J/AJ/159/216ivo://CDS.VizieR/J/AJ/159/216doi:10.26093/cds/vizier.51590216CDSPointon S.K.Kacprzak G.G.Nielsen N.M.Murphy M.T.Muzahid S.,Churchill C.W.Charlton J.C.2021-01-28T09:12:25Z2020-10-01T07:19:35ZCDS support team

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

cds-question@unistra.frintergalactic-mediumquasarsgalaxiesspectroscopyultraviolet-astronomyvisible-astronomyredshiftedchemical-abundancesWe explore how environment affects the metallicity of the circumgalactic medium (CGM) using 13 low-mass galaxy groups (two to five galaxies) at <z_abs_>=0.25 identified near background quasars. Using quasar spectra from the Hubble Space Telescope/Cosmic Origins Spectrograph (HST/COS) and from Keck/High Resolution Echelle Spectrometer (Keck/HIRES) or the Very Large Telescope/Ultraviolet and Visual Echelle Spectrograph (VLT/UVES), we measure column densities of or determine limits on CGM absorption lines. We use a Markov Chain Monte Carlo approach with Cloudy to estimate metallicities of cool (T~104K) CGM gas within groups and compare them to CGM metallicities of 47 isolated galaxies. Both group and isolated CGM metallicities span a wide range (-2<[Si/H]<0), where the mean group (-0.54{pm}0.22) and isolated (-0.77{pm}0.14) CGM metallicities are similar. Group and isolated environments have similar distributions of HI column densities as a function of impact parameter. However, contrary to isolated galaxies, we do not find an anticorrelation between HI column density and the nearest group galaxy impact parameter. We additionally divided the groups by member luminosity ratios (i.e., galaxy-galaxy and galaxy-dwarf groups). While there was no significant difference in their mean metallicities, a modest increase in sample size should allow one to statistically identify a higher CGM metallicity in galaxy-dwarf groups compared to galaxy-galaxy groups. We conclude that either environmental effects have not played an important role in the metallicity of the CGM at this stage and expect that this may only occur when galaxies are strongly interacting or merging or that some isolated galaxies have higher CGM metallicities due to past interactions. Thus, environment does not seem to be the cause of the CGM metallicity bimodality.2020AJ....159..216Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/159/216CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/508/200 : QSO low-z Ly{alpha} absorbers (Tripp+, 1998)J/ApJ/559/654 : Ly{alpha} absorption systems. V. (Chen+, 2001)J/ApJ/679/1144 : Galaxy clusters in LOS to background QSOs. I. (Lopez+, 2008)J/ApJ/701/1219 : Galaxy survey in 3 QSO fields (Chen+, 2009)J/ApJ/714/1521 : Spectroscopy of galaxies around distant QSOs (Chen+, 2010)J/ApJ/724/L176 : MgII absorbing gas around galaxies (Chen+, 2010)J/ApJ/710/613 : Broad HI absorbers (Danforth+, 2010)J/ApJ/740/91 : Ly{alpha} and OVI galaxies around quasars (Prochaska+, 2011)J/ApJ/774/40 : Galaxy clusters aligned with quasars. III. (Andrews+, 2013)J/MNRAS/434/1765 : Catalog of galaxies around PKS 0405-123 (Johnson+, 2013)J/ApJ/770/138 : Metallicities of Lyman limit systems and DLA (Lehner+, 2013)J/ApJ/776/114 : MAGIICAT. I. MgII Absorber-Galaxy Catalog (Nielsen+, 2013)J/ApJ/796/140 : Circumgalactic medium surrounding z~2 QSOs (Prochaska+,2014)J/ApJ/804/79 : HST/COS obs. of QSOs within 600kpc of M31 (Lehner+, 2015)J/MNRAS/449/3263 : Extended galaxy halo gas through HI and OVI (Johnson+, 2015)J/ApJ/866/33 : The COS CGM compendium. I. Initial results (Lehner+, 2018)J/ApJ/871/35 : HST/COS spectra of QSOs with SiIV data (Zheng+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/159/216https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/159/216http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/159/216https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/159/216https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/159/216http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/159/216GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/159/216/table1 (Quasar observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/159/216/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/159/216/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/159/216/table1?GETtext/xml+votable180.050000true21.3701667-0.09886940.0055555555555555566/4204 5773 7176 7381 18005 22659 25472 27526 28356 35180 36313https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/159/216?format=asciiUVOpticaldefaultJ/AJ/159/216/table1Quasar observationsSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOJ-Name of the quasarmeta.notecharprimaryz[0.17/1.08] Quasar redshiftsrc.redshiftfloatRAJ2000[1/11] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainInstUVInstrument used for UV observations (1)meta.id;instrGratCOSGrating for COS instrumentinstrcharPIDCOS[11541/13398] PID(s) for COS instrumentmeta.id;obsintInstoptInstrument used for optical observations (1)meta.id;instrcharPIDoptPID for optical instrumentmeta.id;obscharNobsNumber of observations in this field (link to table4)meta.numberintnullableJ/AJ/159/216/table4Measured column densitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQSOJ-Name of the quasarmeta.notecharprimaryz[0.05/0.38] Galaxy redshiftsrc.redshiftdoubleIonIon identifier (C, Ca, Fe, H, Mg, N, O and Si ions)phys.atmol.ionStagecharl_logN[<>]Limit flag on logNmeta.code.errorcharlogN[10.85/19.58] log column density (1)log(cm**-2)phys.columnDensityfloatuplogN[19]? Upper limit on logN (1)log(cm**-2)phys.columnDensityfloatnullablee_logN[0.01/7.8]? Uncertainty in logNlog(cm**-2)stat.errorfloatnullable