J/MNRAS/476/4965ivo://CDS.VizieR/J/MNRAS/476/4965doi:10.26093/cds/vizier.74764965CDSMuzahid S.Fonseca G.Roberts A.Rosenwasser B.Richter P.,Narayanan A.Churchill C.Charlton J.2024-08-18T20:18:44Z2021-05-31T16:36:07ZCDS support team

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

cds-question@unistra.frquasarsredshiftedWe present a sample of 34 weak metal line absorbers at z<0.3 selected by the simultaneous >3{sigma} detections of the SiII{lambda}1260 and CII{lambda}1334 absorption lines, with W_r_(SiII)<0.2 {AA} and W_r_(CII)<0.3{AA}, in archival HST/COS spectra. Our sample increases the number of known low-z 'weak absorbers' by a factor of >5. The column densities of HI and low-ionization metal lines obtained from Voigt profile fitting are used to build simple photoionization models. The inferred densities and line-of-sight thicknesses of the absorbers are in the ranges of -3.3<logn_H_/cm^-3^<-2.4 and ~1pc-50kpc (median ~=500pc), respectively. Most importantly, 85 per cent (50 per cent) of these absorbers show a metallicity of [Si/H]>-1.0(0.0). The fraction of systems showing near-/supersolar metallicity in our sample is significantly higher than in the HI-selected sample of Wotta et al., and the galaxy-selected sample of Prochaska et al., of absorbers probing the circum-galactic medium at similar redshift. A search for galaxies has revealed a significant galaxy-overdensity around these weak absorbers compared to random positions with a median impact parameter of 166 kpc from the nearest galaxy. Moreover, we find the presence of multiple galaxies in ~=80 per cent of the cases, suggesting group environments. The observed dN/dz of 0.8+/-0.2 indicates that such metal-enriched, compact, dense structures are ubiquitous in the haloes of low-z group galaxies. We suggest that these are transient structures that are related to galactic outflows and/or stripping of metal-rich gas from galaxies.2018MNRAS.476.4965Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/476/4965CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/476/4965https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/476/4965http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/476/4965https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/476/4965https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/476/4965http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/476/4965GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/476/4965/tableb1 (List of QSO spectra with S/N>5 per pixel searched for weak MgII analogs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/476/4965/tableb1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/476/4965/tableb1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/476/4965/tableb1?GETtext/xml+votable180.050000true0.10167-12.763330.005555555555555556Cone search capability for table J/MNRAS/476/4965/tableb2 (List of QSO spectra with S/N<5 per pixel that are not used in this study)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/476/4965/tableb2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/476/4965/tableb2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/476/4965/tableb2?GETtext/xml+votable180.050000true2.6292510.974860.005555555555555556Cone search capability for table J/MNRAS/476/4965/tableb3 (List of strong CII/SiII systems. These systems are not part of the studied here)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/476/4965/tableb3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/476/4965/tableb3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/476/4965/tableb3?GETtext/xml+votable180.050000true3.10004-10.374030.0055555555555555565/6930 6/0 552 2414 2621 2663 2754 4107 4193 4204 4256 4328 4410 4506 4590 4821 4824 4946 4959 4961 4966 5061 5117 5121 5215 5244 5249 5262 5274 5284 5304-5305 5355 5371 5409 5413 5423 5437 5481 5529 5570 5639 5657 5687 5731 5757 5759 5773 5820-5821 5861 5929 5974 6021 6081 6087 6104 6223 6488 6557 