J/ApJ/755/89ivo://CDS.VizieR/J/ApJ/755/89doi:10.26093/cds/vizier.17550089CDSRafelski M.Wolfe A.M.Prochaska J.X.Neeleman M.Mendez A.J.2017-11-10T11:16:44Z2014-04-09T10:45:18ZCDS support team

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

cds-question@unistra.frchemical-abundancesvisible-astronomysloan-photometryredshiftedquasarsline-intensitiesWe present chemical abundance measurements for 47 damped Ly{alpha} (DLA) systems, 30 at z>4, observed with the Echellette Spectrograph and Imager and the High Resolution Echelle Spectrometer on the Keck telescopes. H I column densities of the DLAs are measured with Voigt profile fits to the Ly{alpha} profiles, and we find an increased number of false DLA identifications with Sloan Digital Sky Survey at z>4 due to the increased density of the Ly{alpha} forest. Ionic column densities are determined using the apparent optical depth method, and we combine our new metallicity measurements with 195 from previous surveys to determine the evolution of the cosmic metallicity of neutral gas. We find the metallicity of DLAs decreases with increasing redshift, improving the significance of the trend and extending it to higher redshifts, with a linear fit of -0.22+/-0.03 dex per unit redshift from z=0.09-5.06. The metallicity "floor" of {approx}1/600 solar continues out to z~5, despite our sensitivity for finding DLAs with much lower metallicities. However, this floor is not statistically different from a steep tail to the distribution. We also find that the intrinsic scatter of metallicity among DLAs of ~0.5dex continues out to z~5. In addition, the metallicity distribution and the {alpha}/Fe ratios of z>2 DLAs are consistent with being drawn from the same parent population with those of halo stars. It is therefore possible that the halo stars in the Milky Way formed out of gas that commonly exhibits DLA absorption at z>2.2012ApJ...755...89Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/755/89CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)J/A+A/547/L1 : SDSS-III DR9 DLA catalogue (Noterdaeme+, 2012)J/A+A/530/A33 : Evolutionary tracks to estimate DLA depletions (Vladilo+,J/ApJ/721/1 : Keck ESI observations of Ly{alpha} systems (Penprase+, 2010)J/ApJ/683/321 : Metallicities of GRB, DLA, & Ly{alpha} galaxies (Fynbo+, 2008)J/ApJ/675/1002 : Proximate DLA systems in SDSS-DR5 (Prochaska+, 2008)J/ApJS/171/29 : UCSD/Keck DLA Abundance Database (Prochaska+, 2007)J/A+A/473/791 : CIV absorption in DLAs and sub-DLAs systems (Fox+, 2007)J/ApJ/636/610 : Damped Ly{alpha} systems at z<1.65 (Rao+, 2006)J/ApJ/635/123 : The SDSS-DR3 damped Ly{alpha} survey (Prochaska+, 2005)J/AJ/130/1345 : Optical-infrared colors of CORALS QSOs (Ellison+, 2005)J/MNRAS/354/L31 : SDSS DR2 QSO and DLA properties (Murphy+, 2004)J/PASP/116/622 : SDSS damped Ly{alpha} survey: DR1 (Prochaska+, 2004)J/A+A/370/426 : APM BR J0307-4945 UVES spectrum (Dessauges-Zavadsky+, 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/ApJ/755/89https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/755/89http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/755/89https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/755/89https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/755/89http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/755/89GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/755/89/table1 (Journal of observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/755/89/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/755/89/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/755/89/table1?GETtext/xml+votable180.050000true10.227917-9.25750.005555555555555556Cone search capability for table J/ApJ/755/89/table3 (Literature DLA metallicities)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/755/89/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/755/89/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/755/89/table3?GETtext/xml+votable180.050000true0.4583333-1.99444440.0055555555555555566/2 579 2172 2247 2348 4273 4279 4448 4623 4729 4754 4820 4946 4947 5039 5061 5098 5229 5234 5270 5306 5333 5413 5439 5452 5458 5563 5696 5723 5752 5780 5825 5848 6042 6106 6219 6252 6403 6415 6425 6500 6579 6591 6618 6644 6647 7168 7307 7472 7964 8192 8301 8395 8515 8939 9046 9095 9252 9275 9285 9523 9730 10061 10098 10193 10432 10571 10609 10742 10753 10788 10933 10939 10962 11092 11115 11258 11268 11290 11319 11498 11765 11796 12552 12563 13314 15278 16589 16644 16752 16831 17190 17239 17317 17404 17518 17662 17751 17812 17895 17917 18039 18084 18086 18200 18271 18366 18642 18765 18769 18772 18790 18857 18858 18859 18943 18949 19206 19411 19490 19667 19680 19682 19688 20010 20016 20249 20384 20450 20516 21012 21180 22595 22917 23016 23099 25245 25285 25307 25413 25427 25540 25677 25863 25938 25986 26098 26165 26196 26209 26267 26280 26288 26453 26479 26542 26553 26614 26882 27037 27118 27161 27225 27226 27232 27248 27302 