J/MNRAS/392/998ivo://CDS.VizieR/J/MNRAS/392/998doi:10.26093/cds/vizier.73920998CDSEllison S.L.Murphy M.T.Dessauges-Zavadsky M.2024-07-08T20:15:13Z2009-06-28T21:23:17ZCDS support team

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

cds-question@unistra.frquasarsredshiftedline-intensitiesUsing a sample of 21 damped Lyman alpha systems (DLAs) and 35 sub-DLAs, we evaluate the D-index=[EW({AA})/{Delta}v(km/s)]x1000 from high-resolution spectra of the MgII {lambda}2796 profile. This sample represents an increase in the sub-DLA statistics by a factor of 4 over the original D-index sample. We investigate various techniques to define the velocity spread ({Delta}v) of the MgII line to determine an optimal D-index for the identification of DLAs. The success rate of DLA identification is 50-55 per cent, depending on the velocity limits used, improving by a few per cent when the column density of FeII is included in the D-index calculation. We recommend the set of parameters that are judged to be most robust, have a combination of high DLA identification rate (57 per cent) and low DLA miss rate (6 per cent) and most cleanly separate the DLAs and sub-DLAs (Kolmogorov-Smirnov probability 0.5 per cent). These statistics demonstrate that the D-index is the most efficient technique for selecting low-redshift DLA candidates.2009MNRAS.392..998Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/392/998CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/636/610 : Damped Ly{alpha} systems at z<1.65 (Rao+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/392/998https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/392/998http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/392/998https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/392/998https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/392/998http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/392/998GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/392/998/table4 (*MgII 2796 equivalent widths (and errors) and dV for the 3 approaches used in this paper)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/392/998/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/392/998/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/392/998/table4?GETtext/xml+votable180.050000true126.5065539-22.50755670.0055555555555555566/4279 4820 7426 8395 9252 10353 10940 12886 17190 17816 17917 18042 18081 18096 18366 18772 18790-18791 18856 19206 19483 19682 19807 21126 22578 25120 25245 25285 26276 26288 26614 26878 27034 27213 27215 27650 27704 28039 28042 28148 31386 31686 34291 36101 40479 44028 48474 48965https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/392/998?format=asciiOpticaldefaultJ/MNRAS/392/998/table4*MgII 2796 equivalent widths (and errors) and dV for the 3 approaches used in this paperrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO namemeta.id;meta.maincharlogNHIHI column densitylog(cm**-2)phys.columnDensityfloate_logNHIrms uncertainty on logNHIlog(cm**-2)stat.errorfloatEW(ew)Equivalent width at 90% EW0.1nmspect.line.eqWidthfloate_EW(ew)rms uncertainty on EW(ew)0.1nmstat.errorfloatDV(ew)Velocity spread (DeltaV) at 90% EWkm/sspect.line.widthfloatEW(vel)Equivalent width at 90% velkm/sspect.line.eqWidthfloate_EW(vel)rms uncertainty on EW(vel)km/sstat.errorfloatDV(vel)Velocity spread (DeltaV) at 90% of the velocity rangekm/sspect.line.widthfloatEW(3s)Equivalent width at 3{sigma}km/sspect.line.eqWidthfloate_EW(3s)rms uncertainty on EW(3s)km/sstat.errorfloatDV(3s)Velocity spread (DeltaV) at bounds set by 3{sigma} absorptionkm/sspect.line.widthfloatSimbadNameSimbad column added by the CDSmeta.idchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main