6606 7176 7277 7381 7460 7508 7896 7902-7903 7998 8071 8245-8246 8266 8282 8303 8392 8469 8528 8641 8700 8702 8755 8812 8838 8845 8858 8867 8910 8915 8918 8927 8938-8939 8952 9018-9019 9031 9111 9146 9175 9186 9194 9305 9440 9457 9753 9756 9783 9817 10162 10170 10219 10261 10287 10297-10298 10300 10376 10379 10411 10418 10433 10468 10472 10500 10517 10528 10602 10604 10624 10634 10659 10674 10691 10764 10889 10940 10969 11014 11021 11096 11101 11206 11209 11217 11327 11378 11382 11388 11396 11435 11456 11462 11473 11475 11490 11529-11530 11557 11596 11610 11658 11668 11686 11777 11781 11829 12033 12047 12380 12752 15247 15351 16447 16894 17075 17186 17203 17251 17488 17499 17673 17703 17730 17772 17898 17990 18005 18125 18601 18769 18782 19416 19433 19567 19700 19730 19746 19883 20008 20099 21126 21991 22659 23060 23212 25132 25392 25472 25742 25932 25964 26029 26058 26065 26088 26097 26238 26268 26270 26292 26334 26350 26396 26509 26606 26859 26902 26965 27006 27056 27065 27079 27084 27090 27096 27115-27116 27155 27229 27250 27338 27349-27350 27376 27410 27423 27435 27486 27509 27515-27516 27526 27542 27562 27580 27607 27646 27715 27725 27727-27728 27745 27751 27755 27760 27766 27834 27902 27964 28034 28060 28083 28117-28118 28143 28158 28180 28201 28232 28356 28383 28395 28401 28468 28471 28527 28546 28564 28571 28589 28636 29398 30873 31405 31422 31658 31663 32948 32998 33126 33233 33796 33930 33950 33968 34065 34210 34881 35018 35180 35205 35542 35741 35743 35987 35992-35993 36313 36443 36788 37385 38205 38383 38837 38916 40213 42666 44988 45341 45500 46143 46281 46299 46444 46549 46555 46647 46795 47014 47375 47510 48614 48965 49042https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/476/4965?format=asciidefaultJ/MNRAS/476/4965/tableb1List of QSO spectra with S/N>5 per pixel searched for weak MgII analogsSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name sorted by increasing RAmeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzqsoQSO redshiftsrc.redshift;pos.heliocentricfloatGratingsCOS gratings used for observations (G1)instr.setup;obsintzminMinimum search redshiftsrc.redshiftfloatzmaxMaximum search redshiftsrc.redshiftfloatS/NG130M? S/N of the G130M data estimated near 1400{AA} (-1 when data are not available)stat.snrintnullableS/NG160M? S/N of the G160M data estimated near 1600{AA} (-1 when data are not available)stat.snrintnullableFlag[0/2] Spectrum flag (G2)meta.code.errorintPIDHST proposal ID(s)meta.id;obscharJ/MNRAS/476/4965/tableb2List of QSO spectra with S/N<5 per pixel that are not used in this studySimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOQSO name sorted by increasing RAmeta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzqsoQSO redshiftsrc.redshift;pos.heliocentricfloatGratingsCOS gratings used for observations (G1)instr.setup;obsintzminMinimum search redshiftsrc.redshiftfloatzmaxMaximum search redshiftsrc.redshiftfloatS/NG130M? S/N of the G130M data estimated near 1400{AA} (-1 when data are not available)stat.snrintnullableS/NG160M? S/N of the G160M data estimated near 1600{AA} (-1 when data are not available)stat.snrintnullableFlag[0/2] Spectrum flag (G2)meta.code.errorintPIDHST proposal ID(s)meta.id;obscharJ/MNRAS/476/4965/tableb3List of strong CII/SiII systems. These systems are not part of the studied hereSimbadNameSimbad column added by the CDSmeta.idcharnullableQSOQSO namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzqsoQSO redshiftsrc.redshift;pos.heliocentricfloatzabsAbsorption redshiftsrc.redshiftdoubleGratingsCOS gratings used for observations (G1)instr.setup;obsintzminMinimum search redshiftsrc.redshiftfloatzmaxMaximum search redshiftsrc.redshiftfloatS/NG130MS/N of the G130M data estimated near 1400{AA}stat.snrintS/NG160M? S/N of the G160M data estimated near 1600{AA}. S/N is -1 when data are not availablestat.snrintnullableFlag[0/2] Spectrum flag (G2)meta.code.errorintPIDHST proposal ID(s)meta.id;obschar