994 34809 35522 35749 35880 36110 36766 40446 44629 44724 45517 46165 46577 46793 47154 47941 48166 48498 48610https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/221/2?format=asciiOpticaldefaultJ/ApJS/221/2/table1Journal of HIRES observationsIDQuasar identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNDisplay the ionic column densities for this QSO if anymeta.ref.urlintnullableANameAlternative namemeta.idcharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainmag[16/19.1] r-band or V-band magnitude (1)phot.magfloatzem[1.8/4.5] Quasar emission redshiftsrc.redshiftfloatDateObservation UT datetime.epoch;obsnullableSlitSlit (Decker employed)meta.notecharModeMode (only for table 1)instr.setupcharExp[1295/21600] Exposure timestime.duration;obs.exposureintS/NHIRES signal to noise ratio (3)pixel**-1stat.snrcharJ/ApJS/221/2/colIonic column summary for Si, C, Al, Fe and OrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDQuasar identifiermeta.id;meta.maincharzabs[1.7/4.4] Redshift derived from absorption linessrc.redshiftfloatlogNHI[16.9/20.3] Log H I column densitylog(cm**-2)phys.columnDensityfloate_logNHILower uncertainty in logNHIlog(cm**-2)stat.errorfloatE_logNHIUpper uncertainty in logNHIlog(cm**-2)stat.error;stat.maxfloatl_logNC+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNC+? Log C^+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNC+? Uncertainty in logNC+log(cm**-2)stat.errorfloatnullablel_logNC3+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNC3+? Log C^3+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNC3+? Uncertainty in logNC3+log(cm**-2)stat.errorfloatnullablel_logNSi+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNSi+? Log Si^+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNSi+? Uncertainty in logNSi+log(cm**-2)stat.errorfloatnullablel_logNSi3+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNSi3+? Log Si^3+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNSi3+? Uncertainty in logNSi3+log(cm**-2)stat.errorfloatnullablel_logNO0Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNO0? Log O^0^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNO0? Uncertainty in logNO0log(cm**-2)stat.errorfloatnullablel_logNAl+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNAl+? Log Al^+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNAl+? Uncertainty in logNAl+log(cm**-2)stat.errorfloatnullablel_logNAl++Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNAl++? Log Al^++^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNAl++? Uncertainty in logNAl++log(cm**-2)stat.errorfloatnullablel_logNFe+Lower or upper limit at 95% confidence limitmeta.code.errorcharlogNFe+? Log Fe^+^ column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNFe+? Uncertainty in logNFe+log(cm**-2)stat.errorfloatnullableJ/ApJS/221/2/table6Ionic column densities for 130 unique quasarsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDQuasar identifiermeta.id;meta.maincharprimaryRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainzabs[1.7/4.4] Absorption redshift of LLSsrc.redshiftdoublelogNHI[17.3/20.3] Log H I column densitylog(cm**-2)phys.columnDensityfloatlambda[922.2/2853] Transition rest wavelength in Angstroms0.1nmem.wl;phys.atmol.transitiondoublevmin[-984/75] Minimum velocity limitkm/sphys.velocintvmax[-183/2931] Maximum velocity limitkm/sphys.velocintl_logNLimit flag on logNmeta.code.errorcharlogN[11.1/18] Log column densitylog(cm**-2)phys.columnDensityfloate_logN[0/0.2]? Standard deviation in logN)log(cm**-2)stat.errorfloatnullableIon[6.2/30.2]? Numeric ion designation (1)phys.atmol.ionStagefloatnullablel_logNionLimit flag on logNionmeta.code.errorcharlogNion[11.1/15.8]? Log ion column densitylog(cm**-2)phys.columnDensityfloatnullablee_logNion[0.05/0.2]? Standard deviation in logNionlog(cm**-2)stat.errorfloatnullableSLink to ionic column summarymeta.ref.urlcharJ/ApJS/221/2/table2Journal of MIKE observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNDisplay the ionic column densities for this QSO if anymeta.ref.urlintnullableIDQuasar identifiermeta.id;meta.maincharANameAlternative namemeta.idcharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainmag[16/19.1] r-band or V-band magnitude (1)phot.magfloatzem[1.8/4.5] Quasar emission redshiftsrc.redshiftfloatDateObservation UT datetime.epoch;obsnullableSlitSlit width in arcsec (2)instr.setupcharExp[1295/21600] Exposure timestime.duration;obs.exposureintS/NMIKE signal to noise ratio (blue) (3)pixel**-1stat.snrcharS/NrSignal to noise ratio (red) (only for table2) (4)pixel**-1stat.snrchar