27508 27526 27650 27728 27747 27943 28023 28039 28042 28281 28419 28539 28614 28644 28669 32438 32466 33746 33971 34044 34210 34379 34503 34763 34809 35570 35737 35751 35781 35842 35901 35995 36086 36346 36725 38639 38744 38878 39100 44724 45525 46529 46651 46851 46856 48474 49086https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/755/89?format=asciiOpticaldefaultJ/ApJ/755/89/table1Journal of observationsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name (JHHMM+DDMM)meta.id;meta.maincharprimaryMSimbad column added by the CDSmeta.ref.urlcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainrmag[17.5/21.7] SDSS-DR7 r-band AB magnitude (Cat. II/294)magphot.mag;em.opt.RfloatimagSDSS-DR7 i band AB magnitude (Cat. II/294)magphot.mag;em.opt.Ifloatzem[2.5/5.4] QSO emission line redshiftsrc.redshiftfloatzabsAbsorption line redshift(s) (1)src.redshiftcharDateUT Date of observationtime.epoch;obsnullableInstInstrument used (G1)instr.setupcharSlit[0.5/0.9] Slit width usedarcsecinstr.setupfloatExp[900/17400] Exposure timestime.duration;obs.exposureintSN[4/40]? Signal-to-noise per pixel (2)pixel**-1stat.snr;instr.pixelintnullableP05Cross-match with the Prochaska+, 2005, Cat. J/ApJ/635/123, within 5"meta.ref.urlintnullableDR10QCross-match with the SDSS-DR10 quasars catalog (VII/270), within 5"meta.ref.urlintnullableVV10Cross-match with the Veron+, 2010 (Cat. VII/258), within 5"meta.ref.urlintnullableJ/ApJ/755/89/table2New DLA metallicitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name (1)meta.id;meta.maincharz[0.09/5.2] Absorption line redshiftsrc.redshiftfloatNHI[20.3/21.9] Log of the hydrogen column densitylog(cm**-2)phys.columnDensityfloate_NHIError in NHIlog(cm**-2)stat.errorfloatf_[a/H]? Origin of [a/H] (2)meta.codeintnullable[a/H][-2.8/0]? Log of {alpha} elements i to hydrogen number abundancelog(Sun)phys.abundfloatnullablee_[a/H]Error in [a/H]log(Sun)stat.error;phys.abundfloatf_[Fe/H]? Origin of [Fe/H] (3)meta.codeintnullable[Fe/H][-3/0]? Log of iron to hydrogen number abundancelog(Sun)meta.idfloatnullablee_[Fe/H]Error in [Fe/H]log(Sun)stat.error;phys.abund.Fefloatf_[M/H]Origin of [M/H] (4)meta.codeint[M/H][-3/0.08] Log of "M" to hydrogen number abundancelog(Sun)meta.idfloate_[M/H]Error in [M/H]log(Sun)stat.error;phys.abundfloatJ/ApJ/755/89/table3Literature DLA metallicitiesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name (1)meta.id;meta.maincharz[0.09/5.2] Absorption line redshiftsrc.redshiftfloatNHI[20.3/21.9] Log of the hydrogen column densitylog(cm**-2)phys.columnDensityfloate_NHIError in NHIlog(cm**-2)stat.errorfloatf_[a/H]? Origin of [a/H] (2)meta.codeintnullable[a/H][-2.8/0]? Log of {alpha} elements i to hydrogen number abundancelog(Sun)phys.abundfloatnullablee_[a/H]Error in [a/H]log(Sun)stat.error;phys.abundfloatf_[Fe/H]? Origin of [Fe/H] (3)meta.codeintnullable[Fe/H][-3/0]? Log of iron to hydrogen number abundancelog(Sun)meta.idfloatnullablee_[Fe/H]Error in [Fe/H]log(Sun)stat.error;phys.abund.Fefloatf_[M/H]Origin of [M/H] (4)meta.codeint[M/H][-3/0.08] Log of "M" to hydrogen number abundancelog(Sun)meta.idfloate_[M/H]Error in [M/H]log(Sun)stat.error;phys.abundfloatRefReference (see refs.dat file)meta.ref;pos.framecharP05Cross-match with the Prochaska+, 2005, Cat. J/ApJ/635/123, within 5"meta.ref.urlintnullableDR10QCross-match with the SDSS-DR10 quasars catalog (VII/270), within 5"meta.ref.urlintnullableVV10Cross-match with the Veron+, 2010 (Cat. VII/258), within 5"meta.ref.urlintnullable_RAPositions from SIMBAD database (right ascension part)degpos.eq.ra;meta.main_DEPositions from SIMBAD database (declination part)degpos.eq.dec;meta.mainJ/ApJ/755/89/table4Ionic column densitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name (JHHMM+DDMM)meta.id;meta.maincharz[2.4/5.2] Absorption line redshiftsrc.redshiftfloatIonIon namephys.atmol.ionStagecharlambda[1250/2261] Rest-frame wavelength of Ion ({AA})0.1nmem.wl;phys.atmol.transitiondoublelogf[-2.9/0.3] Log of oscillator strengthphys.atmol.oscStrengthfloatInstInstrument used for measurement (G1)instr.setupcharVmin[-500/50]? Lower velocity interval of measurement (1)km/sphys.velocintnullableVmax[10/500]? Upper velocity interval of measurement (1)km/sphys.velocintnullablel_EWLimit flag on EWmeta.code.error;spect.line.eqWidthcharEW[3/2832]? Rest equivalent width (m{AA})1e-13mspect.line.eqWidthfloatnullablee_EW? Error in EW (m{AA})1e-13mstat.error;spect.line.eqWidthfloatnullablel_MIonLimit flag on MIonmeta.code.errorcharMIon[11.8/16.2] Measured column density of Ioncm**-2phys.columnDensityfloate_MIon? Error in MIoncm**-2stat.errorfloatnullablel_NIonLimit flag on NIonmeta.code.errorcharNIon? Adopted column density of Ioncm**-2phys.columnDensityfloatnullablee_NIon? Error in NIoncm**-2stat.errorfloatnullableJ/ApJ/755/89/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.noteintBibCodeBibcodemeta.bib.bibcodecharAutAuthor's name(s)meta.bib.authorcharCommCommentmeta.notechar